[FFmpeg-user] DVB H264 chunk transcoding => merging in MP4 => out of sync

[ffmpeg at me.com]

Dear Carl,

many thanks for your feedback. Hope you can help! 
We used the current dev version (ffmpeg-84005-g3ba7b47 from today morning) - same result. 

Example-Files could be taken from here: https://www.wetransfer.com/downloads/ba29067a28723c12373dbfdd25c4bfae20170317093643/10cb1a9e9693b86ae921cc0b9838ffc520170317093643/3ae8a8
Command we used to concat and create MP4: 

ffmpeg -f concat -safe 0 -i files.txt -y -metadata creation_time=now -c:v copy -vsync 1 -c:a copy -fflags +genpts -movflags faststart -use_editlist 0 -f mp4 work_tmp0.mp4
ffmpeg version N-84005-g3ba7b47-tessus Copyright (c) 2000-2017 the FFmpeg developers
 built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
 configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzmq --enable-libzvbi --enable-version3 --disable-ffplay --disable-indev=qtkit --disable-indev=x11grab_xcb
 libavutil      55. 48.100 / 55. 48.100
 libavcodec     57. 83.100 / 57. 83.100
 libavformat    57. 66.104 / 57. 66.104
 libavdevice    57.  3.100 / 57.  3.100
 libavfilter     6. 76.100 /  6. 76.100
 libswscale      4.  3.101 /  4.  3.101
 libswresample   2.  4.100 /  2.  4.100
 libpostproc    54.  2.100 / 54.  2.100
Input #0, concat, from 'files.txt':
 Duration: N/A, start: 0.000000, bitrate: N/A
   Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], 50 fps, 50 tbr, 90k tbn, 100 tbc
   Stream #0:1(deu): Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp, 235 kb/s
Output #0, mp4, to 'work_tmp0.mp4':
 Metadata:
   creation_time   : now
   encoder         : Lavf57.66.104
   Stream #0:0: Video: h264 (High) ([33][0][0][0] / 0x0021), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 50 fps, 50 tbr, 90k tbn, 90k tbc
   Stream #0:1(deu): Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, fltp, 235 kb/s
Stream mapping:
 Stream #0:0 -> #0:0 (copy)
 Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[mp4 @ 0x7fbc4e0b6000] Starting second pass: moving the moov atom to the beginning of the file    
frame=27000 fps=8929 q=-1.0 Lsize=  224240kB time=00:09:00.18 bitrate=3400.7kbits/s speed= 179x    
video:210889kB audio:12843kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.227265%

The delay is visible at minute 2~3. At minute 4 it's very visible in Quicktime. Remember: do not scrub in the timeline during playback. Scrubbing does an alignment and everything is back in sync. No problems in VLC.

Any help is very, very appreciated.
Best, Andreas


> Am 16.03.2017 um 20:50 schrieb Carl Eugen Hoyos <ceffmpeg at gmail.com>:
> 
> 2017-03-15 13:03 GMT+01:00  <ffmpeg at me.com>:
>> ffmpeg version 3.2.4-tessus Copyright (c) 2000-2017 the FFmpeg developers
> 
> Please test current FFmpeg git head (and tell us if anything is unclear on
> tessus's homepage) and if the issue is reproducible, please provide input
> file(s).
> 
> Carl Eugen
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