[MPlayer-dev-eng] Fwd: Re: tech question: A-V sync in avi

Arpi arpi at thot.banki.hu
Mon Dec 31 02:08:19 CET 2001


Worth to read his page about windows avi parsers, at link bellow.
(the 3 avi parser library under windows behaves differently about vbr audio)

I think i'll build my avi info doc over this article.

--------- Forwarded message ---------
From: Avery Lee <phaeron at virtualdub.org>
To: Arpi <arpi at thot.banki.hu>
Subject: Re: tech question: A-V sync in avi

I know that the last email we exchanged on this subject was months
ago, but I was browsing the mplayer-dev mail archives, and noticed
that you are still looking for the answer to how to read VBR audio in
AVI.  Well, I finally solved the puzzle about a month ago. :)

Nandub/vdub-mp3 actually encode VBR audio by exploiting a bug in the
DirectShow AVI parser, in the way that it handles audio chunks whose
size isn't evenly divisible by the nBlockAlign of the audio format. I
posted the full gory details in the 12/02/2001 update of the
VirtualDub news page:

  http://www.virtualdub.org/virtualdub_news

I hope this helps the mplayer team implement fully functional seeking
for AVI files with VBR audio.  Unfortunately, this method isn't very
reliable, so I don't recommend encoding any AVI files this way, i.e.
please don't! :)

--
Avery Lee <phaeron at virtualdub.org>   http://www.virtualdub.org
The latest version of VirtualDub is V1.4.8 (build 13719).





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