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Unable to Flush the Audio Resampler

Created by: khwong-c

Overview

The Audio Resampler Cannot be flushed with

Expected behavior

I expect the resampler can be reused and resample audio files with different input sampling rates, by applying a flush. resampler.resample(None).

Actual behavior

The resampler crashed right at the flush. File "/home/khwong/projects/audio_feature_extraction/audio_utils/audio_input.py", line 38, in post_process return self.resampler.resample(audio)[0] File "av/audio/resampler.pyx", line 34, in av.audio.resampler.AudioResampler.resample File "av/audio/resampler.pyx", line 101, in av.audio.resampler.AudioResampler.resample File "av/filter/graph.pyx", line 211, in av.filter.graph.Graph.push File "av/filter/context.pyx", line 89, in av.filter.context.FilterContext.push File "av/error.pyx", line 336, in av.error.err_check av.error.ValueError: [Errno 22] Invalid argument

Build report:

It is a release from PyAV v10.0.0.

Investigation

Try not to flush the resampler by resample(None) The code is able to run until an audio file with a different sampling rate is loaded.

Reproduction

class BatchAudioLoader:
        def __init__(self,
                 sample_rate=16000, layout='mono',
                 output_format='flt', output_planar=False
                 ):
        self._output_format = f'{output_format}{"p" if output_planar else ""}'
        self.resampler = av.audio.resampler.AudioResampler(self._output_format, layout, sample_rate)

    def post_process(self, audio):
        self.resampler.resample(None)
        return self.resampler.resample(audio)[0]

    def load(self, filename):
        buffer = av.audio.fifo.AudioFifo()
        with av.open(filename) as source:
            for frame in source.decode(source.streams.audio[0]):
                buffer.write(frame)
        whole_audio = buffer.read(0)
        if isinstance(whole_audio, list):
            whole_audio = whole_audio[0]
        whole_audio = self.post_process(whole_audio)
        sample_rate = whole_audio.sample_rate
        audio_arr = whole_audio.to_ndarray(format=self._output_format)
        return audio_arr, sample_rate

loader = BatchAudioLoader(sample_rate=16000)
loader.load('file1')
loader.load('file2')

Versions

Python 3.10

  • OS: Ubuntu Linux 20.04
  • PyAV runtime:
PyAV v10.0.0
library configuration: --disable-static --enable-shared --libdir=/tmp/vendor/lib --prefix=/tmp/vendor --disable-alsa --disable-doc --disable-mediafoundation --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-lzma --enable-version3 --enable-zlib
library license: GPL version 3 or later
libavcodec     59. 37.100
libavdevice    59.  7.100
libavfilter     8. 44.100
libavformat    59. 27.100
libavutil      57. 28.100
libswresample   4.  7.100
libswscale      6.  7.100

Research

I have done the following:

Additional context