Revert "Move H264/QPEL specific asm from dsputil.asm to h264_qpel_*.asm."

This reverts commit f90ff772e7e35b4923c2de429d1fab9f2569b568.

The code should be put back in h264_qpel_8bit.asm, but unfortunately
it is unconditionally used from dsputil_mmx.c since 71155d7.
lls: #ifndef --> #if in FF_API_ version guard
lls: Do not return from void functions
flvdec: Don't read the VP6 header byte when setting codec type based on metadata

This header byte is only present when actually reading a VP6 frame,
not when reading the codec type field in the metadata. This
potential bug has been present since 5b54a90c.

CC: libav-stable@libav.org
Signed-off-by: Martin Storsjö <martin@martin.st>
flvdec: Check the return value of a malloc

The callers of this function can't report errors sanely. If this
one malloc fails, don't write the extradata byte, make sure we
try to malloc it the next time we're called instead, and make sure
we still consume the input data byte.

CC: libav-stable@libav.org
Signed-off-by: Martin Storsjö <martin@martin.st>
h264: do not copy ref count/ref2frm when updating per-frame context

They are filled in decode_slice_header() anyway.
h264: on reference overflow, reset the reference count to 0, not 1.

Since decode_slice_header() returns before the reference lists are
constructed, there are zero valid references.

CC:libav-stable@libav.org
h264: set ref_count to 0 for intra slices.

CC:libav-stable@libav.org
rtpdec: Initialize some variables to silence compiler warnings

The warnings are false positives, older gcc versions (such as 4.5)
think the variables can be used uninitialized while they in
practice can't, while newer (4.6) gets it right.

Signed-off-by: Martin Storsjö <martin@martin.st>
fate: remove last incomplete frame from mpeg2-field-enc test
configure: Fix silly typo in logging command of check_struct()
configure: Add sanitize_var_name convenience function

This is useful in all the places where special characters in
variable names are manually translated to underscores.
configure: Add check_builtin convenience function
configure: Use check_builtin() where appropriate
hwaccel: consistent name prefixes for start_frame/end_frame/decode_slice

Some hwaccels use name prefixes, some do not, others only use them for
some codecs.  Add prefixes everywhere for consistency.
h264: check for luma and chroma bit dept being equal

The decoder assumes a single bit depth for all the planes
while the specification allows different bit depths for luma
and chroma.

Avoid the possible problems described in CVE-2013-2277

CC: libav-stable@libav.org
vorbisdec: check memory allocations
shorten: set invalid channels count to 0

Prevent the loop shorten_decode_close from writing and freeing out of
the array boundary.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
shorten: K&R formatting cosmetics
shorten: report meaningful errors