Lumi masking and quarterpel

[blackdiamond]

I have a question. Use these checked or no, for 1 CD rip? I use latest Koepi binaries. Is there a wider explanation what they do?

[Teegedeck]

Koepi's build uses an alternative lumi-masking that doesn't really perform adaptive quantization but acts as sort of a 'human visual system'-based custom quantization. It doesn't hurt, it works together with lumi-masking, but it doesn't help much either as far as I can trust my eyes IMHO. The original lumi-masking (present in the other builds) isn't recommended at all; its adaptive quantization hurts more than it helps - meaning that it's a rather crude way to save a lot of bitrate and that this isn't neccessary anymore, because nowadays XviD already compresses so well without it.

Yes, I would recommend to always use quarterpel. But other people strongly disagree. Choose whatever looks better to you.

There's been written so much about 'what these things do' that I don't want to repeat it. Search for it.

[sysKin]

Originally posted by Teegedeck
Koepi's build uses an alternative lumi-masking that doesn't really perform adaptive quantization but acts as sort of a 'human visual system'-based custom quantization.
Didin't you mean to say:
"Koepi's build uses an alternative lumi-masking that doesn't really perform lumi masking but acts as sort of a 'human visual system'-based adaptive quantization."
:)

Lumimasking was a crude HVS model for adaptive quantization. This new HVS model (coded by Refdivx) might be better, but in fact is mostly slower and doesn't do anything in 99% of frames (quantizer is still constant there).

@blackdiamond: there is a "Quarterpel" thread in this forum, many comments and opinions on qpel can be found there. It's recent, doesn't include any absolote information. Have fun reading.

Regards,
Radek

[Teegedeck]

Didin't you mean to say:
"Koepi's build uses an alternative lumi-masking that doesn't really perform lumi masking but acts as sort of a 'human visual system'-based adaptive quantization."


bummer:(

I really thought it only played with coefficients but didn't alter MB quants.

[symonjfox]

IMHO lumimasking is useless with nowadays Xvid version. I think that VHQ 4 works better than Lumimasking and it doesn't broke quality NO MORE! :D

A question:Lumimasking was a crude HVS model for adaptive quantization. This new HVS model (coded by Refdivx) might be better, but in fact is mostly slower and doesn't do anything in 99% of frames (quantizer is still constant there).Are you talking about Dev4 or Koepi Dev3 build?

I really hope that Dev4 will contain a good lumimasking. I think that if it is well done, it will still be useful @ low bitrates.
And also would be useful in real time caputres on "slow" computers, where VHQ is too heavy.