On 1/30/23, Nicolas George <geo...@nsup.org> wrote: > Paul B Mahol (12023-01-27): >> From b4f835c4ef6e0e0bbe6adef8235381e56f3f91df Mon Sep 17 00:00:00 2001 >> From: Paul B Mahol <one...@gmail.com> >> Date: Fri, 27 Jan 2023 23:34:02 +0100 >> Subject: [PATCH 1/4] avfilter/framesync: calculate frame duration too >> >> Signed-off-by: Paul B Mahol <one...@gmail.com> >> --- >> libavfilter/framesync.c | 20 ++++++++++++++++---- >> libavfilter/framesync.h | 15 +++++++++++++++ >> 2 files changed, 31 insertions(+), 4 deletions(-) > > It does not work. For example, with the following filter graph: > > testsrc2=r=1/3[a];testsrc2=r=1/5[b];[a][b]vstack > > and adding a line of debug at the beginning of process_frame() in > vf_stack.c, you get: > > got event: pts = 0, duration = 3 > got event: pts = 3, duration = 3 ← should be 2 > got event: pts = 5, duration = 5 ← should be 1 > got event: pts = 6, duration = 3 … > got event: pts = 9, duration = 3 > got event: pts = 10, duration = 5 > got event: pts = 12, duration = 3 > got event: pts = 15, duration = 3 > got event: pts = 18, duration = 3 > got event: pts = 20, duration = 5 > > I was wrong saying it cannot work, you can compute the duration of the > new frame without increasing the latency, but you have to duplicate the > whole frame synchronization logic. > > I was against adding the duration field to libavfilter, and this is a > very good illustration of the reason. The duration field is redundant > with other information, it takes a lot of code to maintain it, and we > cannot trust it anyway.
It is not redundant, it describes how much frame lasts. There is no other way to derive it. > > For libavfilter, my advice would be to disregard it entirely. Let us > just clear it in buffersrc and be done with it. > I think you do not understand why frame duration is needed. > Regards, > > -- > Nicolas George > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
