how to write NV12 byte buffer into a image using opencv?

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Hi I want to save the NV12 video buffer into series of the image file. I want to know how to do ?

In NV12 the chroma is stored as interleaved U and V values in an array immediately following the array of Y values. Therefore, to get to the UV array we need to skip past the Y array - IE width of each pixel line (m_stride) times the number of pixel lines in the image (m_imageHeightInPixels)