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Mp3Compression

Added in v0.12.0

Compress the audio using an MP3 encoder to lower the audio quality. This may help machine learning models deal with compressed, low-quality audio.

This transform depends on either lameenc or pydub/ffmpeg.

Note that bitrates below 32 kbps are only supported for low sample rates (up to 24000 Hz).

Note: When using the "lameenc" backend, the output may be slightly longer than the input due to the fact that the LAME encoder inserts some silence at the beginning of the audio.

Warning: This transform writes to disk, so it may be slow.

Mp3Compression API

min_bitrate: int • unit: kbps • range: [8, max_bitrate]
Default: 8. Minimum bitrate in kbps
max_bitrate: int • unit: kbps • range: [min_bitrate, 320]
Default: 64. Maximum bitrate in kbps
backend: str • choices: "pydub", "lameenc"

Default: "pydub".

  • "pydub": May use ffmpeg under the hood. Pro: Seems to avoid introducing latency in the output. Con: Slightly slower than "lameenc".
  • "lameenc": Pro: With this backend you can set the quality parameter in addition to the bitrate (although this parameter is not exposed in the audiomentations API yet). Con: Seems to introduce some silence at the start of the audio.
p: float • range: [0.0, 1.0]
Default: 0.5. The probability of applying this transform.