Quantization values

[erossetto]

Ok, I'm using:

Min/Max I-frame: 2/31
Min/Max P-frame: 2/31

Anyway, I don't get great quality... bitrate is ok (around 950kBit/s) so I think this values may be wrong...

Any tip on how set them to get nice results?

/ I use lumimasking BTW

[manono]

Hi-

I don't think you can blame it on XviD. It probably has more to do with the bit rate, resolution, and your source DVD. I'd suggest running a Compression Test first to make sure you've chosen the correct resolution for the given audio and video file size.

[erossetto]

I don't blame XviD, I blame myself for not knowing how to use it, that's why I came here for help :)

I've tried with this:

Min/Max I-frame: 2/3
Min/Max P-frame: 2/6

The result it's better, but I think I still need to work a little with the AltCC config.

Well, thanks anyway.

/ The DVD source is very good

[Teegedeck]

If you gotta reign it in by quantizer-limitations, try 'low aggression' for alt.CC. Alternatively, some people have reached very good results by using 'linear' scaling, i.e. traditional CC with high and low set to '0'.

[Koepi]

For getting a basic idea of the options to fidle around with you may want to read the help-file which is included in my builds. It is the same as XviD Options Explained which you can find following the link in my signature.

Regards
Koepi

[iago]

@erossetto

Even using the default values (with only a few changes: Motion search precision -> 6.UltraHigh) you can achieve good-quality encodes with XviD. However, I'd suggest NOT to use "lumi masking" and "MV hints". Moreover, disabling "alternative curve system" and setting high/low: 0/0 in the "Two Pass" tab will also give you good results. However, the compressibility of the source is an important factor, as mentioned by manono, to decide on the target size and the resizing method.

BTW,

Min/Max I-frame: 2/3
Min/Max P-frame: 2/6

may be too restrictive values (for most sources) that will prevent you from achieving good quality. Try setting them as:

Min/Max I-frame: 2/6
Min/Max P-frame: 2/12 (or 2/16)

regards,
iago


edit1: you can set Min I-frame distance to 5 (default: 1) to prevent the overuse of bits for consecutive I-frames.

edit2: you can also consider using a stable build (Koepi's 04102002-1 for example) to avoid possible problems that might arise from the B-frames and QPel options in dev. builds, though they also seem to work well for most people.

[erossetto]

@Koepi
I will, I'm using your latest build.

@iago
I'll try with:

Min/Max I-frame: 2/6
Min/Max P-frame: 2/12

With no lumimasking.



Later I'll post how the results came.