[FFmpeg-devel] [BUG] transcode DVD films have a/v sync issue
Wed Sep 12 06:12:58 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
So when we need to enable vsync? what's the purpose of vsync? why vsync is
enable default, but async is disable default?
> 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
OK, I'll try to search these patches to get some basic understanding.
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