Quarter pixels???

[dragoman]

"Quarter pel. DivX Pro includes the capability to analyze block movements from frame to frame to the quarter pel level."

Hi,

I'm wondering about the quarter pixel feature in DivX 5.0 Pro. The readme says it can anaylyze the difference down to the quarter pixel level. Does this mean that when encoding the different delta frames with reference to the key frames, the size of the macroblocks that change in the keyframe will be smaller, thereby looking smoother?

I know I'm kinda asking this clumsily. Anyone get me?

dragoman

[Helmut Hamburger]

uve got it dude

have u seen how small the macroblocks are? its nuts

[trbarry]

Is it just my imagination or do 1/4 pixels shift the color a bit, making it slightly more greenish?

- Tom

[Teegedeck]

Qpel actually doesn't relate to macroblocks but to motion-vector-search accuracy. The size of macroblocks is defined in the MPEG4-specs.

Greater accuracy in motion search is supposed to be more efficient, i.e. produce a smaller bitstream. But that's theory for you, and there are reports that activating qpel in DivX5 has an adverse effect on filesize. Can't test it now, though. Would you mind doing that?

[dragoman]

Hi,

Well, just completed my second encode with DivX Pro 5.0

I activated everything again, using Qpel, GMC, Psycho-whatever, etc...

The first was Independence Day: Special Edition. With an average bitrate settins of 1000kps, min quant 2, max 12, I got a filesize of .99GB for a 2hr, 35min movie. NOt bad, muxed with ac3 sound for almost perfect 2cd rip.

Quality? Outstanding. Could not see any macroblocks on surfaces, which was a major gripe of mine for DivX 3/4. Now there are none.

Second rip was of Mr. Mom dvd. (just leave that alone, shall we? :) )

Settings were almost same, but abr was set to 900kb/sec. All other goodies were turned on, no post processing used.

Filesize is 591MB with no audio. And the quality is great. Sometimes in the past I had trouble with DivX 3/4 rips turning out darker, more subdued with the colors on my monitor. If you played the dvd and encode side by side there was no trouble seeing which was which.

No longer. DivX 5.0 Pro encodes so far are as bright and artifact free as the dvds, at least from what I can see.

So far I love this codec!!

dragoman