Problems with color gradient and ConvertToRGB24

[LadyMiles]

Hi I am having problems with gradients in the background of my svcds(non anime, regular movies). For example if the background is white and a person's shadow is cast on the white wall it's not smooth coloring. It's like the mpeg can't understand or detect the various shades of color and its very blocky around the colors that it does detect in the gradient. Since the filters I use like PeachSmooth and Cr2() use YUv coloring, I don't think I can use "ConvertToRGB24 # For TMPGEnc or VFAPI" which is inputed by fitcd. Could the problem be a dvd2avi problem like YUV -> RGB--PC SCale or Lumaniance filter. Or is there filter to correct this.

[LigH]

There are several possible reasons for such a flaw:


Rounding errors while converting between color spaces (shall not be very much visible)
Quantisation artefacts due to the limited bitrate during MPEG compression (this shall be one of the most probable reasons)

To reproduce a smooth color ramp, a DCT transformed block requires not only the lowest, but also a few higher frequencies. Unfortunately, high frequencies are treated as unwanted noise, thus are likely to be removed by the quantisation process. So, they are removed even more than it would be good for such parts, just to save bitrate...

You could try to use a noise generator to avoid that (e.g. BlockBuster) - this forces the encoder to spend a few more bits for high frequencies. The compressibility will decrease, though.

[High Speed Dubb]

If you’re running Peach Smoother, another easy way to add noise to otherwise smooth areas is to reduce the stability value. (It can go down to -100.)