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GStreamer multimedia framework
e876d9a581
A GstVideoOverlayRectangle is created whenever the underlying pixels data change. However, when global-alpha is supported, it is possible to re-use the same GstVideoOverlayRectangle but with a change to the global-alpha value. This process causes a change of sequence number, so we can no longer check for that. Still, if sequence numbers did not change, then there was no change in global-alpha either. So, we need a way to compare the underlying GstBuffer pointers. There is no API to retrieve the original pixels buffer from a GstVideoOverlayRectangle. So, we use the following heuristics: 1. Use gst_video_overlay_rectangle_get_pixels_unscaled_argb() with the same format flags from which the GstVideoOverlayRectangle was created. This will work if there was no prior consumer of the GstVideoOverlayRectangle with alternate (non-"native") format flags. 2. In overlay_rectangle_has_changed_pixels(), we have to use the same gst_video_overlay_rectangle_get_pixels_unscaled_argb() function but with flags that match the subpicture. This is needed to cope with platforms that don't support global-alpha in HW, so the gst-video layer takes care of that and fixes this up with a possibly new GstBuffer, and hence pixels data (or) in-place by caching the current global-alpha value applied. So we have to determine the rectangle was previously used, based on what previous flags were used to retrieve the ARGB pixels buffer. |
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gstreamer-vaapi
VA-API support to GStreamer
Copyright (C) 2010-2011 Splitted-Desktop Systems
Copyright (C) 2011-2012 Intel Corporation
Copyright (C) 2011 Collabora Ltd.
License
-------
gstreamer-vaapi helper libraries and plugin elements are available
under the terms of the GNU Lesser General Public License v2.1+
Overview
--------
gstreamer-vaapi consists in a collection of VA-API based plugins for
GStreamer and helper libraries.
* `vaapidecode' is used to decode JPEG, MPEG-2, MPEG-4, H.264, VC-1,
WMV3 videos to video/x-vaapi-surfaces surfaces, depending on the
underlying HW capabilities.
* `vaapiupload' is used to convert from video/x-raw-yuv pixels to
video/x-vaapi-surface surfaces.
* `vaapidownload' is used to convert from video/x-vaapi-surface
surfaces to video/x-raw-yuv pixels.
* `vaapipostproc' is used to postprocess video/x-vaapi-surface
surfaces, for e.g. deinterlacing.
* `vaapisink' is used to display video/x-vaapi-surface surfaces to
screen.
Features
--------
* VA-API support from 0.29 to 0.32
* JPEG, MPEG-2, MPEG-4, H.264 and VC-1 ad-hoc decoders
* OpenGL rendering through VA/GLX or GLX texture-from-pixmap + FBO
* Support for the Wayland display server
* Support for headless decode pipelines with VA/DRM
* Support for major HW video decoding solutions on Linux (AMD, Intel, NVIDIA)
Requirements
------------
Software requirements
* GStreamer 0.10.x:
libglib2.0-dev (>= 2.28)
libgstreamer0.10-dev (>= 0.10.36)
or with GstBaseSink::query()
libgstreamer-plugins-base0.10-dev (>= 0.10.36)
libgstreamer-plugins-bad0.10-dev (>= 0.10.22.1)
or with GstVideoContext, GstSurfaceBuffer, codecparsers
* Renderers:
DRM: libva-dev (>= 1.1.0), libdrm-dev, libudev-dev
X11: libva-dev (>= 1.0.1)
GLX: libva-dev (>= 1.0.3)
Wayland: libva-dev (>= 1.1.0), libwayland-dev (>= 0.95.0)
Hardware requirements
* AMD platforms with UVD2 (XvBA supported)
* Intel Eaglelake (G45)
* Intel Ironlake, Sandy Bridge and Ivy Bridge (HD Graphics)
* Intel Poulsbo (US15W)
* Intel Medfield or Cedar Trail
* NVIDIA platforms with PureVideo (VDPAU supported)
Usage
-----
VA elements are automatically plugged into GStreamer pipelines. So,
using playbin2 should work as is. However, here are a few alternate
pipelines constructed manually.
* Play an H.264 video with an MP4 container in fullscreen mode
$ gst-launch-0.10 -v filesrc location=/path/to/video.mp4 ! \
qtdemux ! vaapidecode ! vaapisink fullscreen=true
* Play a raw MPEG-2 interlaced stream
$ gst-launch-0.10 -v filesrc location=/path/to/mpeg2.bits ! \
mpegvideoparse ! vaapidecode ! vaapipostproc ! vaapisink