![]() In the following diagram, the MFTs labeled "A" and "B" represent functional blocks within the same hardware. There is no need to copy the data into system memory and then back to the device. If two MFTs represent the same physical device, they can exchange data within the hardware-for example, over a hardware bus. Indicates that the MFT supports dynamic format changes. The topology loader uses the presence of this attribute to test whether an MFT represents a hardware device. Indicates that the MFT performs asynchronous processing.Ĭontains the symbolic link for the hardware device. When the MFT is first created, it must set the following attributes on its own global attribute store (that is, the attribute store returned by GetAttributes): Attribute IMFTransform::GetOutputStreamAttributes: Returns an attribute store for an output stream.IMFTransform::GetInputStreamAttributes: Returns an attribute store for an input stream.IMFTransform::GetAttributes: Returns an attribute store for global MFT attributes.Hardware MFTs must support dynamic format changes, as described in Dynamic Format Changes.Ī hardware MFT must implement following methods related to attributes:.Hardware MFTs must use the new asynchronous processing model, as described in Asynchronous MFTs.Hardware MFTs have the following general requirements: If the hardware does not support frame scaling or format conversion, Media Foundation provides a software video processor. If the hardware offers frame scaling and format conversions, place those functions in a separate video processor, registered in the MFT_CATEGORY_VIDEO_PROCESSOR category. A hardware MFT should never act as a multi-purpose "transcoder." Instead, put encoding functions into an encoder MFT and decoding functions into a decoder MFT. A hardware codec might incorporate several distinct functional blocks:Įach of these functions should be managed by a separate MFT. This topic contains the following sections:Īny hardware codec that is not based on AVStream must provide its own MFT to act as a proxy to the driver. For more information, see Hardware Codec Support in AVStream. ![]() The information in this topic applies only in the special case where the hardware codec does not use AVStream. Media Foundation provides an AVStream proxy for this purpose. If a hardware codec uses the AVStream multimedia class driver, it does not require a custom MFT.
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