[XviD-devel] minor changes / todo list

[Marco Al]

From: "skal" <skal at planet-d.net>

> But, one could imagine maximizing the PSNR for a particular
> block (or frame, say) is not what it's all about. Maybe
> lowering the bias will incur damage on the PSNR, but since
> it decreases the coded level by 1, the bits saved coding
> l'-1 instead of l' will later (next frame) be better used.
> That's why one could image a decimal quantizer, where the
> integer part is the real Quant value, and the fractional one
> controls the bias... or the dead-zone (in this latter
> case, the fractional part control the amount of RUNs
> being coded). This seems to me like a poor's man
> rd-optimization almost free of computational burden.

I dont think it unlikely that the level adaption this method supplies is
mostly inconsequential, and maybe even counterproductive in a R-D
sense, and most of the gain comes from the increased deadzone ...

Even if you want very low overhead there are smarter ways to adapt
the deadzone I think (but Id have to think a lot harder to come up
with one :).

How much faster could the trellis search be done if you only allowed
zeroing of coefficients BTW?

> does it make sense?

FFMPEG uses this right? It seems to make sense to some.

Marco