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• YUV4:2:0 conversion to RGB outputs overly green image

  27 février 2023, par luckybroma

  I'm decoding video and getting YUV 420 frames. In order to render them using D3D11, they need to get converted to RGB (or at least I assume that the render target view cannot be YUV itself).

  


  The YUV frames are all in planar format, meaning UV and not packed. I'm creating 3 textures and ShaderResourceViews of type DXGI_FORMAT_R8G8_UNORM. I'm copying each plane from the frame into it's own ShaderResourceView. I'm then relying on the sampler to account for the differences in size between the Y and UV planes. Black/White only looks great. If I add in color though, I get an overly Green Picture :


  


  I'm at a huge loss of what I could be doing wrong.. I've tried switching the UV and planes around, I've also tried tweaking the conversion values. I'm following Microsoft's guide on picture conversion.

  


  Here is my shader :

  


  min16float4 main(PixelShaderInput input) : SV_TARGET
{
    float y = YChannel.Sample(defaultSampler, input.texCoord).r;
    float u = UChannel.Sample(defaultSampler, input.texCoord).r - 0.5;
    float v = VChannel.Sample(defaultSampler, input.texCoord).r - 0.5;

    float r = y + 1.13983 * v;
    float g = y - 0.39465 * u - 0.58060 * v;
    float b = y + 2.03211 * u;

    return min16float4(r, g, b , 1.f);
}


  


  Creating my ShaderResourceViews :

  


  D3D11_TEXTURE2D_DESC texDesc;
    ZeroMemory(&texDesc, sizeof(texDesc));
    texDesc.Width = 1670;
    texDesc.Height = 626;
    texDesc.MipLevels = 1;
    texDesc.ArraySize = 1;
    texDesc.Format = DXGI_FORMAT_R8_UNORM;
    texDesc.SampleDesc.Count = 1;
    texDesc.SampleDesc.Quality = 0;
    texDesc.Usage = D3D11_USAGE_DYNAMIC;
    texDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
    texDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;


    dev->CreateTexture2D(&texDesc, NULL, &pYPictureTexture);
    dev->CreateTexture2D(&texDesc, NULL, &pUPictureTexture);
    dev->CreateTexture2D(&texDesc, NULL, &pVPictureTexture);
    
    D3D11_SHADER_RESOURCE_VIEW_DESC shaderResourceViewDesc;
    shaderResourceViewDesc.Format = DXGI_FORMAT_R8_UNORM;
    shaderResourceViewDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
    shaderResourceViewDesc.Texture2D.MostDetailedMip = 0;
    shaderResourceViewDesc.Texture2D.MipLevels = 1;

    dev->CreateShaderResourceView(pYPictureTexture, &shaderResourceViewDesc, &pYPictureTextureResourceView);

    dev->CreateShaderResourceView(pUPictureTexture, &shaderResourceViewDesc, &pUPictureTextureResourceView);
    
    dev->CreateShaderResourceView(pVPictureTexture, &shaderResourceViewDesc, &pVPictureTextureResourceView);



  


  And then How I'm copying the decoded ffmpeg AVFrames :

  


      int height = 626;
    int width = 1670;    

    D3D11_MAPPED_SUBRESOURCE msY;
    D3D11_MAPPED_SUBRESOURCE msU;
    D3D11_MAPPED_SUBRESOURCE msV;
    devcon->Map(pYPictureTexture, 0, D3D11_MAP_WRITE_DISCARD, 0, &msY);

    memcpy(msY.pData, frame->data[0], height * width);
    devcon->Unmap(pYPictureTexture, 0);

    devcon->Map(pUPictureTexture, 0, D3D11_MAP_WRITE_DISCARD, 0, &msU);
    memcpy(msU.pData, frame->data[1], (height*width) / 4);
    devcon->Unmap(pUPictureTexture, 0);


    devcon->Map(pVPictureTexture, 0, D3D11_MAP_WRITE_DISCARD, 0, &msV);
    memcpy(msV.pData, frame->data[2], (height*width) / 4);
    devcon->Unmap(pVPictureTexture, 0);


  


  PS : Happy to provide any more additional requested code ! I just wanted to be concise as possible.

  


• riff : don’t overwrite bps from WAVEFORMATEX if EXTENSIBLE doesn’t contain that data.

  2 mai 2012, par Hendrik Leppkes

  riff : don’t overwrite bps from WAVEFORMATEX if EXTENSIBLE doesn’t contain that data.
  According to the specification on the MSDN [1], 0 is valid for that
  
  particular field, and it should be ignored in that case.
  [1] : http://msdn.microsoft.com/en-us/library/windows/desktop/dd757714(v=vs.85).aspx
  Bug-Id : 950
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] libavformat/riffdec.c

• How to create a video in .net6 [closed]

  22 mai 2023, par mans

  I am trying to create a video from a series of images i .net core (6.0)

  


  I am looking for a solution like this :

  


  VideoCreator video=new VideoCreator("MyVideo.mp4");

for (int i=0;i<1000;i++)
{
     var image=getImage();
     video.addFrame(image);
}
video.close();


  


  I already tried these solutions, and I could not make them work or compile :

  


  OpenCVSharp

  


  This is compiling properly in .net 6 but is sot reliable when writing videos. I could get a blank video, especially if the getImage function took a long time to return an image (for example, 20 sec) and the above code is run in a thread. All in one : the system did not produce video reliably.

  


  AForge.net

  


  This library and its related library (Accord.NET) don't work on.net core. My attempt to use them did not produce any compilable software (for example AForge.video.ffmpeg or AForge.Video.VFW) are not available in .net core).

  


  So my questions :

  


  

  1. What is the best way to create a video in .net core reliably ?

  


  2. I am using .net core as I am using Microsoft ML engine, is the ML engine available for framework ?

  


  3. My target platform is Windows, is there any way that I can combine .net and framework applications/libraries ?