[FFmpeg-devel] [BUG] transcode DVD films have a/v sync issue

Michael Niedermayer michaelni
Wed Sep 12 01:22:13 CEST 2007


On Tue, Sep 11, 2007 at 07:19:25PM +0800, Limin Wang wrote:
> Hi,
> I'm try to transcode some dvd to ts(h264) by ffmpeg, if the dvd is DVD films,
> the output will lose A/V sync and video can't play smoothly.
> Below is simple command line to reproduce it:
> lmwang at test1-desktop:~/dev/ffmpeg$ ./ffmpeg -i
> /home/lmwang/bitstream/24fps.vob -b 1500kb -bf 3 -coder 1 -refs 4 -partitions
> all -vcodec libx264 -ab 96kb -ar 48000 -ac 2 -acodec mp2
> /mnt/dvd_result/test_1500kb.ts

our mpeg ts muxer is broken, it writes random timesamps (yes i verified that
the dts/pts ffmpeg feeds into the muxer are quite different from the totally
nonsensical dts/pts that our mpeg ts demuxer returns)
use mpeg-ps and -vsync 0 it works, without -vsync 0 your output will be
full of duplicated frames, though it works as well if your system is fast

if you want to fix the mpeg ts muxer look at the patches from xiaohui
(some on the mailinglist some in the soc svn) and help cleaning them up
maybe they fix the timestamps


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Complexity theory is the science of finding the exact solution to an
approximation. Benchmarking OTOH is finding an approximation of the exact
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