libavcodec/dvdsubdec: Add option forced_subs_only to only decode forced subtitle frames.

Signed-off-by: Nicholas Robbins <nickrobbins@yahoo.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
doc/decoders: adding documentation for lavc/dvdsubdec.c option "forced_subs_only"

Signed-off-by: Nicholas Robbins <nickrobbins@yahoo.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
ffmpeg: replace impossible dts/pts combinations by a reasonable guess instead of hard failing

Fixes stream copy from tserror270.ts

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
x86/vp9: add AVX and AVX2 MC

Roughly 25% faster MC than ssse3 for blocksizes 32 and 64.

Reviewed-by: Ronald S. Bultje <rsbultje@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>