Videos encoded w/ Vdubmod = less saturated/vibrant? (Example video inside)

[ahphoto]

I use a Canon EOS 5D Mark II to record video and in order to get the videos into a playable non-laggy format for my computer I'll usually convert them from H.264 MOV files to Xvid AVI files with VirtualDubMod and AviSynth using the steps in these instructions. However, I noticed that when I do this the resulting video is significantly duller/less saturated than the original. I tried encoding a few videos with Avidemux with the same settings and the saturation was no different than the original. Why is this, and what can I do about it?

I'm used to Virtualdub/Virtualdubmod and Avisynth so I'd like to continue using them, I'd just like to figure out how to get the videos I edit with them to have the same levels of saturation as the originals.

By the way, here's what I mean about the difference in encoded videos:
http://vimeo.com/16639535

The first 6 seconds were encoded with Avidemux and the second 6 seconds were encoded with Virtualdubmod + Avisynth. They were both encoded using the same settings (Xvid, Single Pass, Quality = 4) and no other filters or changes were applied.

Thanks in advance for any help!

[manono]

Did you set Video for Fast Recompress in VDubMod, as you should have?

[jagabo]

Quicktime alternative converted to RGB without using the usual rec.709 contrast expansion (it used the PC.709 matrix instead). You can use the levels filter to adjust the levels after DirectShowSource(). I think this is right:

DirectShowSource(...)
Levels(16,1,235,0,255,coring=false)

You can also use VirtualDub's Levels filter with those settings.

Or you can use ConvertToYUY2() with the proper matrix:

DirectShowSource(...)
ConvertToYUY2(matrix="PC.601")

Then VirtualDub will convert to RGB with the correct levels when filtering.

Of course the best solution is to use a decoder that doesn't convert to RGB. Get rid of Quicktime Alternative and use Haali along with ffdshow or some other h.264 decoder.