Quality Difference: 'Full Processing vs. Fast Recomp.?

[kilg0r3]

Just found the following post from kappa in thread http://forum.doom9.org/showthread.php?s=&threadid=24351:


[...] I too use light P[sychovisual]E[nhancement] for all my rips [...] I had found that using full processing mode [...] the known artifacts disappeared. I also use ligh pre- processing, it has absolutely no visible difference and it improves compresability.


I repost it here as a new thread in order to get a more differentiated response. What are your experiences? Do you get better results with DivX in full processing mode?

[midi]

I've always avoided full processing mode in virtualdub as the few test encodes where I used it had their colors altered (comparing DVD playback vs fast recomp divx playback vs. full proc divx playback). I find the damage done to blues from that extra RGB color space conversion (and back since its compressed in YUV, isn't it?) particularly bad. I realize thats a tad OT, but it is an issue here. ^^

In regards to full proc. mode in virtualdub affecting artifacts from psychovis. in the divx codec, it seems an odd claim to me. I admit its possible especially since divx.com lists both RGB and YUV input to the encoder are acceptable, so the codec would be getting different data from virtualdub to work with. So my experience would say no full proc. although for reasons first mentioned I avoid it like the plague anyway.

[unplugged]

In fact, avisynth + mpeg2dec.dll is the key to use flawlessly VirtualDub...

Avisynth can make everything (and by default) in YUV mode.

Note however, that mpeg2dec.dll does NOT fit standard IEEE image quality requirements and has pretty visible decoding bugs with certain M2Vs.

[theReal]

I have never seen any visual differences between the compression modes, but I try to use fast recompress if I can because it's faster.

What I find highly questionable is this:
I also use ligh pre- processing, it has absolutely no visible difference and it improves compresability. I agree it improves compressability, but it does clearly show visible differences! It's a smoother filter, the question is only if it looks better with or without, but you see a difference for sure!