add silence removal using pydub and multithreading

+ fix favorites endpoint returning items less than limit
+ add endpoint to remove get silence padding
+ add 'the ulitimate' and 'compilation' to compilation album filters
+ misc

app/api/favorites.py

@@ -153,49 +153,45 @@ def get_all_favorites():
     track_limit = int(track_limit)
     album_limit = int(album_limit)
     artist_limit = int(artist_limit)
+
+    # largest is x2 to accound for broken hashes if any
     largest = max(track_limit, album_limit, artist_limit)
 
     favs = favdb.get_all()
     favs.reverse()
 
-    count = {
-        "tracks": 0,
-        "albums": 0,
-        "artists": 0,
-    }
-
     tracks = []
     albums = []
     artists = []
 
-    for fav in favs:
+    track_master_hash = set(t.trackhash for t in TrackStore.tracks)
-        if fav[2] == FavType.track:
+    album_master_hash = set(a.albumhash for a in AlbumStore.albums)
-            count["tracks"] += 1
+    artist_master_hash = set(a.artisthash for a in ArtistStore.artists)
 
-        if fav[2] == FavType.album:
+    for fav in favs:
-            count["albums"] += 1
+        hash = fav[1]
+        if fav[2] == FavType.track:
+            tracks.append(hash) if hash in track_master_hash else None
 
         if fav[2] == FavType.artist:
-            count["artists"] += 1
+            artists.append(hash) if hash in artist_master_hash else None
-
-        if not len(tracks) >= largest:
-            if fav[2] == FavType.track:
-                tracks.append(fav[1])
-
-        if not len(artists) >= largest:
-            if fav[2] == FavType.artist:
-                artists.append(fav[1])
 
         if fav[2] == FavType.album:
-            albums.append(fav[1])
+            albums.append(hash) if hash in album_master_hash else None
+
+    count = {
+        "tracks": len(tracks),
+        "albums": len(albums),
+        "artists": len(artists),
+    }
 
     src_tracks = sorted(TrackStore.tracks, key=lambda x: x.trackhash)
     src_albums = sorted(AlbumStore.albums, key=lambda x: x.albumhash)
     src_artists = sorted(ArtistStore.artists, key=lambda x: x.artisthash)
 
-    tracks = UseBisection(src_tracks, "trackhash", tracks)()
+    tracks = UseBisection(src_tracks, "trackhash", tracks, limit=track_limit)()
     albums = UseBisection(src_albums, "albumhash", albums, limit=album_limit)()
-    artists = UseBisection(src_artists, "artisthash", artists)()
+    artists = UseBisection(src_artists, "artisthash", artists, limit=artist_limit)()
 
     tracks = remove_none(tracks)
     albums = remove_none(albums)

app/api/send_file.py

@@ -4,6 +4,7 @@ Contains all the track routes.
 import os
 
 from flask import Blueprint, send_file, request
+from app.lib.trackslib import get_silence_paddings
 
 from app.store.tracks import TrackStore
 
@@ -53,3 +54,15 @@ def send_track_file(trackhash: str):
             return msg, 404
 
     return msg, 404
+
+
+@api.route("/file/silence", methods=["POST"])
+def get_audio_silence():
+    data = request.get_json()
+    ending_file = data.get("end", None)  # ending file's filepath
+    starting_file = data.get("start", None)  # starting file's filepath
+
+    if ending_file is None or starting_file is None:
+        return {"msg": "No filepath provided"}, 400
+
+    return get_silence_paddings(ending_file, starting_file)

app/lib/pydub/.github/issue_template.md

@@ -0,0 +1,17 @@
+### Steps to reproduce
+
+### Expected behavior
+Tell us what should happen
+
+### Actual behavior
+Tell us what happens instead
+
+### Your System configuration
+- Python version: 
+- Pydub version: 
+- ffmpeg or avlib?: 
+- ffmpeg/avlib version: 
+
+### Is there an audio file you can include to help us reproduce?
+You can include the audio file in this issue - just put it in a zip file and drag/drop the zip file into the github issue.
+

app/lib/pydub/.travis.yml

@@ -0,0 +1,19 @@
+os: linux
+dist: bionic  # focal
+language: python
+before_install:
+  - sudo apt-get update --fix-missing
+install:
+  - sudo apt-get install -y ffmpeg libopus-dev python-scipy python3-scipy
+python:
+  - "2.7"
+  - "3.6"
+  - "3.7"
+  - "3.8"
+  - "3.9"
+  - "pypy2"
+  - "pypy3"
+script:
+  - python test/test.py
+after_script:
+  - pip install pylama && python -m pylama -i W,E501 pydub/ || true

app/lib/pydub/API.markdown

@@ -0,0 +1,693 @@
+# API Documentation
+
+This document is a work in progress.
+
+If you're looking for some functionality in particular, it's a good idea to take a look at the [source code](https://github.com/jiaaro/pydub). Core functionality is mostly in `pydub/audio_segment.py` – a number of `AudioSegment` methods are in the `pydub/effects.py` module, and added to `AudioSegment` via the effect registration process (the `register_pydub_effect()` decorator function)
+
+Currently Undocumented:
+
+- Playback (`pydub.playback`)
+- Signal Processing (compression, EQ, normalize, speed change - `pydub.effects`, `pydub.scipy_effects`)
+- Signal generators (Sine, Square, Sawtooth, Whitenoise, etc - `pydub.generators`)
+- Effect registration system (basically the `pydub.utils.register_pydub_effect` decorator)
+
+
+## AudioSegment()
+
+`AudioSegment` objects are immutable, and support a number of operators.
+
+```python
+from pydub import AudioSegment
+sound1 = AudioSegment.from_file("/path/to/sound.wav", format="wav")
+sound2 = AudioSegment.from_file("/path/to/another_sound.wav", format="wav")
+
+# sound1 6 dB louder, then 3.5 dB quieter
+louder = sound1 + 6
+quieter = sound1 - 3.5
+
+# sound1, with sound2 appended
+combined = sound1 + sound2
+
+# sound1 repeated 3 times
+repeated = sound1 * 3
+
+# duration
+duration_in_milliseconds = len(sound1)
+
+# first 5 seconds of sound1
+beginning = sound1[:5000]
+
+# last 5 seconds of sound1
+end = sound1[-5000:]
+
+# split sound1 in 5-second slices
+slices = sound1[::5000]
+
+# Advanced usage, if you have raw audio data:
+sound = AudioSegment(
+    # raw audio data (bytes)
+    data=b'…',
+
+    # 2 byte (16 bit) samples
+    sample_width=2,
+
+    # 44.1 kHz frame rate
+    frame_rate=44100,
+
+    # stereo
+    channels=2
+)
+```
+
+Any operations that combine multiple `AudioSegment` objects in *any* way will first ensure that they have the same number of channels, frame rate, sample rate, bit depth, etc. When these things do not match, the lower quality sound is modified to match the quality of the higher quality sound so that quality is not lost: mono is converted to stereo, bit depth and frame rate/sample rate are increased as needed. If you do not want this behavior, you may explicitly reduce the number of channels, bits, etc using the appropriate `AudioSegment` methods.
+
+### AudioSegment(…).from_file()
+
+Open an audio file as an `AudioSegment` instance and return it. there are also a number of wrappers provided for convenience, but you should probably just use this directly.
+
+```python
+from pydub import AudioSegment
+
+# wave and raw don’t use ffmpeg
+wav_audio = AudioSegment.from_file("/path/to/sound.wav", format="wav")
+raw_audio = AudioSegment.from_file("/path/to/sound.raw", format="raw",
+                                   frame_rate=44100, channels=2, sample_width=2)
+
+# all other formats use ffmpeg
+mp3_audio = AudioSegment.from_file("/path/to/sound.mp3", format="mp3")
+
+# use a file you've already opened (advanced …ish)
+with open("/path/to/sound.wav", "rb") as wav_file:
+    audio_segment = AudioSegment.from_file(wav_file, format="wav")
+
+# also supports the os.PathLike protocol for python >= 3.6
+from pathlib import Path
+wav_path = Path("path/to/sound.wav")
+wav_audio = AudioSegment.from_file(wav_path)
+```
+
+The first argument is the path (as a string) of the file to read, **or** a file handle to read from.
+
+**Supported keyword arguments**:
+
+- `format` | example: `"aif"` | default: autodetected
+  Format of the output file. Supports `"wav"` and `"raw"` natively, requires ffmpeg for all other formats. `"raw"` files require 3 additional keyword arguments, `sample_width`, `frame_rate`, and `channels`, denoted below with: **`raw` only**. This extra info is required because raw audio files do not have headers to include this info in the file itself like wav files do.
+- `sample_width` | example: `2`
+  **`raw` only** — Use `1` for 8-bit audio `2` for 16-bit (CD quality) and `4` for 32-bit. It’s the number of bytes per sample.
+- `channels` | example: `1`
+  **`raw` only** — `1` for mono, `2` for stereo.
+- `frame_rate` | example: `2`
+  **`raw` only** — Also known as sample rate, common values are `44100` (44.1kHz - CD audio), and `48000` (48kHz - DVD audio)
+- `start_second` | example: `2.0` | default: `None`
+  Offset (in seconds) to start loading the audio file. If `None`, the audio will start loading from the beginning.
+- `duration` | example: `2.5` | default: `None`
+  Number of seconds to be loaded. If `None`, full audio will be loaded.
+
+
+### AudioSegment(…).export()
+
+Write the `AudioSegment` object to a file – returns a file handle of the output file (you don't have to do anything with it, though).
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("/path/to/sound.wav", format="wav")
+
+# simple export
+file_handle = sound.export("/path/to/output.mp3", format="mp3")
+
+# more complex export
+file_handle = sound.export("/path/to/output.mp3",
+                           format="mp3",
+                           bitrate="192k",
+                           tags={"album": "The Bends", "artist": "Radiohead"},
+                           cover="/path/to/albumcovers/radioheadthebends.jpg")
+
+# split sound in 5-second slices and export
+for i, chunk in enumerate(sound[::5000]):
+  with open("sound-%s.mp3" % i, "wb") as f:
+    chunk.export(f, format="mp3")
+```
+
+The first argument is the location (as a string) to write the output, **or** a file handle to write to. If you do not pass an output file or path, a temporary file is generated.
+
+**Supported keyword arguments**:
+
+- `format` | example: `"aif"` | default: `"mp3"`
+  Format of the output file. Supports `"wav"` and `"raw"` natively, requires ffmpeg for all other formats.
+- `codec` | example: `"libvorbis"`
+  For formats that may contain content encoded with different codecs, you can specify the codec you'd like the encoder to use. For example, the "ogg" format is often used with the "libvorbis" codec. (requires ffmpeg)
+- `bitrate` | example: `"128k"`
+  For compressed formats, you can pass the bitrate you'd like the encoder to use (requires ffmpeg). Each codec accepts different bitrate arguments so take a look at the [ffmpeg documentation](https://www.ffmpeg.org/ffmpeg-codecs.html#Audio-Encoders) for details (bitrate usually shown as `-b`, `-ba` or `-a:b`).
+- `tags` | example: `{"album": "1989", "artist": "Taylor Swift"}`
+  Allows you to supply media info tags for the encoder (requires ffmpeg). Not all formats can receive tags (mp3 can).
+- `parameters` | example: `["-ac", "2"]`
+  Pass additional [command line parameters](https://www.ffmpeg.org/ffmpeg.html) to the ffmpeg call. These are added to the end of the call (in the output file section).
+- `id3v2_version` | example: `"3"` | default: `"4"`
+  Set the ID3v2 version used by ffmpeg to add tags to the output file. If you want Windows Exlorer to display tags, use `"3"` here ([source](http://superuser.com/a/453133)).
+- `cover` | example: `"/path/to/imgfile.png"`
+  Allows you to supply a cover image (path to the image file). Currently, only MP3 files allow this keyword argument. Cover image must be a jpeg, png, bmp, or tiff file.
+
+
+### AudioSegment.empty()
+
+Creates a zero-duration `AudioSegment`.
+
+```python
+from pydub import AudioSegment
+empty = AudioSegment.empty()
+
+len(empty) == 0
+```
+
+This is useful for aggregation loops:
+```python
+from pydub import AudioSegment
+
+sounds = [
+  AudioSegment.from_wav("sound1.wav"),
+  AudioSegment.from_wav("sound2.wav"),
+  AudioSegment.from_wav("sound3.wav"),
+]
+
+playlist = AudioSegment.empty()
+for sound in sounds:
+  playlist += sound
+```
+
+### AudioSegment.silent()
+
+Creates a silent audiosegment, which can be used as a placeholder, spacer, or as a canvas to overlay other sounds on top of.
+
+```python
+from pydub import AudioSegment
+
+ten_second_silence = AudioSegment.silent(duration=10000)
+```
+
+**Supported keyword arguments**:
+
+- `duration` | example: `3000` | default: `1000` (1 second)
+  Length of the silent `AudioSegment`, in milliseconds
+- `frame_rate` | example `44100` | default: `11025` (11.025 kHz)
+  Frame rate (i.e., sample rate) of the silent `AudioSegment` in Hz
+
+### AudioSegment.from_mono_audiosegments()
+
+Creates a multi-channel audiosegment out of multiple mono audiosegments (two or more). Each mono audiosegment passed in should be exactly the same length, down to the frame count.
+
+```python
+from pydub import AudioSegment
+
+left_channel = AudioSegment.from_wav("sound1.wav")
+right_channel = AudioSegment.from_wav("sound1.wav")
+
+stereo_sound = AudioSegment.from_mono_audiosegments(left_channel, right_channel)
+```
+
+### AudioSegment(…).dBFS
+
+Returns the loudness of the `AudioSegment` in dBFS (db relative to the maximum possible loudness). A Square wave at maximum amplitude will be roughly 0 dBFS (maximum loudness), whereas a Sine Wave at maximum amplitude will be roughly -3 dBFS.
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+loudness = sound.dBFS
+```
+
+### AudioSegment(…).channels
+
+Number of channels in this audio segment (1 means mono, 2 means stereo)
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+channel_count = sound.channels
+```
+
+### AudioSegment(…).sample_width
+
+Number of bytes in each sample (1 means 8 bit, 2 means 16 bit, etc). CD Audio is 16 bit, (sample width of 2 bytes).
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+bytes_per_sample = sound.sample_width
+```
+
+### AudioSegment(…).frame_rate
+
+CD Audio has a 44.1kHz sample rate, which means `frame_rate` will be `44100` (same as sample rate, see `frame_width`). Common values are `44100` (CD), `48000` (DVD), `22050`, `24000`, `12000` and `11025`.
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+frames_per_second = sound.frame_rate
+```
+
+### AudioSegment(…).frame_width
+
+Number of bytes for each "frame". A frame contains a sample for each channel (so for stereo you have 2 samples per frame, which are played simultaneously). `frame_width` is equal to `channels * sample_width`. For CD Audio it'll be `4` (2 channels times 2 bytes per sample).
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+bytes_per_frame = sound.frame_width
+```
+
+### AudioSegment(…).rms
+
+A measure of loudness. Used to compute dBFS, which is what you should use in most cases. Loudness is logarithmic (rms is not), which makes dB a much more natural scale.
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+loudness = sound.rms
+```
+
+### AudioSegment(…).max
+
+The highest amplitude of any sample in the `AudioSegment`. Useful for things like normalization (which is provided in `pydub.effects.normalize`).
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+peak_amplitude = sound.max
+```
+
+### AudioSegment(…).max_dBFS
+
+The highest amplitude of any sample in the `AudioSegment`, in dBFS (relative to the highest possible amplitude value). Useful for things like normalization (which is provided in `pydub.effects.normalize`).
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+normalized_sound = sound.apply_gain(-sound.max_dBFS)
+```
+
+### AudioSegment(…).duration_seconds
+
+Returns the duration of the `AudioSegment` in seconds (`len(sound)` returns milliseconds). This is provided for convenience; it calls `len()` internally.
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+assert sound.duration_seconds == (len(sound) / 1000.0)
+```
+
+### AudioSegment(…).raw_data
+
+The raw audio data of the AudioSegment. Useful for interacting with other audio libraries or weird APIs that want audio data in the form of a bytestring. Also comes in handy if you’re implementing effects or other direct signal processing.
+
+You probably don’t need this, but if you do… you’ll know.
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+raw_audio_data = sound.raw_data
+```
+
+### AudioSegment(…).frame_count()
+
+Returns the number of frames in the `AudioSegment`. Optionally you may pass in a `ms` keywork argument to retrieve the number of frames in that number of milliseconds of audio in the `AudioSegment` (useful for slicing, etc).
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file("sound1.wav")
+
+number_of_frames_in_sound = sound.frame_count()
+
+number_of_frames_in_200ms_of_sound = sound.frame_count(ms=200)
+```
+
+**Supported keyword arguments**:
+
+- `ms` | example: `3000` | default: `None` (entire duration of `AudioSegment`)
+  When specified, method returns number of frames in X milliseconds of the `AudioSegment`
+
+### AudioSegment(…).append()
+
+Returns a new `AudioSegment`, created by appending another `AudioSegment` to this one (i.e., adding it to the end), Optionally using a crossfade. `AudioSegment(…).append()` is used internally when adding `AudioSegment` objects together with the `+` operator.
+
+By default a 100ms (0.1 second) crossfade is used to eliminate pops and crackles.
+
+```python
+from pydub import AudioSegment
+sound1 = AudioSegment.from_file("sound1.wav")
+sound2 = AudioSegment.from_file("sound2.wav")
+
+# default 100 ms crossfade
+combined = sound1.append(sound2)
+
+# 5000 ms crossfade
+combined_with_5_sec_crossfade = sound1.append(sound2, crossfade=5000)
+
+# no crossfade
+no_crossfade1 = sound1.append(sound2, crossfade=0)
+
+# no crossfade
+no_crossfade2 = sound1 + sound2
+```
+
+**Supported keyword arguments**:
+
+- `crossfade` | example: `3000` | default: `100` (entire duration of `AudioSegment`)
+  When specified, method returns number of frames in X milliseconds of the `AudioSegment`
+
+### AudioSegment(…).overlay()
+
+Overlays an `AudioSegment` onto this one. In the resulting `AudioSegment` they will play simultaneously. If the overlaid `AudioSegment` is longer than this one, the result will be truncated (so the end of the overlaid sound will be cut off). The result is always the same length as this `AudioSegment` even when using the `loop`, and `times` keyword arguments.
+
+Since `AudioSegment` objects are immutable, you can get around this by overlaying the shorter sound on the longer one, or by creating a silent `AudioSegment` with the appropriate duration, and overlaying both sounds on to that one.
+
+```python
+from pydub import AudioSegment
+sound1 = AudioSegment.from_file("sound1.wav")
+sound2 = AudioSegment.from_file("sound2.wav")
+
+played_togther = sound1.overlay(sound2)
+
+sound2_starts_after_delay = sound1.overlay(sound2, position=5000)
+
+volume_of_sound1_reduced_during_overlay = sound1.overlay(sound2, gain_during_overlay=-8)
+
+sound2_repeats_until_sound1_ends = sound1.overlay(sound2, loop=true)
+
+sound2_plays_twice = sound1.overlay(sound2, times=2)
+
+# assume sound1 is 30 sec long and sound2 is 5 sec long:
+sound2_plays_a_lot = sound1.overlay(sound2, times=10000)
+len(sound1) == len(sound2_plays_a_lot)
+```
+
+**Supported keyword arguments**:
+
+- `position` | example: `3000` | default: `0` (beginning of this `AudioSegment`)
+  The overlaid `AudioSegment` will not begin until X milliseconds have passed
+- `loop` | example: `True` | default: `False` (entire duration of `AudioSegment`)
+  The overlaid `AudioSegment` will repeat (starting at `position`) until the end of this `AudioSegment`
+- `times` | example: `4` | default: `1` (entire duration of `AudioSegment`)
+  The overlaid `AudioSegment` will repeat X times (starting at `position`) but will still be truncated to the length of this `AudioSegment`
+- `gain_during_overlay` | example: `-6.0` | default: `0` (no change in volume during overlay)
+  Change the original audio by this many dB while overlaying audio. This can be used to make the original audio quieter while the overlaid audio plays.
+
+### AudioSegment(…).apply_gain(`gain`)
+
+Change the amplitude (generally, loudness) of the `AudioSegment`. Gain is specified in dB. This method is used internally by the `+` operator.
+
+```python
+from pydub import AudioSegment
+sound1 = AudioSegment.from_file("sound1.wav")
+
+# make sound1 louder by 3.5 dB
+louder_via_method = sound1.apply_gain(+3.5)
+louder_via_operator = sound1 + 3.5
+
+# make sound1 quieter by 5.7 dB
+quieter_via_method = sound1.apply_gain(-5.7)
+quieter_via_operator = sound1 - 5.7
+```
+
+### AudioSegment(…).fade()
+
+A more general (more flexible) fade method. You may specify `start` and `end`, or one of the two along with duration (e.g., `start` and `duration`).
+
+```python
+from pydub import AudioSegment
+sound1 = AudioSegment.from_file("sound1.wav")
+
+fade_louder_for_3_seconds_in_middle = sound1.fade(to_gain=+6.0, start=7500, duration=3000)
+
+fade_quieter_beteen_2_and_3_seconds = sound1.fade(to_gain=-3.5, start=2000, end=3000)
+
+# easy way is to use the .fade_in() convenience method. note: -120dB is basically silent.
+fade_in_the_hard_way = sound1.fade(from_gain=-120.0, start=0, duration=5000)
+fade_out_the_hard_way = sound1.fade(to_gain=-120.0, end=0, duration=5000)
+```
+
+**Supported keyword arguments**:
+
+- `to_gain` | example: `-3.0` | default: `0` (0dB, no change)
+  Resulting change at the end of the fade. `-6.0` means fade will be be from 0dB (no change) to -6dB, and everything after the fade will be -6dB.
+- `from_gain` | example: `-3.0` | default: `0` (0dB, no change)
+  Change at the beginning of the fade. `-6.0` means fade (and all audio before it) will be be at -6dB will fade up to 0dB – the rest of the audio after the fade will be at 0dB (i.e., unchanged).
+- `start` | example: `7500` | NO DEFAULT
+  Position to begin fading (in milliseconds). `5500` means fade will begin after 5.5 seconds.
+- `end` | example: `4` | NO DEFAULT
+  The overlaid `AudioSegment` will repeat X times (starting at `position`) but will still be truncated to the length of this `AudioSegment`
+- `duration` | example: `4` | NO DEFAULT
+  You can use `start` or `end` with duration, instead of specifying both - provided as a convenience.
+
+### AudioSegment(…).fade_out()
+
+Fade out (to silent) the end of this `AudioSegment`. Uses `.fade()` internally.
+
+**Supported keyword arguments**:
+
+- `duration` | example: `5000` | NO DEFAULT
+  How long (in milliseconds) the fade should last. Passed directly to `.fade()` internally
+
+### AudioSegment(…).fade_in()
+
+Fade in (from silent) the beginning of this `AudioSegment`. Uses `.fade()` internally.
+
+**Supported keyword arguments**:
+
+- `duration` | example: `5000` | NO DEFAULT
+  How long (in milliseconds) the fade should last. Passed directly to `.fade()` internally
+
+### AudioSegment(…).reverse()
+
+Make a copy of this `AudioSegment` that plays backwards. Useful for Pink Floyd, screwing around, and some audio processing algorithms.
+
+### AudioSegment(…).set_sample_width()
+
+Creates an equivalent version of this `AudioSegment` with the specified sample width (in bytes). Increasing this value does not generally cause a reduction in quality. Reducing it *definitely* does cause a loss in quality. Higher Sample width means more dynamic range.
+
+### AudioSegment(…).set_frame_rate()
+
+Creates an equivalent version of this `AudioSegment` with the specified frame rate (in Hz). Increasing this value does not generally cause a reduction in quality. Reducing it *definitely does* cause a loss in quality. Higher frame rate means larger frequency response (higher frequencies can be represented).
+
+### AudioSegment(…).set_channels()
+
+Creates an equivalent version of this `AudioSegment` with the specified number of channels (1 is Mono, 2 is Stereo). Converting from mono to stereo does not cause any audible change. Converting from stereo to mono may result in loss of quality (but only if the left and right chanels differ).
+
+### AudioSegment(…).split_to_mono()
+
+Splits a stereo `AudioSegment` into two, one for each channel (Left/Right). Returns a list with the new `AudioSegment` objects with the left channel at index 0 and the right channel at index 1.
+
+### AudioSegment(…).apply_gain_stereo()
+
+```python
+from pydub import AudioSegment
+sound1 = AudioSegment.from_file("sound1.wav")
+
+# make left channel 6dB quieter and right channe 2dB louder
+stereo_balance_adjusted = sound1.apply_gain_stereo(-6, +2)
+```
+Apply gain to the left and right channel of a stereo `AudioSegment`. If the `AudioSegment` is mono, it will be converted to stereo before applying the gain.
+
+Both gain arguments are specified in dB.
+
+### AudioSegment(…).pan()
+
+```python
+from pydub import AudioSegment
+sound1 = AudioSegment.from_file("sound1.wav")
+
+# pan the sound 15% to the right
+panned_right = sound1.pan(+0.15)
+
+# pan the sound 50% to the left
+panned_left = sound1.pan(-0.50)
+```
+
+Takes one positional argument, *pan amount*, which should be between -1.0 (100% left) and +1.0 (100% right)
+
+When pan_amount == 0.0 the left/right balance is not changed.
+
+Panning does not alter the *perceived* loundness, but since loudness
+is decreasing on one side, the other side needs to get louder to
+compensate. When panned hard left, the left channel will be 3dB louder and
+the right channel will be silent (and vice versa).
+
+### AudioSegment(…).get_array_of_samples()
+
+Returns the raw audio data as an array of (numeric) samples. Note: if the audio has multiple channels, the samples for each channel will be serialized – for example, stereo audio would look like `[sample_1_L, sample_1_R, sample_2_L, sample_2_R, …]`.
+
+This method is mainly for use in implementing effects, and other processing.
+
+```python
+from pydub import AudioSegment
+sound = AudioSegment.from_file(“sound1.wav”)
+
+samples = sound.get_array_of_samples()
+
+# then modify samples...
+
+new_sound = sound._spawn(samples)
+```
+
+note that when using numpy or scipy you will need to convert back to an array before you spawn:
+
+```python
+import array
+import numpy as np
+from pydub import AudioSegment
+
+sound = AudioSegment.from_file(“sound1.wav”)
+samples = sound.get_array_of_samples()
+
+# Example operation on audio data
+shifted_samples = np.right_shift(samples, 1)
+
+# now you have to convert back to an array.array
+shifted_samples_array = array.array(sound.array_type, shifted_samples)
+
+new_sound = sound._spawn(shifted_samples_array)
+```
+
+Here's how to convert to a numpy float32 array:
+
+```python
+import numpy as np
+from pydub import AudioSegment
+
+sound = AudioSegment.from_file("sound1.wav")
+sound = sound.set_frame_rate(16000)
+channel_sounds = sound.split_to_mono()
+samples = [s.get_array_of_samples() for s in channel_sounds]
+
+fp_arr = np.array(samples).T.astype(np.float32)
+fp_arr /= np.iinfo(samples[0].typecode).max
+```
+
+And how to convert it back to an AudioSegment:
+
+```python
+import io
+import scipy.io.wavfile
+
+wav_io = io.BytesIO()
+scipy.io.wavfile.write(wav_io, 16000, fp_arr)
+wav_io.seek(0)
+sound = pydub.AudioSegment.from_wav(wav_io)
+```
+
+### AudioSegment(…).get_dc_offset()
+
+Returns a value between -1.0 and 1.0 representing the DC offset of a channel. This is calculated using `audioop.avg()` and normalizing the result by samples max value.
+
+**Supported keyword arguments**:
+
+- `channel` | example: `2` | default: `1`
+  Selects left (1) or right (2) channel to calculate DC offset. If segment is mono, this value is ignored.
+
+### AudioSegment(…).remove_dc_offset()
+
+Removes DC offset from channel(s). This is done by using `audioop.bias()`, so watch out for overflows.
+
+**Supported keyword arguments**:
+
+- `channel` | example: `2` | default: None
+  Selects left (1) or right (2) channel remove DC offset. If value if None, removes from all available channels. If segment is mono, this value is ignored.
+
+- `offset` | example: `-0.1` | default: None
+  Offset to be removed from channel(s). Calculates offset if it's None. Offset values must be between -1.0 and 1.0.
+
+## Effects
+
+Collection of DSP effects that are implemented by `AudioSegment` objects.
+
+### AudioSegment(…).invert_phase()
+
+Make a copy of this `AudioSegment` and inverts the phase of the signal. Can generate anti-phase waves for noise suppression or cancellation.
+
+## Silence
+
+Various functions for finding/manipulating silence in AudioSegments. For creating silent AudioSegments, see AudioSegment.silent().
+
+### silence.detect_silence()
+
+Returns a list of all silent sections [start, end] in milliseconds of audio_segment. Inverse of detect_nonsilent(). Can be very slow since it has to iterate over the whole segment.
+
+```python
+from pydub import AudioSegment, silence
+
+print(silence.detect_silence(AudioSegment.silent(2000)))
+# [[0, 2000]]
+```
+
+**Supported keyword arguments**:
+
+- `min_silence_len` | example: `500` | default: 1000
+  The minimum length for silent sections in milliseconds. If it is greater than the length of the audio segment an empty list will be returned.
+
+- `silence_thresh` | example: `-20` | default: -16
+  The upper bound for how quiet is silent in dBFS.
+
+- `seek_step` | example: `5` | default: 1
+  Size of the step for checking for silence in milliseconds. Smaller is more precise. Must be a positive whole number.
+
+### silence.detect_nonsilent()
+
+Returns a list of all silent sections [start, end] in milliseconds of audio_segment. Inverse of detect_silence() and has all the same arguments. Can be very slow since it has to iterate over the whole segment.
+
+**Supported keyword arguments**:
+
+- `min_silence_len` | example: `500` | default: 1000
+  The minimum length for silent sections in milliseconds. If it is greater than the length of the audio segment an empty list will be returned.
+
+- `silence_thresh` | example: `-20` | default: -16
+  The upper bound for how quiet is silent in dBFS.
+
+- `seek_step` | example: `5` | default: 1
+  Size of the step for checking for silence in milliseconds. Smaller is more precise. Must be a positive whole number.
+
+### silence.split_on_silence()
+
+Returns list of audio segments from splitting audio_segment on silent sections.
+
+**Supported keyword arguments**:
+
+- `min_silence_len` | example: `500` | default: 1000
+  The minimum length for silent sections in milliseconds. If it is greater than the length of the audio segment an empty list will be returned.
+
+- `silence_thresh` | example: `-20` | default: -16
+  The upper bound for how quiet is silent in dBFS.
+
+- `seek_step` | example: `5` | default: 1
+  Size of the step for checking for silence in milliseconds. Smaller is more precise. Must be a positive whole number.
+
+- `keep_silence` ~ example: True | default: 100
+  How much silence to keep in ms or a bool. leave some silence at the beginning and end of the chunks. Keeps the sound from sounding like it is abruptly cut off.
+  When the length of the silence is less than the keep_silence duration it is split evenly between the preceding and following non-silent segments.
+  If True is specified, all the silence is kept, if False none is kept.
+
+### silence.detect_leading_silence()
+
+Returns the millisecond/index that the leading silence ends. If there is no end it will return the length of the audio_segment.
+
+```python
+from pydub import AudioSegment, silence
+
+print(silence.detect_silence(AudioSegment.silent(2000)))
+# 2000
+```
+
+**Supported keyword arguments**:
+
+- `silence_thresh` | example: `-20` | default: -50
+  The upper bound for how quiet is silent in dBFS.
+
+- `chunk_size` | example: `5` | default: 10
+  Size of the step for checking for silence in milliseconds. Smaller is more precise. Must be a positive whole number.

app/lib/pydub/AUTHORS

@@ -0,0 +1,101 @@
+James Robert
+    github: jiaaro
+    twitter: @jiaaro
+    web: jiaaro.com
+    email: pydub@jiaaro.com
+
+Marc Webbie
+    github: marcwebbie
+
+Jean-philippe Serafin
+    github: jeanphix
+
+Anurag Ramdasan
+    github: AnuragRamdasan
+
+Choongmin Lee
+    github: clee704
+
+Patrick Pittman
+    github: ptpittman
+
+Hunter Lang
+    github: hunterlang
+
+Alexey
+    github: nihisil
+
+Jaymz Campbell
+    github: jaymzcd
+
+Ross McFarland
+    github: ross
+
+John McMellen
+    github: jmcmellen
+
+Johan Lövgren
+    github: dashj
+
+Joachim Krüger
+    github: jkrgr
+
+Shichao An
+    github: shichao-an
+
+Michael Bortnyck
+    github: mbortnyck
+
+André Cloete
+    github: aj-cloete
+
+David Acacio
+    github: dacacioa
+
+Thiago Abdnur
+    github: bolaum
+
+Aurélien Ooms
+    github: aureooms
+
+Mike Mattozzi
+    github: mmattozzi
+
+Marcio Mazza
+    github: marciomazza
+
+Sungsu Lim
+    github: proflim
+
+Evandro Myller
+    github: emyller
+
+Sérgio Agostinho
+    github: SergioRAgostinho
+
+Antonio Larrosa
+    github: antlarr
+
+Aaron Craig
+    github: craigthelinguist
+
+Carlos del Castillo
+    github: greyalien502
+
+Yudong Sun
+    github: sunjerry019
+
+Jorge Perianez
+    github: JPery
+
+Chendi Luo
+    github: Creonalia
+
+Daniel Lefevre
+    gitHub: dplefevre
+
+Grzegorz Kotfis
+    github: gkotfis
+
+Pål Orby
+    github: orby

app/lib/pydub/CHANGELOG.md

@@ -0,0 +1,168 @@
+# v0.25.1
+- Fix crashing bug in new scipy-powered EQ effects
+
+# v0.25.0
+- Don't show a runtime warning about the optional ffplay dependency being missing until someone trys to use it
+- Documentation improvements
+- Python 3.9 support
+- Improved efficiency of loading wave files with `pydub.AudioSegment.from_file()`
+- Ensure `pydub.AudioSegment().export()` always retuns files with a seek position at the beginning of the file   
+- Added more EQ effects to `pydub.scipy_effects` (requires scipy to be installed)
+- Fix a packaging bug where the LICENSE file was not included in the source distribution
+- Add a way to instantiate a `pydub.AudioSegment()` with a portion of an audio file via `pydub.AudioSegment().from_file()`
+
+# v0.24.1
+- Fix bug where ffmpeg errors in Python 3 are illegible
+- Fix bug where `split_on_silence` fails when there are one or fewer nonsilent segments
+- Fix bug in fallback audioop implementation
+
+# v0.24.0
+- Fix inconsistent handling of 8-bit audio
+- Fix bug where certain files will fail to parse
+- Fix bug where pyaudio stream is not closed on error
+- Allow codecs and parameters in wav and raw export
+- Fix bug in `pydub.AudioSegment.from_file` where supplied codec is ignored
+- Allow `pydub.silence.split_on_silence` to take a boolean for `keep_silence`
+- Fix bug where `pydub.silence.split_on_silence` sometimes adds non-silence from adjacent segments
+- Fix bug where `pydub.AudioSegment.extract_wav_headers` fails on empty wav files
+- Add new function `pydub.silence.detect_leading_silence`
+- Support conversion between an arbitrary number of channels and mono in `pydub.AudioSegment.set_channels`
+- Fix several issues related to reading from filelike objects
+
+# v0.23.1
+- Fix bug in passing ffmpeg/avconv parameters for `pydub.AudioSegment.from_mp3()`, `pydub.AudioSegment.from_flv()`, `pydub.AudioSegment.from_ogg()`, and `pydub.AudioSegment.from_wav()`
+- Fix logic bug in `pydub.effects.strip_silence()`
+
+# v0.23.0
+- Add support for playback via simpleaudio
+- Allow users to override the type in `pydub.AudioSegment().get_array_of_samples()` (PR #313)
+- Fix a bug where the wrong codec was used for 8-bit audio (PR #309 - issue #308)
+
+# v0.22.1
+- Fix `pydub.utils.mediainfo_json()` to work with newer, backwards-incompatible versions of ffprobe/avprobe
+
+# v0.22.0
+- Adds support for audio with frame rates (sample rates) of 48k and higher (requires scipy) (PR #262, fixes #134, #237, #209)
+- Adds support for PEP 519 File Path protocol (PR #252)
+- Fixes a few places where handles to temporary files are kept open (PR #280)
+- Add the license file to the python package to aid other packaging projects (PR #279, fixes #274)
+- Big fix for `pydub.silence.detect_silence()` (PR #263)
+
+# v0.21.0
+- NOTE: Semi-counterintuitive change: using the a stride when slicing AudioSegment instances (for example, `sound[::5000]`) will return chunks of 5000ms (not 1ms chunks every 5000ms) (#222)
+- Debug output from ffmpeg/avlib is no longer printed to the console unless you set up logging (see README for how to set up logging for your converter) (#223)
+- All pydub exceptions are now subclasses of `pydub.exceptions.PydubException` (PR #244)
+- The utilities in `pydub.silence` now accept a `seek_step`argument which can optionally be passed to improve the performance of silence detection (#211)
+- Fix to `pydub.silence` utilities which allow you to detect perfect silence (#233)
+- Fix a bug where threaded code screws up your terminal session due to ffmpeg inheriting the stdin from the parent process. (#231)
+- Fix a bug where a crashing programs using pydub would leave behind their temporary files (#206)
+
+# v0.20.0
+- Add new parameter `gain_during_overlay` to `pydub.AudioSegment.overlay` which allows users to adjust the volume of the target AudioSegment during the portion of the segment which is overlaid with the additional AudioSegment.
+- `pydub.playback.play()` No longer displays the (very verbose) playback "banner" when using ffplay
+- Fix a confusing error message when using invalid crossfade durations (issue #193)
+
+# v0.19.0
+- Allow codec and ffmpeg/avconv parameters to be set in the `pydub.AudioSegment.from_file()` for more control while decoding audio files
+- Allow `AudioSegment` objects with more than two channels to be split using `pydub.AudioSegment().split_to_mono()`
+- Add support for inverting the phase of only one channel in a multi-channel `pydub.AudioSegment` object
+- Fix a bug with the latest avprobe that broke `pydub.utils.mediainfo()`
+- Add tests for webm encoding/decoding
+
+# v0.18.0
+- Add a new constructor: `pydub.AudioSegment.from_mono_audiosegments()` which allows users to create a multi-channel audiosegment out of multiple mono ones.
+- Refactor `pydub.AudioSegment._sync()` to support an arbitrary number of audiosegment arguments.
+
+# v0.17.0
+- Add the ability to add a cover image to MP3 exports via the `cover` keyword argument to `pydub.AudioSegment().export()`
+- Add `pydub.AudioSegment().get_dc_offset()` and `pydub.AudioSegment().remove_dc_offset()` which allow detection and removal of DC offset in audio files.
+- Minor fixes for windows users
+
+# v0.16.7
+- Make `pydub.AudioSegment()._spawn()` accept array.array instances containing audio samples
+
+# v0.16.6
+- Make `pydub.AudioSegment()` objects playable inline in ipython notebooks.
+- Add scipy powered high pass, low pass, and band pass filters, which can be high order filters (they take `order` as a keyword argument). They are used for `pydub.AudioSegment().high_pass_filter()`, `pydub.AudioSegment().low_pass_filter()`, `pydub.AudioSegment().band_pass_filter()` when the `pydub.scipy_effects` module is imported.
+- Fix minor bug in `pydub.silence.detect_silence()`
+
+# v0.16.5
+- Update `pydub.AudioSegment()._spawn()` method to allow user subclassing of `pydub.AudioSegment`
+- Add a workaround for incorrect duration reporting of some mp3 files on macOS
+
+# v0.16.4
+- Add support for radd (basically, allow `sum()` to operate on an iterable of `pydub.AudioSegment()` objects)
+- Fix bug in 24-bit wav support (understatement. It didn't work right at all the first time)
+
+# v0.16.3
+- Add support for python 3.5 (overstatement. We just added python 3.5 to CI and it worked 😄)
+- Add native support for 24-bit wav files (ffmpeg/avconv not required)
+
+# v0.16.2
+- Fix bug where you couldn't directly instantiate `pydub.AudioSegment` with `bytes` data in python 3
+
+# v0.16.1
+- pydub will use any ffmpeg/avconv binary that's in the current directory (as reported by `os.getcwd()`) before searching for a system install
+
+# v0.16.0
+- Make it easier to instantiate `pydub.AudioSegment()` directly when creating audio segments from raw audio data (without having to write it to a file first)
+- Add `pydub.AudioSegment().get_array_of_samples()` method which returns the samples which make up an audio segment (you should usually prefer this over `pydub.AudioSegment().raw_data`)
+- Add `pydub.AudioSegment().raw_data` property which returns the raw audio data for an audio segment as a bytes (python 3) or a bytestring (python 3)
+- Allow users to specify frame rate in `pydub.AudioSegment.silent()` constructor
+
+# v0.15.0
+- Add support for RAW audio (basically WAV format, but without wave headers)
+- Add a new exception `pydub.exceptions.CouldntDecodeError` to indicate a failure of ffmpeg/avconv to decode a file (as indicated by ffmpeg/avconv exit code)
+
+# v0.14.2
+- Fix a bug in python 3.4 which failed to read wave files with no audio data (should have been audio segments with a duration of 0 ms)
+
+# v0.14.1
+- Fix a bug in `pydub.utils.mediainfo()` that caused inputs containing unescaped characters to raise a runtime error (inputs are not supposed to require escaping)
+
+# v0.14.0
+- Rename `pydub.AudioSegment().set_gain()` to `pydub.AudioSegment().apply_gain_stereo()` to better reflect it's place in the world (as a counterpart to `pydub.AudioSegment().apply_gain()`)
+
+# v0.13.0
+- Add `pydub.AudioSegment().pan()` which returns a new stereo audio segment panned left/right as specified.
+
+# v0.12.0
+- Add a logger, `"pydub.converter"` which logs the ffmpeg commands being run by pydub.
+- Add `pydub.AudioSegment().split_to_mono()` method which returns a list of mono audio segments. One for each channel in the original audio segment.
+- Fix a bug in `pydub.silence.detect_silence()` which caused the function to break when a silent audio segment was equal in length to the minimum silence length. It should report a single span of silence covering the whole silent audio segment. Now it does.
+- Fix a bug where uncommon wav formats (those not supported by the stdlib wave module) would throw an exception rather than converting to a more common format via ffmpeg/avconv
+
+# v0.11.0
+- Add `pydub.AudioSegment().max_dBFS` which reports the loudness (in dBFS) of the loudest point (i.e., highest amplitude sample) of an audio segment
+
+# v0.10.0
+- Overhaul Documentation
+- Improve performance of `pydub.AudioSegment().overlay()`
+- Add `pydub.AudioSegment().invert_phase()` which (shocker) inverts the phase of an audio segment
+- Fix a type error in `pydub.AudioSegment.get_sample_slice()`
+
+# v0.9.5
+- Add `pydub.generators` module containing simple signal generation functions (white noise, sine, square wave, etc)
+- Add a `loops` keyword argument to `pydub.AudioSegment().overlay()` which allows users to specify that the overlaid audio should be repeated (i.e., looped) a certain number of times, or indefinitely
+
+# 0.9.4
+- Fix a bug in db_to_float() where all values were off by a factor of 2
+
+# 0.9.3
+- Allow users to set the location of their converter by setting `pydub.AudioSegment.converter = "/path/to/ffmpeg"` and added a shim to support the old method of assigning to `pydub.AudioSegment.ffmpeg` (which is deprecated now that we support avconv)
+
+# v0.9.2
+- Add support for Python 3.4
+- Audio files opened with format "wave" are treated as "wav" and "m4a" are treated as "mp4"
+- Add `pydub.silence` module with simple utilities for detecting and removing silence.
+- Fix a bug affecting auto-detection of ffmpeg/avconv on windows.
+- Fix a bug that caused pydub to only work when ffmpeg/avconv is present (it should be able to work with WAV data without any dependencies)
+
+# v0.9.1
+- Add a runtime warning when ffmpeg/avconv cannot be found to aid debugging
+
+# v0.9.0
+- Added support for pypy (by reimplementing audioop in python). Also, we contributed our implementation to the pypy project, so that's 💯
+- Add support for avconv as an alternative to ffmpeg
+- Add a new helper module `pydub.playback` which allows you to quickly listen to an audio segment using ffplay (or avplay)
+- Add new function `pydub.utils.mediainfo('/path/to/audio/file.ext')` which reports back the results of ffprobe (or avprobe) including codec, bitrate, channels, etc

app/lib/pydub/CONTRIBUTING.md

@@ -0,0 +1,45 @@
+Pydub loves user contributions. 
+
+We are happy to merge Pull Requests for features and bug fixes, of course. But, also spelling corrections, PEP 8 conformity, and platform-specific fixes.
+
+Don't be shy!
+
+### How to contribute:
+
+1. Fork [pydub on github](https://github.com/jiaaro/pydub)
+2. Commit changes
+3. Send a Pull Request
+
+you did it! 
+
+don't forget to append your name to the AUTHORS file ;)
+
+There _are_ a few things that will make your Pull Request more likely to be merged:
+
+1. Maintain backward compatibility
+2. Avoid new dependencies
+3. Include tests (and make sure they pass)
+4. Write a short description of **what** is changed and **why**
+5. Keep your Pull Request small, and focused on fixing one thing. 
+
+  Smaller is easier to review, and easier to understand. 
+  
+  If you want to fix spelling and PEP 8 violations, send two pull requests :)
+  
+  
+### Want to pitch in?
+  
+Take a look at our issue tracker for anything tagged [`bug`][bugs] or [`todo`][todos] - these are goals of the project and your improvements are _very_ likely to be merged!
+
+That being said, there are many possible contributions we haven't thought of already. Those are welcome too!
+
+Here are some general topics of interest for future development:
+
+- Make it easier to get started with pydub
+- More/better audio effects
+- Support more audio formats
+- Improve handling of large audio files
+- Make things faster and use less memory.
+
+[bugs]: https://github.com/jiaaro/pydub/issues?q=is%3Aissue+is%3Aopen+label%3Abug
+[todos]: https://github.com/jiaaro/pydub/issues?q=is%3Aissue+is%3Aopen+label%3Atodo

app/lib/pydub/LICENSE

@@ -0,0 +1,20 @@
+Copyright (c) 2011 James Robert, http://jiaaro.com
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

app/lib/pydub/MANIFEST.in

@@ -0,0 +1 @@
+include LICENSE

app/lib/pydub/README.markdown

@@ -0,0 +1,333 @@
+# Pydub [![Build Status](https://travis-ci.org/jiaaro/pydub.svg?branch=master)](https://travis-ci.org/jiaaro/pydub) [![Build status](https://ci.appveyor.com/api/projects/status/gy1ucp9o5khq7fqi/branch/master?svg=true)](https://ci.appveyor.com/project/jiaaro/pydub/branch/master)
+
+Pydub lets you do stuff to audio in a way that isn't stupid.
+
+**Stuff you might be looking for**:
+ - [Installing Pydub](https://github.com/jiaaro/pydub#installation)
+ - [API Documentation](https://github.com/jiaaro/pydub/blob/master/API.markdown)
+ - [Dependencies](https://github.com/jiaaro/pydub#dependencies)
+ - [Playback](https://github.com/jiaaro/pydub#playback)
+ - [Setting up ffmpeg](https://github.com/jiaaro/pydub#getting-ffmpeg-set-up)
+ - [Questions/Bugs](https://github.com/jiaaro/pydub#bugs--questions)
+ 
+
+##  Quickstart
+
+Open a WAV file
+
+```python
+from pydub import AudioSegment
+
+song = AudioSegment.from_wav("never_gonna_give_you_up.wav")
+```
+
+...or a mp3
+
+```python
+song = AudioSegment.from_mp3("never_gonna_give_you_up.mp3")
+```
+
+... or an ogg, or flv, or [anything else ffmpeg supports](http://www.ffmpeg.org/general.html#File-Formats)
+
+```python
+ogg_version = AudioSegment.from_ogg("never_gonna_give_you_up.ogg")
+flv_version = AudioSegment.from_flv("never_gonna_give_you_up.flv")
+
+mp4_version = AudioSegment.from_file("never_gonna_give_you_up.mp4", "mp4")
+wma_version = AudioSegment.from_file("never_gonna_give_you_up.wma", "wma")
+aac_version = AudioSegment.from_file("never_gonna_give_you_up.aiff", "aac")
+```
+
+Slice audio:
+
+```python
+# pydub does things in milliseconds
+ten_seconds = 10 * 1000
+
+first_10_seconds = song[:ten_seconds]
+
+last_5_seconds = song[-5000:]
+```
+
+Make the beginning louder and the end quieter
+
+```python
+# boost volume by 6dB
+beginning = first_10_seconds + 6
+
+# reduce volume by 3dB
+end = last_5_seconds - 3
+```
+
+Concatenate audio (add one file to the end of another)
+
+```python
+without_the_middle = beginning + end
+```
+
+How long is it?
+
+```python
+without_the_middle.duration_seconds == 15.0
+```
+
+AudioSegments are immutable
+
+```python
+# song is not modified
+backwards = song.reverse()
+```
+
+Crossfade (again, beginning and end are not modified)
+
+```python
+# 1.5 second crossfade
+with_style = beginning.append(end, crossfade=1500)
+```
+
+Repeat
+
+```python
+# repeat the clip twice
+do_it_over = with_style * 2
+```
+
+Fade (note that you can chain operations because everything returns
+an AudioSegment)
+
+```python
+# 2 sec fade in, 3 sec fade out
+awesome = do_it_over.fade_in(2000).fade_out(3000)
+```
+
+Save the results (again whatever ffmpeg supports)
+
+```python
+awesome.export("mashup.mp3", format="mp3")
+```
+
+Save the results with tags (metadata)
+
+```python
+awesome.export("mashup.mp3", format="mp3", tags={'artist': 'Various artists', 'album': 'Best of 2011', 'comments': 'This album is awesome!'})
+```
+
+You can pass an optional bitrate argument to export using any syntax ffmpeg 
+supports.
+
+```python
+awesome.export("mashup.mp3", format="mp3", bitrate="192k")
+```
+
+Any further arguments supported by ffmpeg can be passed as a list in a 
+'parameters' argument, with switch first, argument second. Note that no 
+validation takes place on these parameters, and you may be limited by what 
+your particular build of ffmpeg/avlib supports.
+
+```python
+# Use preset mp3 quality 0 (equivalent to lame V0)
+awesome.export("mashup.mp3", format="mp3", parameters=["-q:a", "0"])
+
+# Mix down to two channels and set hard output volume
+awesome.export("mashup.mp3", format="mp3", parameters=["-ac", "2", "-vol", "150"])
+```
+
+## Debugging
+
+Most issues people run into are related to converting between formats using
+ffmpeg/avlib. Pydub provides a logger that outputs the subprocess calls to 
+help you track down issues:
+
+```python
+>>> import logging
+
+>>> l = logging.getLogger("pydub.converter")
+>>> l.setLevel(logging.DEBUG)
+>>> l.addHandler(logging.StreamHandler())
+
+>>> AudioSegment.from_file("./test/data/test1.mp3")
+subprocess.call(['ffmpeg', '-y', '-i', '/var/folders/71/42k8g72x4pq09tfp920d033r0000gn/T/tmpeZTgMy', '-vn', '-f', 'wav', '/var/folders/71/42k8g72x4pq09tfp920d033r0000gn/T/tmpK5aLcZ'])
+<pydub.audio_segment.AudioSegment object at 0x101b43e10>
+```
+
+Don't worry about the temporary files used in the conversion. They're cleaned up 
+automatically.
+
+## Bugs & Questions
+
+You can file bugs in our [github issues tracker](https://github.com/jiaaro/pydub/issues), 
+and ask any technical questions on 
+[Stack Overflow using the pydub tag](http://stackoverflow.com/questions/ask?tags=pydub). 
+We keep an eye on both.
+
+## Installation
+
+Installing pydub is easy, but don't forget to install ffmpeg/avlib (the next section in this doc)
+
+    pip install pydub
+
+Or install the latest dev version from github (or replace `@master` with a [release version like `@v0.12.0`](https://github.com/jiaaro/pydub/releases))…
+
+    pip install git+https://github.com/jiaaro/pydub.git@master
+
+-OR-
+
+    git clone https://github.com/jiaaro/pydub.git
+
+-OR-
+
+Copy the pydub directory into your python path. Zip 
+[here](https://github.com/jiaaro/pydub/zipball/master)
+
+## Dependencies
+
+You can open and save WAV files with pure python. For opening and saving non-wav 
+files – like mp3 – you'll need [ffmpeg](http://www.ffmpeg.org/) or 
+[libav](http://libav.org/).
+
+### Playback
+
+You can play audio if you have one of these installed (simpleaudio _strongly_ recommended, even if you are installing ffmpeg/libav):
+
+ - [simpleaudio](https://simpleaudio.readthedocs.io/en/latest/)
+ - [pyaudio](https://people.csail.mit.edu/hubert/pyaudio/docs/#)
+ - ffplay (usually bundled with ffmpeg, see the next section)
+ - avplay (usually bundled with libav, see the next section)
+ 
+```python
+from pydub import AudioSegment
+from pydub.playback import play
+
+sound = AudioSegment.from_file("mysound.wav", format="wav")
+play(sound)
+```
+
+## Getting ffmpeg set up
+
+You may use **libav or ffmpeg**.
+
+Mac (using [homebrew](http://brew.sh)):
+
+```bash
+# libav
+brew install libav
+
+####    OR    #####
+
+# ffmpeg
+brew install ffmpeg
+```
+
+Linux (using aptitude):
+
+```bash
+# libav
+apt-get install libav-tools libavcodec-extra
+
+####    OR    #####
+
+# ffmpeg
+apt-get install ffmpeg libavcodec-extra
+```
+
+Windows:
+
+1. Download and extract libav from [Windows binaries provided here](http://builds.libav.org/windows/).
+2. Add the libav `/bin` folder to your PATH envvar
+3. `pip install pydub`
+
+## Important Notes
+
+`AudioSegment` objects are [immutable](http://www.devshed.com/c/a/Python/String-and-List-Python-Object-Types/1/)
+
+
+### Ogg exporting and default codecs
+
+The Ogg specification ([http://tools.ietf.org/html/rfc5334](rfc5334)) does not specify
+the codec to use, this choice is left up to the user. Vorbis and Theora are just
+some of a number of potential codecs (see page 3 of the rfc) that can be used for the
+encapsulated data.
+
+When no codec is specified exporting to `ogg` will _default_ to using `vorbis`
+as a convenience. That is:
+
+```python
+from pydub import AudioSegment
+song = AudioSegment.from_mp3("test/data/test1.mp3")
+song.export("out.ogg", format="ogg")  # Is the same as:
+song.export("out.ogg", format="ogg", codec="libvorbis")
+```
+
+## Example Use
+
+Suppose you have a directory filled with *mp4* and *flv* videos and you want to convert all of them to *mp3* so you can listen to  them on your mp3 player.
+
+```python
+import os
+import glob
+from pydub import AudioSegment
+
+video_dir = '/home/johndoe/downloaded_videos/'  # Path where the videos are located
+extension_list = ('*.mp4', '*.flv')
+
+os.chdir(video_dir)
+for extension in extension_list:
+    for video in glob.glob(extension):
+        mp3_filename = os.path.splitext(os.path.basename(video))[0] + '.mp3'
+        AudioSegment.from_file(video).export(mp3_filename, format='mp3')
+```
+
+### How about another example?
+
+```python
+from glob import glob
+from pydub import AudioSegment
+
+playlist_songs = [AudioSegment.from_mp3(mp3_file) for mp3_file in glob("*.mp3")]
+
+first_song = playlist_songs.pop(0)
+
+# let's just include the first 30 seconds of the first song (slicing
+# is done by milliseconds)
+beginning_of_song = first_song[:30*1000]
+
+playlist = beginning_of_song
+for song in playlist_songs:
+
+    # We don't want an abrupt stop at the end, so let's do a 10 second crossfades
+    playlist = playlist.append(song, crossfade=(10 * 1000))
+
+# let's fade out the end of the last song
+playlist = playlist.fade_out(30)
+
+# hmm I wonder how long it is... ( len(audio_segment) returns milliseconds )
+playlist_length = len(playlist) / (1000*60)
+
+# lets save it!
+with open("%s_minute_playlist.mp3" % playlist_length, 'wb') as out_f:
+    playlist.export(out_f, format='mp3')
+```
+
+## License ([MIT License](http://opensource.org/licenses/mit-license.php))
+
+Copyright © 2011 James Robert, http://jiaaro.com
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+

app/lib/pydub/appveyor.yml

@@ -0,0 +1,30 @@
+build: false
+environment:
+  matrix:
+    - PYTHON: "C:/Python27"
+      FFMPEG: "4.2.3"
+    - PYTHON: "C:/Python34"
+      FFMPEG: "4.2.3"
+    - PYTHON: "C:/Python35"
+      FFMPEG: "4.2.3"
+    - PYTHON: "C:/Python36"
+      FFMPEG: "4.2.3"
+    - PYTHON: "C:/Python36"
+      FFMPEG: "latest"
+matrix:
+  allow_failures:
+    - FFMPEG: "latest"
+init:
+  - "ECHO %PYTHON%"
+  - ps: "ls C:/Python*"
+install:
+  - "%PYTHON%/python.exe -m pip install wheel"
+  - "%PYTHON%/python.exe -m pip install -e ."
+  # Install ffmpeg
+  - ps: Start-FileDownload ('https://github.com/advancedfx/ffmpeg.zeranoe.com-builds-mirror/releases/download/20200915/ffmpeg-' + $env:FFMPEG + '-win64-shared.zip') ffmpeg-shared.zip
+  - 7z x ffmpeg-shared.zip > NULL
+  - "SET PATH=%cd%\\ffmpeg-%FFMPEG%-win64-shared\\bin;%PATH%"
+  # check ffmpeg installation (also shows version)
+  - "ffmpeg.exe -version"
+test_script:
+  - "%PYTHON%/python.exe test/test.py"

app/lib/pydub/pydub/__init__.py

@@ -0,0 +1 @@
+from .audio_segment import AudioSegment

app/lib/pydub/pydub/effects.py

@@ -0,0 +1,341 @@
+import sys
+import math
+import array
+from .utils import (
+    db_to_float,
+    ratio_to_db,
+    register_pydub_effect,
+    make_chunks,
+    audioop,
+    get_min_max_value
+)
+from .silence import split_on_silence
+from .exceptions import TooManyMissingFrames, InvalidDuration
+
+if sys.version_info >= (3, 0):
+    xrange = range
+
+
+@register_pydub_effect
+def apply_mono_filter_to_each_channel(seg, filter_fn):
+    n_channels = seg.channels
+
+    channel_segs = seg.split_to_mono()
+    channel_segs = [filter_fn(channel_seg) for channel_seg in channel_segs]
+
+    out_data = seg.get_array_of_samples()
+    for channel_i, channel_seg in enumerate(channel_segs):
+        for sample_i, sample in enumerate(channel_seg.get_array_of_samples()):
+            index = (sample_i * n_channels) + channel_i
+            out_data[index] = sample
+
+    return seg._spawn(out_data)
+
+
+@register_pydub_effect
+def normalize(seg, headroom=0.1):
+    """
+    headroom is how close to the maximum volume to boost the signal up to (specified in dB)
+    """
+    peak_sample_val = seg.max
+    
+    # if the max is 0, this audio segment is silent, and can't be normalized
+    if peak_sample_val == 0:
+        return seg
+    
+    target_peak = seg.max_possible_amplitude * db_to_float(-headroom)
+
+    needed_boost = ratio_to_db(target_peak / peak_sample_val)
+    return seg.apply_gain(needed_boost)
+
+
+@register_pydub_effect
+def speedup(seg, playback_speed=1.5, chunk_size=150, crossfade=25):
+    # we will keep audio in 150ms chunks since one waveform at 20Hz is 50ms long
+    # (20 Hz is the lowest frequency audible to humans)
+
+    # portion of AUDIO TO KEEP. if playback speed is 1.25 we keep 80% (0.8) and
+    # discard 20% (0.2)
+    atk = 1.0 / playback_speed
+
+    if playback_speed < 2.0:
+        # throwing out more than half the audio - keep 50ms chunks
+        ms_to_remove_per_chunk = int(chunk_size * (1 - atk) / atk)
+    else:
+        # throwing out less than half the audio - throw out 50ms chunks
+        ms_to_remove_per_chunk = int(chunk_size)
+        chunk_size = int(atk * chunk_size / (1 - atk))
+
+    # the crossfade cannot be longer than the amount of audio we're removing
+    crossfade = min(crossfade, ms_to_remove_per_chunk - 1)
+
+    # DEBUG
+    #print("chunk: {0}, rm: {1}".format(chunk_size, ms_to_remove_per_chunk))
+
+    chunks = make_chunks(seg, chunk_size + ms_to_remove_per_chunk)
+    if len(chunks) < 2:
+        raise Exception("Could not speed up AudioSegment, it was too short {2:0.2f}s for the current settings:\n{0}ms chunks at {1:0.1f}x speedup".format(
+            chunk_size, playback_speed, seg.duration_seconds))
+
+    # we'll actually truncate a bit less than we calculated to make up for the
+    # crossfade between chunks
+    ms_to_remove_per_chunk -= crossfade
+
+    # we don't want to truncate the last chunk since it is not guaranteed to be
+    # the full chunk length
+    last_chunk = chunks[-1]
+    chunks = [chunk[:-ms_to_remove_per_chunk] for chunk in chunks[:-1]]
+
+    out = chunks[0]
+    for chunk in chunks[1:]:
+        out = out.append(chunk, crossfade=crossfade)
+
+    out += last_chunk
+    return out
+    
+
+@register_pydub_effect
+def strip_silence(seg, silence_len=1000, silence_thresh=-16, padding=100):
+    if padding > silence_len:
+        raise InvalidDuration("padding cannot be longer than silence_len")
+
+    chunks = split_on_silence(seg, silence_len, silence_thresh, padding)
+    crossfade = padding / 2
+
+    if not len(chunks):
+        return seg[0:0]
+
+    seg = chunks[0]
+    for chunk in chunks[1:]:
+        seg = seg.append(chunk, crossfade=crossfade)
+
+    return seg
+
+
+@register_pydub_effect
+def compress_dynamic_range(seg, threshold=-20.0, ratio=4.0, attack=5.0, release=50.0):
+    """
+    Keyword Arguments:
+        
+        threshold - default: -20.0
+            Threshold in dBFS. default of -20.0 means -20dB relative to the
+            maximum possible volume. 0dBFS is the maximum possible value so
+            all values for this argument sould be negative.
+
+        ratio - default: 4.0
+            Compression ratio. Audio louder than the threshold will be 
+            reduced to 1/ratio the volume. A ratio of 4.0 is equivalent to
+            a setting of 4:1 in a pro-audio compressor like the Waves C1.
+        
+        attack - default: 5.0
+            Attack in milliseconds. How long it should take for the compressor
+            to kick in once the audio has exceeded the threshold.
+
+        release - default: 50.0
+            Release in milliseconds. How long it should take for the compressor
+            to stop compressing after the audio has falled below the threshold.
+
+    
+    For an overview of Dynamic Range Compression, and more detailed explanation
+    of the related terminology, see: 
+
+        http://en.wikipedia.org/wiki/Dynamic_range_compression
+    """
+
+    thresh_rms = seg.max_possible_amplitude * db_to_float(threshold)
+    
+    look_frames = int(seg.frame_count(ms=attack))
+    def rms_at(frame_i):
+        return seg.get_sample_slice(frame_i - look_frames, frame_i).rms
+    def db_over_threshold(rms):
+        if rms == 0: return 0.0
+        db = ratio_to_db(rms / thresh_rms)
+        return max(db, 0)
+
+    output = []
+
+    # amount to reduce the volume of the audio by (in dB)
+    attenuation = 0.0
+    
+    attack_frames = seg.frame_count(ms=attack)
+    release_frames = seg.frame_count(ms=release)
+    for i in xrange(int(seg.frame_count())):
+        rms_now = rms_at(i)
+        
+        # with a ratio of 4.0 this means the volume will exceed the threshold by
+        # 1/4 the amount (of dB) that it would otherwise
+        max_attenuation = (1 - (1.0 / ratio)) * db_over_threshold(rms_now)
+        
+        attenuation_inc = max_attenuation / attack_frames
+        attenuation_dec = max_attenuation / release_frames
+        
+        if rms_now > thresh_rms and attenuation <= max_attenuation:
+            attenuation += attenuation_inc
+            attenuation = min(attenuation, max_attenuation)
+        else:
+            attenuation -= attenuation_dec
+            attenuation = max(attenuation, 0)
+        
+        frame = seg.get_frame(i)
+        if attenuation != 0.0:
+            frame = audioop.mul(frame,
+                                seg.sample_width,
+                                db_to_float(-attenuation))
+        
+        output.append(frame)
+    
+    return seg._spawn(data=b''.join(output))
+
+
+# Invert the phase of the signal.
+
+@register_pydub_effect
+
+def invert_phase(seg, channels=(1, 1)):
+    """
+    channels- specifies which channel (left or right) to reverse the phase of.
+    Note that mono AudioSegments will become stereo.
+    """
+    if channels == (1, 1):
+        inverted = audioop.mul(seg._data, seg.sample_width, -1.0)  
+        return seg._spawn(data=inverted)
+    
+    else:
+        if seg.channels == 2:
+            left, right = seg.split_to_mono()
+        else:
+            raise Exception("Can't implicitly convert an AudioSegment with " + str(seg.channels) + " channels to stereo.")
+            
+        if channels == (1, 0):    
+            left = left.invert_phase()
+        else:
+            right = right.invert_phase()
+        
+        return seg.from_mono_audiosegments(left, right)
+        
+
+
+# High and low pass filters based on implementation found on Stack Overflow:
+#   http://stackoverflow.com/questions/13882038/implementing-simple-high-and-low-pass-filters-in-c
+
+@register_pydub_effect
+def low_pass_filter(seg, cutoff):
+    """
+        cutoff - Frequency (in Hz) where higher frequency signal will begin to
+            be reduced by 6dB per octave (doubling in frequency) above this point
+    """
+    RC = 1.0 / (cutoff * 2 * math.pi)
+    dt = 1.0 / seg.frame_rate
+
+    alpha = dt / (RC + dt)
+    
+    original = seg.get_array_of_samples()
+    filteredArray = array.array(seg.array_type, original)
+    
+    frame_count = int(seg.frame_count())
+
+    last_val = [0] * seg.channels
+    for i in range(seg.channels):
+        last_val[i] = filteredArray[i] = original[i]
+
+    for i in range(1, frame_count):
+        for j in range(seg.channels):
+            offset = (i * seg.channels) + j
+            last_val[j] = last_val[j] + (alpha * (original[offset] - last_val[j]))
+            filteredArray[offset] = int(last_val[j])
+
+    return seg._spawn(data=filteredArray)
+
+
+@register_pydub_effect
+def high_pass_filter(seg, cutoff):
+    """
+        cutoff - Frequency (in Hz) where lower frequency signal will begin to
+            be reduced by 6dB per octave (doubling in frequency) below this point
+    """
+    RC = 1.0 / (cutoff * 2 * math.pi)
+    dt = 1.0 / seg.frame_rate
+
+    alpha = RC / (RC + dt)
+
+    minval, maxval = get_min_max_value(seg.sample_width * 8)
+    
+    original = seg.get_array_of_samples()
+    filteredArray = array.array(seg.array_type, original)
+    
+    frame_count = int(seg.frame_count())
+
+    last_val = [0] * seg.channels
+    for i in range(seg.channels):
+        last_val[i] = filteredArray[i] = original[i]
+
+    for i in range(1, frame_count):
+        for j in range(seg.channels):
+            offset = (i * seg.channels) + j
+            offset_minus_1 = ((i-1) * seg.channels) + j
+
+            last_val[j] = alpha * (last_val[j] + original[offset] - original[offset_minus_1])
+            filteredArray[offset] = int(min(max(last_val[j], minval), maxval))
+
+    return seg._spawn(data=filteredArray)
+    
+    
+@register_pydub_effect
+def pan(seg, pan_amount):
+    """
+    pan_amount should be between -1.0 (100% left) and +1.0 (100% right)
+    
+    When pan_amount == 0.0 the left/right balance is not changed.
+    
+    Panning does not alter the *perceived* loundness, but since loudness
+    is decreasing on one side, the other side needs to get louder to
+    compensate. When panned hard left, the left channel will be 3dB louder.
+    """
+    if not -1.0 <= pan_amount <= 1.0:
+        raise ValueError("pan_amount should be between -1.0 (100% left) and +1.0 (100% right)")
+    
+    max_boost_db = ratio_to_db(2.0)
+    boost_db = abs(pan_amount) * max_boost_db
+    
+    boost_factor = db_to_float(boost_db)
+    reduce_factor = db_to_float(max_boost_db) - boost_factor
+    
+    reduce_db = ratio_to_db(reduce_factor)
+    
+    # Cut boost in half (max boost== 3dB) - in reality 2 speakers
+    #   do not sum to a full 6 dB.
+    boost_db = boost_db / 2.0
+    
+    if pan_amount < 0:
+        return seg.apply_gain_stereo(boost_db, reduce_db)
+    else:
+        return seg.apply_gain_stereo(reduce_db, boost_db)
+        
+    
+@register_pydub_effect
+def apply_gain_stereo(seg, left_gain=0.0, right_gain=0.0):
+    """
+    left_gain - amount of gain to apply to the left channel (in dB)
+    right_gain - amount of gain to apply to the right channel (in dB)
+    
+    note: mono audio segments will be converted to stereo
+    """
+    if seg.channels == 1:
+        left = right = seg
+    elif seg.channels == 2:
+        left, right = seg.split_to_mono()
+    
+    l_mult_factor = db_to_float(left_gain)
+    r_mult_factor = db_to_float(right_gain)
+    
+    left_data = audioop.mul(left._data, left.sample_width, l_mult_factor)
+    left_data = audioop.tostereo(left_data, left.sample_width, 1, 0)
+    
+    right_data = audioop.mul(right._data, right.sample_width, r_mult_factor)
+    right_data = audioop.tostereo(right_data, right.sample_width, 0, 1)
+    
+    output = audioop.add(left_data, right_data, seg.sample_width)
+    
+    return seg._spawn(data=output,
+                overrides={'channels': 2,
+                           'frame_width': 2 * seg.sample_width})

app/lib/pydub/pydub/exceptions.py

@@ -0,0 +1,32 @@
+class PydubException(Exception):
+    """
+    Base class for any Pydub exception
+    """
+
+
+class TooManyMissingFrames(PydubException):
+    pass
+
+
+class InvalidDuration(PydubException):
+    pass
+
+
+class InvalidTag(PydubException):
+    pass
+
+
+class InvalidID3TagVersion(PydubException):
+    pass
+
+
+class CouldntDecodeError(PydubException):
+    pass
+
+
+class CouldntEncodeError(PydubException):
+    pass
+
+
+class MissingAudioParameter(PydubException):
+    pass

app/lib/pydub/pydub/generators.py

@@ -0,0 +1,142 @@
+"""
+Each generator will return float samples from -1.0 to 1.0, which can be 
+converted to actual audio with 8, 16, 24, or 32 bit depth using the
+SiganlGenerator.to_audio_segment() method (on any of it's subclasses).
+
+See Wikipedia's "waveform" page for info on some of the generators included 
+here: http://en.wikipedia.org/wiki/Waveform
+"""
+
+import math
+import array
+import itertools
+import random
+from .audio_segment import AudioSegment
+from .utils import (
+    db_to_float,
+    get_frame_width,
+    get_array_type,
+    get_min_max_value
+)
+
+
+
+class SignalGenerator(object):
+    def __init__(self, sample_rate=44100, bit_depth=16):
+        self.sample_rate = sample_rate
+        self.bit_depth = bit_depth
+
+    def to_audio_segment(self, duration=1000.0, volume=0.0):
+        """
+        Duration in milliseconds
+            (default: 1 second)
+        Volume in DB relative to maximum amplitude
+            (default 0.0 dBFS, which is the maximum value)
+        """
+        minval, maxval = get_min_max_value(self.bit_depth)
+        sample_width = get_frame_width(self.bit_depth)
+        array_type = get_array_type(self.bit_depth)
+
+        gain = db_to_float(volume)
+        sample_count = int(self.sample_rate * (duration / 1000.0))
+
+        sample_data = (int(val * maxval * gain) for val in self.generate())
+        sample_data = itertools.islice(sample_data, 0, sample_count)
+
+        data = array.array(array_type, sample_data)
+        
+        try:
+            data = data.tobytes()
+        except:
+            data = data.tostring()
+
+        return AudioSegment(data=data, metadata={
+            "channels": 1,
+            "sample_width": sample_width,
+            "frame_rate": self.sample_rate,
+            "frame_width": sample_width,
+        })
+
+    def generate(self):
+        raise NotImplementedError("SignalGenerator subclasses must implement the generate() method, and *should not* call the superclass implementation.")
+
+
+
+class Sine(SignalGenerator):
+    def __init__(self, freq, **kwargs):
+        super(Sine, self).__init__(**kwargs)
+        self.freq = freq
+
+    def generate(self):
+        sine_of = (self.freq * 2 * math.pi) / self.sample_rate
+        sample_n = 0
+        while True:
+            yield math.sin(sine_of * sample_n)
+            sample_n += 1
+
+
+
+class Pulse(SignalGenerator):
+    def __init__(self, freq, duty_cycle=0.5, **kwargs):
+        super(Pulse, self).__init__(**kwargs)
+        self.freq = freq
+        self.duty_cycle = duty_cycle
+
+    def generate(self):
+        sample_n = 0
+
+        # in samples
+        cycle_length = self.sample_rate / float(self.freq)
+        pulse_length = cycle_length * self.duty_cycle
+
+        while True:
+            if (sample_n % cycle_length) < pulse_length:
+                yield 1.0
+            else:
+                yield -1.0
+            sample_n += 1
+
+
+
+class Square(Pulse):
+    def __init__(self, freq, **kwargs):
+        kwargs['duty_cycle'] = 0.5
+        super(Square, self).__init__(freq, **kwargs)
+
+
+
+class Sawtooth(SignalGenerator):
+    def __init__(self, freq, duty_cycle=1.0, **kwargs):
+        super(Sawtooth, self).__init__(**kwargs)
+        self.freq = freq
+        self.duty_cycle = duty_cycle
+
+    def generate(self):
+        sample_n = 0
+
+        # in samples
+        cycle_length = self.sample_rate / float(self.freq)
+        midpoint = cycle_length * self.duty_cycle
+        ascend_length = midpoint
+        descend_length = cycle_length - ascend_length
+
+        while True:
+            cycle_position = sample_n % cycle_length
+            if cycle_position < midpoint:
+                yield (2 * cycle_position / ascend_length) - 1.0
+            else:
+                yield 1.0 - (2 * (cycle_position - midpoint) / descend_length)
+            sample_n += 1
+
+
+
+class Triangle(Sawtooth):
+    def __init__(self, freq, **kwargs):
+        kwargs['duty_cycle'] = 0.5
+        super(Triangle, self).__init__(freq, **kwargs)
+
+
+class WhiteNoise(SignalGenerator):
+    def generate(self):
+        while True:
+            yield (random.random() * 2) - 1.0

app/lib/pydub/pydub/logging_utils.py

@@ -0,0 +1,14 @@
+"""
+
+"""
+import logging
+
+converter_logger = logging.getLogger("pydub.converter")
+
+def log_conversion(conversion_command):
+    converter_logger.debug("subprocess.call(%s)", repr(conversion_command))
+
+def log_subprocess_output(output):
+    if output:
+        for line in output.rstrip().splitlines():
+            converter_logger.debug('subprocess output: %s', line.rstrip())

app/lib/pydub/pydub/playback.py

@@ -0,0 +1,71 @@
+"""
+Support for playing AudioSegments. Pyaudio will be used if it's installed,
+otherwise will fallback to ffplay. Pyaudio is a *much* nicer solution, but
+is tricky to install. See my notes on installing pyaudio in a virtualenv (on
+OSX 10.10): https://gist.github.com/jiaaro/9767512210a1d80a8a0d
+"""
+
+import subprocess
+from tempfile import NamedTemporaryFile
+from .utils import get_player_name, make_chunks
+
+def _play_with_ffplay(seg):
+    PLAYER = get_player_name()
+    with NamedTemporaryFile("w+b", suffix=".wav") as f:
+        seg.export(f.name, "wav")
+        subprocess.call([PLAYER, "-nodisp", "-autoexit", "-hide_banner", f.name])
+
+
+def _play_with_pyaudio(seg):
+    import pyaudio
+
+    p = pyaudio.PyAudio()
+    stream = p.open(format=p.get_format_from_width(seg.sample_width),
+                    channels=seg.channels,
+                    rate=seg.frame_rate,
+                    output=True)
+
+    # Just in case there were any exceptions/interrupts, we release the resource
+    # So as not to raise OSError: Device Unavailable should play() be used again
+    try:
+        # break audio into half-second chunks (to allows keyboard interrupts)
+        for chunk in make_chunks(seg, 500):
+            stream.write(chunk._data)
+    finally:
+        stream.stop_stream()
+        stream.close()
+
+        p.terminate()
+
+
+def _play_with_simpleaudio(seg):
+    import simpleaudio
+    return simpleaudio.play_buffer(
+        seg.raw_data,
+        num_channels=seg.channels,
+        bytes_per_sample=seg.sample_width,
+        sample_rate=seg.frame_rate
+    )
+
+
+def play(audio_segment):
+    try:
+        playback = _play_with_simpleaudio(audio_segment)
+        try:
+            playback.wait_done()
+        except KeyboardInterrupt:
+            playback.stop()
+    except ImportError:
+        pass
+    else:
+        return
+
+    try:
+        _play_with_pyaudio(audio_segment)
+        return
+    except ImportError:
+        pass
+    else:
+        return
+
+    _play_with_ffplay(audio_segment)

app/lib/pydub/pydub/pyaudioop.py

@@ -0,0 +1,553 @@
+try:
+    from __builtin__ import max as builtin_max
+    from __builtin__ import min as builtin_min
+except ImportError:
+    from builtins import max as builtin_max
+    from builtins import min as builtin_min
+import math
+import struct
+try:
+    from fractions import gcd
+except ImportError:  # Python 3.9+
+    from math import gcd
+from ctypes import create_string_buffer
+
+
+class error(Exception):
+    pass
+
+
+def _check_size(size):
+    if size != 1 and size != 2 and size != 4:
+        raise error("Size should be 1, 2 or 4")
+
+
+def _check_params(length, size):
+    _check_size(size)
+    if length % size != 0:
+        raise error("not a whole number of frames")
+
+
+def _sample_count(cp, size):
+    return len(cp) / size
+
+
+def _get_samples(cp, size, signed=True):
+    for i in range(_sample_count(cp, size)):
+        yield _get_sample(cp, size, i, signed)
+
+
+def _struct_format(size, signed):
+    if size == 1:
+        return "b" if signed else "B"
+    elif size == 2:
+        return "h" if signed else "H"
+    elif size == 4:
+        return "i" if signed else "I"
+
+
+def _get_sample(cp, size, i, signed=True):
+    fmt = _struct_format(size, signed)
+    start = i * size
+    end = start + size
+    return struct.unpack_from(fmt, buffer(cp)[start:end])[0]
+
+
+def _put_sample(cp, size, i, val, signed=True):
+    fmt = _struct_format(size, signed)
+    struct.pack_into(fmt, cp, i * size, val)
+
+
+def _get_maxval(size, signed=True):
+    if signed and size == 1:
+        return 0x7f
+    elif size == 1:
+        return 0xff
+    elif signed and size == 2:
+        return 0x7fff
+    elif size == 2:
+        return 0xffff
+    elif signed and size == 4:
+        return 0x7fffffff
+    elif size == 4:
+        return 0xffffffff
+
+
+def _get_minval(size, signed=True):
+    if not signed:
+        return 0
+    elif size == 1:
+        return -0x80
+    elif size == 2:
+        return -0x8000
+    elif size == 4:
+        return -0x80000000
+
+
+def _get_clipfn(size, signed=True):
+    maxval = _get_maxval(size, signed)
+    minval = _get_minval(size, signed)
+    return lambda val: builtin_max(min(val, maxval), minval)
+
+
+def _overflow(val, size, signed=True):
+    minval = _get_minval(size, signed)
+    maxval = _get_maxval(size, signed)
+    if minval <= val <= maxval:
+        return val
+
+    bits = size * 8
+    if signed:
+        offset = 2**(bits-1)
+        return ((val + offset) % (2**bits)) - offset
+    else:
+        return val % (2**bits)
+
+
+def getsample(cp, size, i):
+    _check_params(len(cp), size)
+    if not (0 <= i < len(cp) / size):
+        raise error("Index out of range")
+    return _get_sample(cp, size, i)
+
+
+def max(cp, size):
+    _check_params(len(cp), size)
+
+    if len(cp) == 0:
+        return 0
+
+    return builtin_max(abs(sample) for sample in _get_samples(cp, size))
+
+
+def minmax(cp, size):
+    _check_params(len(cp), size)
+
+    max_sample, min_sample = 0, 0
+    for sample in _get_samples(cp, size):
+        max_sample = builtin_max(sample, max_sample)
+        min_sample = builtin_min(sample, min_sample)
+
+    return min_sample, max_sample
+
+
+def avg(cp, size):
+    _check_params(len(cp), size)
+    sample_count = _sample_count(cp, size)
+    if sample_count == 0:
+        return 0
+    return sum(_get_samples(cp, size)) / sample_count
+
+
+def rms(cp, size):
+    _check_params(len(cp), size)
+
+    sample_count = _sample_count(cp, size)
+    if sample_count == 0:
+        return 0
+
+    sum_squares = sum(sample**2 for sample in _get_samples(cp, size))
+    return int(math.sqrt(sum_squares / sample_count))
+
+
+def _sum2(cp1, cp2, length):
+    size = 2
+    total = 0
+    for i in range(length):
+        total += getsample(cp1, size, i) * getsample(cp2, size, i)
+    return total
+
+
+def findfit(cp1, cp2):
+    size = 2
+
+    if len(cp1) % 2 != 0 or len(cp2) % 2 != 0:
+        raise error("Strings should be even-sized")
+
+    if len(cp1) < len(cp2):
+        raise error("First sample should be longer")
+
+    len1 = _sample_count(cp1, size)
+    len2 = _sample_count(cp2, size)
+
+    sum_ri_2 = _sum2(cp2, cp2, len2)
+    sum_aij_2 = _sum2(cp1, cp1, len2)
+    sum_aij_ri = _sum2(cp1, cp2, len2)
+
+    result = (sum_ri_2 * sum_aij_2 - sum_aij_ri * sum_aij_ri) / sum_aij_2
+
+    best_result = result
+    best_i = 0
+
+    for i in range(1, len1 - len2 + 1):
+        aj_m1 = _get_sample(cp1, size, i - 1)
+        aj_lm1 = _get_sample(cp1, size, i + len2 - 1)
+
+        sum_aij_2 += aj_lm1**2 - aj_m1**2
+        sum_aij_ri = _sum2(buffer(cp1)[i*size:], cp2, len2)
+
+        result = (sum_ri_2 * sum_aij_2 - sum_aij_ri * sum_aij_ri) / sum_aij_2
+
+        if result < best_result:
+            best_result = result
+            best_i = i
+
+    factor = _sum2(buffer(cp1)[best_i*size:], cp2, len2) / sum_ri_2
+
+    return best_i, factor
+
+
+def findfactor(cp1, cp2):
+    size = 2
+
+    if len(cp1) % 2 != 0:
+        raise error("Strings should be even-sized")
+
+    if len(cp1) != len(cp2):
+        raise error("Samples should be same size")
+
+    sample_count = _sample_count(cp1, size)
+
+    sum_ri_2 = _sum2(cp2, cp2, sample_count)
+    sum_aij_ri = _sum2(cp1, cp2, sample_count)
+
+    return sum_aij_ri / sum_ri_2
+
+
+def findmax(cp, len2):
+    size = 2
+    sample_count = _sample_count(cp, size)
+
+    if len(cp) % 2 != 0:
+        raise error("Strings should be even-sized")
+
+    if len2 < 0 or sample_count < len2:
+        raise error("Input sample should be longer")
+
+    if sample_count == 0:
+        return 0
+
+    result = _sum2(cp, cp, len2)
+    best_result = result
+    best_i = 0
+
+    for i in range(1, sample_count - len2 + 1):
+        sample_leaving_window = getsample(cp, size, i - 1)
+        sample_entering_window = getsample(cp, size, i + len2 - 1)
+
+        result -= sample_leaving_window**2
+        result += sample_entering_window**2
+
+        if result > best_result:
+            best_result = result
+            best_i = i
+
+    return best_i
+
+
+def avgpp(cp, size):
+    _check_params(len(cp), size)
+    sample_count = _sample_count(cp, size)
+
+    prevextremevalid = False
+    prevextreme = None
+    avg = 0
+    nextreme = 0
+
+    prevval = getsample(cp, size, 0)
+    val = getsample(cp, size, 1)
+
+    prevdiff = val - prevval
+
+    for i in range(1, sample_count):
+        val = getsample(cp, size, i)
+        diff = val - prevval
+
+        if diff * prevdiff < 0:
+            if prevextremevalid:
+                avg += abs(prevval - prevextreme)
+                nextreme += 1
+
+            prevextremevalid = True
+            prevextreme = prevval
+
+        prevval = val
+        if diff != 0:
+            prevdiff = diff
+
+    if nextreme == 0:
+        return 0
+
+    return avg / nextreme
+
+
+def maxpp(cp, size):
+    _check_params(len(cp), size)
+    sample_count = _sample_count(cp, size)
+
+    prevextremevalid = False
+    prevextreme = None
+    max = 0
+
+    prevval = getsample(cp, size, 0)
+    val = getsample(cp, size, 1)
+
+    prevdiff = val - prevval
+
+    for i in range(1, sample_count):
+        val = getsample(cp, size, i)
+        diff = val - prevval
+
+        if diff * prevdiff < 0:
+            if prevextremevalid:
+                extremediff = abs(prevval - prevextreme)
+                if extremediff > max:
+                    max = extremediff
+            prevextremevalid = True
+            prevextreme = prevval
+
+        prevval = val
+        if diff != 0:
+            prevdiff = diff
+
+    return max
+
+
+def cross(cp, size):
+    _check_params(len(cp), size)
+
+    crossings = 0
+    last_sample = 0
+    for sample in _get_samples(cp, size):
+        if sample <= 0 < last_sample or sample >= 0 > last_sample:
+            crossings += 1
+        last_sample = sample
+
+    return crossings
+
+
+def mul(cp, size, factor):
+    _check_params(len(cp), size)
+    clip = _get_clipfn(size)
+
+    result = create_string_buffer(len(cp))
+
+    for i, sample in enumerate(_get_samples(cp, size)):
+        sample = clip(int(sample * factor))
+        _put_sample(result, size, i, sample)
+
+    return result.raw
+
+
+def tomono(cp, size, fac1, fac2):
+    _check_params(len(cp), size)
+    clip = _get_clipfn(size)
+
+    sample_count = _sample_count(cp, size)
+
+    result = create_string_buffer(len(cp) / 2)
+
+    for i in range(0, sample_count, 2):
+        l_sample = getsample(cp, size, i)
+        r_sample = getsample(cp, size, i + 1)
+
+        sample = (l_sample * fac1) + (r_sample * fac2)
+        sample = clip(sample)
+
+        _put_sample(result, size, i / 2, sample)
+
+    return result.raw
+
+
+def tostereo(cp, size, fac1, fac2):
+    _check_params(len(cp), size)
+
+    sample_count = _sample_count(cp, size)
+
+    result = create_string_buffer(len(cp) * 2)
+    clip = _get_clipfn(size)
+
+    for i in range(sample_count):
+        sample = _get_sample(cp, size, i)
+
+        l_sample = clip(sample * fac1)
+        r_sample = clip(sample * fac2)
+
+        _put_sample(result, size, i * 2, l_sample)
+        _put_sample(result, size, i * 2 + 1, r_sample)
+
+    return result.raw
+
+
+def add(cp1, cp2, size):
+    _check_params(len(cp1), size)
+
+    if len(cp1) != len(cp2):
+        raise error("Lengths should be the same")
+
+    clip = _get_clipfn(size)
+    sample_count = _sample_count(cp1, size)
+    result = create_string_buffer(len(cp1))
+
+    for i in range(sample_count):
+        sample1 = getsample(cp1, size, i)
+        sample2 = getsample(cp2, size, i)
+
+        sample = clip(sample1 + sample2)
+
+        _put_sample(result, size, i, sample)
+
+    return result.raw
+
+
+def bias(cp, size, bias):
+    _check_params(len(cp), size)
+
+    result = create_string_buffer(len(cp))
+
+    for i, sample in enumerate(_get_samples(cp, size)):
+        sample = _overflow(sample + bias, size)
+        _put_sample(result, size, i, sample)
+
+    return result.raw
+
+
+def reverse(cp, size):
+    _check_params(len(cp), size)
+    sample_count = _sample_count(cp, size)
+
+    result = create_string_buffer(len(cp))
+    for i, sample in enumerate(_get_samples(cp, size)):
+        _put_sample(result, size, sample_count - i - 1, sample)
+
+    return result.raw
+
+
+def lin2lin(cp, size, size2):
+    _check_params(len(cp), size)
+    _check_size(size2)
+
+    if size == size2:
+        return cp
+
+    new_len = (len(cp) / size) * size2
+
+    result = create_string_buffer(new_len)
+
+    for i in range(_sample_count(cp, size)):
+        sample = _get_sample(cp, size, i)
+        if size < size2:
+            sample = sample << (4 * size2 / size)
+        elif size > size2:
+            sample = sample >> (4 * size / size2)
+
+        sample = _overflow(sample, size2)
+
+        _put_sample(result, size2, i, sample)
+
+    return result.raw
+
+
+def ratecv(cp, size, nchannels, inrate, outrate, state, weightA=1, weightB=0):
+    _check_params(len(cp), size)
+    if nchannels < 1:
+        raise error("# of channels should be >= 1")
+
+    bytes_per_frame = size * nchannels
+    frame_count = len(cp) / bytes_per_frame
+
+    if bytes_per_frame / nchannels != size:
+        raise OverflowError("width * nchannels too big for a C int")
+
+    if weightA < 1 or weightB < 0:
+        raise error("weightA should be >= 1, weightB should be >= 0")
+
+    if len(cp) % bytes_per_frame != 0:
+        raise error("not a whole number of frames")
+
+    if inrate <= 0 or outrate <= 0:
+        raise error("sampling rate not > 0")
+
+    d = gcd(inrate, outrate)
+    inrate /= d
+    outrate /= d
+
+    prev_i = [0] * nchannels
+    cur_i = [0] * nchannels
+
+    if state is None:
+        d = -outrate
+    else:
+        d, samps = state
+
+        if len(samps) != nchannels:
+            raise error("illegal state argument")
+
+        prev_i, cur_i = zip(*samps)
+        prev_i, cur_i = list(prev_i), list(cur_i)
+
+    q = frame_count / inrate
+    ceiling = (q + 1) * outrate
+    nbytes = ceiling * bytes_per_frame
+
+    result = create_string_buffer(nbytes)
+
+    samples = _get_samples(cp, size)
+    out_i = 0
+    while True:
+        while d < 0:
+            if frame_count == 0:
+                samps = zip(prev_i, cur_i)
+                retval = result.raw
+
+                # slice off extra bytes
+                trim_index = (out_i * bytes_per_frame) - len(retval)
+                retval = buffer(retval)[:trim_index]
+
+                return (retval, (d, tuple(samps)))
+
+            for chan in range(nchannels):
+                prev_i[chan] = cur_i[chan]
+                cur_i[chan] = samples.next()
+
+                cur_i[chan] = (
+                    (weightA * cur_i[chan] + weightB * prev_i[chan])
+                    / (weightA + weightB)
+                )
+
+            frame_count -= 1
+            d += outrate
+
+        while d >= 0:
+            for chan in range(nchannels):
+                cur_o = (
+                    (prev_i[chan] * d + cur_i[chan] * (outrate - d))
+                    / outrate
+                )
+                _put_sample(result, size, out_i, _overflow(cur_o, size))
+                out_i += 1
+            d -= inrate
+
+
+def lin2ulaw(cp, size):
+    raise NotImplementedError()
+
+
+def ulaw2lin(cp, size):
+    raise NotImplementedError()
+
+
+def lin2alaw(cp, size):
+    raise NotImplementedError()
+
+
+def alaw2lin(cp, size):
+    raise NotImplementedError()
+
+
+def lin2adpcm(cp, size, state):
+    raise NotImplementedError()
+
+
+def adpcm2lin(cp, size, state):
+    raise NotImplementedError()

app/lib/pydub/pydub/scipy_effects.py

@@ -0,0 +1,175 @@
+"""
+This module provides scipy versions of high_pass_filter, and low_pass_filter
+as well as an additional band_pass_filter.
+
+Of course, you will need to install scipy for these to work.
+
+When this module is imported the high and low pass filters from this module
+will be used when calling audio_segment.high_pass_filter() and
+audio_segment.high_pass_filter() instead of the slower, less powerful versions
+provided by pydub.effects.
+"""
+from scipy.signal import butter, sosfilt
+from .utils import (register_pydub_effect,stereo_to_ms,ms_to_stereo)
+
+
+def _mk_butter_filter(freq, type, order):
+    """
+    Args:
+        freq: The cutoff frequency for highpass and lowpass filters. For
+            band filters, a list of [low_cutoff, high_cutoff]
+        type: "lowpass", "highpass", or "band"
+        order: nth order butterworth filter (default: 5th order). The
+            attenuation is -6dB/octave beyond the cutoff frequency (for 1st
+            order). A Higher order filter will have more attenuation, each level
+            adding an additional -6dB (so a 3rd order butterworth filter would
+            be -18dB/octave).
+
+    Returns:
+        function which can filter a mono audio segment
+
+    """
+    def filter_fn(seg):
+        assert seg.channels == 1
+
+        nyq = 0.5 * seg.frame_rate
+        try:
+            freqs = [f / nyq for f in freq]
+        except TypeError:
+            freqs = freq / nyq
+
+        sos = butter(order, freqs, btype=type, output='sos')
+        y = sosfilt(sos, seg.get_array_of_samples())
+
+        return seg._spawn(y.astype(seg.array_type))
+
+    return filter_fn
+
+
+@register_pydub_effect
+def band_pass_filter(seg, low_cutoff_freq, high_cutoff_freq, order=5):
+    filter_fn = _mk_butter_filter([low_cutoff_freq, high_cutoff_freq], 'band', order=order)
+    return seg.apply_mono_filter_to_each_channel(filter_fn)
+
+
+@register_pydub_effect
+def high_pass_filter(seg, cutoff_freq, order=5):
+    filter_fn = _mk_butter_filter(cutoff_freq, 'highpass', order=order)
+    return seg.apply_mono_filter_to_each_channel(filter_fn)
+
+
+@register_pydub_effect
+def low_pass_filter(seg, cutoff_freq, order=5):
+    filter_fn = _mk_butter_filter(cutoff_freq, 'lowpass', order=order)
+    return seg.apply_mono_filter_to_each_channel(filter_fn)
+
+
+@register_pydub_effect
+def _eq(seg, focus_freq, bandwidth=100, mode="peak", gain_dB=0, order=2):
+    """
+    Args:
+        focus_freq - middle frequency or known frequency of band (in Hz)
+        bandwidth - range of the equalizer band
+        mode - Mode of Equalization(Peak/Notch(Bell Curve),High Shelf, Low Shelf)
+        order - Rolloff factor(1 - 6dB/Octave 2 - 12dB/Octave)
+    
+    Returns:
+        Equalized/Filtered AudioSegment
+    """
+    filt_mode = ["peak", "low_shelf", "high_shelf"]
+    if mode not in filt_mode:
+        raise ValueError("Incorrect Mode Selection")
+        
+    if gain_dB >= 0:
+        if mode == "peak":
+            sec = band_pass_filter(seg, focus_freq - bandwidth/2, focus_freq + bandwidth/2, order = order)
+            seg = seg.overlay(sec - (3 - gain_dB))
+            return seg
+        
+        if mode == "low_shelf":
+            sec = low_pass_filter(seg, focus_freq, order=order)
+            seg = seg.overlay(sec - (3 - gain_dB))
+            return seg
+        
+        if mode == "high_shelf":
+            sec = high_pass_filter(seg, focus_freq, order=order)
+            seg = seg.overlay(sec - (3 - gain_dB))
+            return seg
+        
+    if gain_dB < 0:
+        if mode == "peak":
+            sec = high_pass_filter(seg, focus_freq - bandwidth/2, order=order)
+            seg = seg.overlay(sec - (3 + gain_dB)) + gain_dB
+            sec = low_pass_filter(seg, focus_freq + bandwidth/2, order=order)
+            seg = seg.overlay(sec - (3 + gain_dB)) + gain_dB
+            return seg
+        
+        if mode == "low_shelf":
+            sec = high_pass_filter(seg, focus_freq, order=order)
+            seg = seg.overlay(sec - (3 + gain_dB)) + gain_dB
+            return seg
+        
+        if mode=="high_shelf":
+            sec=low_pass_filter(seg, focus_freq, order=order)
+            seg=seg.overlay(sec - (3 + gain_dB)) +gain_dB
+            return seg
+        
+
+@register_pydub_effect
+def eq(seg, focus_freq, bandwidth=100, channel_mode="L+R", filter_mode="peak", gain_dB=0, order=2):
+    """
+    Args:
+        focus_freq - middle frequency or known frequency of band (in Hz)
+        bandwidth - range of the equalizer band
+        channel_mode - Select Channels to be affected by the filter.
+            L+R - Standard Stereo Filter
+            L - Only Left Channel is Filtered
+            R - Only Right Channel is Filtered
+            M+S - Blumlien Stereo Filter(Mid-Side)
+            M - Only Mid Channel is Filtered
+            S - Only Side Channel is Filtered
+            Mono Audio Segments are completely filtered.
+        filter_mode - Mode of Equalization(Peak/Notch(Bell Curve),High Shelf, Low Shelf)
+        order - Rolloff factor(1 - 6dB/Octave 2 - 12dB/Octave)
+    
+    Returns:
+        Equalized/Filtered AudioSegment
+    """
+    channel_modes = ["L+R", "M+S", "L", "R", "M", "S"]
+    if channel_mode not in channel_modes:
+        raise ValueError("Incorrect Channel Mode Selection")
+        
+    if seg.channels == 1:
+        return _eq(seg, focus_freq, bandwidth, filter_mode, gain_dB, order)
+        
+    if channel_mode == "L+R":
+        return _eq(seg, focus_freq, bandwidth, filter_mode, gain_dB, order)
+        
+    if channel_mode == "L":
+        seg = seg.split_to_mono()
+        seg = [_eq(seg[0], focus_freq, bandwidth, filter_mode, gain_dB, order), seg[1]]
+        return AudioSegment.from_mono_audio_segements(seg[0], seg[1])
+        
+    if channel_mode == "R":
+        seg = seg.split_to_mono()
+        seg = [seg[0], _eq(seg[1], focus_freq, bandwidth, filter_mode, gain_dB, order)]
+        return AudioSegment.from_mono_audio_segements(seg[0], seg[1])
+        
+    if channel_mode == "M+S":
+        seg = stereo_to_ms(seg)
+        seg = _eq(seg, focus_freq, bandwidth, filter_mode, gain_dB, order)
+        return ms_to_stereo(seg)
+        
+    if channel_mode == "M":
+        seg = stereo_to_ms(seg).split_to_mono()
+        seg = [_eq(seg[0], focus_freq, bandwidth, filter_mode, gain_dB, order), seg[1]]
+        seg = AudioSegment.from_mono_audio_segements(seg[0], seg[1])
+        return ms_to_stereo(seg)
+        
+    if channel_mode == "S":
+        seg = stereo_to_ms(seg).split_to_mono()
+        seg = [seg[0], _eq(seg[1], focus_freq, bandwidth, filter_mode, gain_dB, order)]
+        seg = AudioSegment.from_mono_audio_segements(seg[0], seg[1])
+        return ms_to_stereo(seg)
+
+

app/lib/pydub/pydub/silence.py

@@ -0,0 +1,182 @@
+"""
+Various functions for finding/manipulating silence in AudioSegments
+"""
+import itertools
+
+from .utils import db_to_float
+
+
+def detect_silence(audio_segment, min_silence_len=1000, silence_thresh=-16, seek_step=1):
+    """
+    Returns a list of all silent sections [start, end] in milliseconds of audio_segment.
+    Inverse of detect_nonsilent()
+
+    audio_segment - the segment to find silence in
+    min_silence_len - the minimum length for any silent section
+    silence_thresh - the upper bound for how quiet is silent in dFBS
+    seek_step - step size for interating over the segment in ms
+    """
+    seg_len = len(audio_segment)
+
+    # you can't have a silent portion of a sound that is longer than the sound
+    if seg_len < min_silence_len:
+        return []
+
+    # convert silence threshold to a float value (so we can compare it to rms)
+    silence_thresh = db_to_float(silence_thresh) * audio_segment.max_possible_amplitude
+
+    # find silence and add start and end indicies to the to_cut list
+    silence_starts = []
+
+    # check successive (1 sec by default) chunk of sound for silence
+    # try a chunk at every "seek step" (or every chunk for a seek step == 1)
+    last_slice_start = seg_len - min_silence_len
+    slice_starts = range(0, last_slice_start + 1, seek_step)
+
+    # guarantee last_slice_start is included in the range
+    # to make sure the last portion of the audio is searched
+    if last_slice_start % seek_step:
+        slice_starts = itertools.chain(slice_starts, [last_slice_start])
+
+    for i in slice_starts:
+        audio_slice = audio_segment[i:i + min_silence_len]
+        if audio_slice.rms <= silence_thresh:
+            silence_starts.append(i)
+
+    # short circuit when there is no silence
+    if not silence_starts:
+        return []
+
+    # combine the silence we detected into ranges (start ms - end ms)
+    silent_ranges = []
+
+    prev_i = silence_starts.pop(0)
+    current_range_start = prev_i
+
+    for silence_start_i in silence_starts:
+        continuous = (silence_start_i == prev_i + seek_step)
+
+        # sometimes two small blips are enough for one particular slice to be
+        # non-silent, despite the silence all running together. Just combine
+        # the two overlapping silent ranges.
+        silence_has_gap = silence_start_i > (prev_i + min_silence_len)
+
+        if not continuous and silence_has_gap:
+            silent_ranges.append([current_range_start,
+                                  prev_i + min_silence_len])
+            current_range_start = silence_start_i
+        prev_i = silence_start_i
+
+    silent_ranges.append([current_range_start,
+                          prev_i + min_silence_len])
+
+    return silent_ranges
+
+
+def detect_nonsilent(audio_segment, min_silence_len=1000, silence_thresh=-16, seek_step=1):
+    """
+    Returns a list of all nonsilent sections [start, end] in milliseconds of audio_segment.
+    Inverse of detect_silent()
+
+    audio_segment - the segment to find silence in
+    min_silence_len - the minimum length for any silent section
+    silence_thresh - the upper bound for how quiet is silent in dFBS
+    seek_step - step size for interating over the segment in ms
+    """
+    silent_ranges = detect_silence(audio_segment, min_silence_len, silence_thresh, seek_step)
+    len_seg = len(audio_segment)
+
+    # if there is no silence, the whole thing is nonsilent
+    if not silent_ranges:
+        return [[0, len_seg]]
+
+    # short circuit when the whole audio segment is silent
+    if silent_ranges[0][0] == 0 and silent_ranges[0][1] == len_seg:
+        return []
+
+    prev_end_i = 0
+    nonsilent_ranges = []
+    for start_i, end_i in silent_ranges:
+        nonsilent_ranges.append([prev_end_i, start_i])
+        prev_end_i = end_i
+
+    if end_i != len_seg:
+        nonsilent_ranges.append([prev_end_i, len_seg])
+
+    if nonsilent_ranges[0] == [0, 0]:
+        nonsilent_ranges.pop(0)
+
+    return nonsilent_ranges
+
+
+def split_on_silence(audio_segment, min_silence_len=1000, silence_thresh=-16, keep_silence=100,
+                     seek_step=1):
+    """
+    Returns list of audio segments from splitting audio_segment on silent sections
+
+    audio_segment - original pydub.AudioSegment() object
+
+    min_silence_len - (in ms) minimum length of a silence to be used for
+        a split. default: 1000ms
+
+    silence_thresh - (in dBFS) anything quieter than this will be
+        considered silence. default: -16dBFS
+
+    keep_silence - (in ms or True/False) leave some silence at the beginning
+        and end of the chunks. Keeps the sound from sounding like it
+        is abruptly cut off.
+        When the length of the silence is less than the keep_silence duration
+        it is split evenly between the preceding and following non-silent
+        segments.
+        If True is specified, all the silence is kept, if False none is kept.
+        default: 100ms
+
+    seek_step - step size for interating over the segment in ms
+    """
+
+    # from the itertools documentation
+    def pairwise(iterable):
+        "s -> (s0,s1), (s1,s2), (s2, s3), ..."
+        a, b = itertools.tee(iterable)
+        next(b, None)
+        return zip(a, b)
+
+    if isinstance(keep_silence, bool):
+        keep_silence = len(audio_segment) if keep_silence else 0
+
+    output_ranges = [
+        [ start - keep_silence, end + keep_silence ]
+        for (start,end)
+            in detect_nonsilent(audio_segment, min_silence_len, silence_thresh, seek_step)
+    ]
+
+    for range_i, range_ii in pairwise(output_ranges):
+        last_end = range_i[1]
+        next_start = range_ii[0]
+        if next_start < last_end:
+            range_i[1] = (last_end+next_start)//2
+            range_ii[0] = range_i[1]
+
+    return [
+        audio_segment[ max(start,0) : min(end,len(audio_segment)) ]
+        for start,end in output_ranges
+    ]
+
+
+def detect_leading_silence(sound, silence_threshold=-50.0, chunk_size=10):
+    """
+    Returns the millisecond/index that the leading silence ends.
+
+    audio_segment - the segment to find silence in
+    silence_threshold - the upper bound for how quiet is silent in dFBS
+    chunk_size - chunk size for interating over the segment in ms
+    """
+    trim_ms = 0 # ms
+    assert chunk_size > 0 # to avoid infinite loop
+    while sound[trim_ms:trim_ms+chunk_size].dBFS < silence_threshold and trim_ms < len(sound):
+        trim_ms += chunk_size
+
+    # if there is no end it should return the length of the segment
+    return min(trim_ms, len(sound))
+
+

app/lib/pydub/pydub/utils.py

@@ -0,0 +1,440 @@
+from __future__ import division
+from io import BufferedReader
+
+import json
+import os
+import re
+import sys
+from subprocess import Popen, PIPE
+from math import log, ceil
+from tempfile import TemporaryFile
+from warnings import warn
+from functools import wraps
+
+try:
+    import audioop
+except ImportError:
+    import pyaudioop as audioop
+
+if sys.version_info >= (3, 0):
+    basestring = str
+
+FRAME_WIDTHS = {
+    8: 1,
+    16: 2,
+    32: 4,
+}
+ARRAY_TYPES = {
+    8: "b",
+    16: "h",
+    32: "i",
+}
+ARRAY_RANGES = {
+    8: (-0x80, 0x7f),
+    16: (-0x8000, 0x7fff),
+    32: (-0x80000000, 0x7fffffff),
+}
+
+
+def get_frame_width(bit_depth):
+    return FRAME_WIDTHS[bit_depth]
+
+
+def get_array_type(bit_depth, signed=True):
+    t = ARRAY_TYPES[bit_depth]
+    if not signed:
+        t = t.upper()
+    return t
+
+
+def get_min_max_value(bit_depth):
+    return ARRAY_RANGES[bit_depth]
+
+
+def _fd_or_path_or_tempfile(fd, mode='w+b', tempfile=True):
+    close_fd = False
+    if fd is None and tempfile:
+        fd = TemporaryFile(mode=mode)
+        close_fd = True
+
+    if isinstance(fd, basestring):
+        fd = open(fd, mode=mode)
+        close_fd = True
+
+    if isinstance(fd, BufferedReader):
+        close_fd = True
+
+    try:
+        if isinstance(fd, os.PathLike):
+            fd = open(fd, mode=mode)
+            close_fd = True
+    except AttributeError:
+        # module os has no attribute PathLike, so we're on python < 3.6.
+        # The protocol we're trying to support doesn't exist, so just pass.
+        pass
+
+    return fd, close_fd
+
+
+def db_to_float(db, using_amplitude=True):
+    """
+    Converts the input db to a float, which represents the equivalent
+    ratio in power.
+    """
+    db = float(db)
+    if using_amplitude:
+        return 10 ** (db / 20)
+    else:  # using power
+        return 10 ** (db / 10)
+
+
+def ratio_to_db(ratio, val2=None, using_amplitude=True):
+    """
+    Converts the input float to db, which represents the equivalent
+    to the ratio in power represented by the multiplier passed in.
+    """
+    ratio = float(ratio)
+
+    # accept 2 values and use the ratio of val1 to val2
+    if val2 is not None:
+        ratio = ratio / val2
+
+    # special case for multiply-by-zero (convert to silence)
+    if ratio == 0:
+        return -float('inf')
+
+    if using_amplitude:
+        return 20 * log(ratio, 10)
+    else:  # using power
+        return 10 * log(ratio, 10)
+
+
+def register_pydub_effect(fn, name=None):
+    """
+    decorator for adding pydub effects to the AudioSegment objects.
+    example use:
+        @register_pydub_effect
+        def normalize(audio_segment):
+            ...
+    or you can specify a name:
+        @register_pydub_effect("normalize")
+        def normalize_audio_segment(audio_segment):
+            ...
+    """
+    if isinstance(fn, basestring):
+        name = fn
+        return lambda fn: register_pydub_effect(fn, name)
+
+    if name is None:
+        name = fn.__name__
+
+    from .audio_segment import AudioSegment
+    setattr(AudioSegment, name, fn)
+    return fn
+
+
+def make_chunks(audio_segment, chunk_length):
+    """
+    Breaks an AudioSegment into chunks that are <chunk_length> milliseconds
+    long.
+    if chunk_length is 50 then you'll get a list of 50 millisecond long audio
+    segments back (except the last one, which can be shorter)
+    """
+    number_of_chunks = ceil(len(audio_segment) / float(chunk_length))
+    return [audio_segment[i * chunk_length:(i + 1) * chunk_length]
+            for i in range(int(number_of_chunks))]
+
+
+def which(program):
+    """
+    Mimics behavior of UNIX which command.
+    """
+    # Add .exe program extension for windows support
+    if os.name == "nt" and not program.endswith(".exe"):
+        program += ".exe"
+
+    envdir_list = [os.curdir] + os.environ["PATH"].split(os.pathsep)
+
+    for envdir in envdir_list:
+        program_path = os.path.join(envdir, program)
+        if os.path.isfile(program_path) and os.access(program_path, os.X_OK):
+            return program_path
+
+
+def get_encoder_name():
+    """
+    Return enconder default application for system, either avconv or ffmpeg
+    """
+    if which("avconv"):
+        return "avconv"
+    elif which("ffmpeg"):
+        return "ffmpeg"
+    else:
+        # should raise exception
+        warn("Couldn't find ffmpeg or avconv - defaulting to ffmpeg, but may not work", RuntimeWarning)
+        return "ffmpeg"
+
+
+def get_player_name():
+    """
+    Return enconder default application for system, either avconv or ffmpeg
+    """
+    if which("avplay"):
+        return "avplay"
+    elif which("ffplay"):
+        return "ffplay"
+    else:
+        # should raise exception
+        warn("Couldn't find ffplay or avplay - defaulting to ffplay, but may not work", RuntimeWarning)
+        return "ffplay"
+
+
+def get_prober_name():
+    """
+    Return probe application, either avconv or ffmpeg
+    """
+    if which("avprobe"):
+        return "avprobe"
+    elif which("ffprobe"):
+        return "ffprobe"
+    else:
+        # should raise exception
+        warn("Couldn't find ffprobe or avprobe - defaulting to ffprobe, but may not work", RuntimeWarning)
+        return "ffprobe"
+
+
+def fsdecode(filename):
+    """Wrapper for os.fsdecode which was introduced in python 3.2 ."""
+
+    if sys.version_info >= (3, 2):
+        PathLikeTypes = (basestring, bytes)
+        if sys.version_info >= (3, 6):
+            PathLikeTypes += (os.PathLike,)
+        if isinstance(filename, PathLikeTypes):
+            return os.fsdecode(filename)
+    else:
+        if isinstance(filename, bytes):
+            return filename.decode(sys.getfilesystemencoding())
+        if isinstance(filename, basestring):
+            return filename
+
+    raise TypeError("type {0} not accepted by fsdecode".format(type(filename)))
+
+
+def get_extra_info(stderr):
+    """
+    avprobe sometimes gives more information on stderr than
+    on the json output. The information has to be extracted
+    from stderr of the format of:
+    '    Stream #0:0: Audio: flac, 88200 Hz, stereo, s32 (24 bit)'
+    or (macOS version):
+    '    Stream #0:0: Audio: vorbis'
+    '      44100 Hz, stereo, fltp, 320 kb/s'
+
+    :type stderr: str
+    :rtype: list of dict
+    """
+    extra_info = {}
+
+    re_stream = r'(?P<space_start> +)Stream #0[:\.](?P<stream_id>([0-9]+))(?P<content_0>.+)\n?(?! *Stream)((?P<space_end> +)(?P<content_1>.+))?'
+    for i in re.finditer(re_stream, stderr):
+        if i.group('space_end') is not None and len(i.group('space_start')) <= len(
+                i.group('space_end')):
+            content_line = ','.join([i.group('content_0'), i.group('content_1')])
+        else:
+            content_line = i.group('content_0')
+        tokens = [x.strip() for x in re.split('[:,]', content_line) if x]
+        extra_info[int(i.group('stream_id'))] = tokens
+    return extra_info
+
+
+def mediainfo_json(filepath, read_ahead_limit=-1):
+    """Return json dictionary with media info(codec, duration, size, bitrate...) from filepath
+    """
+    prober = get_prober_name()
+    command_args = [
+        "-v", "info",
+        "-show_format",
+        "-show_streams",
+    ]
+    try:
+        command_args += [fsdecode(filepath)]
+        stdin_parameter = None
+        stdin_data = None
+    except TypeError:
+        if prober == 'ffprobe':
+            command_args += ["-read_ahead_limit", str(read_ahead_limit),
+                             "cache:pipe:0"]
+        else:
+            command_args += ["-"]
+        stdin_parameter = PIPE
+        file, close_file = _fd_or_path_or_tempfile(filepath, 'rb', tempfile=False)
+        file.seek(0)
+        stdin_data = file.read()
+        if close_file:
+            file.close()
+
+    command = [prober, '-of', 'json'] + command_args
+    res = Popen(command, stdin=stdin_parameter, stdout=PIPE, stderr=PIPE)
+    output, stderr = res.communicate(input=stdin_data)
+    output = output.decode("utf-8", 'ignore')
+    stderr = stderr.decode("utf-8", 'ignore')
+
+    try:
+        info = json.loads(output)
+    except  json.decoder.JSONDecodeError:
+        # If ffprobe didn't give any information, just return it
+        # (for example, because the file doesn't exist)
+        return None
+    if not info:
+        return info
+
+    extra_info = get_extra_info(stderr)
+
+    audio_streams = [x for x in info['streams'] if x['codec_type'] == 'audio']
+    if len(audio_streams) == 0:
+        return info
+
+    # We just operate on the first audio stream in case there are more
+    stream = audio_streams[0]
+
+    def set_property(stream, prop, value):
+        if prop not in stream or stream[prop] == 0:
+            stream[prop] = value
+
+    for token in extra_info[stream['index']]:
+        m = re.match(r'([su]([0-9]{1,2})p?) \(([0-9]{1,2}) bit\)$', token)
+        m2 = re.match(r'([su]([0-9]{1,2})p?)( \(default\))?$', token)
+        if m:
+            set_property(stream, 'sample_fmt', m.group(1))
+            set_property(stream, 'bits_per_sample', int(m.group(2)))
+            set_property(stream, 'bits_per_raw_sample', int(m.group(3)))
+        elif m2:
+            set_property(stream, 'sample_fmt', m2.group(1))
+            set_property(stream, 'bits_per_sample', int(m2.group(2)))
+            set_property(stream, 'bits_per_raw_sample', int(m2.group(2)))
+        elif re.match(r'(flt)p?( \(default\))?$', token):
+            set_property(stream, 'sample_fmt', token)
+            set_property(stream, 'bits_per_sample', 32)
+            set_property(stream, 'bits_per_raw_sample', 32)
+        elif re.match(r'(dbl)p?( \(default\))?$', token):
+            set_property(stream, 'sample_fmt', token)
+            set_property(stream, 'bits_per_sample', 64)
+            set_property(stream, 'bits_per_raw_sample', 64)
+    return info
+
+
+def mediainfo(filepath):
+    """Return dictionary with media info(codec, duration, size, bitrate...) from filepath
+    """
+
+    prober = get_prober_name()
+    command_args = [
+        "-v", "quiet",
+        "-show_format",
+        "-show_streams",
+        filepath
+    ]
+
+    command = [prober, '-of', 'old'] + command_args
+    res = Popen(command, stdout=PIPE)
+    output = res.communicate()[0].decode("utf-8")
+
+    if res.returncode != 0:
+        command = [prober] + command_args
+        output = Popen(command, stdout=PIPE).communicate()[0].decode("utf-8")
+
+    rgx = re.compile(r"(?:(?P<inner_dict>.*?):)?(?P<key>.*?)\=(?P<value>.*?)$")
+    info = {}
+
+    if sys.platform == 'win32':
+        output = output.replace("\r", "")
+
+    for line in output.split("\n"):
+        # print(line)
+        mobj = rgx.match(line)
+
+        if mobj:
+            # print(mobj.groups())
+            inner_dict, key, value = mobj.groups()
+
+            if inner_dict:
+                try:
+                    info[inner_dict]
+                except KeyError:
+                    info[inner_dict] = {}
+                info[inner_dict][key] = value
+            else:
+                info[key] = value
+
+    return info
+
+
+def cache_codecs(function):
+    cache = {}
+
+    @wraps(function)
+    def wrapper():
+        try:
+            return cache[0]
+        except:
+            cache[0] = function()
+            return cache[0]
+
+    return wrapper
+
+
+@cache_codecs
+def get_supported_codecs():
+    encoder = get_encoder_name()
+    command = [encoder, "-codecs"]
+    res = Popen(command, stdout=PIPE, stderr=PIPE)
+    output = res.communicate()[0].decode("utf-8")
+    if res.returncode != 0:
+        return []
+
+    if sys.platform == 'win32':
+        output = output.replace("\r", "")
+
+
+    rgx = re.compile(r"^([D.][E.][AVS.][I.][L.][S.]) (\w*) +(.*)")
+    decoders = set()
+    encoders = set()
+    for line in output.split('\n'):
+        match = rgx.match(line.strip())
+        if not match:
+            continue
+        flags, codec, name = match.groups()
+
+        if flags[0] == 'D':
+            decoders.add(codec)
+
+        if flags[1] == 'E':
+            encoders.add(codec)
+
+    return (decoders, encoders)
+
+
+def get_supported_decoders():
+    return get_supported_codecs()[0]
+
+
+def get_supported_encoders():
+    return get_supported_codecs()[1]
+
+def stereo_to_ms(audio_segment):
+	'''
+	Left-Right -> Mid-Side
+	'''
+	channel = audio_segment.split_to_mono()
+	channel = [channel[0].overlay(channel[1]), channel[0].overlay(channel[1].invert_phase())]
+	return AudioSegment.from_mono_audiosegments(channel[0], channel[1])
+
+def ms_to_stereo(audio_segment):
+	'''
+	Mid-Side -> Left-Right
+	'''
+	channel = audio_segment.split_to_mono()
+	channel = [channel[0].overlay(channel[1]) - 3, channel[0].overlay(channel[1].invert_phase()) - 3]
+	return AudioSegment.from_mono_audiosegments(channel[0], channel[1])
+

app/lib/pydub/setup.cfg

@@ -0,0 +1,5 @@
+[wheel]
+universal = 1
+
+[pep8]
+max-line-length = 100

app/lib/pydub/setup.py

@@ -0,0 +1,42 @@
+__doc__ = """
+Manipulate audio with an simple and easy high level interface.
+
+See the README file for details, usage info, and a list of gotchas.
+"""
+
+from setuptools import setup
+
+setup(
+    name='pydub',
+    version='0.25.1',
+    author='James Robert',
+    author_email='jiaaro@gmail.com',
+    description='Manipulate audio with an simple and easy high level interface',
+    license='MIT',
+    keywords='audio sound high-level',
+    url='http://pydub.com',
+    packages=['pydub'],
+    long_description=__doc__,
+    classifiers=[
+        'Development Status :: 5 - Production/Stable',
+        'License :: OSI Approved :: MIT License',
+        'Programming Language :: Python',
+        'Programming Language :: Python :: 2',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
+        'Intended Audience :: Developers',
+        'Operating System :: OS Independent',
+        "Topic :: Multimedia :: Sound/Audio",
+        "Topic :: Multimedia :: Sound/Audio :: Analysis",
+        "Topic :: Multimedia :: Sound/Audio :: Conversion",
+        "Topic :: Multimedia :: Sound/Audio :: Editors",
+        "Topic :: Multimedia :: Sound/Audio :: Mixers",
+        "Topic :: Software Development :: Libraries",
+        'Topic :: Utilities',
+    ]
+)

app/lib/trackslib.py

@@ -3,10 +3,14 @@ This library contains all the functions related to tracks.
 """
 import os
 
+from app.lib.pydub.pydub import AudioSegment
+from app.lib.pydub.pydub.silence import detect_leading_silence, detect_silence
 
 from app.db.sqlite.tracks import SQLiteTrackMethods as tdb
 from app.store.tracks import TrackStore
 from app.utils.progressbar import tqdm
+from app.utils.threading import ThreadWithReturnValue
+
 
 def validate_tracks() -> None:
     """
@@ -16,3 +20,66 @@ def validate_tracks() -> None:
         if not os.path.exists(track.filepath):
             TrackStore.remove_track_obj(track)
             tdb.remove_tracks_by_filepaths(track.filepath)
+
+
+def get_leading_silence_end(filepath: str):
+    """
+    Returns the leading silence of a track.
+    """
+    format = filepath.split(".")[-1]
+    audio = AudioSegment.from_file(filepath, format=format)
+    silence = detect_leading_silence(audio, silence_threshold=-40.0, chunk_size=10)
+
+    return silence if silence > 1000 else 0
+
+
+def get_trailing_silence_start(filepath: str):
+    """
+    Returns the trailing silence of a track.
+    """
+    format = filepath.split(".")[-1]
+    audio = AudioSegment.from_file(filepath, format=format)
+    duration = len(audio)
+
+    audio = audio[-30000:] if len(audio) > 30000 else audio
+    silence_groups = detect_silence(audio, silence_thresh=-40.0, seek_step=10)
+
+    if len(silence_groups) == 0:
+        return duration
+
+    silence_group = silence_groups[-1]
+    is_ok = silence_group[1] == len(audio)
+
+    if is_ok:
+        return duration - (silence_group[1] - silence_group[0])
+
+    return duration
+
+
+def get_silence_paddings(ending_file: str, starting_file: str):
+    """
+    Returns the ending silence of a track and the starting silence of the next.
+    """
+    silence = {"start": 0, "end": 0}
+    ending_thread = None
+    starting_thread = None
+
+    if os.path.exists(ending_file):
+        ending_thread = ThreadWithReturnValue(
+            target=get_trailing_silence_start, args=(ending_file,)
+        )
+        ending_thread.start()
+
+    if os.path.exists(starting_file):
+        starting_thread = ThreadWithReturnValue(
+            target=get_leading_silence_end, args=(starting_file,)
+        )
+        starting_thread.start()
+
+    if ending_thread:
+        silence["end"] = ending_thread.join()
+
+    if starting_thread:
+        silence["start"] = starting_thread.join()
+
+    return silence

app/models/album.py

@@ -118,7 +118,7 @@ class Album:
         """
         Checks if the album is a compilation.
         """
-        artists = [a.name for a in self.albumartists]  # type: ignore
+        artists = [a.name for a in self.albumartists]
         artists = "".join(artists).lower()
 
         if "various artists" in artists:
@@ -136,6 +136,8 @@ class Album:
             "great hits",
             "biggest hits",
             "the hits",
+            "the ultimate",
+            "compilation"
         }
 
         for substring in substrings:

app/utils/threading.py

@@ -10,3 +10,25 @@ def background(func):
         threading.Thread(target=func, args=a, kwargs=kw).start()
 
     return background_func
+
+
+class ThreadWithReturnValue(threading.Thread):
+    """
+    A thread class that returns a value on join.
+
+    Credit: https://stackoverflow.com/a/6894023
+    """
+
+    def __init__(
+        self, group=None, target=None, name=None, args=(), kwargs={}, Verbose=None
+    ):
+        threading.Thread.__init__(self, group, target, name, args, kwargs)
+        self._return = None
+
+    def run(self):
+        if self._target is not None:
+            self._return = self._target(*self._args, **self._kwargs)
+
+    def join(self, *args):
+        threading.Thread.join(self, *args)
+        return self._return