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Index H.261

H.261 is an ITU-T video compression standard, first ratified in November 1988. [1]

43 relations: Chroma subsampling, Chrominance, Color space, Common Intermediate Format, Data compression, Deblocking filter, Decimation (signal processing), Discrete cosine transform, Entropy encoding, Ffdshow, FFmpeg, GNU Lesser General Public License, H.120, H.262/MPEG-2 Part 2, H.263, H.264/MPEG-4 AVC, H.323, High Efficiency Video Coding, Image, Integrated Services Digital Network, Inter frame, International Telecommunication Union, Interoperability, ITU-T, K. R. Rao, Libavcodec, Luma (video), Macroblock, Motion compensation, Motion estimation, Motion vector, MPEG-4 Part 2, MPlayer, N. Ahmed, Nippon Telegraph and Telephone, Quantization (signal processing), Run-length encoding, Transform coding, Variable-length code, Video Coding Experts Group, Video coding format, VLC media player, YCbCr.

Chroma subsampling

Chroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for color differences than for luminance.

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Chrominance (chroma or C for short) is the signal used in video systems to convey the color information of the picture, separately from the accompanying luma signal (or Y for short).

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Color space

A color space is a specific organization of colors.

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Common Intermediate Format

CIF (Common Intermediate Format or Common Interchange Format), also known as FCIF (Full Common Intermediate Format), is a standardized format for the picture resolution, frame rate, color space, and color subsampling of digital video sequences used in video teleconferencing systems.

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Data compression

In signal processing, data compression, source coding, or bit-rate reduction involves encoding information using fewer bits than the original representation.

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Deblocking filter

A deblocking filter is a video filter applied to decoded compressed video to improve visual quality and prediction performance by smoothing the sharp edges which can form between macroblocks when block coding techniques are used.

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Decimation (signal processing)

In digital signal processing, decimation is the process of reducing the sampling rate of a signal.

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Discrete cosine transform

A discrete cosine transform (DCT) expresses a finite sequence of data points in terms of a sum of cosine functions oscillating at different frequencies.

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Entropy encoding

In information theory an entropy encoding is a lossless data compression scheme that is independent of the specific characteristics of the medium.

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ffdshow is a codec mainly used for decoding of video in the MPEG-4 ASP (e.g. encoded with DivX or Xvid) and H.264/MPEG-4 AVC video formats, but it supports numerous other video and audio formats as well.

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FFmpeg is a free software project, the product of which is a vast software suite of libraries and programs for handling video, audio, and other multimedia files and streams.

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GNU Lesser General Public License

The GNU Lesser General Public License (LGPL) is a free software license published by the Free Software Foundation (FSF).

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H.120 was the first digital video compression standard.

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H.262/MPEG-2 Part 2

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 developed and maintained jointly by ITU-T Video Coding Experts Group (VCEG) and ISO/IEC Moving Picture Experts Group (MPEG).

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H.263 is a video compression standard originally designed as a low-bit-rate compressed format for videoconferencing.

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H.264/MPEG-4 AVC

H.264 or MPEG-4 Part 10, Advanced Video Coding (MPEG-4 AVC) is a block-oriented motion-compensation-based video compression standard.

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H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network.

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High Efficiency Video Coding

High Efficiency Video Coding (HEVC), also known as H.265 and MPEG-H Part 2, is a video compression standard, one of several potential successors to the widely used AVC (H.264 or MPEG-4 Part 10).

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An image (from imago) is an artifact that depicts visual perception, for example, a photo or a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person, thus providing a depiction of it.

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Integrated Services Digital Network

Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network.

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Inter frame

An inter frame is a frame in a video compression stream which is expressed in terms of one or more neighboring frames.

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International Telecommunication Union

The International Telecommunication Union (ITU; Union Internationale des Télécommunications (UIT)), originally the International Telegraph Union (Union Télégraphique Internationale), is a specialized agency of the United Nations (UN) that is responsible for issues that concern information and communication technologies.

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Interoperability is a characteristic of a product or system, whose interfaces are completely understood, to work with other products or systems, at present or in the future, in either implementation or access, without any restrictions.

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The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU); it coordinates standards for telecommunications.

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K. R. Rao


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libavcodec is a free and open-source library of codecs for encoding and decoding video and audio data.

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Luma (video)

In video, luma represents the brightness in an image (the "black-and-white" or achromatic portion of the image).

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Macroblock is a processing unit in image and video compression formats based on linear block transforms, such as the discrete cosine transform (DCT).

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Motion compensation

Motion compensation is an algorithmic technique used to predict a frame in a video, given the previous and/or future frames by accounting for motion of the camera and/or objects in the video.

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Motion estimation

Motion estimation is the process of determining motion vectors that describe the transformation from one 2D image to another; usually from adjacent frames in a video sequence.

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Motion vector

In video compression, a motion vector is the key element in the motion estimation process.

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MPEG-4 Part 2

MPEG-4 Part 2, MPEG-4 Visual (formally ISO/IEC 14496-2) is a video compression format developed by MPEG.

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MPlayer is a free and open media player software.

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N. Ahmed

Nasir Ahmed (born 1940 in Bangalore, India) is a Professor Emeritus of Electrical and Computer and Engineering at University of New Mexico (UNM).

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Nippon Telegraph and Telephone

, commonly known as NTT, is a Japanese telecommunications company headquartered in Tokyo, Japan.

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Quantization (signal processing)

Quantization, in mathematics and digital signal processing, is the process of mapping input values from a large set (often a continuous set) to output values in a (countable) smaller set.

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Run-length encoding

Run-length encoding (RLE) is a very simple form of lossless data compression in which runs of data (that is, sequences in which the same data value occurs in many consecutive data elements) are stored as a single data value and count, rather than as the original run.

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Transform coding

Transform coding is a type of data compression for "natural" data like audio signals or photographic images.

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Variable-length code

In coding theory a variable-length code is a code which maps source symbols to a variable number of bits.

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Video Coding Experts Group

The Video Coding Experts Group or Visual Coding Experts Group (VCEG, also known as Question 6) is a working group of the ITU Telecommunication Standardization Sector (ITU-T) concerned with video coding standards.

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Video coding format

A video coding format (or sometimes video compression format) is a content representation format for storage or transmission of digital video content (such as in a data file or bitstream).

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VLC media player

VLC media player (commonly known as VLC) is a free and open-source, portable, cross-platform media player and streaming media server developed by the VideoLAN project.

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YCbCr, Y′CbCr, or Y Pb/Cb Pr/Cr, also written as YCBCR or Y'CBCR, is a family of color spaces used as a part of the color image pipeline in video and digital photography systems.

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Redirects here:

H.261 standard, H261, P x 64, P × 64.


[1] https://en.wikipedia.org/wiki/H.261

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