Video compression format
Encyclopedia
A video compression format or a video compression specification is a specification for digital
ly representing a video
as a file or a bitstream
. Examples of video compression formats are MPEG-2 Part 2
, MPEG-4 Part 2
, H.264
(MPEG-4 Part 10), Theora
, Dirac, RealVideo
RV40, and VP8
. A specific software or hardware implementation of video compression and/or decompression using a specific video compression format is called a video codec
; an example of a video codec is Xvid
, which implements encoding and decoding videos using the MPEG-4 Part 2
video compression format in software.
A video encoded according to a video compression format is normally bundled with an audio stream (encoded using an audio compression format) inside a multimedia container format such as AVI
, MP4, FLV, RealMedia
, or Matroska
. As such, the user normally doesn't have a H.264
file, but instead has a .mp4 file, which is an MP4 container containing H.264-encoded video, normally alongside AAC
-encoded audio. Multimedia container formats can contain any one of a number of different video compression formats; for example the MP4 container format can contain video in either the MPEG-2 Part 2 or the H.264 video compression format, among others. Another example is the file type WebM
, which specifies the container format (Matroska), but also exactly which video (VP8
) and audio (Vorbis
) compression format is used inside the Matroska container, even though the Matroska container format itself is capable of containing other video compression formats.
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
ly representing a video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
as a file or a bitstream
Bitstream format
A bitstream format is the format of the data found in some stream of bits used in a digital communication or data storage application. The term typically refers to the format of the output of an encoder or the format of the input to a decoder when using data compression.Standardized...
. Examples of video compression formats are MPEG-2 Part 2
H.262/MPEG-2 Part 2
H.262 or MPEG-2 Part 2 is a digital video compression and encoding standard developed and maintained jointly by ITU-T Video Coding Experts Group and ISO/IEC Moving Picture Experts Group . It is the second part of the ISO/IEC MPEG-2 standard...
, MPEG-4 Part 2
MPEG-4 Part 2
MPEG-4 Part 2, MPEG-4 Visual is a video compression technology developed by MPEG. It belongs to the MPEG-4 ISO/IEC standards. It is a discrete cosine transform compression standard, similar to previous standards such as MPEG-1 and MPEG-2...
, H.264
H.264/MPEG-4 AVC
H.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...
(MPEG-4 Part 10), Theora
Theora
Theora is a free lossy video compression format. It is developed by the Xiph.Org Foundation and distributed without licensing fees alongside their other free and open media projects, including the Vorbis audio format and the Ogg container....
, Dirac, RealVideo
RealVideo
RealVideo is a suite of proprietary video compression formats developed by RealNetworks – the specific format changes with the version. It was first released in 1997 and is at version 10. RealVideo is supported on many platforms, including Windows, Mac, Linux, Solaris, and several mobile...
RV40, and VP8
VP8
VP8 is an open video compression format released by Google, originally created by On2 Technologies.After purchasing On2 Technologies in early 2010, Google has provided an irrevocable patent promise for underlying patents for the VP8 format, and released a bitstream format specification under a...
. A specific software or hardware implementation of video compression and/or decompression using a specific video compression format is called a video codec
Video codec
A video codec is a device or software that enables video compression and/or decompression for digital video. The compression usually employs lossy data compression. Historically, video was stored as an analog signal on magnetic tape...
; an example of a video codec is Xvid
XviD
Xvid is a video codec library following the MPEG-4 standard, specifically MPEG-4 Part 2 Advanced Simple Profile . It uses ASP features such as b-frames, global and quarter pixel motion compensation, lumi masking, trellis quantization, and H.263, MPEG and custom quantization matrices.Xvid is a...
, which implements encoding and decoding videos using the MPEG-4 Part 2
MPEG-4 Part 2
MPEG-4 Part 2, MPEG-4 Visual is a video compression technology developed by MPEG. It belongs to the MPEG-4 ISO/IEC standards. It is a discrete cosine transform compression standard, similar to previous standards such as MPEG-1 and MPEG-2...
video compression format in software.
A video encoded according to a video compression format is normally bundled with an audio stream (encoded using an audio compression format) inside a multimedia container format such as AVI
Audio Video Interleave
Audio Video Interleave , known by its acronym AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. AVI files can contain both audio and video data in a file container that allows synchronous audio-with-video playback...
, MP4, FLV, RealMedia
RealMedia
RealMedia is a proprietary multimedia container format created by RealNetworks. Its extension is ".rm". It is typically used in conjunction with RealVideo and RealAudio and is used for streaming content over the Internet....
, or Matroska
Matroska
The Matroska Multimedia Container is an open standard free container format, a file format that can hold an unlimited number of video, audio, picture or subtitle tracks in one file. It is intended to serve as a universal format for storing common multimedia content, like movies or TV shows...
. As such, the user normally doesn't have a H.264
H.264/MPEG-4 AVC
H.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...
file, but instead has a .mp4 file, which is an MP4 container containing H.264-encoded video, normally alongside AAC
Advanced Audio Coding
Advanced Audio Coding is a standardized, lossy compression and encoding scheme for digital audio. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at similar bit rates....
-encoded audio. Multimedia container formats can contain any one of a number of different video compression formats; for example the MP4 container format can contain video in either the MPEG-2 Part 2 or the H.264 video compression format, among others. Another example is the file type WebM
WebM
WebM is an audio-video format designed to provide a royalty-free, open video compression format for use with HTML5 video. The project's development is sponsored by Google....
, which specifies the container format (Matroska), but also exactly which video (VP8
VP8
VP8 is an open video compression format released by Google, originally created by On2 Technologies.After purchasing On2 Technologies in early 2010, Google has provided an irrevocable patent promise for underlying patents for the VP8 format, and released a bitstream format specification under a...
) and audio (Vorbis
Vorbis
Vorbis is a free software / open source project headed by the Xiph.Org Foundation . The project produces an audio format specification and software implementation for lossy audio compression...
) compression format is used inside the Matroska container, even though the Matroska container format itself is capable of containing other video compression formats.