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Creating Compressed Buffers and Decode Render Targets

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The Microsoft Direct3D runtime calls the user-mode display driver's CreateResource function to create compressed buffers and render targets for decoding.

Each compressed buffer type has its own surface format as well as a special flag that indicates that the surface that the runtime creates contains compressed buffer information for accelerated video decode. The user-mode display driver determines to create a compressed buffer if the DecodeCompressedBuffer bit-field flag in the Flags member of the D3DDDIARG_CREATERESOURCE structure that the pResource parameter of CreateResource points to is set. The user-mode display driver determines the type of compressed buffer to create by the format value in the Format member of D3DDDIARG_CREATERESOURCE. The following formats are defined:

D3DDDIFMT_PICTUREPARAMSDATA       = 150
D3DDDIFMT_MACROBLOCKDATA          = 151
D3DDDIFMT_RESIDUALDIFFERENCEDATA  = 152
D3DDDIFMT_DEBLOCKINGDATA          = 153
D3DDDIFMT_INVERSEQUANTIZATIONDATA = 154
D3DDDIFMT_SLICECONTROLDATA        = 155
D3DDDIFMT_BITSTREAMDATA           = 156

The Direct3D runtime creates each decode render target independently in a call to the user-mode display driver's CreateResource function. Each of the targets is referenced as a subresource index of a single resource. The user-mode display driver determines to create a decode render target if the DecodeRenderTarget bit-field flag in the Flags member of D3DDDIARG_CREATERESOURCE is set.