[FFmpeg-user] Audio duration difference

[Felix Muster]

Hello

 

Can you please explain me this difference:

 

I have an audio-stream from a blu-ray (23.976 fps).

When I calculate the duration it should be: 133799/(24000/1001) =
5580.533292 seconds.

 

When I encode the extracted audio stream it is:

_ffmpeg -i _audio2.flac -f null -

ffmpeg version N-95216-ge6625ca41f Copyright (c) 2000-2019 the FFmpeg
developers

  built with gcc 9.2.1 (GCC) 20190918

  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-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-libvorbis --enable-libvo-amrwbenc
--enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom
--enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-d3d11va
--enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
--enable-libopenmpt --enable-amf

  libavutil      56. 35.100 / 56. 35.100

  libavcodec     58. 59.101 / 58. 59.101

  libavformat    58. 33.100 / 58. 33.100

  libavdevice    58.  9.100 / 58.  9.100

  libavfilter     7. 61.100 /  7. 61.100

  libswscale      5.  6.100 /  5.  6.100

  libswresample   3.  6.100 /  3.  6.100

  libpostproc    55.  6.100 / 55.  6.100

Input #0, flac, from '_audio2.flac':

  Metadata:

    title           : THE_GIRL_WITH_THE_DRAGON_TATTOO.Title1

    encoder         : Lavf58.20.100

  Duration: 01:33:00.70, start: 0.000000, bitrate: 1111 kb/s

    Stream #0:0: Audio: flac, 48000 Hz, 5.1(side), s16

Stream mapping:

  Stream #0:0 -> #0:0 (flac (native) -> pcm_s16le (native))

Press [q] to stop, [?] for help

Output #0, null, to 'pipe:':

  Metadata:

    title           : THE_GIRL_WITH_THE_DRAGON_TATTOO.Title1

    encoder         : Lavf58.33.100

    Stream #0:0: Audio: pcm_s16le, 48000 Hz, 5.1(side), s16, 4608 kb/s

    Metadata:

      encoder         : Lavc58.59.101 pcm_s16le

size=N/A time=01:33:00.70 bitrate=N/A speed= 435x    

video:0kB audio:3139146kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: unknown

 

à 01:33:00.70 = 5580.7 seconds

 

Why is there a difference of 0.166708 seconds?

 

Best

Felix