[XviD-devel] Trellis Quant problems with current dev-api-4

[skal]

	Hi all,

On Thu, 2003-06-19 at 17:02, Char Acter wrote:
> Trellis quant produces DC offset on some blocks.  I'm
> getting visible 8x8 block artifacts in my image
> (especially noticeable in flat areas) where the DC
> luminance level is way too low (dark).  At least
> that's how it appears to me.
> 
> I'd like to ask a couple of questions to the TQ
> developers:
> 
>     Is TQ in current dev-api-4 functioning correctly?
> and
>     Does TQ modify the DC coefficient?
> 

	i've been asking on IRC, but it seems
	not all people have experienced this
	bug with VHQ4. Looking at the code,
	i didn't see anything obviously wrong
	with the levels modification. It might
	well be an overflow problem elsewhere
	in the code, triggered by the TQ, dunno.
	So,

	do you have the exact setting (H264 Quant?
	Q? 1rst pass, etc...) and the version
	number you're using that cause the bug?
	Could try do add some printf() in the
	code before and after the TQ? etc...

	bye
		Skal