[XviD-devel] "Automatic" settings

[Michael Militzer]

Hi,

----- Original Message -----
From: "peter ross" <suxen_drol@hotmail.com>
To: <xvid-devel@xvid.org>
Sent: Monday, November 04, 2002 11:31 AM
Subject: Re: [XviD-devel] "Automatic" settings


> >From: Christoph Lampert <chl@math.uni-bonn.de>
> >Hi,
> >
>
> g'day
>
> >with the new features in branch, we should start working on another
> >target: Usability/User friendlyness! It's impossible that Joe User who
may
> >not even be able write the word "Quarterpel" would know what it means and
> >when to activate it. Even us programmers don't know when Quarterpel
lowers
> >filesize and when it doesn't...

yes, fully agreed. Therefore I suggested some time ago to create new quality
presets ranging from 1-10 and all those new features should be somehow
hidden into those quality levels (bframes, qpel, gmc etc.). As a result, Joe
User has only one quality slider which determines picture quality as well as
encoding speed - I think this should be easy enough...

> i like michael's idea of having a profile selection box, which lets
> the user limit encoding features to the selected profile.

I like the idea too ;-))

> >I would suggest we try to create some kind of "automatic" mode for
> >some of the flags: Either based on heuristics (like dynamic bframes:
"long
> >MVs -> no bframes") or on simple trial and error (encode the first frame
> >after an I-VOP with and without a feature like QPel/GMC, use the best
> >combination for all other frames of this sequence.
> >
> >Then the GUI could have buttons like "Auto" for every special feature,
> >and if the user changes this to "On" or "Off" it's his own fault.

I'd suggest not to introduce special checkboxes for the new features at all
(at least not in the standard GUI, maybe we could create a special
developer's GUI with more options as well which is hidden by default...).
Joe User has no idea what "quarter precision motion estimation" / "global
motion compensation" etc. means. So those options should be hidden (maybe
within one quality slider as proposed above). It should of course be one of
our major goals to develop clever automatic modes (like dynamic b-frames,
adaptive qpel etc.). If this works reliable, it should simply be activated
by default (without any further checkboxes)....

> dan suggested something like this, an XVID_ENC_RENCODE function,
> which reencodes the data using a different configuration.
> the problem is, that quant_type, gmc, and qpel are all vol-based
> parameters. its unknown whether changing these during a video
> sequence is permited by the mpeg-4 standard.

that's true. And even if VOL placement at i-frames only is ok (which I
believe it is), then features like "modulated quant" are not really possible
anymore (and adaptive qpel is at least not easy to do...)

bye,
Michael