Video Acceleration API

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libVA
Stable release 1.3.0 / March 24, 2014 (2014-03-24)
Development status current
Written in C
Operating system Linux, BSD, GNU, and Android
Type Library
License MIT License
Website www.freedesktop.org/wiki/Software/vaapi

Video Acceleration API (VA API) is a royalty-free API as well as its implementation as free and open-source library (libVA) distributed under the MIT License.

The VA API interface is to be implemented by device drivers to offer end-user software, such as VLC media player or GStreamer, access to available video acceleration hardware, such a PureVideo or Unified Video Decoder and make use of it.

The cross-platform[weasel words] API enables and provides access to hardware accelerated video processing, using hardware like for example graphics processing units (GPU) to accelerate video processing in order to offload the central processing unit (CPU) to decode and encode compressed digital video.

VA API video decode/encode interface is platform and window system independent but is today primarily targeted at Direct Rendering Infrastructure (DRI) in X Window System on Unix-like operating systems (including GNU/Linux, FreeBSD, Solaris), and Android, however it can potentially also be used with direct framebuffer and graphics sub-systems for video output. Accelerated processing includes support for video decoding, video encoding, subpicture blending, and rendering.[1]

The VA API specification was originally designed by Intel for its GMA (Graphics Media Accelerator) series of GPU hardware with the specific purpose of some day fully replacing the XvMC standard as the default Unix multi-platform equivalent of Microsoft Windows DirectX Video Acceleration (DxVA) API, but today the API is no longer limited to only GPUs nor to Intel specific hardware.[2] Other hardware and manufacturers can freely use this open standard API for hardware accelerated video processing with their own hardware without paying a royalty fee.[3]

Overview[edit]

The main motivation for VA API is to enable hardware accelerated video decode at various entry-points (VLD, IDCT, Motion Compensation, deblocking[4]) for the prevailing coding standards today (MPEG-2, MPEG-4 ASP/H.263, MPEG-4 AVC/H.264, and VC-1/WMV3). Extending XvMC was considered, but due to its original design for MPEG-2 MotionComp only, it made more sense to design an interface from scratch that can fully expose the video decode capabilities in today's GPUs.[5]

Supported hardware and drivers[edit]

As of January 17, 2012 VA API is natively supported by :

Supported video codecs[edit]

VA API currently supports these video codecs in the official mainline version, but note that exactly which video codecs are supported depends on the hardware and the driver's capabilities.

  • Supports MPEG-2 decode acceleration Main Profile
  • Supports VC-1 / WMV3 decode acceleration Advanced Profile
  • Supports MPEG-4 Part 2 (H.263) (a.k.a. MPEG-4 SP / MPEG-4 ASP, more commonly known as Xvid) decode acceleration
  • Supports H.264 AVC encode acceleration Main Profile
  • Supports H.264 AVC decode acceleration High Profile
    • H.264 / AVC Hardware Variable Length Decoding (VLD) - CABAC
    • H.264 / AVC Hardware Variable Length Decoding (VLD) - CAVLC
    • H.264 / AVC Hardware Inverse Transform (IT)
    • H.264 / AVC Hardware Motion Compensation (HWMC)
    • H.264 / AVC Hardware In-Loop Deblocking (ILDB)

Processes that can be accelerated with VA API[edit]

Video decoding and post-processing processes that can be offloaded and accelerated if both the device drivers and GPU hardware supports them:

Software architecture[edit]

Video Acceleration API (VA API) interface architecture

The current interface is window system independent, so that it can potentially be used with graphics sub-systems other than the DRI (Direct Rendering Infrastructure) in X Window System, such as direct with framebuffer, and it can work with third-party DRM (Direct Rendering Manager) libraries. In a nutshell, it is a scheme to pass various types of data buffers from the application to the GPU for decoding or encoding a compressed bit-stream.

Sources[edit]

"The main motivation for VA-API (Video Acceleration API) is to enable hardware accelerated video decode/encode at various entry-points (VLD, IDCT, Motion Compensation etc.) for the prevailing coding standards today (MPEG-2, MPEG-4 ASP/H.263, MPEG-4 AVC/H.264, and VC-1/VMW3)." http://www.freedesktop.org/wiki/Software/vaapi

"A new video acceleration API is being developed, in an effort led by Intel. This new API supports more complete offload (VLD) as well as iDCT+MC, and can support acceleration of MPEG4, H.264, VC-1, as well as MPEG-2." http://www.mythtv.org/wiki/XvMC

The "VA API" and "libVA" can also be read about here: "The end user impact is improved performance of H.264, VC-1, MPEG-2 and MPEG-4 video playback with media players that use the new API compared to playback using a pure software implementation." https://wiki.ubuntu.com/mobile-hw-decode

Software supporting VA API[edit]

Some software may gain VA API support in the future : Lightspark (Flash / SWF player),[23] and Xine (via "xine-lib-vaapi" library).[24]

See also[edit]

References[edit]

  1. ^ http://www.phoronix.com/scan.php?page=news_item&px=MTA0NDI VA-API Video Acceleration On Intel Medfield
  2. ^ https://events.linuxfoundation.org/images/stories/pdf/lceu2012_debski.pdf Video4Linux2 - Path to a Standardized Video Codec API
  3. ^ Nathan Willis (2009-07-01). "VA API slowly, but surely, making progress". lwn.net. 
  4. ^ MPlayer, FFmpeg Gain VA-API Support
  5. ^ freedesktop.org - Software/vaapi, About
  6. ^ http://gitorious.org/crystalhd-video CrystalHD backend for VA-API (libva)
  7. ^ http://intellinuxgraphics.org/h264.html Intel hardware-accelerated media decoding and encoding on Linux
  8. ^ http://intellinuxgraphics.org/documentation.html
  9. ^ Intel's Poulsbo Driver A Bloody Mess?
  10. ^ a b http://www.phoronix.com/scan.php?page=news_item&px=MTA0NDI VA-API Video Acceleration On Intel Medfield
  11. ^ S3 Graphics Releases Linux Driver With OpenGL 3.0, VA API
  12. ^ Michael Larabel (2009-02-03). "A NVIDIA VDPAU Back-End For Intel's VA-API". Phoronix. Retrieved 2009-03-13. 
  13. ^ Mailing list entry that describes uses of VA-API
  14. ^ https://community.helixcommunity.org/Licenses/realplayer_for_mid_faq.html RealPlayer for MID & Intel/Linux FAQ
  15. ^ .264 VA-API GPU Video Acceleration For Flash
  16. ^ "gstreamer-vaapi git". 
  17. ^ Gnash uses libavcodec's VA-API code for hardware accelerated video decoding
  18. ^ Fluendo's New Codecs Support VDPAU, VA-API
  19. ^ mplayer branch soon to be merged mainline
  20. ^ a b XBMC Gets Working Intel VA-API Support
  21. ^ VLC 1.1.0 release notes
  22. ^ MythTV 0.25 release notes
  23. ^ (English) Bug report on Launchpad
  24. ^ (English) VA API support for Xine on xine-devel mailing list

External links[edit]