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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 (through the libva-vdpau driver, which implements VA API in terms of VDPAU) or Unified Video Decoder and make use of it. The cross-platform ( *nix so far) 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 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.〔http://www.phoronix.com/scan.php?page=news_item&px=MTA0NDI VA-API Video Acceleration On Intel Medfield〕 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.〔https://events.linuxfoundation.org/images/stories/pdf/lceu2012_debski.pdf Video4Linux2 - Path to a Standardized Video Codec API〕 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. == Overview == The main motivation for VA API is to enable hardware-accelerated video decode at various entry-points (VLD, IDCT, motion compensation, deblocking〔(MPlayer, FFmpeg Gain VA-API Support )〕) 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.〔(freedesktop.org - Software/vaapi, About )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Video Acceleration API」の詳細全文を読む スポンサード リンク
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