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Ogg 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. The libtheora video codec is the reference implementation of the Theora video compression format being developed by the Xiph.Org Foundation. Theora is derived from the formerly proprietary VP3 codec, released into the public domain by On2 Technologies. It is broadly comparable in design and bitrate efficiency to MPEG-4 Part 2, early versions of Windows Media Video, and RealVideo while lacking some of the features present in some of these other codecs. It is comparable in open standards philosophy to the BBC's Dirac codec. Theora is named after Theora Jones, Edison Carter's Controller on the ''Max Headroom'' television program. Technical details Theora is a variable-bitrate, DCT-based video compression scheme. Like most common video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiph
Xiph.Org Foundation is a nonprofit organization that produces free multimedia formats and software tools. It focuses on the Ogg family of formats, the most successful of which has been Vorbis, an open and freely licensed audio format and codec designed to compete with the patented WMA, MP3 and AAC. As of 2013, development work was focused on Daala, an open and patent-free video format and codec designed to compete with VP9 and the patented High Efficiency Video Coding. In addition to its in-house development work, the foundation has also brought several already-existing but complementary free software projects under its aegis, most of which have a separate, active group of developers. These include Speex, an audio codec designed for speech, and FLAC, a lossless audio codec. The Xiph.Org Foundation has criticized Microsoft and the RIAA for their lack of openness. They state that if companies like Microsoft had owned patents on the Internet, then other companies would have tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprietary Software
Proprietary software is software that is deemed within the free and open-source software to be non-free because its creator, publisher, or other rightsholder or rightsholder partner exercises a legal monopoly afforded by modern copyright and intellectual property law to exclude the recipient from freely sharing the software or modifying it, and—in some cases, as is the case with some patent-encumbered and EULA-bound software—from making use of the software on their own, thereby restricting his or her freedoms. It is often contrasted with open-source or free software. For this reason, it is also known as non-free software or closed-source software. Types Origin Until the late 1960s computers—large and expensive mainframe computers, machines in specially air-conditioned computer rooms—were usually leased to customers rather than sold. Service and all software available were usually supplied by manufacturers without separate charge until 1969. Computer vendors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Block (data Storage)
In computing (specifically data transmission and data storage), a block, sometimes called a physical record, is a sequence of bytes or bits, usually containing some whole number of records, having a maximum length; a ''block size''. Data thus structured are said to be ''blocked''. The process of putting data into blocks is called ''blocking'', while ''deblocking'' is the process of extracting data from blocks. Blocked data is normally stored in a data buffer, and read or written a whole block at a time. Blocking reduces the overhead and speeds up the handling of the data stream. For some devices, such as magnetic tape and CKD disk devices, blocking reduces the amount of external storage required for the data. Blocking is almost universally employed when storing data to 9-track magnetic tape, NAND flash memory, and rotating media such as floppy disks, hard disks, and optical discs. Most file systems are based on a block device, which is a level of abstraction for the hardwar ... [...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] |
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] |
Max Headroom (TV Series)
''Max Headroom'' is an American satirical science fiction television series by Chrysalis Visual Programming and Lakeside Productions for Lorimar-Telepictures that aired in the United States on ABC from March 31, 1987, to May 5, 1988. The series is set in a futuristic dystopia ruled by an oligarchy of television networks, and features the character and media personality Max Headroom. The story is based on the Channel 4 British TV film produced by Chrysalis, '' Max Headroom: 20 Minutes into the Future''. Premise In the future, an oligarchy of television networks rules the world. Even the government functions primarily as a puppet of the network executives, serving mainly to pass laws—such as banning "off" switches on televisions—that protect and consolidate the networks' power. Television technology has advanced to the point that viewers' physical movements and thoughts can be monitored through their television sets. Almost all non-television technology has been discontinu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edison Carter
''Max Headroom'' is an American satirical science fiction television series by Chrysalis Visual Programming and Lakeside Productions for Lorimar-Telepictures that aired in the United States on ABC from March 31, 1987, to May 5, 1988. The series is set in a futuristic dystopia ruled by an oligarchy of television networks, and features the character and media personality Max Headroom. The story is based on the Channel 4 British TV film produced by Chrysalis, '' Max Headroom: 20 Minutes into the Future''. Premise In the future, an oligarchy of television networks rules the world. Even the government functions primarily as a puppet of the network executives, serving mainly to pass laws—such as banning "off" switches on televisions—that protect and consolidate the networks' power. Television technology has advanced to the point that viewers' physical movements and thoughts can be monitored through their television sets. Almost all non-television technology has been discontinue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theora Jones
''Max Headroom'' is an American satirical science fiction television series by Chrysalis Visual Programming and Lakeside Productions for Lorimar-Telepictures that aired in the United States on ABC from March 31, 1987, to May 5, 1988. The series is set in a futuristic dystopia ruled by an oligarchy of television networks, and features the character and media personality Max Headroom. The story is based on the Channel 4 British TV film produced by Chrysalis, '' Max Headroom: 20 Minutes into the Future''. Premise In the future, an oligarchy of television networks rules the world. Even the government functions primarily as a puppet of the network executives, serving mainly to pass laws—such as banning "off" switches on televisions—that protect and consolidate the networks' power. Television technology has advanced to the point that viewers' physical movements and thoughts can be monitored through their television sets. Almost all non-television technology has been discontinu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dirac (video Compression Format)
Dirac is an open and royalty-free video compression format, specification and system developed by BBC Research & Development. Schrödinger and dirac-research (formerly just called "Dirac") are open and royalty-free software implementations (video codecs) of Dirac. Dirac format aims to provide high-quality video compression for Ultra High Definition Television, Ultra HDTV and beyond, and as such competes with existing formats such as H.264 and VC-1. The specification was finalised in January 2008, and further developments are only bug fixes and constraints. In September of that year, version 1.0.0 of an I-frame only subset known as ''Dirac Pro'' was released and has since been standardised by the Society of Motion Picture and Television Engineers, SMPTE as ''VC-2''. Version 2.2.3 of the full Dirac specification, including motion compensation and inter-frame coding, was issued a few days later. Dirac Pro was used internally by the BBC to transmit HDTV pictures at the 2008 Summer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RealVideo
RealVideo, or also spelled as Real Video, 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 was at version 10. RealVideo is supported on many platforms, including Windows, Mac, Linux, Solaris, and several mobile phones. RealVideo is usually paired with RealAudio and packaged in a RealMedia (.rm) container. RealMedia is suitable for use as a streaming media format, that is one which is viewed while it is being sent over the network. Streaming video can be used to watch live television, since it does not require downloading the entire video in advance. Technology The first version of RealVideo was announced in 1997 and was based on the H.263 format. At the time, RealNetworks issued a press release saying they had licensed Iterated Systems' ClearVideo technology and were including it as the RealVideo Fractal Codec. However, support for ClearVideo quietly disappeared in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows Media Video
Windows Media Video (WMV) is a series of video codecs and their corresponding video coding formats developed by Microsoft. It is part of the Windows Media framework. WMV consists of three distinct codecs: The original video compression technology known as ''WMV'', was originally designed for Internet streaming applications, as a competitor to RealVideo. The other compression technologies, ''WMV Screen'' and ''WMV Image'', cater for specialized content. After standardization by the Society of Motion Picture and Television Engineers (SMPTE), WMV version 9 was adapted for physical-delivery formats such as HD DVD and Blu-ray Disc and became known as VC-1. Microsoft also developed a digital container format called Advanced Systems Format to store video encoded by Windows Media Video. History In 2003, Microsoft drafted a video compression specification based on its WMV 9 format and submitted it to SMPTE for standardization. The standard was officially approved in March 2006 as SMPTE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
