Fast recompress vs Full processing

[jerets]

Im using vdub to both capture and encode my tv captures. Im trying to use xvid to encode them. On the xvid-vdub guide in the Guides section (link below) it says to use Fast recompress... i was wondering why not Full processing mode? Whats the differences between the two and whats the benefit of one over the other?

http://www.doom9.org/xvid-vdub.htm

Thanks :)
jerets

[Belgabor]

Rule 1 does not only apply to forum content. This info can be found in the VitualDub help file :p

Please read up a bit more before you ask next time!

[jerets]

i read the help file in vdub and saw these.. but im still not 100% sure how all that effects what im trying to do. im still not sure whats best for me and what would give me the best results..

i cap in huffyvu and want to encode into xvid..

what are the advantages/disadvantages for using one over the other for what im doing?

thanks
jerets

[Belgabor]

Fast recompress is (like it says) faster and avoids unnecessary color space conversions, but can fail if the codecs can't find a common colorspace to use (Never happened to me). Full processing always uses RGB as intermediate color space (which is necessary if you want to apply vdub filters) and is therefore slower. Also keep in mind that color space conversions are somewhat lossy due to rounding errors (though you probably won't ever notice if you don't do it like a dozen times back and forth ;)).

[jerets]

thanks man. i appreciate the help.. guess im going to go w/ Full processing mode so i can use filters.

thanks :)!
jerets

[Belgabor]

I recommend you read around a bit on avisynth. Nearly everything you can possibly do with virtualdub filters you can also do there. It's a bit more complicated, but the speed gain can be tremendous.

[lancer]

theoretically a speed increase. I've yet to see it.

avisynth is no faster than virtual dub in my experience.

[Belgabor]

well, it entirely depends on your filter chain. If you e.g. use VDub filters in avisynth the speed gain is marginal. If you just crop&resize you will have a speed increase if you do it with avisynth in contrast to vdub.

[lancer]

this is it thought

I use either dust or a combination of STmedian and convolution for noise reduction, along with decomb, resize and letterbox.

Decomb kills me, convolution double kills me and if I use dust it drops to a crawl.

however that's to make the interim. then I can open the interim in tmpgenc using an avs file and that is stunningly fast. before it was about 30:1, it drops to about 5:1 in TMPgenc.