lavc/vp6: Implement "slice" threading for VP6A decode

The YUV channels of VP6 are encoded in a highly linear fashion which does
not have any slice-like concept to thread.  The alpha channel of VP6A is
fairly independent of the YUV and comprises 40% of the work.  This patch
uses the THREAD_SLICE capability to split the YUV and A decodes into
separate threads.

Two bugs are fixed by splitting YUV and alpha state:
- qscale_table from VP6A decode was for alpha channel instead of YUV
- alpha channel filtering settings were overwritten by YUV header parse

Signed-off-by: Ben Jackson <[email protected]>
Signed-off-by: Michael Niedermayer <[email protected]>

0 files changed, 0 insertions, 0 deletions