Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Fixes ticket #6356.

(cherry picked from commit 66aa9b94)

This is something of a hack.  It allocates a new hwframe context for
the target format, then maps it back to the source link and overwrites
the input link hw_frames_ctx so that the previous filter will receive
the frames we want from ff_get_video_buffer().  It may fail if
the previous filter imposes any additional constraints on the frames
it wants to use as output.

(cherry picked from commit 81a4cb8e)

Also refactor a little and improve error messages to make failure
cases easier to understand.

(cherry picked from commit 38cb05f1)

Use the flags argument of av_hwframe_ctx_create_derived() to pass the
mapping flags which will be used on allocation.  Also, set the format
and hardware context on the allocated frame automatically - the user
should not be required to do this themselves.

(cherry picked from commit c5714b51)

(cherry picked from commit e1c5d56b)

Factorises out existing surface initialisation code to reuse.

(cherry picked from commit eaa5e071)

Some frames contexts are not usable without additional format-specific
state in hwctx.  This change adds new functions frames_derive_from and
frames_derive_to to initialise this state appropriately when deriving
a frames context which will require it to be set.

(cherry picked from commit 27978155)

(cherry picked from commit aa51bb3d)

This only supports one device globally, but more can be used by
passing them with input streams in hw_frames_ctx or by deriving new
devices inside a filter graph with hwmap.

(cherry picked from commit e669db76)

Uses the just-added ALLOW_PROFILE_MISMATCH flag.

(cherry picked from commit 7acb9033)

(cherry picked from commit 64a5260c)

The non-H.26[45] codecs already use this form.  Since we don't
currently generate I frames for codecs which support them separately
to IDR, the p_per_i variable is set to infinity by default so that it
doesn't interfere with any other calculation.  (All the code for I
frames still exists, and it works for H.264 if set manually.)

(cherry picked from commit 6af014f4)

(cherry picked from commit 3d197514)

(cherry picked from commit 8848ba0b)

(cherry picked from commit 4936a48b)

In order to work correctly with the i965 driver, this also fixes the
direction of forward/backward references - forward references are
intended to be those from the past to the current frame, not from the
current frame to the future.

(cherry picked from commit 9aa251c9)

(cherry picked from commit 303fadf5)

(cherry picked from commit aa6b2e08)

(cherry picked from commit 62a1ef9f)

Not yet enabled for any hwaccels.

(cherry picked from commit d2e6dd32)
(cherry picked from commit 9203aac2)

Adds functions to convert to/from strings and a function to iterate
over all supported device types.  Also adds a new invalid type
AV_HWDEVICE_TYPE_NONE, which acts as a sentinel value.

(cherry picked from commit b7487f4f)

Creates a new device context from another of a different type which
refers to the same underlying hardware.

(cherry picked from commit b266ad56)

Previously this was leaking, though it actually hit an assert making
sure that the buffer had already been cleared when freeing the picture.

(cherry picked from commit 17aeee58)

The driver is somewhat bitrotten (not updated for years) but is still
usable for decoding with this change.  To support it, this adds a new
driver quirk to indicate no support at all for surface attributes.

Based on a patch by wm4 <nfxjfg@googlemail.com>.

(cherry picked from commit e791b915)

Fixes trac issue 6459.

Fixes CIDs 1403234 and 1403235

Fixes CID 1396267

Fixes CID 1396837

Fixes CIDs 1396414 and 1396415

Fixes CID 1396855

Fixes regression introduced by 5d0b8b1a.

Fixes: runtime error: signed integer overflow: 2147483584 + 128 cannot be represented in type 'int'
Fixes: 2164/clusterfuzz-testcase-minimized-4715936172998656

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

Fixes: runtime error: shift exponent -10 is negative

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

Fixes: 1775/clusterfuzz-testcase-minimized-5330288148217856

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

Signed-off-by: Paul B Mahol <onemda@gmail.com>

820 cpu cycles -> 660 cpu cycles for 100 put_bits32()
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>