Editing Mesa (computer graphics) (section)

=== Implementations of video acceleration APIs ===
There are three possible ways to do the calculations necessary for the encoding and decoding of video streams:

# use a software implementation of a video compression or decompression algorithm (commonly called a CODEC) and execute this software on the ''C''PU
# use a software implementation of a video compression or decompression algorithm (commonly called a CODEC) and execute this software on the ''G''PU (the [[rendering (computer graphics)|3D rendering engine]])
# use a complete (or partial) hardware implementation of a video compression or decompression algorithm; it has become very common to integrate such [[ASICs]] into the chip of the GPU/CPU/SoC and therefore abundantly available; for marketing reasons companies have established brands for their ASICs, such as [[PureVideo]] (Nvidia), [[Unified Video Decoder]] (AMD), [[Video Coding Engine]] (AMD), [[Quick Sync Video]] (Intel), [[Texas Instruments DaVinci|DaVinci]] (Texas Instruments), [[CedarX]] (Allwinner), [[Broadcom Crystal HD|Crystal HD]] (Broadcom); some ASICs are available for licensing as [[semiconductor intellectual property core]]; usually different versions implement different video compression and/or video decompression algorithms; support for such ASICs usually belong into the kernel driver, to initialize the hardware and do low-level stuff. Mesa, which runs in user-space, houses the implementations of several [[API]]s for software, e.g. [[VLC media player]], [[GStreamer]], [[HandBrake]], etc., to conveniently access such ASICs:

* [[Video Acceleration API]] (VAAPI) – the most common API for Linux, used by AMD and Intel
* [[Video Decode and Presentation API for Unix]] (VDPAU) – used by Nvidia
* [[DirectX Video Acceleration]] (DXVA) – Microsoft Windows-only
* [[OpenMAX IL]] – designed by Khronos Group for video compression
* [[Distributed Codec Engine]] (DCE) – designed by Texas Instruments
* [[X-Video Bitstream Acceleration]] (XvBA) – extension to [[X video extension|Xv]] - succeeded by VAAPI
* [[X-Video Motion Compensation]] (XvMC) – extension to [[X video extension|Xv]] - succeeded by VAAPI

For example, [[nouveau (software)|Nouveau]], which has been developed as part of Mesa, but also includes a Linux kernel component, which is being developed as part of the Linux kernel, supports the [[PureVideo]]-branded ASICs and provides access to them through [[VDPAU]] and partly through [[XvMC]].<ref>{{cite web |url=https://nouveau.freedesktop.org/wiki/VideoAcceleration/ |title=Nouveau Video Acceleration |work=[[freedesktop.org]]}}</ref>

The free radeon driver supports [[Unified Video Decoder]] and [[Video Coding Engine]] through VDPAU and OpenMAX.<ref>{{cite web |url=http://xorg.freedesktop.org/wiki/RadeonFeature/ |title=Radeon Feature Matrix |work=[[freedesktop.org]]}}</ref>

[[V4L2]] is a [[Linux API|kernel-to-user-space interface]] for video bit streams delivered by webcams or TV tuners.

Due to [[patent]] concerns regarding the [[H.264]], [[H.265]] and [[VC-1]] video codecs, [[Fedora Linux]] disabled support for VAAPI acceleration for those in its build of Mesa in September 2022.<ref>{{Cite web |title=Fedora Linux Disabling Mesa's H.264 / H.265 / VC1 VA-API Support Over Legal Concerns |url=https://www.phoronix.com/news/Fedora-Disable-Bad-VA-API |access-date=2022-10-01 |website=Phoronix |language=en}}</ref>