vp9: fix mvref finding to adhere to bug in libvpx.

Fixes a particular youtube video that I unfortunately can't share.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
vp9: fix bugs in updating coef probabilities with parallelmode=1

- The memcpy was completely wrong because
s->prob_ctx[s->framectxid].coef is a [4][2][2][6][6][3] array, whereas
s->prob.coef is a [4][2][2][6][6][11] array.
- The additional check was committed to ffmpeg by Ronald S. Bultje.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
Merge commit 'bd01412313c728400f1fc5448ede0ad8b51da0d1'

* commit 'bd01412313c728400f1fc5448ede0ad8b51da0d1':
  vp9: fix mvref finding to adhere to bug in libvpx.

Conflicts:
	libavcodec/vp9mvs.c

No change
See: dd3d0f46bdb0b9bd204159c67f522cd6f3db7e7c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  vp9: fix bugs in updating coef probabilities with parallelmode=1

Conflicts:
	libavcodec/vp9.c

No change, the bug/buggy code doesnt seem to be in FFmpeg
Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpeg12dec: Make mpeg2_fast_decode_block_intra() more robust by breaking out on invalid vlcs

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpeg12dec: check for overread in mpeg1_fast_decode_block_inter()

No speedloss meassured

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpeg12dec: Optimize mpeg1_decode_block_intra()

sandybridge i7 274->260 cycles

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpeg12dec: check block index in mpeg2_fast_decode_block_non_intra()

Prevents some overreads at the cost of 1 cpu cycle

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpeg12dec: Check for overread in mpeg_decode_slice()

This is needed in case the checked bitstream reader is disabled

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpeg12dec: Disable the checked bitstream reader

Mpeg1/2 should not need it

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpeg12dec: fix mis-indented line

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>