DVD Quality at SVCD Bitrates

[SaSi]

There is a whole community at www.kvcd.net built around "tweaked MPEG encoding templates" that aim towards achieving ultra high compression.

Although the aim is self-defeating at times (you simply can't store 3 hours of DVD quality video on a CD - but barely viewable), there is a very interesting concept there.

The issue is around modifying the Quantization Matrix for intra and non-intra frames as well as the GOP structure, meaning increasing the B frames and decreasing the P frames.

There are some "templates" for Tmpgenc. I have downloaded the DVD versions of them and found out that the matrices are very interestingly modified.

If you go to CCE and select to edit the q.matrix, you will find there are several and a couple for low bitrate and ultra low bitrate. They have a resemblance to the KVCD ones.

I did some testing with CCE, MCE and Tmpgenc and found that although you really can't fit 3 hours on a CD, you can achieve very good image quality at a VBR of 2500kbps for progressive frames on PAL.

Interesting aspect for research and tuning of encoding.

Anybody with experience on the matter?

[DJRumpy]

This was were I went when I finally read the CCE docs. They used to say CCE did poor VCD. Set the matrix properly, and it does excellent VCD output. I don't know how far you can tweak a matrix before it becomes non-standard, or distorted enough that you have playback problems. Some of the more experienced could probably tell you. I recall a discussion about this, but it's been about a year ago.