formatting buffer according to the YUV420P format
c#, color-space, yuv
Solution
YUV 4:2:0 planar looks like this:
----------------------
| Y | Cb|Cr |
----------------------
where:
Y = width x height pixels (bytes)
Cb = Y / 4 pixels (bytes)
Cr = Y / 4 pixels (bytes)
Total num pixels (bytes) = width * height * 3 / 2
This is how pixels are placed in 4:2:0 sub-sampling:
As you can see, each chroma value is shared between 4 luma-pixels.
Problem
i have a an image size of `640 x480` and i want to use yv12 as an output format from that. the image is being processed by some API and i want to get the output in YV12 format. What i am trying at the moment is that int width = 640; int height = 480; byte[] byteArray = new byte[Convert.ToInt32((width * height + (2 * ((width * height) / 4))) * 1.5) ]; captureDevice.GetPreviewBufferYCbCr(byteArray)"); ``` int YLength = Convert.ToInt32(width * height * 1.5); // UVlength multipled by 2 because it is for both u and v int UVLength = Convert.ToInt32(2 * (width / 2) * (weight / 2)) * 1.5); var inputYBuffer = byteArray.AsBuffer(0, YLength); var inputUVBuffer = byteArray.AsBuffer(YLength, UVLength); var inputBuffers = new IBuffer[] { inputYBuffer, inputUVBuffer }; var inputScanlines = new uint[] { (uint)YLength, (uint)UVLength }; /////Creating input buffer that supports Nv12 format Bitmap inputBtm = new Bitmap( outputBufferSize, ColorMode.Yvu420Sp, inputScanlines, // 1.5 bytes per pixel in Yuv420Sp mode inputBuffers); //As v length is same as u length in output buffer so v length can be used in both place. int vLength = UVLength / 2; var outputYBuffer = byteArray.AsBuffer(0, YLength); var outputVBuffer = byteArray.AsBuffer(YLength, vLength); var outputUBuffer = byteArray.AsBuffer(YLength + vLength, vLength); var outputBuffers = new IBuffer[] { outputYBuffer, outputVBuffer, outputUBuffer }; // var outputScanlines = new uint[] { (uint)YLength, (uint)vLength, (uint)vLength }; Bitmap outputBtm = new Bitmap( outputBufferSize, ColorMode.Yuv420P, outputScanlines, outputBuffers);**strong text** ``` so what i want to ask that am i creating the outputbuffer properly according to the format YUV420P. There is an API in which i am passing the input buffer in the of NV12 and i am assuming that it will give me the output buffer in YV12 (YUV420P) format. So i have created the Y plane and it have `width x height x 1.5` bytes. 1.5 because YV12 is a 12 bits for mat and similarly U plane is having `width/2 x height/2 x 1.5` bytes and similarly the V plane. I don't care at the moment about the YUV420P and YVU420P as long as my format is correct and i just have to swap and U and V planes.