Video coding format in the context of Motion compensation

A video file format is a type of file format for storing digital video data on a computer system. Video is almost always stored using lossy compression to reduce the file size.

A video file normally consists of a container (e.g. in the Matroska format) containing visual (video without audio) data in a video coding format (e.g. VP9) alongside audio data in an audio coding format (e.g. Opus). The container can also contain synchronization information, subtitles, and metadata such as title. A standardized (or in some cases de facto standard) video file type such as .webm is a profile specified by a restriction on which container format and which video and audio compression formats are allowed.

VP9 is an open and royalty-free video coding format developed by Google.

VP9 is the successor to VP8 and competes mainly with MPEG's High Efficiency Video Coding (HEVC/H.265).At first, VP9 was mainly used on Google's video platform YouTube. The emergence of the Alliance for Open Media, and its support for the ongoing development of the successor AV1, of which Google is a part, led to growing interest in the format.

Nasir Ahmed (born 1940) is an American electrical engineer and computer scientist. He is Professor Emeritus of Electrical and Computer Engineering at University of New Mexico (UNM). He is best known for inventing the discrete cosine transform (DCT) in the early 1970s. The DCT is the most widely used data compression transformation, the basis for most digital media standards (image, video and audio) and commonly used in digital signal processing. He also described the discrete sine transform (DST), which is related to the DCT.

MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) (ISO/IEC JTC 1/SC29/WG11) under the formal standard ISO/IEC 14496 – Coding of audio-visual objects. Uses of MPEG-4 include compression of audiovisual data for Internet video and CD distribution, voice (telephone, videophone) and broadcast television applications. The MPEG-4 standard was developed by a group led by Touradj Ebrahimi (later the JPEG president) and Fernando Pereira.

H.262 or MPEG-2 Part 2 (formally known as ITU-T Recommendation H.262 and ISO/IEC 13818-2, also known as MPEG-2 Video) is a video coding format standardised and jointly maintained by ITU-T Study Group 16 Video Coding Experts Group (VCEG) and ISO/IEC Moving Picture Experts Group (MPEG), and developed with the involvement of many companies. It is the second part of the ISO/IEC MPEG-2 standard. The ITU-T Recommendation H.262 and ISO/IEC 13818-2 documents are identical.

The standard is available for a fee from the ITU-T and ISO. MPEG-2 Video is very similar to MPEG-1, but also provides support for interlaced video (an encoding technique used in analog NTSC, PAL and SECAM television systems). MPEG-2 video is not optimized for low bit-rates (e.g., less than 1 Mbit/s), but somewhat outperforms MPEG-1 at higher bit rates (e.g., 3 Mbit/s and above), although not by a large margin unless the video is interlaced. All standards-conforming MPEG-2 Video decoders are also fully capable of playing back MPEG-1 Video streams.

MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression methods, which permit storage and transmission of movies using currently available storage media and transmission bandwidth. While MPEG-2 is not as efficient as newer standards such as H.264/AVC and H.265/HEVC, backwards compatibility with existing hardware and software means it is still widely used, for example in over-the-air digital television broadcasting and in the DVD-Video standard.

AOMedia Video 1 (AV1) is an open, royalty-free video coding format initially designed for video transmissions over the Internet. It was developed as a successor to VP9 by the Alliance for Open Media (AOMedia), a consortium founded in 2015 that includes semiconductor firms, video on demand providers, video content producers, software development companies and web browser vendors. The AV1 bitstream specification includes a reference video codec. In 2018, Facebook conducted testing that approximated real-world conditions, and the AV1 reference encoder achieved 34%, 46.2%, and 50.3% higher data compression than libvpx-vp9, x264 High profile, and x264 Main profile respectively.

Like VP9, but unlike H.264 (AVC) and H.265 (HEVC), AV1 has a royalty-free licensing model that does not hinder adoption in open-source projects.

A video codec is software or hardware that compresses and decompresses digital video. In the context of video compression, codec is a portmanteau of encoder and decoder, while a device that only compresses is typically called an encoder, and one that only decompresses is a decoder.

The compressed data format usually conforms to a standard video coding format. The compression is typically lossy, meaning that the compressed video lacks some information present in the original video. A consequence of this is that decompressed video has lower quality than the original, uncompressed video because there is insufficient information to accurately reconstruct the original video.

VP8 is an open and royalty-free video compression format released by On2 Technologies in 2008.

Initially released as a proprietary successor to On2's previous VP7 format, VP8 was released as an open and royalty-free format in May 2010 after Google acquired On2 Technologies. Google provided an irrevocable patent promise on its patents for implementing the VP8 format, and released a specification of the format under the Creative Commons Attribution 3.0 license. That same year, Google also released libvpx, the reference implementation of VP8, under the revised BSD license.

High Efficiency Video Coding (HEVC), also known as H.265 and MPEG-H Part 2, is a proprietary 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). The standard was published in 2013. 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. It supports resolutions up to 8192×4320, including 8K UHD, and unlike the primarily eight-bit AVC, HEVC's higher-fidelity Main 10 profile has been incorporated into nearly all supporting hardware. The High Efficiency Image Format (HEIF) is a container format whose default codec is 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.

The Alliance for Open Media (AOMedia) is a non-profit industry consortium headquartered in Wakefield, Massachusetts, and formed to develop open, royalty-free technology for multimedia delivery. It uses the ideas and principles of open web standard development to create video standards that can serve as alternatives to the hitherto dominant standards of the Moving Picture Experts Group (MPEG).

Its first project was to develop AV1, a new open video codec and format, as a successor to VP9 and an alternative to HEVC. AV1 uses elements from Daala, Thor, and VP10, three preceding open video codecs.

HTML video is a subject of the HTML specification as the standard way of playing video via the web. Introduced in HTML5, it is designed to partially replace the object element and the previous de facto standard of using the proprietary Adobe Flash plugin, though early adoption was hampered by lack of agreement as to which video coding formats and audio coding formats should be supported in web browsers. As of 2020, HTML video is the only widely supported video playback technology in modern browsers, with the Flash plugin being phased out.