Quick VP6 and XviD test

[Bulletproof]

Here's a quick test I did with the latest XviD and VP6 builds..

Subject:
Hellboy

2-Pass Bitrate:
2160

Settings:
XviD - Qpel, Chroma Motion, VHQ1 only, vbr options default.
VP6 - Sharpness 10, Keyframe 300, Q2 to Q31 (as in XviD), rest vbr options default.

Notes:
VP6 can deliver more detail now than XviD by setting it's sharpness level to 10, however you also have to keep in mind that this also shows sharper macroblocks. Also, even though VP6 delivered a sharper picture, it did not raise the filesize at all, in fact it came out 2 megs less than the XviD file. VP6 still has problems with keyframes, it still misses them and possibly uses too high quantizer for them. Even though XviD does not deliver the same detail as VP6 it is still more practical to use, macroblocks are nicely blended and when you use every single option available to save bits then your picture integrity will be better when you have size constraints. VP6's strong points are that if you don't care about bitrate it can deliver a better picture, it also handles extremely low bitrates very well and it's post processing engine is one of the best i've seen, it really helps to improve the picture without making it look "pastey". You could argue that even the sharp macroblocking would go away with post processing, which might be true, but in any case both VP6 and XviD are really good codecs and I'm hearing H.264 is going to stir things up as well. Also, for some reason the VP6 file had a green line at the bottom.

Seems like images aren't working, if they arent then try http://pbase.com/dfein/inbox

Pictures:

VP6 (Note his cheek, you can see the pores):
http://genji.image.pbase.com/u43/dfein/upload/27917775.VP61.PNG

XVID:
http://genji.image.pbase.com/u43/dfein/upload/27917964.XVID1.PNG

VP6 (VP6 did not do well here, the smoke is too blocky, possible missed keyframe?):
http://genji.image.pbase.com/u43/dfein/upload/27917779.VP62.PNG

XVID:
http://genji.image.pbase.com/u43/dfein/upload/27917840.XVID2.PNG

VP6 (Hair and clothes seem sharper):
http://genji.image.pbase.com/u43/dfein/upload/27917788.VP63.PNG

XVID:
http://genji.image.pbase.com/u43/dfein/upload/27917868.XVID3.PNG

VP6 (Missed Keyframe!):
http://genji.image.pbase.com/u43/dfein/upload/27917790.VP64.PNG

XVID:
http://genji.image.pbase.com/u43/dfein/upload/27917873.XVID4.PNG

VP6 (Macroblocks are sharp here, and are smoother in XviD):
http://genji.image.pbase.com/u43/dfein/upload/27917794.VP65.PNG

XVID:
http://genji.image.pbase.com/u43/dfein/upload/27917900.XVID5.PNG

VP6 (Smoother macroblocks in XviD make better high action transitions):
http://genji.image.pbase.com/u43/dfein/upload/27917828.VP66.PNG

XVID:
http://genji.image.pbase.com/u43/dfein/upload/27917902.XVID6.PNG

[GolovachLena]

Originally posted by Bulletproof
Also, for some reason the VP6 file had a green line at the bottom.


The reason for this is incorrect height to width ratio or incorrect height modul (not 16 or 32).
I don't think limiting Quantization in VP6 in Xvid-like way have much sense, because VP6 treats Q in different way than Xvid. A one can play with undershoot, variability and min/max section settings, think it's more useful.

[virus]

Originally posted by Bulletproof
Also, for some reason the VP6 file had a green line at the bottom.

Probably the reason is that you use 450 as height. This is not even mod4... :)
I'd suggest to resize to 800x448 in your case.
Have you tried setting sharpness to 7-8? It may reduce artifacts quite a bit, with very little loss in sharpness.
Also, note that default quantizers are 2-31 for XviD (this was recently changed to 1-31 but the old settings are better IMHO), and 4-56 for VP6: there must be some reason behind ;)

hope this helps
virus

[Sirber]

no need to overresize, matroska supports anamorphic :)

[edit]

Doed someone know about VP6 and grainy source?

[kilg0r3]

This confirms what I have been thinking for quite some time now. Since the sharpness is mainly a matter of the quantization matrix applied, the postprocessing becomes an important factor for judging the quality of a codec package. And, I must say the VP6 postprocessing currently is definitely the best out there. One reason is that it seems to use noise to cover blocks, adjusting the amount of noise applied to the degree of blockyness.

Without PP the VP6 codec is not very good because it easily produces many visible blocks when using a shapness value like 7.

[bond]

i dont think the sharpness option is only postprocessing, as to use it on2 created a new profile, which means that its not compatible anymore to the other profiles i think

[kilg0r3]

Originally posted by bond
i dont think the sharpness option is only postprocessing I said: 'the postprocessing becomes an important factor for judging the quality of a codec package.' Sharpness is more a matter of the quantization matrix applied; strong or weak compression of high frequencies.
What makes PP so important, is the fact that bad PP (e.g. IMHO ffdshow's) can affect the material so badly that it degrades the perceived visual quality considerably; e.g. pumping macro blocks, excessive blurring. Bad PP makes itself recognizable as such.
Good PP as in the case of VP6 is not recognizable, at least not immediately and it 'corrects' errors effected by the encoder. IMO noise in the form of artificial film grain is one of the best ways to hide artifacts. However it does not make sense to apply the same amount of noise to regions with less blocking as to those which contain a lot of blocks.

After all, the result we see on the screen is the product of both compression and PP. So there is no rational reason for that 'purist' attitude towards PP as something useful only for the visually impared.

In Xvid's case we have a very good compressor which IMHO lacks a PP counterpart of parallel quality. I really hope that the Xvid devs put some effort in the PP routines because it is a relevant aspect regarding the choice which codec to use.

all the best, kilg0r3

[bond]

maybe i should read other peoples posts more carefully next time :D
sorry, somehow i thought you talked about the sharpness option as PP :)

[kilg0r3]

at least, we talk to each other ;)

[Bulletproof]

Sorry I didn't reply sooner, I forgot to mention there is no post processing in any of those pics, and although you could give a quantizer matrix to XviD to increase its sharpness it often increases the size of the resulting file, the VP6 file came out 2 megs less than the XviD one using H.263.

[kilg0r3]

Originally posted by Bulletproof
although you could give a quantizer matrix to XviD to increase its sharpness it often increases the size of the resulting file If you do two-pass there is no impact on filesize.

BTW are there any known problems of VP6 in Matroska?

[Sirber]

For a 2h55 movie,

XviD: 20h
VP6: 30h

Hardware in my signature.