Quality Jumps

[BlacKnighTTT]

Hi all !

I'm new to XviD and have a question before my problem : Whic version of the xvid codec is the latest ? 1.1 or 1.0.3 ?


Well, I notice some macroblocks with a movie encoded in 2 passes at 905kbps.


Sometimes, the quality is very good :



http://membres.lycos.fr/guiloknight/good.jpg



But sometimes, we can notice a lot of macroblocks :



http://membres.lycos.fr/guiloknight/bad.jpg




How can i reduce these macroblocks ??

Configuration :

Xmpeg 5.02
H.263 quantization
Adaptive quantization
GMC
B-VOPS
Closed GOV
Motion search precision ultra high
VHQ Mode : Mode decision
Use Chroma motion
All the ohter settings are default

[communist]

Originally posted by BlacKnighTTT
Hi all !

I'm new to XviD and have a question before my problem : Whic version of the xvid codec is the latest ? 1.1 or 1.0.3 ?
1.1 is the latest unstable version.
1.0.3 is the latest stable version.

If you like it safe then go with 1.0.3 - if you want to experiment with the latest stuff then go with 1.1 but note that its really only for testing out the newest features.

[Teegedeck]

Could you try with VirtualDub instead of Xmpeg?

[Ark]

Originally posted by BlacKnighTTT
Configuration :

Xmpeg 5.02
H.263 quantization
Adaptive quantization
GMC
B-VOPS
Closed GOV
Motion search precision ultra high
VHQ Mode : Mode decision
Use Chroma motion
All the ohter settings are default

I suggest you to use VirtualDub (i don't know if xmpeg has problems in xvid encoding, and afaik is discontinued, but VDub is more used and probably a "safer" choice).

For settings:

- Try some custom matrices like Sharktooth's (there's a thread just here in xvid section), or Jawor's (1cd and the new 2cd) or the infamous SixofNine.
- B-vops at default values (in case you changed them)
- VHQ: use 4 for best quality (but that slow down encoding a lot)
- I suggest you to select Trellis quantization.

If you try the 1.1 build you can even select VHQ for b-vops too (that should increase b-vops quality)

Btw, what's your movie resolution/lenght, target media and size...

[BlacKnighTTT]

I have unactivates Aaptive quatization and results are better. Are the custom matrices better than the H.263 in all cases ?

Trellis quantization : Does it slow donw encoding ? What does itdo ?

Xmpeg : Never heard of problems with Xvid and VirtualDubMod is slower.

Thanks a lot

[Ark]

Originally posted by BlacKnighTTT
I have unactivates Aaptive quatization and results are better. Are the custom matrices better than the H.263 in all cases ?

Trellis quantization : Does it slow donw encoding ? What does itdo ?

Xmpeg : Never heard of problems with Xvid and VirtualDubMod is slower.

Thanks a lot

AQ in short quantize more very dark/bright areas that the eye can't see very well, but it's not perfect, though it should slightly increase overall quality at the same filesize.

Custom matrices are a hard task to judge. There are matrices well suited for specific encoding situations, so my answer it's that it depends on your source and compressibility ratio.

In some cases H263 may be better, in another may be MPEG , in other etc...

You have to try for yourself, or to do a search in this forum, there are many comparisons (like Soulhunter's).

Trellis do a different type of quantization that in general *should* increase quality.

Probably Xmpeg has nothing wrong, but VDmod is safer for me, and i can't say if Xmpeg force a colorspace conversion (i.e. YV12 > RGB > YV12 (xvid)) like other programs do.

And why you say that VDMod is slower? The fastest encoding application i know is AVS2AVI, and AFAIK VDMod is only slightly slower...