Xvid File prediction problem with Koepi's XviD-09122002-1.exe

[tfh69]

Hello ,
Recently I have tried encoding several movies with Xvid which ended up undersized . Latest example ( the worst ) :

Film :Audition
Asked for 636558kB Ended up with 533502kb


My settings are exactly the one advised in "Xvid Two pass ENcoding" :
Bframes enabled
Qpel enabled
Lumi MAsking enabled
Chroma Motion Estimation enabled
GMC Disabled
Linear Curve
( Forced Credits to be encoded at Q25 )


Anybody encountered the same problem ??
Anyone has an idea to solve it ?

Thanks

tfh

[serbersan]

Maybe the undersized problem is due to the use of bframes.

There are more threads about this problem. The bframes decrease significantly the final size and in some cases this could cause the undersize... but only because with your settings you have saturated the codec.

Use more resolution, better resize filtering or disable b-frames.... and search before post, please.

[mikeson]

@tfh69:

I don't think it is because of B-frames, maybe good compressible movie.

Some movies (Matrix for example) are very good compressible. So you can end with undersized file even when using constant quant 2 encoding.

because with your settings you have saturated the codec

Yes, it is possible, I agree with that.

Just my 2 cents. :)

[tfh69]

I think you might be right because the movie is very dark with little motion .

I'm still surprised the codec doesn't have any use for the extra 100 mb :)



tfh

[mikeson]

@tfh69:

Try to increase resolution or you may disable extra codec features (b-frames and so on).

[DBaT]

@tfh69

It just seems that you use way to aggressive settings for your
encode. I haven't had any problems with filesize using current build and b-frames. Just increase resolution, drop Qpel and Lumi and/or maybe use lancroz resize filter. If you still have space go for AC3
audio.

With your next encode save your first pass or use debugview to see your quants distribution for second pass. Propobly your first pass already hit under your target file size with quant2.

[neo_sapien]

I'm getting an undersized file too, with default settings, more or less:

Settings for XviD (11/24/2002 12:50:10 PM)
Mode: 2 Pass - 2nd pass Int.
Dummy 2nd Pass: OFF
Desired Size: 1011609KB
I-frame Boost: 0%
Below I-frame Distance: 10%
I-frame Bitrate Reduction: 30%
Curve Compression: Payback with Bias, Bitrate Payback Delay: 250frames
High Bitrate Scenes: 25%, Low Bitrate Scenes: 10%
Hinted Motion Estimation: OFF
Alternative Curve System: ON, Curve Aggression: Medium
High Distance from Average: 25% Low Distance from Average: 10%
Automatic Minimum Relative Quality: ON, Strength: 30
Automatic Bonus Bias Calculation: ON
Motion Search Precision: 6 - Ultra
Quantization Type: MPEG
FourCC Used: XVID
Max I-frame Interval: 240, Min I-frame Interval: 5
Lumimasking: OFF
Interlacing: OFF
Greyscale: OFF
Chroma Motion: ON
Quarterpel: OFF
Global Motion Compensation: OFF
Max B-frames: 4
B-frames Quantizer Ratio: 100%
Packed Bitstream: OFF
DX50 B-VOP Compatibility: ON
Print debug info on each frame: OFF
Min I-frame Quantizer: 2, Max I-frame Quantizer: 2
Min P-frame Quantizer: 2, Max P-frame Quantizer: 31
Max Bitrate: 10000kbps, Max Overflow Improvement: 60%, Max Overflow Degradation: 60%
Start Credits: OFF, End Credits: 174384-180843
Encode credits in greyscale: OFF
Credits I-frame Quantizer: 14, Credits P-frame Quantizer: 14

These are basically default settings with B-frames and chroma turned on, i-frames locked at 2 and MPEG quant plus credits. The first pass stats file loads in GKnot as 90.9% at the desired file size, so it's not too saturated, and the resulting file comes in 80 megs too short, which would make it about 82%.

I've been using Iago's settings for a while now and just yesterday pushed "Load Defaults" to see how it worked, I'm guessing it's the alt curve compression which is generating a smaller file. I'm running a 2nd pass now w/out alt curve to see if it's the right size.

EDIT~Crap, I shouldn't have posted this, I'm using 11/24/02 version.