The VP3/4/5/6 reference decoders all use three IDCT versions: one for the
DC-only case, another for blocks with more than 10 coefficients, and an
optimised one for blocks with up to 10 AC coefficents. VP6 relies on the
sparse 10 coefficient version, and without it, IDCT drift occurs.
Fixes: https://trac.ffmpeg.org/ticket/1282
Signed-off-by: Peter Ross <pross@xvid.org>
For codecs where decoding of a whole plane can simply
be skipped, we should offer applications to not decode
alpha for better performance (ca. 30% less CPU usage
and 40% reduced memory bandwidth).
It also means applications do not need to implement support
(even if it is rather simple) for YUVA formats in order to be
able to play these files.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
