concat demuxer truncates output duration

[Jeremiah Seeley]

Summary of the bug:
The Concat demuxer is truncating output; I didn't start seeing this until moving to version 3.0.2. Normally I'm joining multiple files, but for simplicity the steps below are using the concat demuxer with a single file. The source file is about 90secs, but after running via the concat demuxer the output is only 7secs. ffmpeg lists the error 'concat.txt: Invalid argument' however I am getting a 0 exit code.

How to reproduce:

ffmpeg -f concat -i concat.txt -c copy -y output.flv
ffmpeg version 3.0.2 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.9.2 (Debian 4.9.2-10)
  configuration: --prefix=/usr --extra-version=streamme --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --disable-debug --disable-shared --enable-static --extra-cflags=--static --enable-gpl --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-openal --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-opengl --enable-nonfree --enable-libfdk-aac --enable-libx264 --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
  libavutil      55. 17.103 / 55. 17.103
  libavcodec     57. 24.102 / 57. 24.102
  libavformat    57. 25.100 / 57. 25.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 31.100 /  6. 31.100
  libavresample   3.  0.  0 /  3.  0.  0
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
[flv @ 0x3a72620] Auto-inserting h264_mp4toannexb bitstream filter
Input #0, concat, from 'concat.txt':
  Duration: N/A, start: 0.000000, bitrate: 3 kb/s
    Stream #0:0: Video: h264 (Baseline), yuv420p(tv), 640x360 [SAR 1:1 DAR 16:9], 30.30 fps, 30 tbr, 1k tbn, 60 tbc
    Stream #0:1: Audio: speex, 16000 Hz, mono, s16, 3 kb/s
Output #0, flv, to 'output.flv':
  Metadata:
    encoder         : Lavf57.25.100
    Stream #0:0: Video: h264 ([7][0][0][0] / 0x0007), yuv420p, 640x360 [SAR 1:1 DAR 16:9], q=2-31, 30.30 fps, 30 tbr, 1k tbn, 1k tbc
    Stream #0:1: Audio: speex ([11][0][0][0] / 0x000B), 16000 Hz, mono, 3 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
concat.txt: Invalid argument
frame=  150 fps=0.0 q=-1.0 Lsize=     712kB time=00:00:07.37 bitrate= 791.0kbits/s speed= 186x    
video:702kB audio:4kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.923229%

[Jeremiah Seeley]

I can't attach an exmaple video file to the ticket(8mb flv file), but you can download it from here->
​https://storage.googleapis.com/testpds/test/test1.flv

[Carl Eugen Hoyos]

Is the issue reproducible with current FFmpeg git head?

[Jeremiah Seeley]

updated to 3.1, problem seems resolved. Sorry to waste anyone's time!

[Carl Eugen Hoyos]

This was a regression since 3331213e2ac5a0fe5c574e9cd3da44df5e0d1d18, fixed in 0cb19c30c6a14418eaa6858db303602815fe3ab1

[Carl Eugen Hoyos]

$ ffmpeg -f concat -i concat.txt -c copy output.flv
ffmpeg version n3.0.3 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl --enable-libspeex
  libavutil      55. 17.103 / 55. 17.103
  libavcodec     57. 24.102 / 57. 24.102
  libavformat    57. 25.100 / 57. 25.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 31.100 /  6. 31.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
[flv @ 0x2078660] Auto-inserting h264_mp4toannexb bitstream filter
Input #0, concat, from 'concat.txt':
  Duration: N/A, start: 0.000000, bitrate: 3 kb/s
    Stream #0:0: Video: h264 (Baseline), yuv420p(tv), 640x360 [SAR 1:1 DAR 16:9], 30.30 fps, 30 tbr, 1k tbn, 60 tbc
    Stream #0:1: Audio: speex, 16000 Hz, mono, s16, 3 kb/s
Output #0, flv, to 'output.flv':
  Metadata:
    encoder         : Lavf57.25.100
    Stream #0:0: Video: h264 ([7][0][0][0] / 0x0007), yuv420p, 640x360 [SAR 1:1 DAR 16:9], q=2-31, 30.30 fps, 30 tbr, 1k tbn, 1k tbc
    Stream #0:1: Audio: speex ([11][0][0][0] / 0x000B), 16000 Hz, mono, 3 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
concat.txt: Invalid argument
frame=  150 fps=0.0 q=-1.0 Lsize=     712kB time=00:00:07.37 bitrate= 791.0kbits/s speed=1.99e+03x
video:702kB audio:4kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.923229%

[Elon Musk]

Since when we are tracking non git master bugs?
Also there is error in attached concat.txt

[Carl Eugen Hoyos]

Replying to richardpl:

Since when we are tracking non git master bugs?

We are tracking crashes and regressions in supported releases for as long as this bug tracker existed (and also on roundup afair).