XviD encoding in 16 bits?

[lmb]

I'm sorry I was not sure where this thread belongs so I posted here. Mods if I am in error please move the thread.

Anyway, I have been re-encoding files using XviD for a little while now and if I use GK ripping a DVD it works extremely well for some reason or or other. But however if I convert a standard MPEG file to an XviD AVI it seems that it will encode the file in 16 bits as opposed to 24 bits which tends to make the video stream look a bit more washed and blurry than the original. I have been using VDub and VDub mod exclusively which is why I was not sure where to put this. Is this an error on my part? In VDub I made sure that the color depth is always set to 24 bit. Or is this a function of how I compress it? I am using a 2 pass method. If I set the compression to high, will it automatically fall back in color depth? I checked the color depth using QuickTime player on both the Mac and PC and it reports the same 16 bit. Is this an error in QT? The PC version, 6.2, won't play an XviD encoded file at all, but on OS X it will (sort of) play with the 3viD or ffmpeg codec installed. Are there any other utilities besides GSpot and VDub that will give me the info I need?

[mf]

ALL MPEG-4 video streams are YV12. That means 16 (or was it 12?) bits per pixel. There is no 24 bit. Some codecs will output that to satisfy some other applications, but your bpp will NOT affect your encode in any way. This only matters in RGB.

[Acaila]

The problem is that most applications only look at the bits-per-pixel-flag that is read from the AVI. And unfortunately VDub sometimes writes 16, sometimes 24 in there depending on the mode of operation you've used.
This does not however say anything about the actual bpp of the containing video stream. For YV12 this is 12 bpp btw, 8 bits for Y and an average of 2 bits each for U and V for every pixel.