Apple has been granted a patent (number 7994971) by the US Patent & Trademark Office for encoding video. Some embodiments of the invention provide a method for encoding a video signal that is formed by a series of successive images.

Each image includes several sections, and each section has a set of image values. To encode a particular section of a particular image, the method initially partitions the particular section into several sub-sections. For each of at least two particular sub-sections, the method then computes a statistical parameter regarding the image values of the particular sub-section.

The method compares the computed statistical parameters, and based on the comparison, selects an encoding technique from a set of encoding techniques to encode the particular section. In some embodiments, the set of encoding schemes includes a first scheme that encodes the selected section without reference to any other section of any other image, and a second scheme that encodes the selected section by reference to at least one other section. The inventors are Thomas Pun, Roger Kumar, Xiachun Nie and Hsi-Jung Wu.

Here's Apple's summary of the invention: "Some embodiments of the invention provide a method for encoding a video signal that is formed by a series of successive images. Each image includes several sections, and each section has a set of image values. To encode a particular section of a particular image, the method initially partitions the particular section into several sub-sections. For each of at least two particular sub-sections, the method then computes a statistical parameter regarding the image values of the particular sub-section.

"The method compares the computed statistical parameters, and based on the comparison, selects an encoding technique from a set of encoding techniques to encode the particular section. In some embodiments, the set of encoding schemes includes a first scheme that encodes the selected section without reference to any other section of any other image, and a second scheme that encodes the selected section by reference to at least one other section.

In some embodiments, the method initially selects a section. It then determines whether the image values in the section are centered about a particular value. If the selected section's image values are centered about the particular value, the method uses a first equation to compute a first metric score for the image values of the selected section. Otherwise, the method uses a second equation to compute a second metric score for the image values of the selected section.

"The method next selects an encoding scheme from a set of encoding schemes based on the computed metric score, and then encodes the selected section according to the selected encoding scheme. In some embodiments, the method determines whether the image values of the particular section are centered about a particular value by comparing the image values of each sub-section with image values of the other sub-sections. In some embodiments, this comparison entails: (1) for a first sub-section, computing a first energy value that expresses the deviation of the image values of the first sub-section from an average of the image values of the first sub-section, (2) for a second sub-section, computing a second energy value that expresses the deviation of the image values of the second sub-section from an average of the image values of the second sub-section, (3) determining whether the first and second energy values differ by more than a first threshold; and (4) if the first and second energy values differ by more than the first threshold, specifying that the selected section's image values are not centered about the particular value."

Apple also won design patents for the latest iPod nano (patent D638,030), an iPad case (D637,814) and the 27-inch Cinema Display (D638,013).

-- Dennis Sellers