The primary changes for HEVC include the expansion of the pattern comparison and difference-coding areas from 16×16 pixel to sizes up to 64×64, improved variable-block-size segmentation, improved 'intra' prediction within the same picture, improved motion vector prediction and motion region merging, improved motion compensation filtering, and an additional filtering step called sample-adaptive offset filtering. These redundant areas are then replaced with a short description instead of the original pixels.

Both work by comparing different parts of a frame of video to find areas that are redundant, both within a single frame and between consecutive frames. In most ways, HEVC is an extension of the concepts in H.264/MPEG-4 AVC.

As of 2019, HEVC is used by 43% of video developers, and is the second most widely used video coding format after AVC. The High Efficiency Image Format (HEIF) is based on HEVC. While AVC uses the integer discrete cosine transform (DCT) with 4×4 and 8×8 block sizes, HEVC uses both integer DCT and discrete sine transform (DST) with varied block sizes between 4×4 and 32×32. It supports resolutions up to 8192×4320, including 8K UHD, and unlike the primarily 8-bit AVC, HEVC's higher fidelity Main 10 profile has been incorporated into nearly all supporting hardware.

In comparison to AVC, HEVC offers from 25% to 50% better data compression at the same level of video quality, or substantially improved video quality at the same bit rate. High Efficiency Video Coding ( HEVC), also known as H.265 and MPEG-H Part 2, is a video compression standard designed as part of the MPEG-H project as a successor to the widely used Advanced Video Coding (AVC, H.264, or MPEG-4 Part 10). SG16 (Secretary: Simao Campos) ( VCEG), MPEG Video compression format, succeeds H.264/MPEG-4 AVC HEVC / H.265 / MPEG-H Part 2 High efficiency video coding

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