Some patent holders and pools designate their patents as relevant or essential to a standard without proper scrutiny or analysis. As part of an ongoing series examining this dubious practice, we highlight U.S. Patent 10,575,014. The ‘014 patent is owned by the Electronics and Telecommunications Research Institute (ETRI) and Korea’s Kyung Hee University. The ‘014 patent is purportedly essential to the H.265 (HEVC) standard as part of the Access Advance Patent Pool and it is part of a family of at least 30 applications globally. It should not be considered essential.
The ‘014 patent is directed to the encoding/decoding and partitioning/reconstruction phases of video coding. Generally, instead of transmitting every frame (i.e., image) of every video, including its corresponding data, the encoder and decoder will each generate a prediction of the image and only transmit the difference between the prediction and the original image (i.e., the residual). The decoder will then use its prediction (and the residual, if one was sent) to reconstruct the image.
The ‘014 patent requires that when residual information is sent from the encoder to the decoder, then the decoder will add it to the predicted pixel values it generated in order to reconstruct the image. See, e.g., claim 1 (“generating the target block based on an intra prediction value and the residual block information”). However, when the encoder decides not to send residual information for a given pixel, the decoder then must look to a neighboring pixel in order to generate the reconstructed image. See, e.g., claim 1 (“generating the target block based on intra prediction direction information decoded from the bitstream”). Stated differently, the ‘014 patent creates a dependency between the prediction mode and the residual flag designating whether or not residual information was transmitted.
HEVC, in contrast, does not have the same dependency that the ‘014 patent requires. In HEVC, when the decoder decides not to send residual information, the reconstructed image is generated based on the predicted pixel value (not the value of a neighboring block). See HEVC, §§ 7.4.9.5, 7.3.8.8, 7.4.9.8, 9.3.3, 9.3.3.8. Indeed, in the HEVC syntax tree, the predicted value and the flag that designates whether residual information is sent are separate and distinct elements. See HEVC, § 7.3.8.5. They are, simply, not dependent on one another. In modern coding, predictions are accurate and a necessary first step in the order of operations. Thus, there is little reason to complete a prediction, then ignore it in favor of using the neighboring block’s value when reconstructing an image.
Thus, the ‘014 patent does not appear to be essential to the HEVC standard even though it has been declared essential and actively licensed as being so. The public would benefit from appropriate scrutiny of such large patent pools that allegedly cover critical technical standards.