Fixes ffvp9_fails_where_libvpx.succeeds.webm.

Bug-Id: ffmpeg/3849.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

Palette format is always in RGBA.

This simplifies the code a bit, does not change output data in any way.

This is required for 10-bit surfaces.

A decoder may need this to be set correctly to output frames in the
right order.

This was not observed earlier because the only syntax element which
it normally misses with the current setup is slice_qp_delta, but that
is always going to be zero (in IDR frames QP isn't varied on the
slice) which will always exp-golomb code as a single 1 bit.  The
immediately following part is the byte alignment, which is always a 1
bit followed by 0s which are ignored, so as long as the bitstream is
never aligned at that point we will never notice because the only
difference is that an ignored bit is a 1 instead of a 0.

This was always too late; several fields related to it have been incorrectly
zero since the encoder was added.

It has been replaced by C11 stdatomic.h and is now unused.

Current code uses a plain int in a racy way, which is UB.

Adapted from the code by Rémi Denis-Courmont from VLC

Adapted from the code by Rémi Denis-Courmont from VLC

Adapted from the code by Rémi Denis-Courmont from VLC

Adapted from the code by Rémi Denis-Courmont from VLC

Adapted from the code by Rémi Denis-Courmont from VLC

Since this is a C11 feature, it requires -std=c11.

Not actually used for anything yet, that will be added in the following
commits.

Confirmed to work by checkasm.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

Errors during decoding are currently considered non-fatal and do not
terminate transcoding, so even if parts of the data are corrupted, the
rest may be decodable.

However, that should apply only to the actual decoding calls, not to the
failures elsewhere (e.g. configuring filters).

The filtergraph's existence is used in several places to mean that the
filtergraph is fully configured. This causes problems if it's allocated,
but the initialization fails (e.g. if a non-existent filter is
specified).

Bug-Id: 966

The Intel binary iHD driver does not support the
VASurfaceAttribMemoryType, so surface allocation will fail when using
it.

Adds a wrapper function for downmixing which detects channel count changes
and updates the selected downmix function accordingly.

Simplification and porting to current x86inc infrastructure by Diego Biurrun.
Signed-off-by: Diego Biurrun <diego@biurrun.de>

This is about 200% faster for in-decoder downmixing of 5.0 and 5.1 content.
Signed-off-by: Diego Biurrun <diego@biurrun.de>

Also use (float **) instead of (float (*)[2]). This matches the matrix
layout in libavresample so we can reuse assembly code between the two.
Signed-off-by: Diego Biurrun <diego@biurrun.de>

Move the doxy above the definition, change the value itself to the
(1 << n) pattern, which is more readable for flags.