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>
AV12 is an internally conceived format that is actually the
combination of NV12 and an alpha plane.
This format is to add to gstreamer's webM transparency support for
vp8 and vp9. To this end, two I420 streams are independently decoded
simultaneously for the actual content and the alpha plane respectively
and these are then combined into A420.
This patch adds GL conversion support so that it is possible to convert
from AV12 to RGBA for the purposes of rendering it on a display.
The reverse conversion is also supplied.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1152>
AV12 is an internally conceived format that is actually
the combination of NV12 and an alpha plane.
This format is to add to gstreamer's webM
transparency support for vp8 and vp9. To this end, two
I420 streams are independently decoded simultaneously for
the actual content and the alpha plane respectively
and these are then combined into A420.
Since most hardware decoders output NV12, this patch adds
NV12+A to make the same workflow possible.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1152>
A420 is a four planar format similar to I420 but with an extra buffer
for alpha values.
A common use of the gl stack is for GPU format conversions using
shaders, in which case one can use glupload, glcolorconvert and
gldownload elements to upload their buffer to the GPU context, perform
the conversion on the GPU itself and then retrieve the data to CPU
context.
A420 was not supported. This patch adds said support mainly by adding
the corresponding shader to perform the conversion and updating the
supported caps.
Both A420->RGBA and RGBA->A420 conversions are supported.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1153>
While so far it worked, we are about to introduce a format that break this
assuming. We have a format which consist of NV12 with alpha, and this format
does not have a direct mapping of the component against their plane indexes.
Fix this by using gst_video_format_info_component() introduced in 1.18 for
this purpose.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1151>
e.g. if running a dual wgl/egl built library, then egl will always
succeed in creating the GstGLContext because almost anything could
support egl, as long as eglGetDisplay() works.
wgl, however has a check for the correct display type so should move
earlier in the tried list.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1154>
New API:
- gst_gl_context_get_config()
- gst_gl_context_request_config()
A GL context configuration is a GstStructure that has some well-known
names for common values that can also be extended in platform-specific
ways if necessary.
Wrapped OpenGL contexts may be able to retrieve the GL context
configuration depending on the platform. If that information is
available, GstGLContext will attempt to create an context that matches
the shared OpenGL context config unless gst_gl_context_request_config()
has been called.
A new environment variable 'GST_GL_CONFIG' will be read to influence the
configuration chosen. The environment variable will only be used as a
fallback if gst_gl_context_request_config() has not been called.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/809>
This meta hold one buffer of the same codec data as the parent memory. This
extra frame luma will be used as the alpha values for the final combined
frame. This is notably used to support VP8/VP9 alpha as defined in WebM and
matroska specification.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1128>
These work the same way as the corresponding properties on queue and
allow to control the internal buffer size of the appsrc in a more
flexible way.
Unlike in queue the max-buffers and max-time properties are 0 (i.e.
disabled) by default for backwards compatibility reasons.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1133>
`@` references are used to reference function parameters, struct members
or enum variants _within_ the current type/function. It cannot and
should not be used to reference to types outside that.
Since C has no notion of member functions it makes little sense to
prefix these with `@`; most of the documentation here was referencing
functions on _different_ types anyway.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1090>
If the alsasink thread starts the write loop but another thread pauses
the underlying alsa device, the sink thread will endlessly loop.
snd_pcm_writei() will return 0 if the state is SND_PCM_STATE_PAUSED
and the loop will never make any progress.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1097>
