Useful to use same matrices like the original source?

[LeXXuz]

Hi all!

I'm still testing and testing (and... you know the deal ;)) to find the best way to backup some of my dvd sources to xvid.

I dont use any resizer. Just crop to a mod16 resolution.

While experimenting with lots of different matrices, I thought about using the same matrix as in the dvd source.

If I understand the use of a quantisation matrix correctly, would'nt the use of the same matrix as the source give you the best ratio between compressibility and picture quality?

What do you think about this?

[Ranguvar]

I'm gonna say no.

Firstly, the matrix they used is an MPEG-2 matrix. I'm not sure about whether it will work with Xvid, and even then how well it will work.

Secondly, their matrix is optimized for bitrates over 6Mb/s, in other words, sharpness and detail above potential blocking, since they have enough bits to not worry about blocking.