|
Libvpx
libvpx is a free software video codec library from Google and the Alliance for Open Media (AOMedia). It serves as the reference software implementation for the VP8 and VP9 video coding formats, and for AV1 a special fork named libaom that was stripped of backwards compatibility. As free software it is published also in source code under the terms of the revised BSD license. It ships with the commandline tools vpxenc/aomenc and vpxdec/aomdec that build on its functionality. History libvpx originates from the video codec company On2 Technologies that sold its first software codec in mid-90s. libvpx was released as free software by Google on May 19, 2010, after the acquisition of On2 Technologies for an estimate of over 120 million US dollars. In June 2010, Google amended the VP8 codec software license to the 3-clause BSD license after some contention over whether the original license was actually open source. Google was criticised for dumping untidy code with bad documenta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On2 Technologies
On2 Technologies, formerly known as The Duck Corporation, was a small publicly traded company (on the American Stock Exchange), founded in New York City in 1992 and headquartered in Clifton Park, New York, that designed video codec technology. It created a series of video codecs called TrueMotion (including TrueMotion S, TrueMotion 2, TrueMotion RT 2.0, TrueMotion VP3, 4, 5, 6, 7 and 8). In February 2010, On2 Technologies was acquired by Google for an estimated $124.6 million. On2's VP8 technology became the core of Google's WebM video file format. History While known by the name ''The Duck Corporation'', they developed TrueMotion S, a codec that was used by some games for full motion video (FMV) sequences during the 1990s. The original office of the Duck Corporation was founded in New York City by Daniel B. Miller, Victor Yurkovsky, and Stan Marder. In 1994 Duck opened its first "satellite" engineering office in Colonie, NY under the management of Eric Ameres. Miller b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source Code
In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source code. The source code is often transformed by an assembler or compiler into binary machine code that can be executed by the computer. The machine code is then available for execution at a later time. Most application software is distributed in a form that includes only executable files. If the source code were included it would be useful to a user, programmer or a system administrator, any of whom might wish to study or modify the program. Alternatively, depending on the technology being used, source code may be interpreted and executed directly. Definitions Richard Stallman's definition, formulated in his 1989 seminal li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultra-high-definition Television
Ultra-high-definition television (also known as Ultra HD television, Ultra HD, UHDTV, UHD and Super Hi-Vision) today includes 4K UHD and 8K UHD, which are two digital video formats with an aspect ratio of 16:9. These were first proposed by NHK Science & Technology Research Laboratories and later defined and approved by the International Telecommunication Union (ITU). The Consumer Electronics Association announced on October 17, 2012, that "Ultra High Definition", or "Ultra HD", would be used for displays that have an aspect ratio of 16:9 or wider and at least one digital input capable of carrying and presenting native video at a minimum resolution of . In 2015, the Ultra HD Forum was created to bring together the end-to-end video production ecosystem to ensure interoperability and produce industry guidelines so that adoption of ultra-high-definition television could accelerate. From just 30 in Q3 2015, the forum published a list up to 55 commercial services available aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Space
A color space is a specific organization of colors. In combination with color profiling supported by various physical devices, it supports reproducible representations of colorwhether such representation entails an analog or a digital representation. A color space may be arbitrary, i.e. with physically realized colors assigned to a set of physical color swatches with corresponding assigned color names (including discrete numbers infor examplethe Pantone collection), or structured with mathematical rigor (as with the NCS System, Adobe RGB and sRGB). A "color space" is a useful conceptual tool for understanding the color capabilities of a particular device or digital file. When trying to reproduce color on another device, color spaces can show whether shadow/highlight detail and color saturation can be retained, and by how much either will be compromised. A "color model" is an abstract mathematical model describing the way colors can be represented as tuples of numbers (e.g. tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SRGB
sRGB is a standard RGB (red, green, blue) color space that HP and Microsoft created cooperatively in 1996 to use on monitors, printers, and the World Wide Web. It was subsequently standardized by the International Electrotechnical Commission (IEC) as IEC 61966-2-1:1999. sRGB is the current defined standard colorspace for the web, and it is usually the assumed colorspace for images that are neither tagged for a colorspace nor have an embedded color profile. sRGB essentially codifies the display specifications for the computer monitors in use at that time, which greatly aided its acceptance. sRGB uses the same color primaries and white point as ITU-R BT.709 standard for HDTV, a transfer function (or gamma) compatible with the era's CRT displays, and a viewing environment designed to match typical home and office viewing conditions. An amendment of the IEC 61966-2-1 standard document that defines sRGB includes the definition of a number of variants including sYCC, which is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adobe RGB Color Space
The Adobe RGB (1998) color space or opRGB is a color space developed by Adobe Systems, Inc. in 1998. It was designed to encompass most of the colors achievable on CMYK color printers, but by using RGB primary colors on a device such as a computer display. The Adobe RGB (1998) color space encompasses roughly 50% of the visible colors specified by the CIELAB color space – improving upon the gamut of the sRGB color space, primarily in cyan-green hues. It was subsequently standardized by the IEC as IEC 61966-2-5:1999 with a name opRGB (optional RGB color space) and is used in HDMI. Historical background Beginning in 1997, Adobe Systems was looking into creating ICC profiles that its consumers could use in conjunction with Photoshop's new color management features. Since not many applications at the time had any ICC color management, most operating systems did not ship with useful profiles. Lead developer of Photoshop, Thomas Knoll decided to build an ICC profile around specif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NTSC
The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplementary references cited in the Reports, and the Petition for adoption of transmission standards for color television before the Federal Communications Commission, n.p., 1953], 17 v. illus., diagrs., tables. 28 cm. LC Control No.:5402138Library of Congress Online Catalog/ref> in 1941. In 1961, it was assigned the designation CCIR System M, System M. In 1953, a second NTSC standard was adopted, which allowed for color television broadcast compatible with the existing stock of black-and-white receivers. It is one of three major color formats for analog television, the others being PAL and SECAM. NTSC color is usually associated with the System M. The only other broadcast television system to use NTSC color was the System J. Since the introdu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Bitrate
Variable bitrate (VBR) is a term used in telecommunications and computing that relates to the bitrate used in sound or video encoding. As opposed to constant bitrate (CBR), VBR files vary the amount of output data per time segment. VBR allows a higher bitrate (and therefore more storage space) to be allocated to the more complex segments of media files while less space is allocated to less complex segments. The average of these rates can be calculated to produce an average bitrate for the file. MP3, WMA and AAC audio files can optionally be encoded in VBR, while Opus and Vorbis are encoded in VBR by default. Variable bit rate encoding is also commonly used on MPEG-2 video, MPEG-4 Part 2 video (Xvid, DivX, etc.), MPEG-4 Part 10/H.264 video, Theora, Dirac and other video compression formats. Additionally, variable rate encoding is inherent in lossless compression schemes such as FLAC and Apple Lossless. Advantages and disadvantages of VBR The advantages of VBR are that it pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. It is used in many video and still image encoding schemesboth analog and digitalincluding in JPEG encoding. Rationale Digital signals are often compressed to reduce file size and save transmission time. Since the human visual system is much more sensitive to variations in brightness than color, a video system can be optimized by devoting more bandwidth to the luma component (usually denoted Y'), than to the color difference components Cb and Cr. In compressed images, for example, the 4:2:2 Y'CbCr scheme requires two-thirds the bandwidth of non-subsampled "4:4:4" R'G'B'. This reduction results in almost no visual difference as perceived by the viewer. How subsampling works At normal viewing distances, there is no perceptible loss incurred by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Depth
Color depth or colour depth (see spelling differences), also known as bit depth, is either the number of bits used to indicate the color of a single pixel, or the number of bits used for each color component of a single pixel. When referring to a pixel, the concept can be defined as bits per pixel (bpp). When referring to a color component, the concept can be defined as bits per component, bits per channel, bits per color (all three abbreviated bpc), and also bits per pixel component, bits per color channel or bits per sample (bps). Modern standards tend to use bits per component, but historical lower-depth systems used bits per pixel more often. Color depth is only one aspect of color representation, expressing the precision with which the amount of each primary can be expressed; the other aspect is how broad a range of colors can be expressed (the gamut). The definition of both color precision and gamut is accomplished with a color encoding specification which assigns a digita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lossless Compression
Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistical redundancy. By contrast, lossy compression permits reconstruction only of an approximation of the original data, though usually with greatly improved compression rates (and therefore reduced media sizes). By operation of the pigeonhole principle, no lossless compression algorithm can efficiently compress all possible data. For this reason, many different algorithms exist that are designed either with a specific type of input data in mind or with specific assumptions about what kinds of redundancy the uncompressed data are likely to contain. Therefore, compression ratios tend to be stronger on human- and machine-readable documents and code in comparison to entropic binary data (random bytes). Lossless data compression is used in many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-source License
An open-source license is a type of license for computer software and other products that allows the source code, blueprint or design to be used, modified and/or shared under defined terms and conditions. This allows end users and commercial companies to review and modify the source code, blueprint or design for their own customization, curiosity or troubleshooting needs. Open-source licensed software is mostly available free of charge, though this does not necessarily have to be the case. Licenses which only permit non-commercial redistribution or modification of the source code for personal use only are generally not considered as open-source licenses. However, open-source licenses may have some restrictions, particularly regarding the expression of respect to the origin of software, such as a requirement to preserve the name of the authors and a copyright statement within the code, or a requirement to redistribute the licensed software only under the same license (as in a copy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
