Ideas Wall

unsolo · Post by **unsolo** » Fri Sep 07, 2007 8:01 am

Idea for mpeg2 decoding with regards to motion

store all I and P frames temporary in RAM so that

384Bytes 16x16 Y 8x8 U and 8x8 V for yuv420
512Bytes 16x16Y 8x16U and 8x16 V for yuv 422
and
762 Bytes for 16x16Y 16x16U and 16x16V yuv 444

can be retrived into the spu for forward and backward motion.

Hence when making the I frame you have to store it as a vector and at the same time generate the Image.

Simple loop
I frame is recreated and stored as a vector and sendt to display as Image at the same time

The P frame is then generated into ram as a vector.

B frames are created and rendered into image

P frame is rendered to display as an image

etc etc

Jim · Post by **Jim** » Fri Sep 07, 2007 9:10 am

Might be worth keeping a cache of these decoded macroblocks to avoid too much reloading, and also might be worth pre-caching strips of decoded macroblocks - 3 (or is it 5?) screen-sized horizontal lines of decoded macroblocks would cover most (all?) cases.

Jim