Question

我的图片大小为640 x480，我希望使用yv12作为输出格式。一些API正在处理图像，我希望得到YV12格式的输出。

我现在正在尝试的是

int width = 640;
  int height = 480;

byte [] byteArray = new byte [Convert.ToInt32（（width * height +（2 *（（width * height）/ 4）））* 1.5）];

captureDevice.GetPreviewBufferYCbCr（字节阵列）“）;

            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**

所以我想问的是我是否正在根据YUV420P格式正确创建outputbuffer。有一个API，我在其中传递NV12的输入缓冲区，我假设它将给我YV12（YUV420P）格式的输出缓冲区。所以我创建了Y平面，它有width x height x 1.5个字节。 1.5因为YV12对于垫子是12比特，并且类似地U盘具有width/2 x height/2 x 1.5字节并且类似地是V平面。我不关心YUV420P和YVU420P，只要我的格式正确，我只需要交换U和V平面。

Answer 1

YUV 4：2：0平面看起来像这样：

----------------------
|     Y      | Cb|Cr |
----------------------

其中：

Y = width x height pixels (bytes)
Cb = Y / 4 pixels (bytes)
Cr = Y / 4 pixels (bytes)

Total num pixels (bytes) = width * height * 3 / 2

这是像素放置在4：2：0子采样中的方式：

420

如您所见，每个色度值在4个亮度像素之间共享。

根据YUV420P格式格式化缓冲区

1 个答案: