According to MacNN, Apple has filed patents on OpenGL multitexturing techniques widely discussed in the public domain:

Apple’s Abstract: A system which utilizes the processing capabilities of the graphics processing unit (GPU) in the graphics controller. Each frame of each video stream is decoded. After decoding the compressed image is separated into an image representing the luminance and an image representing the chroma. The chroma image is resampled as appropriate using the GPU to provide chroma values corresponding to each luminance value at the proper locations. The resampled chroma image and the luminance image are properly combined to produce a 4:4:4 image, preferably in the RGB color space, and provided to the frame buffer for final display. Each of these operations is done in real time for each frame of the video.

Here's some "prior art" OpenGL multitexturing code circa 2004 (Source: fourcc.org).

I think the MacNN patent numbers or links are incorrect, as they link to some unrelated patents.