Question

In application i used AVCaptureVideo. i got video in kCVPixelFormatType_420YpCbCr8BiPlanarFullRange format.

now i am getting y-planar and uv-planar from imagebuffer.

  CVPlanarPixelBufferInfo_YCbCrBiPlanar *planar = CVPixelBufferGetBaseAddress(imageBuffer);

    size_t y-offset = NSSwapBigLongToHost(planar->componentInfoY.offset);
    size_t uv-offset = NSSwapBigLongToHost(planar->componentInfoCbCr.offset);

here yuv is biplanar format(y+UV).

what is UV-planar? is this uuuu,yyyy format or uvuvuvuv format?
How to i get u-planar and y-planar seperatly?

can any one pls help me?

Answer 1

The Y plane represents the luminance component, and the UV plane represents the Cb and Cr chroma components.

In the case of kCVPixelFormatType_420YpCbCr8BiPlanarFullRange format, you will find the luma plane is 8bpp with the same dimensions as your video, your chroma plane will be 16bpp, but only a quarter of the size of the original video. You will have one Cb and one Cr component per pixel on this plane.

so if your input video is 352×288, your Y plane will be 352×288 8bpp, and your CbCr 176×144 16bpp. This works out to be about the same amount of data as a 12bpp 352×288 image, half what would be required for RGB888 and still less than RGB565.

So in the buffer, Y will look like this
[YYYYY . . . ]
and UV
[UVUVUVUVUV . . .]

vs RGB being, of course,
[RGBRGBRGB . . . ]