[FFmpeg-user] Why does this command produce different size segments depending on the input?

[Grant Curtis]

Yes

ffmpeg -i file1.mp4 -map 0:1 -af aresample=16000,asetnsamples=16000 -f
segment -segment_time 5 -segment_format sw out%04d.sw
ffmpeg version N-79068-g6b7ce0e Copyright (c) 2000-2016 the FFmpeg
developers
  built with gcc 5.3.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r
--enable-gnutls --enable-iconv --enable-libass --enable-libbluray
--enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype
--enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug
--enable-libmfx --enable-libmp3lame --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus
--enable-librtmp --enable-libschroedinger --enable-libsnappy
--enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame
--enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
--enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg
--enable-lzma --enable-decklink --enable-zlib
  libavutil      55. 19.100 / 55. 19.100
  libavcodec     57. 28.103 / 57. 28.103
  libavformat    57. 28.102 / 57. 28.102
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 39.102 /  6. 39.102
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'file1.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2015-04-03 05:49:11
  Duration: 00:28:48.80, start: 0.000000, bitrate: 358 kb/s
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 /
0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 260 kb/s, 29.97 fps, 29.97
tbr, 30k tbn, 59.94 tbc (default)
    Metadata:
      creation_time   : 1970-01-01 00:00:00
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
stereo, fltp, 95 kb/s (default)
    Metadata:
      creation_time   : 2015-04-03 05:49:18
      handler_name    : IsoMedia File Produced by Google, 5-11-2011
Output #0, segment, to 'out%04d.sw':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    encoder         : Lavf57.28.102
    Stream #0:0(und): Audio: pcm_s16le, 16000 Hz, stereo, s16, 512 kb/s
(default)
    Metadata:
      creation_time   : 2015-04-03 05:49:18
      handler_name    : IsoMedia File Produced by Google, 5-11-2011
      encoder         : Lavc57.28.103 pcm_s16le
Stream mapping:
  Stream #0:1 -> #0:0 (aac (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
size=N/A time=00:28:49.00 bitrate=N/A speed= 286x
video:0kB audio:108062kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: unknown