Broken colors throughout a whole video

[Masutin]

Observed in only two files. The picture is mostly black and white or strange colors, colors lost or scattered irregularly. When saved as a snapshot or viewed in VirtualDub, the colors are fine. But when making a capture, the area of the video ends up blank. A latest codec pack installed. Tried a few players. Changing the renderer didn't help. The properties are exactly the same as of other files from the same source that play fine:
DivX5
YUV
Advanced Simple@L5
BVOP Yes
QPel No
GMC No warppoints
Matrix H.263

[johns0]

Best not to install codec packs cause they usually cause that type of problem,uninstall the codec pack and install ffdshow and see if that helps.

[olyteddy]

But when making a capture, the area of the video ends up blank.

ScreenCap doesn't work for overlay video modes. perfectly normal. Use the players frame grab function, or turn off acceleration.

[Masutin]

Using only the ffdshow filters didn't help. Looks like a hardware issue (e.g. the graphic adapter processes correctly but the TFT cannot show it for some reason), because the file plays fine in a standalone player and another PC. It's not a big problem but would interest me to know why the colors are fine in a saved snapshot or VirtualDub. Just in case, do I turn off acceleration in the graphic adapter's settings? Thanks.

[jagabo]

I bet your problematic videos have a mod 2 frame size and your decoder only supports mod 4 or 8 or 16.

[Masutin]

Could you please explain the bit about mods of frame sizes or where to look? I never saw it in the video information.

[jagabo]

Use a tool like MediaInfo or GSpot to determine the frame size. Mod2 means an integer multiple of 2 -- 2,4,6,8.... Mod4 means an integer multiple of 4 -- 4,8,12,16. Etc. Some codecs require a mod4, mod8, or mod16 frame size.

A video might have been compressed with an encoder supports mod2. So it will compress a frame that's, say, 640x478. But a decoder that only supports mod4 will have trouble with that size -- 478 isn't evenly divisible by 4. Some will simply refuse to decode the file, other may just make mistakes and mess up -- very often messing up the colors like you described in your earlier post.

[Masutin]

I checked and it's not the mod count or whatever you call it. Meanwhile, I think codecs have nothing to do with it because playing the faulty file with players that use internal filters (VLC, KMP) produced no improvements. Then one time I copied a file to another medium and it turned out to be a few kilobytes less than the original, although no copying errors were reported. And the shorter file in the other location now had broken colors. Now I presume these problems are caused by errors in transmission or recording. The file lacks some information that that affects the video. Strangely, the file that I originally had problems with, now plays fine, so it is complicated!

[jagabo]

I don't know what's going on, but you can try bypassing Windows video subsystems by setting VLC to:

Tools -> Preferences -> Video (button on left) -> Display (box on right) -> Output (pulldown) -> Windows GDI Video Output.

VLC will then bypass Windows video processing and send an RGB image directly to the Desktop. CPU usage will be higher when playing video.