[FFmpeg-soc] [soc]: r524 - dirac/TODO
marco
subversion at mplayerhq.hu
Tue Jul 24 15:41:29 CEST 2007
Author: marco
Date: Tue Jul 24 15:41:29 2007
New Revision: 524
Log:
Add some ideas for optimization to the TODO
Modified:
dirac/TODO
Modified: dirac/TODO
==============================================================================
--- dirac/TODO (original)
+++ dirac/TODO Tue Jul 24 15:41:29 2007
@@ -4,3 +4,22 @@
- Properly store the amount of codeblocks per subband instead of using
a fixed maximum of 7 subbands
- Unpack motion vectors
+
+Optimizations:
+
+- Calculate the quantization factor just once per block instead of for
+ each coefficient
+- Perhaps a lookup table can be used for quantization factors
+- Just malloc once in decode_intra_frame
+- Determine what's more efficient: memset all coefficients to 0, or
+ just zero out the coefficients that need to be zero'ed out
+- Clipping in the IDWT might be very inefficient
+- Use in place operations in IDWT, if that is possible
+- y * padding_width is inefficient. Loop over y and add padding_width
+- Make a special case for 1x1 codeblocks, perhaps merge the codeblock
+ function into the subband function.
+- coeff_posx and coeff_posy use *, can be avoided
+- blockcnt != 1 in codeblock -> use addition instead of multiplication
+- Write IDWT in assembler
+- Perhaps write arithmetic decoding in assembler
+- Perhaps think about multithreading?
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