[MPlayer-users] VBR sync problem

Michael Collard quadfour at iinet.net.au
Mon Mar 31 11:46:08 CEST 2003

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

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