Codecs (Sorenson / divx)

Cyclone · Post by **Cyclone** » Thu Jul 26, 2007 11:59 am

Hi I have a question regarding these two codecs. I noticed when I output my animation to Sorenson(quicktime) the colors look really washed out and the blacks not really black. On the flip side Divx(wmp) looks a bit oversaturated compared to the original uncompressed animation. Blacks still look black though.

So I am wondering why Sorenson compression looks so washed out and blacks looking dull. Am I doing something wrong?

Thanks for your help.

MD-2389 · Post by **MD-2389** » Thu Jul 26, 2007 7:35 pm

It has to do with the compression method. When I tried different codecs (I've got a vid capture card), I found that straight mpeg2 looked the best. Both Divx and Quicktime looked horrible by comparison.

fliptw · Post by **fliptw** » Thu Jul 26, 2007 7:45 pm

you have to get into the nitty gritty settings of each codec in order to get reasonable results outside of video that moves at a average pace.

Krom · Post by **Krom** » Thu Jul 26, 2007 8:31 pm

It can also be the result of the video card/driver doing crappy color conversions. Those can generally be cured by forcing the CPU to do the color space conversions, and setting the video driver overlay surface to do nothing. It slows down the decoding slightly, not so much that it will impact most standard definition DVD sized encodes, but HD stuff at 1280x720 might get iffy and 1920x1080 is going to be unplayable on all but the absolute top of the line systems.

Cyclone · Post by **Cyclone** » Fri Jul 27, 2007 3:35 pm

I think krom is right in the fact its drivers?

For some reason when I go into the quicktime player preferences and uncheck all of the boxes in the DirectX category my animation apears almost identicle to the uncompressed animation.

So this must be a video card/driver issue? I noticed the same problem on some other computers which were using similer video cards... but i dunno

Krom · Post by **Krom** » Fri Jul 27, 2007 4:24 pm

What is the video card exactly?

Cyclone · Post by **Cyclone** » Fri Jul 27, 2007 7:24 pm

I am using a Geforce 6800 ultra. The comps at my school that had the same issue were also geforce 6800 but not ultra.

Krom · Post by **Krom** » Fri Jul 27, 2007 8:38 pm

Driver version? I had no problem with my 6800 GT (granted, I was using CCCP which is based off ffdshow with settings designed to avoid those problems and quick time alternative).

Cyclone · Post by **Cyclone** » Sat Jul 28, 2007 12:11 am

hmm... not sure if this is right but it says Video BIOS 5.40.02.15.11 and ForceWare version 91.31.

I just tried playing the sorenson3 quicktime animation in VLC Player and the picture was very saturated even more so then when I play the divX version in windows media player.

This is a bit confusing since theres so many inconsistencies.

Sorenson3 in quicktime = light
Sorenson3 in quicktime with directx off = almost perfect to the original
Sorenson3 in VLC = too dark and saturated

DivX in WMP = more contrasty colours and blacker blacks but I actually kinda like this more then the original
DivX in VLC = a bit darker then in WMP

I don't know how all this stuff works but I think each video player uses filters on the video while playing and thats why things are inconsistant. Maybe theres also problems with my display settings since the video looks more accurate with DirectX off in Quicktime?

thanks

Krom · Post by **Krom** » Sat Jul 28, 2007 9:14 am

Well you can update the driver version to 94.24 which is the latest, and then go into the nvidia control panel. Select Video & Television then Adjust video color settings. Check and see what the sliders are all set to (+50 is the neutral setting), defaults make the video slightly rich.

Cyclone · Post by **Cyclone** » Wed Aug 08, 2007 1:46 pm

Thanks Krom. I downloaded the latest drivers and they did seem to make a difference I think in quicktime. All my nvidia settings were messed up though and the defualts made vids in media player look even darker and my monitor colors changed a bit to.

I wrote my settings before I installed the new drivers but these settings didn't seem to look the same.
I ended up reinstalling the older drivers. I will install the new ones when I have time to reconfigure my monitor.

I really need one of those monitor calibrators!

Thanks for the advice.