task-list.md

@@ -17,8 +17,6 @@ Multi-threading:
 - by not adding invisible frames to `out_delayed[]` and/or growing it so it can be bigger than the number of frame threads (and thus making the indexing between `out_delayed[]` and the actual frame thread doing the decoding independent), we could grow concurrency and scalability on typical sequences with frame-multithreading enabled.
 
 Removing redundancies:
-- `backup_lpf()` in `lr_apply_tmpl.c` backs up 4 lines per 64 pixels per plane, and copies bottom to top per superblock (each 128 or 64 pixels). Most of this is unnecessary. Using a flippable index means we don't need the second copy, and using 64-pixel instead of sb (64 or 128) pixel cdef runs (and then running LR, and then optionally the second cdef and second LR) means we only need to copy the pre-cdef top pixels, not the bottom ones, saving 50% copies. CDEF backup already does all of this;
-- bonus points for merging the CDEF backup and LR backup together so LR backs up nothing at all;
 - the identity_* inverse transforms are stored transposed (as are all other coefficient tables). In all other cases, this saves a transpose in assembly, but for those, it actually means we have to transpose, even though in theory we wouldn't have to at all. Therefore, a potential optimization would be to have a special untransposed zigzag coefficient table and remove the transpose from the assembly, which would make those inverse transforms slightly faster.
 
 Other speed optimizations: