Interpreting ffmpeg output in Python

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I started working in FFmpeg and I want to create a list that will contain start and end timestamps of silence intervals. I did print out these intervals using the FFmpeg but I need to format that output so it looks a bit more readable, so that is why I want to create a list out of it and then print it using a custom function. I know that I should go with regex here but I am not sure how should I write it nor how should I read the FFmpeg console output. My function for silence detection looks like:

def detect_silence_ffmpeg():
    command = r"ffmpeg -i audio.wav -af silencedetect=n=-40dB:d=0.5 -f null - "
    subprocess.call(command, shell=True)

And the output of this function on a 7 second long sample video is:

ffmpeg version git-2020-06-03-b6d7c4c Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9.3.1 (GCC) 20200523
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --disable-w32threads --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  libavutil      56. 49.100 / 56. 49.100
  libavcodec     58. 90.100 / 58. 90.100
  libavformat    58. 44.100 / 58. 44.100
  libavdevice    58.  9.103 / 58.  9.103
  libavfilter     7. 84.100 /  7. 84.100
  libswscale      5.  6.101 /  5.  6.101
  libswresample   3.  6.100 /  3.  6.100
  libpostproc    55.  6.100 / 55.  6.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, wav, from 'audio.wav':
  Metadata:
    encoder         : Lavf58.44.100
  Duration: 00:00:07.34, bitrate: 1411 kb/s
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf58.44.100
    Stream #0:0: Audio: pcm_s16le, 44100 Hz, stereo, s16, 1411 kb/s
    Metadata:
      encoder         : Lavc58.90.100 pcm_s16le
[silencedetect @ 00000202fc71e680] silence_start: 0
[silencedetect @ 00000202fc71e680] silence_end: 1.16374 | silence_duration: 1.16374
[silencedetect @ 00000202fc71e680] silence_start: 1.94558
[silencedetect @ 00000202fc71e680] silence_end: 3.41345 | silence_duration: 1.46787
[silencedetect @ 00000202fc71e680] silence_start: 3.8578
[silencedetect @ 00000202fc71e680] silence_end: 5.84844 | silence_duration: 1.99063
[silencedetect @ 00000202fc71e680] silence_start: 6.43653
size=N/A time=00:00:07.33 bitrate=N/A speed= 308x    
video:0kB audio:1264kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[silencedetect @ 00000202fc71e680] silence_end: 7.33868 | silence_duration: 0.902154

And this code should be implemented on an hour or so long videos so I really need to find a way to format this output a bit better than this. That would be it, any help would be much appreciated :)

P.S: the idea is that this should work on Windows mainly, but if the cross-platform is possible too it would be great.

1 Answers

I found an answer. The following can be done:

command = r"ffmpeg -i audio.wav -af silencedetect=n=-40dB:d=0.5 -f null - "
out = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)

stdout, stderr = out.communicate()

this way the stdout variable will get become the string that represents the output on the console. Of course, this requires the subprocess module to be imported.

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