[MEncoder-users] sync problem with -oac faac

Jonathan jonathan at kc8onw.net
Tue Feb 28 21:17:41 CET 2006

Victor Condino wrote:
> On 2/28/06, Jonathan <jonathan at kc8onw.net> wrote:
>> Victor Condino wrote:
>> [snip]
>>> my main issue after doing a few
>>> test encodes is with faac... it seems that when using -oac faac the
>>> audio leads by several seconds (!)... not sure if sync drifts yet, so
>>> a possible workaround might be manually determining an offset and
>>> encoding with it, but still... i tried reencoding using x264 and -oac
>>> mp3lame and sync was fine.
>>> anyone else experienced this sync problem with faac? anone know of a solution?
>> It may not be the same issue but when I was encoding to x264 with CVS
>> from a couple of months back I found that the video was delayed by
>> frame_duration*max_bframes.  I don't know if it was an encoding or
>> decoding issue and I wound up hacking around it by using
>> raw[audio|video], muxing to matroska and setting an audio delay in
>> matroska.  I was also using Vorbis audio instead of faac because I never
>> got faac working on windows and the files where destined for PC only
>> playback anyway.
> hrmmm... that is interesting, although i'm pretty sure that my problem
> is being caused by the faac audio export module and not the x264 video
> export mod... like i said i ran controls, and in fact since i have
> also tried encoding to -ovc xvid and even -ovc copy (source material
> was MPEG-2 program stream, i.e. DVD VOB) with -oac faac and -oac
> mp3lame, and in all cases, the audio is extremely (in the range of a
> few seconds) ahead of video in ALL cases where -oac faac is used, and
> fine with any other combination of output codecs.

If your not worried about WMP playing it why not use something other
than faac?  I've not even seen claims that faac is better than vorbis
for a given bitrate and as I said before VLC (and I'm pretty sure
mplayer) plays H.264 video and Vorbis audio without a problem.  I can
post the commands I used to rip encode and mux if anyone is interested.
 I would be interested in feedback on them anyway.  Matroska has also
been much nicer to work with than for example MP4box.  There is a
graphical interface you can use to do the muxing that also shows the
exact command line you would use so you can set all your options in the
gui and get everything how you like it and the copy the command line
into a script.

> but as far as watching media goes i generally just reboot into linux
> and fire up mplayer
Ever tried VLC?  Not trying to stop someone switching to linux, I'm a
BSD guy myself, but VLC is cross platform and works quite well on windows.

[big snip]

> perhaps i should repost this thread as a cross-post on the mplayer-dev list?
That I can't really say.


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