[FFmpeg-user] Forcing ffmpeg to detect duration reliably

[Robert Krüger]

Hi,

I assumed that if I make probesize large enough (larger than the
entire file in my case, which is a bit over 4 MB) that ffmpeg would be
able to detect the accurate duration if necessary by parsing the
bitstream but this does not happen in my example:

ffmpeg -probesize 100000000 -analyzeduration 100000000 -i
EncounterRoughcut6-MPEG-2-SD-PAL-DVD-Video-only.m2v
ffmpeg version N-46900-g19660a8 Copyright (c) 2000-2012 the FFmpeg developers
  built on Feb 21 2013 16:06:45 with llvm-gcc 4.2.1 (LLVM build 2336.1.00)
  configuration: --enable-shared --disable-static --disable-doc
--enable-libmp3lame
--prefix=/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg.build/build/ffmpeg-lgpl
--extra-cflags=-I/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg.build/build/mp3lame/include/
--extra-ldflags=-L/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg.build/build/mp3lame/lib/
--extra-ldflags='-Wl,-rpath, at loader_path/../lib'
  libavutil      52.  8.100 / 52.  8.100
  libavcodec     54. 73.100 / 54. 73.100
  libavformat    54. 37.100 / 54. 37.100
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 23.101 /  3. 23.101
  libswscale      2.  1.102 /  2.  1.102
  libswresample   0. 16.100 /  0. 16.100
[mpegvideo @ 0x101806600] Estimating duration from bitrate, this may
be inaccurate
Input #0, mpegvideo, from 'EncounterRoughcut6-MPEG-2-SD-PAL-DVD-Video-only.m2v':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: mpeg2video (Main), yuv420p, 720x576 [SAR 64:45
DAR 16:9], 25 fps, 25 tbr, 1200k tbn, 50 tbc
At least one output file must be specified

Anything I am doing wrong or is this just a known limitation or a not
yet implemented feature or a conscious decision for some reason?

Thanks,

Robert