Change of CQM in 2-Pass Mode.

[Splashdriver]

Hi, I have a quick question here. I'm doing a 2-pass encode (DVD-rip)and since I've got a few matrices which are supposed to be good to deal with, I would like to find out which of them could suit my eyes best for this particular encode, visually. I'm encoding on P3 1Ghz, so you might understand that encoding time is very very precious to me. My question: Is it a safe option to change your choice of QM in 2nd-pass?

Thanks in advance.

[Edit: Slight change of word choice]

[Sharktooth]

no.

[Splashdriver]

You must be a real master providing me such a short answer;) . Aah, whatever man.....Thanks!:)

[Andrey]

Any parameter [really] used in the first pass should not be changed, if possible.
So, it is better to stay with equal parameters in the both passes.

EDIT: added [really] to reflect what supposed to be ment.

[Selur]

during plays the major role during DCT (google: mpeg matrix dct for a detailed explaination) and since DCT plays a major role in the mpeg compression the codec wouldn't be able to collect reliable data during the 1st pass that would be useful in the 2nd pass.

Cu Selur

[drcl]

make some samples is the obvious answer. you dont need to encode an entire film to get an idea of which matrix is your preference