[XviD-devel] [FRONTEND UPDATE] mplayer modules.

Guillaume POIRIER guigui-nospam at laposte.net
Fri Sep 3 13:13:47 CEST 2004


Hello,
First of all, thanks for this lengthy and detailed response to my mail.
You guys a pretty busy people, so I'm pleased that you took time to
answer both questions

Le jeu 02/09/2004 à 23:22, Edouard Gomez a écrit :
> Guillaume POIRIER (guigui-nospam at laposte.net) wrote:
> So what happenned then... transcode did accept all the
> terminology change, after all, that was a major change, so
> users were to learn new option (for their own good).
> 
> mplayers' maintainers refused the changes, because, according
> to their opinions, there is no point in changing codec
> options. I refused stating that this was a major rewrite of
> the module, not a simple -- common let's port this to xvid
> 1.0. So in the end, my module has been accepted minus lot of
> options renamed to their old equivalent.
Ok, so does that mean that the documentation of XviD options in the
manpage might be incorrect? (you can check that on a fresh mplayer's
cvs)

I understand though why having a great codec, and not being able to
squeeze all the juice outta it because mplayers' maintainers seem to do
all what they can to put libavcodec in front, despite doom9 codec
comparison, can be frustrating.


> That explains why, today, you have a ve_xvid4.c module sharing
> lot of options names with the old ve_xvid.c though their
> behavior differs slightly. Same remark concerning the codec's
> default, some maintainers complained that xvid 1.0 was too
> slow and they wanted it to be as fast as xvidcore 0.9.x...
> they didn't find any better solution than returning to 0.9.x
> codec default values... that is disabling almost all new
> features in xvid 1.0 except bframes.
Umm... I'm kinda puzzled... did those people benchmarked a XviD-2-pass
with lavc-2-pass? With all XviD advanced options activated (including
qpel and turbo mode) XviD beasts lavc right up both speed-wise and
quality-wise. Ok, maybe lavc has so many options that you can carefully
tune them to reach XviD's quality and speed, but I gave up.

> So now i understand your position, you want to ddoucment all
> this, but you're left with a mess.
> 
> To answer your very specific question:
> 4mv was depreciated, and all is taken care by the me_quality
> option, me_quality>4, 4mv is activated.
> 
> If at anytime you need precise information about what option
> does what, refer to the dispatch_settings() function. It
> embends the entire logic hidden behind the options.
Thanks for pointing me to this piece of code. It was pretty
enlightening.

> > I also saw that the option that allowed manually raise the quantizers
> > for credits (at least with a 0.9.x build) was out too... Is it also not
> > supported by XviD-1.0.x too ?
> > I personally find this kind of option quite convenient.
> 
> There is no strict equivalent, but a better solution in xvid
> 1.x. That's called zones.
I saw some occurrences in libmpcodecs/ve_xvid4.c
/* Encodings zones */
        memset(mod->zones, 0, sizeof(mod->zones));
        create->zones     = mod->zones;
        create->num_zones = 0;

and (about CBR)

 /* Quantizer mode uses the same plugin, we have only to define
                 * a constant quantizer zone beginning at frame 0 */

So, if I understand correctly, zone are currently used in XviD, but
instead of having several zone, for normal movie, credits and stuff,
there's just one zone?

> So... the time going, i just forgot about this feature.
That's maybe a silly question, but do you have any idea if it would make
sense (would it be wise too?) to partially support multiple zones with a
semantic close to lavc's "vrc_override"?

> > Please consider not this mail as a user request, but as someone who
> > wants to bless mencoder users with the best XviD support I can afford.
> 
> All feedback is good, even if sometimes it's negative.
Glad to know that.

I have one more questions if you don't mind:
when compressing an intrelaced video (say, from a camcorder) is it still
wise to activate the "interlacing" option when the video is rescaled? (I
tend, from my experiments, to think that "interlacing" can't work well
on rescaled content, but I'm maybe wrong).

Thanks for the good work and I'll see you around Linuxfr! ;-)

Regards,
Guillaume



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