如何使用directx 11和Windows 7的硬件加速视频/ H.264解码？

1)从您的ID3D11Device获取ID3D11VideoDevice实例,并从即时D3D11设备上下文获取ID3D11VideoContext
注意：在Win7上,您必须创建功能级别为9_3的设备才能获得视频支持！ (在Win8它只是工作)

2)为h.264创建ID3D11VideoDecoder实例
使用ID3D11VideoDevice :: GetVideoDecoderProfileCount,GetVideoDecoderProfile,CheckVideoDecodeRFormat …
遍历所有受支持的配置文件,并找到GUID D3D11_DECODER_PROFILE_H264_VLD_NOFGT
对于h264没有电影.作为OutputFormat,你最好的选择是DXGI_FORMAT_NV12.

3)单个帧的解码参见Supporting Direct3D 11 Video Decoding in Media Foundation：

> ID3D11VideoContext :: DecoderBeginFrame(decode,outputView – >解码的帧纹理)
>填充缓冲区：

> D3D11_VIDEO_DECODER_BUFFER_PICTURE_PARAMETERS
> D3D11_VIDEO_DECODER_BUFFER_INVERSE_QUANTIZATION_MATRIX
> D3D11_VIDEO_DECODER_BUFFER_BITSTREAM
> D3D11_VIDEO_DECODER_BUFFER_SLICE_CONTROL

缓冲区用相应的DXVA2结构填充(见dxva2.h)
完整的DXVA2规范在这里,您需要它相应地映射h.264 sps / pps字段.

看到：

> About DXVA 2.0
> https://software.intel.com/sites/default/files/m/b/4/7/DXVA_H264.pdf

然后：

> ID3D11VideoContext :: SubmitBuffers提交所有填充的缓冲区
> ID3D11VideoContext :: DecoderEndFrame完成当前帧

3)D3D11_VIDEO_DECODER_BUFFER_PICTURE_PARAMETERS缓冲区还包含所有参考帧/表面上的信息
– 您需要自己管理,即确保GPU /表面可用.

这是相当复杂的,检查ffmpeg和媒体播放器经典,他们都有DXVA2(虽然不通过DX11)的支持.

4)从NV12转换为RGB(A),某些GPU(D3D11功能级别)允许使用NV12作为着色器输入,有些则不使用.如果无法直接使用NV12,请查看所有具有D3D11支持的GPU的D3D11VideoProcessor接口,它们具有NV12 / YUV420-> RGB转换功能.

转换可以用这样的代码执行：

// Setup ID3D11Video*
ID3D11VideoProcessor * d3dVideoProc = ...;
ID3D11VideoDevice    * d3dVideoDevice = ...;
ID3D11VideoProcessorEnumerator * d3dVideoProcEnum = ...;


ID3D11Texture2D * srcTextureNV12Fmt = ...;
ID3D11Texture2D * dstTextureRGBFmt = ...;

// Use Video Processor

// Create views for VideoProc In/Output
ID3D11VideoProcessorInputView * videoProcInputView;
ID3D11VideoProcessorOutputView * videoProcOutputView;

{

    D3D11_VIDEO_PROCESSOR_INPUT_VIEW_DESC inputViewDesc = { 0 };
    inputViewDesc.ViewDimension = D3D11_VPIV_DIMENSION_TEXTURE2D;
    inputViewDesc.Texture2D.ArraySlice = arraySliceIdx;
    inputViewDesc.Texture2D.MipSlice = 0;
    hr = d3dVideoDevice->CreateVideoProcessorInputView(srcTextureNV12Fmt,d3dVideoProcEnum,&inputViewDesc,&videoProcInputView);
}


{
    D3D11_VIDEO_PROCESSOR_OUTPUT_VIEW_DESC outputViewDesc = { D3D11_VPOV_DIMENSION_TEXTURE2D };
    outputViewDesc.Texture2D.MipSlice = 0;
    hr = d3dVideoDevice->CreateVideoProcessorOutputView(dstTextureRGBFmt,&outputViewDesc,&videoProcOutputView);
}


// Setup streams
D3D11_VIDEO_PROCESSOR_STREAM streams = { 0 };
streams.Enable = TRUE;
streams.pInputSurface = videoProcInputView.get();

RECT srcRect = { /* source rectangle in pixels*/ };
RECT dstRect = { /* destination rectangle in pixels*/ };

// Perform VideoProc Blit Operation (with color conversion)
hr = videoCtx_->VideoProcessorBlt(d3dVideoProc,videoProcOutputView.get(),1,&streams);