[FFmpeg-devel] GSoC VQA v3 : some more help needed
The Deep Explorer
Sat Apr 4 23:02:36 CEST 2009
I need some help in understanding how each frame is decoded in
VQA v3. Please let me know how to proceed on the following :
1) VPTR Decoding
Read 1 short int ( 2 bytes)
Read bits 15,14,13 and based on the command do actions.
The document says e.g. :
a) 000 - Skip Count blocks. Count is (Val & 0x1fff).
What is the Count blocks ?
What is this Val and where am I supposed to get it from ?
b) 001 - Write block number (Val & 0xff) Count times.
Count is (((Val/256) & 0x1f)+1)*2. Note that this can
only index the first 256 blocks.
What is the block number ?
<<Every row of blocks is processed individually of others.
When you encounter the end of a row, proceed to the next row
(blocks are processed left to right, top to down).
Repeat this process until all blocks in the frame are covered and
So is this the layout mechanism for v3 ? How are Count, Block, and Val
There are two for loops, first one for the y axis and the second one for
the x axis for the v1 and v2. so in case3 will the decoding of vptr will take
place ? Read the three bits and then do the actions as specified ?
2) For VPRZ, first decode it with format80 and then follow the vptR thing
so the VPRZ is dependent on the VPTR :)
I will wait for the replies :)
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