[MPlayer-DOCS] complete documentation

[Guillaume POIRIER]

Le ven 10/09/2004 à 12:48, Diego Biurrun a écrit :

> Can I get you interested in documenting some of the other encoding
> options?

That's possible, but not right now as I have postponed quite a lot of
personal work in order to complete French manpage synch and XviD
documentation. I'm also the maintainer of a DVD-rip script based on
MPlayer/Mencoder and transcode called tuxrip (http://tuxrip.free.fr if I
recall right).
It was originally written by someone else (Jotenakis) in bash, but since
it had no design, it just can't be extended or it would explode ! ;-)

So I'm re-coding it in Perl, with a much better design, but it takes
time!

> Now that you have finished XviD we can safely tell you that
> lavc is much faster and even better ;-).

Umh... talking about speed, it all depends on which encoding options you
use! With lavc and qns=3, plus other fancy HQ options (qpel, tellis), I
had a film (about 1h40) that took around 2 days to encode on a
P4-1.8Ghz! I agree that this option improves visual quality quite a bit,
and isn't supposed to be particularly fast, but still!
Don't get me wrong. Libavcodec is a feature-rich amazing codec, but it
isn't foolproof!
I agree with you, it does need to be better documented so that "Joe
users" don't say that it is slow. It is not. It needs to be properly
used, though.

Maybe that isn't the right place to talk about features, but I'd like to
point out a really cool XviD feature that could maybe get ported in
lavc.
It's called... turbo mode!
Basically, what it does is during first pass of 2-pass mode, it uses
simpler MV search fonctions and I think it also disables some CPU-hungry
options. On my machine, the first pass will run at 40fps and 9fps, with
not that much of a PSNR reduction actually.
I wish it could be implemented in lavc.

> The documentation is very
> terse, though, and it would benefit a lot from better documentation.
> I think we should try to promote lavc a bit, it deserves to be known
> better.  Good user documentation should help boost it quite a bit.

Right. I remember when I read doom9 codec comparison, about 9 month from
now that they were quite confused with how lavc works... and that's
maybe due to the lack of documentation, but also the fact that XviD has
a strong Windows base, so documentation is available everywhere.
...it's kinda the same situation for DivX: here's a crappy encoder
that's still heavily used, because many people now it, and use it.


> Guillaume, you've done such a good job with XviD, could you repeat
> that for lavc?

Thanks Diego, what you're saying me is going right to my heart ;-)
As I said, I don't plan to do that for at least a week... but after
that, I should have more time to harvest some docs around the net to
better document lavc. I'd also need the original devs of new options to
help me, just like XviD devs kindly helped me, but I see no reason why
wouldn't! ;-)

Regards,

Guillaume

-- 
La science est asymptote à la vérité, elle l'approche sans cesse et ne
la touche jamais.
        -+- Hugo, Victor -+-