Update CVImageBufferRef with pixels in capture format with bgra pixels using libyuv

libyuv.cc

// Function to update image buffer in NV12 format with BGRA pixel buffer
// Assumptions:
// bgra buffer is 32bpp
// bgra buffer width and height equal to imageBuffer
// bgra buffer stride is equal to imageBuffer width
int UpdateSampleBufferWithBGRAPixels(CVImageBufferRef imageBuffer, void *bgraPixels) {
    const OSType pixelFormat = CVPixelBufferGetPixelFormatType(imageBuffer);
    assert(pixelFormat == kCVPixelFormatType_420YpCbCr8BiPlanarFullRange || pixelFormat == kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange);
    
    const size_t width = CVPixelBufferGetWidth(imageBuffer);
    const size_t height = CVPixelBufferGetHeight(imageBuffer);

    CVPixelBufferLockBaseAddress(imageBuffer, NULL);

    const int retval = ARGBToNV12(bgraPixels, 4 * width,
            CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0), CVPixelBufferGetBytesPerRowOfPlane(imageBuffer, 0),
            CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 1), CVPixelBufferGetBytesPerRowOfPlane(imageBuffer, 1),
            width, height);

    CVPixelBufferUnlockBaseAddress(imageBuffer, NULL);

    return retval;
}