[MPlayer-users] A/V Sync Problem

Arpi arpi at thot.banki.hu
Thu Aug 1 23:54:02 CEST 2002


Hi,

> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Hi,
> 
> AVSync problems still present, 
> 
> 13fantavsync.avi  13fantavsync.txt  cdfr.avsync.avi  cdfr.avsync.txt 
> 
> uploaded, i still can u/l some other files with the same problem
> 
> 
> -ni switch has no effect

hmm. i've just checked 13fantavsync.avi, eh, it's broken to hell...

try to dump the mp3 audio track (-dumpaudio) and see with an hexeditor
or playback it. the first 570kb of that is pure _zero_...

now, the problem. they have used nandub to multiplex video with this broken
mp3 track (i try to avoid assuming that nandub added those zeroes...).
as nandub didn't find any mp3 at the start of their mp3 file, it assumed
maximum possible block size, and used nonsense values for chunksizes, filled
by those zeroes... dunno if it ever worked with any player, aviplay cannot
play the audio at all. probably it exploits another avi bug, this time in
windows mp3 audio decoder, maybe it can 'decode' zeroes too...

at least mplayer can't, so it skip the whole junk and start the audio
immediately, causing ~12sec a-v desync. due to the bogus chunk sizes, it
reports only 6s desync :)

anyway, i get the good old interleaving-based sync method (nandub at least
does interleaving well), -nobps, and it worked! i had to add -mc 0.05 to get
a-v syncing faster, and now the a-v is almost-perfect. there is still about
0.2s desync, can be corrected by +/- keys.

normaly i would say delete this file, but it seems there are many of such
shit out there, so i cannot avoid implementing some workaround :(

what players (linux/win) are able to play it without a-v desync ?


A'rpi / Astral & ESP-team

--
Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu




More information about the MPlayer-users mailing list