Some questions regarding MaroBlocks and Quants.

[ReferenceDivx]

I was wondering if only 1 custom matrix could be used for each frame. I also want to know if all the macroblocks in each frame are encoded with the same quant. value. I'm trying to figure out the best methods to implement custom matrices for each frame, based on several factors.

I'll proably have a few more questions.

[-h]

Two matrices are used - one for intra blocks, the other for inter. Thus, in say a P-frame, most of the blocks will use the inter matrix and only a few will use the intra one.

Quantizers will be the same for every block, unless lumi masking is enabled, in which case block quantizers will differ from block to block.

Also, remember that for inter blocks you're not quantizing "real" image data, but bland grey prediction errors from motion compensation.

-h

[ReferenceDivx]

So if i wanted to optimize matrices frame by frame, should i only be concerned about optimizing intra matrices using hvs? Then should inter matrices even be optimized then? Or does it still help to optimize inter matrices using hvs. I noticed for Mpeg inter matrices all have the values of 32 for all the frequencies right?

thanks -h and everyone for the responses so far!

[-h]

It would help to optimize the inter matrices as well (since that's what 90% of blocks are going to use), however you'll have to optimize them based on motion-compensated data inside the encoder, and I'm not sure how well that will work.

-h