#9524: concat of videos with different frame rates ends with endless loop of frame duplication --------------------------------+---------------------------------- Reporter: rotemc | Owner: (none) Type: defect | Status: new Priority: normal | Component: ffmpeg Version: 4.4.1 | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 1 Analyzed by developer: 1 | --------------------------------+---------------------------------- Changes (by rotemc): * Attachment "second.mp4" added. -- Ticket URL: <https://trac.ffmpeg.org/ticket/9524> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

#9524: concat of videos with different frame rates ends with endless loop of frame duplication -----------------------------------+---------------------------------- Reporter: rotemc | Owner: (none) Type: defect | Status: new Priority: normal | Component: ffmpeg Version: 4.4.1 | Resolution: Keywords: framerate | Blocked By: Blocking: | Reproduced by developer: 1 Analyzed by developer: 1 | -----------------------------------+---------------------------------- Changes (by rotemc): * keywords: => framerate Old description:

Summary of the bug: It seems that concatenation command for videos with different frame rates gets into endless loop of duplicating frames. Debug tracing for example: cur_dts is invalid st:0 (0) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream) Last message repeated 2 times *** 33331 dup! More than 1000 frames duplicated

It works fine in 4.2

How to reproduce: {{{ % /opt/ffmpeg-4.4.1/bin/ffmpeg -loglevel debug -y -timelimit 2880 -i spec/videos/first.mp4 -i spec/videos/second.mp4 -sws_flags lanczos -filter_complex "[0:v]null[j1] ; [0:a]anull[a1] ; [1:v]null[j2] ; [1:a]anull[a2] ; [j1][a1][j2][a2]concat=n=2:a=1:v=1[v9][a3]" -codec:v libx264 -map '[v9]' -map '[a3]' -start_at_zero public/test.mp4 ffmpeg version 4.4.1 built on Ubuntu/mac }}} Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.

New description: Summary of the bug: ------------------- It seems that concatenation command for videos with different frame rates gets into endless loop of duplicating frames. Debug tracing for example: -------------------------- cur_dts is invalid st:0 (0) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream) Last message repeated 2 times *** 33331 dup! More than 1000 frames duplicated It works fine in 4.2 How to reproduce: ----------------- {{{ % /opt/ffmpeg-4.4.1/bin/ffmpeg -loglevel debug -y -timelimit 2880 -i spec/videos/first.mp4 -i spec/videos/second.mp4 -sws_flags lanczos -filter_complex "[0:v]null[j1] ; [0:a]anull[a1] ; [1:v]null[j2] ; [1:a]anull[a2] ; [j1][a1][j2][a2]concat=n=2:a=1:v=1[v9][a3]" -codec:v libx264 -map '[v9]' -map '[a3]' -start_at_zero public/test.mp4 ffmpeg version 4.4.1 built on Ubuntu/mac }}} -- -- Ticket URL: <https://trac.ffmpeg.org/ticket/9524#comment:1> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker