Some decoding APIs support delayed output for performance reasons.
One example would be to request decoding for multiple frames and
then query for the oldest frame in the output queue.
This also increases throughput for transcoding and improves seek
performance when supported by the underlying backend.
Introduce support in the vp8 base class, so that backends that
support render delays can actually implement it.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2150>
While this was already possible through the GLContext machinary, this simply
request an alpha channel by default and fallback if this is not possible. This
obsolete some RPi Dispmanx hack, since this is near equivalent will allow see
through when playgin WebM Alpha or other transparent files.
Application are still free to pass their own EGLContext attribute, this is
specially for the case the application let GStreamer chose (e.g. gst-launch).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1176>
On Windows with MSVC, jpeg_header_size would end up 2 bytes larger
than it should be. This then leads to the first 2 bytes of the
actual jpeg image data to be dropped, because we think those
belong to the header, which results in an undecodable image when
reconstructed in the depayloader.
What happens is that when the compiler evaluates
jpeg_header_size = mem.offset + read_u16_and_inc_offset_by_2(&mem);
it actually uses the mem.offset value after it has been increased
by the function call on the right hand size of the equation.
From section 6.5 of the C99 spec:
3. The grouping of operators and operands is indicated by the syntax [74].
Except as specified later (for the function-call (), &&, ||, ?:, and
comma operators), the order of evaluation of subexpressions and the
order in which side effects take place are both unspecified.
Fixes https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/issues/889
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/999>
This allows us to cover the case where we're on some unknown system that
doesn't have a known native precision monotonic time source. Sadly this
reintroduces some of the complexity removed in previous commits.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/829>
This add src format validation, this avoid registering element for
drivers we don't support any of their src formats. This also special
case the AlphaDecodeBin wrapper, as we know that alphacombine element
only support I420 and NV12 for now.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2272>
codecalpha is a new plugin introduced to support VP8/VP9 alpha as
defined in the WebM and Matroska specifications. It splits the stream
into two streams, one for the alpha and one for the actual content,
then it decodes them separately with vpxdec and finally combine the
results as A420 or AV12 (i.e. YUV + an extra alpha plane).
The workflow above is setup by means of a bin, gstcodecalphabin.
This patch simulates the same workflow into the v4l2codecs namespace,
thus using the new v4l2 stateless decoders for hardware acceleration.
This is so we can register the new alpha decode elements only if the
hardware produces formats we support, i.e. I420 or NV12 for now.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2272>
No reason not to use directy the GstCaps serialization function here
This commits avoids needing regenerated all expectations to remove
the `;` which is not generated anymore as it is simple and makes
merging simpler.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-devtools/-/merge_requests/248>
Alpha combine works by appending the GstMemory for the alpha channel
to the GstBuffer containing I420, thereby pushing A420 on its src pad.
Add support for the same workflow for NV12, thereby producing the
recently introduced AV12 format (NV12 + Alpha).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2277>
The gst_system_clock_get_internal_time and
gst_system_clock_get_resolution functions had some nested defined checks
making this code somewhat harder to reason about and much harder to
change. The logical meaning of the checks has changed but the actual
code coming out of the pre-processor should not have changed
significantly. The main logical change was flattening the checks for
existence of posix timing functionality, from what I can tell these
functions aren't available on Windows where they were trying to be
included. I have checked the Linux and macOS output and they are
functionally unchanged.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/829>
