YUV & RGB stuff

[Enchanter]

Would be interested if someone can explain these things to me, as in the similarities and differences. A guide (if it exists) would be most appreciated.

[Enchanter]

Does no one have the slightest idea?

[khp]

Well you have posed a rather broad question. Unless you can be more specific, the best answer I can offer would be something like this

http://www.inforamp.net/~poynton/notes/Timo/colorspace-faq

[Enchanter]

Thanks, khp.

Basically what I want to know is what colour space DVD uses and what colour conversions are done during conversion to DivX (whether there is any at all).

By the way, the article is a long and useful one. Will take some time to finish it.

[khp]

OK, both MPEG2 - DVD video and mpeg-4 video is stored in the yuv4:2:0 format which means that each pixel has an 8bit luminance value, while the 2 8bit chrominance values are shared by 4 pixels in 2*2 formation.

AFAIK the only way to stay in this colorspace durring conversion is to use avisynth frameserving into vdub/nandub in fast recompress mode. Which is exactly what GKnot does.

Other encoding methods convert to RGB (which is 3 8-bit values denoting the R,G,B values for each pixel), and send that to the divx codec, the codec will then convert it back to YUV4:2:0.

[Enchanter]

Other encoding methods convert to RGB (which is 3 8-bit values denoting the R,G,B values for each pixel), and send that to the divx codec, the codec will then convert it back to YUV4:2:0.

Is there any negative aspect from this?

[khp]

Nothing you would notice, I think there is always a small chance that the conversion RgbToYuv(YuvToRgb(YuvColor)) will not result in exactly the same color but the difference will be very small.

[DVnewie]

rbg-svhs

Hi Enchanter & khp,
Any source of a hardware rbg (scart) to svhs converter? I want to connect my satellite rec' (scart) to my graphics card (svhs in) and the g.c. (seperate svhs out) to my TV Scart) I tried wiring a scart plug using pins 15/13 and 20/18 to a svhs plug but got only B+W. My TV and sat rec' have no svhs menus. A source in MAPLINS (uk) offers a rbg-svhs out only item.