Bright red on blue background = Encoding artifacts

[kallekill]

I've tried to encode a CGI clip that has several scenes with red colors against blue background and I find that objects with red color get really fuzzy and pixilated edges and look very low resolution. I suspect that this has something to do with the color compression, but I am wondering if there is some workaround. I tried both CCE and TMPG and while TMPG gives better results it is still very apparent. It is even more apparent when it is moving because there is a floating movement in the edges. I didn't find a way to do still captures from the uncompressed AVI for comparison.


http://www.geomatics.kth.se/sjoberg/homepage/screenshot/ugly.png

Notice the red edges in the picture. Is this something you have to live with when encoding MPEG2?

I'm encoding CBR, 9000 kbits/s with TMPG 2.513 and CCE 2.67.

[RB]

Play with "Quantizer characteristics (Flat Part Priority)" in CCE, lower values should be better for your CGI material.

[kallekill]

I've come to the conclution that this is caused by a RGB24 to YUV conversion. CCE just seems to be worse at converting colors. I tried to use avisynth to make the color conversion and it looked like the TMPG clip.

Is there any good way to go about this? I created the uncompressed AVI by first rendering TGA still images in 3D Studio and then merging them to a uncompressed RGB24 avi-file. As I've understand it you have to color convert it to YUV to encode it to mpeg. Is there any way to store the pictures in some format so you don't loose as much color quality when encoding it as mpeg?

[RB]

I'm afraid there isn't.

[kallekill]

I'm wondering how companies like Pixar accomplish this. I know Industrial Light and Magic have some kind of special image format that can store a lot more data than a normal 24-bit RGB Image.