Opened 9 months ago

Last modified 9 months ago

#9524 new defect

concat of videos with different frame rates ends with endless loop of frame duplication

Reported by: rotemc Owned by:
Priority: normal Component: ffmpeg
Version: 4.4.1 Keywords: framerate
Cc: rotemc Blocked By:
Blocking: Reproduced by developer: yes
Analyzed by developer: yes

Description (last modified by rotemc)

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

Attachments (2)

second.mp4 (58.8 KB ) - added by rotemc 9 months ago.
first.mp4 (173.4 KB ) - added by rotemc 9 months ago.
use file with the given command

Download all attachments as: .zip

Change History (3)

by rotemc, 9 months ago

Attachment: second.mp4 added

by rotemc, 9 months ago

Attachment: first.mp4 added

use file with the given command

comment:1 by rotemc, 9 months ago

Description: modified (diff)
Keywords: framerate added
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