metal

问题 Consider this admirable script which draws a (circular) gradient, https://github.com/paiv/AngleGradientLayer/blob/master/AngleGradient/AngleGradientLayer.m int w = CGRectGetWidth(rect); int h = CGRectGetHeight(rect); and then angleGradient(data, w, h .. and the it loops over all those for (int y = 0; y < h; y++) for (int x = 0; x < w; x++) { basically setting the color *p++ = color; But wait - wouldn't this be working by points, not pixels ? How, really, would you draw to the physical pixels

问题 I have read the BT.709 spec a number of times and the thing that is just not clear is should an encoded H.264 bitstream actually apply any gamma curve to the encoded data? Note the specific mention of a gamma like formula in the BT.709 spec. Apple provided examples of OpenGL or Metal shaders that read YUV data from CoreVideo provided buffers do not do any sort of gamma adjustment. YUV values are being read and processed as though they are simple linear values. I also examined the source code