Use explicit GStreamer plugins path.

This interface was no longer used since GstVideoContext was added to
the main GStreamer APIs.

Drop @LIBVA_EXTRA_{CFLAGS,LIBS}@ substitutions and slightly improve
descriptions with clearer renderer names.

When playback stops the GstVaapiDecode object is reset into a clean
state. However, surfaces may still be referenced by library users and
unreferencing them after the reset triggers an access to an unset mutex.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Forward declaring enums is not allowed by the C standard and aborts
compilation if the header file is included in a C++ project.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Retain the VA surface until another surface is to be displayed only
if VA display rendering mode is determined to be "overlay" mode.

Keep VA surface proxy associated with the surface that is currently
being displayed. This makes sure that surface is not released back
to the pool of surfaces free to use for decoding. This is necessary
with VA driver implementations that support rendering to an overlay
pipe. Otherwise, there could be cases where we are decoding into a
surface that is being displayed, hence some flickering.

Some VA drivers (e.g. EMGD) can have completely random values for initial
display attributes. So, try to improve the discovery process to check the
initial display attribute values actually fall within valid bounds. If not,
try to reset those to some sensible values like the default value reported
through vaQueryDisplayAttributes().

A rendering mode can be "overlay" or "texture"'ed blit.

The former mode implies that a VA surface used for rendering can't be
re-used right away for decoding, so the sink shall make provisions to
retain the associated surface proxy until the next surface is to be
displayed.

The latter mode implies that the VA surface is implicitly copied to an
intermediate backing store, or back buffer of a frame buffer, so the
associated surface proxy can be disposed right away.

The VA display attributes are mapped to properties so that to maintain the
GStreamer terminology. Properties are to be identified by name, but internal
functions are available to lookup the property by the actual VA display
attribute type.

Integrate the start code prefix in the slice data buffer that is submitted
to the hardware. VA-API specifies that slice_data_offset is the offset to
the first byte of slice data. And, for MPEG-2, slice() data begins with
the slice_start_code. Some VA driver implementations (EMGD) expect this.

decode_current_picture() was converted to return a gboolean instead
of a GstVaapiDecoderStatus, so we were not getting out of the decode
loop as expected, or could cause an error instead.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Cherry picked from commits:
75e8a7d6: add initial JPEG decoder
449606ef: fix build without JPEG decoder
4e1a3543: update to current VA/JPEG decoding API
06be1afe: fix build with VA-API < 0.32.0
c7587e87: fix configure check for VA/JPEG decoding API
11399084: update to match latest parser API
4f95b622: add missing doc entries for the JPEG decoder
7c1b9b48

: update to the latest VA-API changes (0.32.1+)
Signed-off-by: Wind Yuan <feng.yuan@intel.com>
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Cherry picked from commits:
c350a080: add JPEG parser
0cf06cdb: simplify and optimize parser API
53cbdcc1: update to match latest parser API
4c5cc7ef: make gst_jpeg_parse() support multiple scans
90e6532f: add new GstJpegHuffmanTables structure
e61f4c44: use U_READ_UINT*() wherever possible
326a2296: track valid quantization and Huffman tables
8f93bbc9: tweak parser API
f8832385: compute default Huffman tables
0b3d75f1: fix default quantization tables
fbb9a5e1

: fix make dist
Signed-off-by: Wind Yuan <feng.yuan@intel.com>
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

If GLX window was created from a foreign Display, then that same Display shall
be used for subsequent glXMakeCurrent(). This means that gl_create_context()
will now use the same Display that the parent, if available.

This fixes cluttersink with the Intel GenX VA driver.

It has been replaced with a GstAdapter and gst_adapter_prev_pts().

Declaring a function as const enables better optimization of calls to
the function.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

This is a preferred thread-safe version. Also add an inline version of
g_clear_object() if compiling with glib < 2.28.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Declaring a function as const enables better optimization of calls
to the function.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

Also do not generate tamplate files as all the documentation is inline.
Drop un-needed code in autogen.sh as well.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>