[FFmpeg-trac] #9524(ffmpeg:new): concat of videos with different frame rates ends with endless loop of frame duplication
FFmpeg
trac at avcodec.org
Mon Nov 22 17:51:49 EET 2021
#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
}}}
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Ticket URL: <https://trac.ffmpeg.org/ticket/9524#comment:1>
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