Thread: Documentation
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Old 4th October 2008
adicoto adicoto is offline
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Video rendering filters
Originally, the way to play video in DirectShow was to use the Video Renderer filter. This drew the images using DirectDraw, but could also fall back to GDI drawing in some circumstances. [28] It had limited access to the video window. Video for Windows had been plagued with deadlocks caused by applications' incorrect handling of the video windows, so in early DirectShow releases, the handle to the playback window was hidden from applications. There was also no reliable way to draw caption text or graphics on top of the video.

DirectShow 6.0, released as part of DirectX Media introduced the Overlay Mixer renderer designed for DVD playback and broadcast video streams with closed captioning and subtitles. The Overlay Mixer uses DirectDraw for rendering. Downstream connection with the Video Renderer is required for window management. Overlay Mixer also supports Video Port Extensions (VPE), enabling to work with analog TV tuners with overlay capability (sending video directly to a video card via an analog link rather than via the PCI bus). Overlay Mixer also supports DXVA connections.

Windows XP introduced a new filter called the Video Mixing Renderer 7 (VMR-7 or sometimes just referred to as VMR). The number 7 was because VMR-7 only used DirectDraw version 7 to render the video and did not have the option to use GDI drawing. The main new feature of VMR-7 was the ability to mix multiple streams and graphics, allowing applications to draw text and graphics over the video.[29] VMR-7 also featured a "windowless mode" which fixed the problems with access to the window handle.[30] VMR-7 was only officially released for Windows XP.

DirectX 9 included VMR-9. This version uses Direct3D 9 instead of DirectDraw. [31] It is available for all Windows platforms as part of the DirectX 9 redistributable.

Windows Vista ships with a new renderer, available as both a Media Foundation component and a DirectShow filter, called the Enhanced Video Renderer (EVR). [32] EVR supports DXVA 2.0, which is exclusive to Windows Vista. [33]


Besides this, you can find RGB mode, wich means that the CPU decode all the information and send data directly to the video card.
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