[MPlayer-users] VBR sync problem
cm5oom at post.com
cm5oom at post.com
Tue Apr 1 08:35:09 CEST 2003
this sounds like a bug i just found in mencoder when i tryed to reencoded a
divx/ac3 movie with -ovc copy -oac mp3lame. in the first 6s, mencoder skips 5
frames causing the audio to be ~250ms ahead of the video. i later found that this
is a genarale bug that happens with -ovc copy -ofps ??? ( DVD's ), i've bin
looking at mencoder.c for two day's now, but i havn't found it 'cause the code is
heavly odfuscated and i'm not to upto speed with c ( i'm a c++ coder )
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Sorry again to reply to myself.
> I have now ruled out many things trying to fix this problem of sync out
> by 200ms - 300ms
> 1) It is not related to the version of libmp3lame.
> 2) Occurs with most all versions of MPlayer tried (RC2,RC3,RC4,RC5)
> 3) Occurs in 2 pass, 3 pass and single pass mode.
> 4) Does not happen when using CBR MP3.
> 5) Occurs on MDK9 (despite what I said), Gentoo & MDK9.1
> 6) Allowing normal users access to /dev/rtc does not fix ALL encodings.
> 7) Occurs under any user, or superuser.
> 8) Occurs with different -vo or -ao options when playing.
> This is very frustrating FFS. I would simply like a confirmation if this
> is a known problem or just something sporadic. I will most certainly
> give anyone a clip of these encoding if they wish to test.
> MPlayer has not given me this grief before & I don't like rebooting to
> windows to offset the audio stream by 300ms!
> I could accept this issue is caused by the source files but I see no
> evidence of this. The -autosync option is not able to fix these files
> How bout a new function, such as a user-specified delay in the audio
> when encoding?
> On Sun, 2003-03-30 at 22:01, Michael Collard wrote:
> > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > Finally I have found a fix but the question remains why. Enabling normal
> > users access to the RTC (Real Time Clock) fixes playback of these files
> > that supposedly had this audio-video sync problem. The command to enable
> > the RTC for users on kernels 2.4.19pre8 and later is:
> > echo 1024 > /proc/sys/dev/rtc/max-user-freq
> > Still I would like to know why playback without this on my rather
> > powerful machine results in a sync problem, considering it has been fine
> > for ages in the past.
> > I would just like the MPlayer developers to comment.
> > Thanks.
> > On Sun, 2003-03-30 at 17:48, Michael Collard wrote:
> > > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > > This is kinda regarding my last post except I have interesting
> > > information. The problem I have where audio is out of sync by about
> > > 300ms goes away when using CBR & MP3lame.
> > >
> > > Problem is that under Mandrake 9, and MPlayer RC3 I never had this
> > > issue. Since it is pretty wide-spread is it possible that this is to do
> > > with libraries on this system? Now I am using RC4 and Mdk 9.1.
> > >
> > > There has got to be something to this. After all I never had any such
> > > issue before. I am wondering if LAME w/ Mdk 9.1 could be causing this.
> > > I will be doing more checks such as going back to RC3.
> > >
> > > Thanks
> Michael Collard, Microsoft Certified Professional
> RTFM!!! http://www.MPlayerHQ.hu/DOCS
> Search: http://www.MPlayerHQ.hu/cgi-bin/htsearch
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