Opened 2 months ago

Last modified 2 months ago

#11268 new defect

[Regression] "-use_wallclock_as_timestamps" ineffective

Reported by: Wes Castro Owned by:
Priority: normal Component: ffmpeg
Version: unspecified Keywords:
Cc: Wes Castro, MasterQuestionable Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no

Description

Summary of the bug:
When piping a raw H264 stream to FFmpeg with -use_wallclock_as_timestamps 1, wallclock times are not used. If the pipe is opened for say 10 seconds, it's expected that the output's duration will be ~10 seconds. Instead it seems to use timing info from the input stream. I didn't test with other types of piped inputs

The issue was introduced in FFmpeg 6.1 and repros on the master branch.

How to reproduce:

ffmpeg -y -f lavfi -i testsrc=duration=1:size=1280x720:rate=30 -f h264 ~/1second.h264
(cat ~/1second.h264; sleep 10; cat ~/1second.h264) | ffmpeg  -use_wallclock_as_timestamps 1 -i pipe: -f mp4 ~/test.mp4 -y

Here are the durations reported by FFprobe when using various FFmpeg versions for the second line:

Change History (1)

comment:1 by MasterQuestionable, 2 months ago

Cc: MasterQuestionable added
Component: undetermined → ffmpeg
Summary: -use_wallclock_as_timestamps 1 not working with piped input → [Regression] "-use_wallclock_as_timestamps" ineffective

͏    See also:
͏    https://ffmpeg.org/ffmpeg-formats.html#Format-Options
͏    ​https://www.google.com/search?hl=en&gl=ca&num=10&q=wallclock+time&nfpr=1

͏    "-use_wallclock_as_timestamps" mostly undocumented...
͏    And search for "wallclock" may give funny results.


͏    I guess it may apply to random formats.
͏    And probably without Pipe.

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