Video coding format: Difference between revisions

Revision as of 04:54, 25 June 2025

Revision as of 15:09, 24 July 2025

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A main problem for many video coding formats has been [[patent]]s, making it expensive to use or potentially risking a patent lawsuit due to [[submarine patent]]s. The motivation behind many recently designed video coding formats such as [[Theora]], [[VP8]], and [[VP9]] have been to create a ([[Free software|libre]]) video coding standard covered only by royalty-free patents.<ref>{{Cite web|url=https://blogs.cisco.com/collaboration/world-meet-thor-a-project-to-hammer-out-a-royalty-free-video-codec|title = World, Meet Thor – a Project to Hammer Out a Royalty Free Video Codec|date = August 11, 2015}}</ref> Patent status has also been a major point of contention for the choice of which video formats the mainstream [[web browser]]s will support inside the [[HTML video]] tag.

The current-generation video coding format is [[HEVC]] (H.265), introduced in 2013. AVC uses the integer DCT with 4x4 and 8x8 block sizes, and HEVC uses integer DCT and [[Discrete sine transform|DST]] transforms with varied block sizes between 4x4 and 32x32.<ref name="apple">{{cite web |last1=Thomson |first1=Gavin |last2=Shah |first2=Athar |title=Introducing HEIF and HEVC |url=https://devstreaming-cdn.apple.com/videos/wwdc/2017/503i6plfvfi7o3222/503/503_introducing_heif_and_hevc.pdf |publisher=[[Apple Inc.]] |year=2017 |access-date=August 5, 2019}}</ref> HEVC is heavily patented, mostly by [[Samsung Electronics]], [[GE]], [[Nippon Telegraph and Telephone|NTT]], and [[JVCKenwood]].<ref name="hevc-patents"/> It is challenged by the [[AV1]] format, intended for free license. {{As of|2019}}, AVC is by far the most commonly used format for the recording, compression, and distribution of video content, used by 91% of video developers, followed by HEVC, which is used by 43% of developers.<ref name="Bitmovin"/>

==List of video coding standards==

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==Lossless, lossy, and uncompressed==

Consumer video is generally compressed using [[lossy]] [[video codec]]s, since that results in significantly smaller files than [[lossless]] compression. Some video coding formats are designed explicitly for either lossy or lossless compression, and some video coding formats such as [[Dirac (video compression format)|Dirac]] and [[H.264]] support both.<ref>{{Cite journal|title=RFC 8761 - Video Codec Requirements and Evaluation Methodology|url=https://datatracker.ietf.org/doc/html/rfc8761|access-date=February 10, 2022|website=datatracker.ietf.org|date=April 2020 |language=en |last1=Filippov |first1=Alexey |last2=Norkin |first2=Aney |last3=Alvarez |first3=José Roberto }}</ref>

[[Uncompressed video]] formats, such as ''Clean HDMI'', is a form of lossless video used in some circumstances, such as when sending video to a display over aan [[HDMI]] connection. Some high-end cameras can also capture video directly in this format.{{Example needed|s|date=December 2024}}

==Intra-frame==

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==Profiles and levels==

A video coding format can define optional restrictions to encoded video, called [[profile (engineering)|profile]]s and levels. It is possible to have a decoder whichthat only supports decoding a subset of profiles and levels of a given video format, for example, to make the decoder program/hardware smaller, simpler, or faster.{{fact|date=January 2025}}

A ''profile'' restricts which encoding techniques are allowed. For example, the H.264 format includes the profiles ''baseline'', ''main'' and ''high'' (and others). While [[Video compression picture types|P-slices]] (which can be predicted based on preceding slices) are supported in all profiles, [[Video compression picture types|B-slices]] (which can be predicted based on both preceding and following slices) are supported in the ''main'' and ''high'' profiles but not in ''baseline''.<ref name="adobe"/>