[MPlayer-dev-eng] Re: [RFC] change lacv's MPEG-4 encoding options defaults

[Corey Hickey]

Matthias Wieser wrote:
>>>>For what it's worth, other codeds supported by MEncoder (XviD and
>>>>x264 at the very least) have defaults which are carefully chosen
>>>>(by people who know what they are talking about) to provide a good
>>>>speed/quality tradeoff, making them a _lot_ more user-friendly.
>>>>Users love that.
>>>
>>>The default number of b-frames for x264 is currently 0 while most
>>>people use 2/3 as standard. Fair enough b-frames stored in avi aren't
>>>perfect, but standalones can play the produced files, most if not all
>>>software can play the produced files, so is this a real problem?
>>
>>Like I said: mencoder is broken so B frames cause a/v desync!!
> 
> 
> ??
> That's only true under some circumstances. Normally mencoder + bframes 
> works very well. Additionally B-frames have been recommended for the 
> doom9 codec comparison. I don't think Corey made this to make mencoder 
> look bad :-)

I was reluctant, though, because I've had bad experiences with mencoder
and B-frames in the past. Since doom9 was going to re-mux the video
anyway, it shouldn't have been a problem.

My experiences so far have been:
- 2 or 3 B-frames yield the best quality; 2 is much faster than 3
- A-V desync varies depending on the movie

Probably, using only 1 B-frame will reduce the amount of possible desync
to an acceptable level; I haven't tried.

I sent a bug report about B-frames and desync ages ago. If and when I
learn enough about mencoder I will try to fix it, but I would be really
happy if someone more capable than I would do so... :)

-Corey