how to convert IMFMediaBuffer to ID3D11Texture2D?

as you know I have IMFMediaBuffer so you can not use what you say.

I only have IMFMediaBuffer which is DXGI_FORMAT_NV12

You can see for example GetTextureFromMFBuffer

or Video Processor

or from AI :

PATH 1: IMFMediaBuffer → IMFDXGIBuffer (zero-copy GPU interop)

If the IMFMediaBuffer wraps GPU memory (common with MFTs like hardware decoders), check if it's actually an IMFDXGIBuffer:

ComPtr<IMFMediaBuffer> mediaBuffer = ...;

ComPtr<IMFDXGIBuffer> dxgiBuffer;

HRESULT hr = mediaBuffer.As(&dxgiBuffer);

if (SUCCEEDED(hr))

{

ComPtr<ID3D11Texture2D> nv12Texture;

UINT subresource;

dxgiBuffer->GetResource(__uuidof(ID3D11Texture2D), (void**)nv12Texture.GetAddressOf());

dxgiBuffer->GetSubresourceIndex(&subresource);



// nv12Texture is ready to use (DXGI_FORMAT_NV12)

return nv12Texture;
}

This is the optimal path: zero-copy, no format conversion, direct GPU interop.

 PATH 2: CPU memory buffer (software decoder or camera)

If As<IMFDXGIBuffer> fails, then you're dealing with a system memory buffer. In this case, you must:

Lock the IMFMediaBuffer to access the NV12 data.

Create a DXGI_FORMAT_NV12 ID3D11Texture2D.

Copy the raw Y and UV data into the texture.

BUT: Direct3D 11 does not allow CPU write to NV12 textures with D3D11_USAGE_DEFAULT.

So the workaround is:

Create a staging texture in NV12 format

Use UpdateSubresource to copy the data (if you really must)

Or convert to BGRA yourself on CPU or GPU (preferred)

Example: CPU NV12 to BGRA via staging texture

If you still want to create a D3D11 NV12 texture from system memory, here’s what you can do:

1. Lock the buffer:

BYTE* pData = nullptr;

DWORD length = 0;

mediaBuffer->Lock(&pData, nullptr, &length);

2. Copy Y and UV planes into a single buffer matching NV12 layout:

// Assume width and height are known

int yStride = width;

int uvStride = width;

int ySize = yStride * height;

int uvSize = uvStride * height / 2;

// pData should be in NV12 layout (Y plane followed by UV interleaved)

3. Create NV12 texture (can only use for copying or as input to VideoProcessor):

D3D11_TEXTURE2D_DESC desc = {};

desc.Width = width;

desc.Height = height;

desc.MipLevels = 1;

desc.ArraySize = 1;

desc.Format = DXGI_FORMAT_NV12;

desc.SampleDesc.Count = 1;

desc.Usage = D3D11_USAGE_DEFAULT;

desc.BindFlags = D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_RENDER_TARGET;

D3D11_SUBRESOURCE_DATA initData = {};

initData.pSysMem = pData;

initData.SysMemPitch = width; // For NV12, pitch = width

ComPtr<ID3D11Texture2D> nv12Texture;

device->CreateTexture2D(&desc, &initData, &nv12Texture);

mediaBuffer->Unlock();

Note: Only some hardware/drivers support creating NV12 textures from CPU memory like this. 

Often it’s better to convert to BGRA yourself on CPU or create a staging BGRA texture.