XviD presets thread

LordIntruder · 1st February 2007, 00:34

Hi,

1) I would like to know what can be the drawbacks of settings Max i p b-frame Quantizer so low (4 or 5)? I can't find any info on that, I get thousands of messages by searching 'max i-frame'

I encoded a whole movie both with default XviD settings (1-31) and the same with 30% preset sett

ings (3-5), Bitrate is 1400 aim at 2 CD.

I can't see any difference except on fast motion where I get a better result but I think it is due to the 'high bitrate scene degradation' setting that improve and give more bit.

Why force a so low i p b-frame quantizer then? Maybe the differences appear very clearly on low bitrate (1400 is already quite a good one)? I spend one hour to examine and compare both encodes and when I get a bad encoded sequence by using default settings (1-31 quantizer), the 30% preset encode looks same. I would like the opinion of those who made comparaisons, thanks.

Another thing: I use DRF Analyser, is that a good tool or is it something better to know how much frames use x quantizer?

2) By using DRF Analyser I get this:

Xvid Default Setting:
-------------------

DRF=1&2: 246 0.1%
DRF=3: 1570 0.9%
DRF=4: 19112 10.5%
DRF=5: 46989 25.7%
DRF=6: 15760 8.6%
DRF=7: 46021 25.2%
DRF=8: 38816 21.2%
DRF=9: 11393 6.2%
DRF>9: 2822 1.5%
KeyF/DeltaF: 0.66%
KeyDRF<4: 23
KeyDRF=4: 589
KeyDRF>4: 599

AverageKeyDRF: 4.78
MAXDRF: 22
AverageDRF: 6.44
Deviation: 1.61

30% preset settings:
-------------------

DRF=1&2: 0 0.0%
DRF=3: 2437 1.3%
DRF=4: 8570 4.7%
DRF=5: 60375 33.0%
DRF=6: 8713 4.8%
DRF=7: 31242 17.1%
DRF=8: 71392 39.1%
DRF=9: 0 0.0%
DRF>9: 0 0.0%
KeyF/DeltaF: 0.66%
KeyDRF<4: 18
KeyDRF=4: 894
KeyDRF>4: 299

AverageKeyDRF: 4.43
MAXDRF: 8
AverageDRF: 6.48
Deviation: 1.47

What I do not understand is that the 30% preset use Quantizer between 3 and 5 but my encode have quantizer 6, 7 and 8 used. Can someone explain me that?

3) I noticed ine MEGUI the 'I-frame boost' is set to '100' with those preset. Is it a bug or a correct setting? I think the correct value is '10' is it not?

Thanks you.

1st February 2007, 00:34	#10 \| Link
LordIntruder Registered User Join Date: Jan 2003 Posts: 109	Hi, 1) I would like to know what can be the drawbacks of settings Max i p b-frame Quantizer so low (4 or 5)? I can't find any info on that, I get thousands of messages by searching 'max i-frame' I encoded a whole movie both with default XviD settings (1-31) and the same with 30% preset sett ings (3-5), Bitrate is 1400 aim at 2 CD. I can't see any difference except on fast motion where I get a better result but I think it is due to the 'high bitrate scene degradation' setting that improve and give more bit. Why force a so low i p b-frame quantizer then? Maybe the differences appear very clearly on low bitrate (1400 is already quite a good one)? I spend one hour to examine and compare both encodes and when I get a bad encoded sequence by using default settings (1-31 quantizer), the 30% preset encode looks same. I would like the opinion of those who made comparaisons, thanks. Another thing: I use DRF Analyser, is that a good tool or is it something better to know how much frames use x quantizer? 2) By using DRF Analyser I get this: Xvid Default Setting: ------------------- DRF=1&2: 246 0.1% DRF=3: 1570 0.9% DRF=4: 19112 10.5% DRF=5: 46989 25.7% DRF=6: 15760 8.6% DRF=7: 46021 25.2% DRF=8: 38816 21.2% DRF=9: 11393 6.2% DRF>9: 2822 1.5% KeyF/DeltaF: 0.66% KeyDRF<4: 23 KeyDRF=4: 589 KeyDRF>4: 599 AverageKeyDRF: 4.78 MAXDRF: 22 AverageDRF: 6.44 Deviation: 1.61 30% preset settings: ------------------- DRF=1&2: 0 0.0% DRF=3: 2437 1.3% DRF=4: 8570 4.7% DRF=5: 60375 33.0% DRF=6: 8713 4.8% DRF=7: 31242 17.1% DRF=8: 71392 39.1% DRF=9: 0 0.0% DRF>9: 0 0.0% KeyF/DeltaF: 0.66% KeyDRF<4: 18 KeyDRF=4: 894 KeyDRF>4: 299 AverageKeyDRF: 4.43 MAXDRF: 8 AverageDRF: 6.48 Deviation: 1.47 What I do not understand is that the 30% preset use Quantizer between 3 and 5 but my encode have quantizer 6, 7 and 8 used. Can someone explain me that? 3) I noticed ine MEGUI the 'I-frame boost' is set to '100' with those preset. Is it a bug or a correct setting? I think the correct value is '10' is it not? Thanks you.