D3D11 texture sharing between two devices

Question

Hello,

i attempt to share D3D11Texture2D textures between two D3D11Device devices but I'm unable to make it work.

This is my function to generate my shared textures: https://pastebin.com/8WVRaHfA (Too long for a code block)

This is what the struct looks like keeping a reference to my textures: https://pastebin.com/avcNV814

First I tried to modify my shared texture and checked the result in renderdoc. My shared texture got updated but the main texture my shared texture points to is still empty:

sharedTextures = createSharedTextures(1920, 1080, pD3d11DeviceUnity, pD3d11DeviceFFmpeg, 3);
pD3d11DeviceCtxFFmpeg->CopyResource(sharedTextures.bufferTextures[0].pFFmpegTex, testTex);
pD3d11DeviceCtxFFmpeg->CopyResource(sharedTextures.bufferTextures[0].pFFmpegTex, testTex); // testTex is owned by pD3d11DeviceFFmpeg

=> sharedTextures.bufferTextures[0].pUnityTex is still blank

Then I attempted to use synchronization:

sharedTextures = createSharedTextures(1920, 1080, pD3d11DeviceUnity, pD3d11DeviceFFmpeg, 3);
DWORD result = sharedTextures.bufferTextures[0].pFFmpegMutex->AcquireSync(1, 5000);

    if (result == WAIT_OBJECT_0) {
        std::cout << "Mutex Acquired" << std::endl;
        pD3d11DeviceCtxFFmpeg->CopyResource(sharedTextures.bufferTextures[0].pFFmpegTex, testTex);
        sharedTextures.bufferTextures[0].pFFmpegMutex->ReleaseSync(0);
        std::cout << "Mutex Released" << std::endl;
    } else if (result == E_FAIL) {
        std::cerr << "E_FAIL" << std::endl;
    } else if (result == WAIT_ABANDONED) {
        std::cerr << "WAIT_ABANDONED" << std::endl;
    } else if (result == WAIT_TIMEOUT) {
        std::cerr << "WAIT_TIMEOUT" << std::endl;
    } else {
        std::cerr << "Unable to acquire shared surface error" << std::endl;
    }

Which just ended in a thread lock until the timeout expired and printed WAIT_TIMEOUT.

I'm not experienced with DirectX at all and hope someone in here is able to help me with my issue.