|
OggPCM
Ogg is a digital multimedia container format designed to provide for efficient streaming and manipulation of digital multimedia. It is maintained by the Xiph.Org Foundation and is free and open, unrestricted by software patents. Its name is derived from "ogging", jargon from the computer game ''Netrek''. The Ogg container format can multiplex a number of independent streams for audio, video, text (such as subtitles), and metadata. In the Ogg multimedia framework, Theora provides a lossy video layer. The audio layer is most commonly provided by the music-oriented Vorbis format or its successor Opus. Lossless audio compression formats include FLAC, and OggPCM. Until 2007, the .ogg filename extension was used for all files whose content used the Ogg container format. Since then, the Xiph.Org Foundation recommends that .ogg only be used for Ogg Vorbis audio files. Xiph.Org decided to create a new set of file extensions and media types to describe different types of content ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiph
The Xiph.Org Foundation is a nonprofit organization that produces free software, 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 Windows Media Audio, WMA, MP3 and Advanced audio coding, 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 Free Lossless Audio Codec, FLAC, a lossless audio codec. The Xiph.Org Foundation has criticized Microsoft and the Recording Industry Association of America, RIAA for their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vorbis
Vorbis is a free and open-source software project headed by the Xiph.Org Foundation. The project produces an audio coding format and software reference encoder/decoder ( codec) for lossy audio compression, libvorbis. Vorbis is most commonly used in conjunction with the Ogg container format and it is therefore often referred to as Ogg Vorbis. Version 1.0 of Vorbis was released in May 2000. Since 2013, the Xiph.Org Foundation has stated that the use of Vorbis should be deprecated in favor of the Opus codec, an improved and more efficient format that has also been developed by Xiph.Org. Name Vorbis is named after the character Exquisitor Vorbis in the '' Discworld'' novel '' Small Gods'' by Terry Pratchett. The Ogg format is named after ''ogging'', jargon from the computer game '' Netrek''. Development Vorbis is a continuation of audio compression development started in 1993 by Chris Montgomery. Intensive development began following a September 1998 letter from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Patent
A software patent is a patent on a piece of software, such as a computer program, library, user interface, or algorithm. The validity of these patents can be difficult to evaluate, as software is often at once a product of engineering, something typically eligible for patents, and an abstract concept, which is typically not. This gray area, along with the difficulty of patent evaluation for intangible, technical works such as libraries and algorithms, makes software patents a frequent subject of controversy and litigation. Different jurisdictions have radically different policies concerning software patents, including a blanket ban, no restrictions, or attempts to distinguish between purely mathematical constructs and "embodiments" of these constructs. For example, an algorithm itself may be judged unpatentable, but its use in software judged patentable. Background A patent is a set of exclusionary rights granted by a state to a patent holder for a limited period of time, usual ... [...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 shrink the size of all possible data: Some data will get longer by at least one symbol or bit. Compression algorithms are usually effective for human- and machine-readable documents and cannot shrink the size of random data that contain no redundancy. 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. Lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitstream Format
A bitstream format is the format of the data found in a stream of bits used in a digital communication or data storage application. The term typically refers to the data format of the output of an encoder, or the data format of the input to a decoder when using data compression. Processing Standardized interoperability specifications such as the video coding standards produced by the MPEG and the ITU-T, and the audio coding standards produced by the MPEG, often specify only the bitstream format and the decoding process. This allows encoder implementations to use any methods whatsoever that produce bitstreams which conform to the specified bitstream format. Normally, decoding of a bitstream can be initiated without having to start from the beginning of a file, or the beginning of the data transmission. Some bitstreams are designed for this to occur, for example by using indexes or key frames. Uses of ''bit stream decoders'' (BSD): * Graphics processing unit (GPU) * H.264/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Coding Format
An audio coding format (or sometimes audio compression format) is a content representation format for storage or transmission of digital audio (such as in digital television, digital radio and in audio and video files). Examples of audio coding formats include MP3, AAC, Vorbis, FLAC, and Opus. A specific software or hardware implementation capable of audio compression and decompression to/from a specific audio coding format is called an '' audio codec''; an example of an audio codec is LAME, which is one of several different codecs which implements encoding and decoding audio in the MP3 audio coding format in software. Some audio coding formats are documented by a detailed technical specification document known as an audio coding specification. Some such specifications are written and approved by standardization organizations as technical standards, and are thus known as an audio coding standard. The term "standard" is also sometimes used for ''de facto'' standards as wel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lossy
In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size for storing, handling, and transmitting content. Higher degrees of approximation create coarser images as more details are removed. This is opposed to lossless data compression (reversible data compression) which does not degrade the data. The amount of data reduction possible using lossy compression is much higher than using lossless techniques. Well-designed lossy compression technology often reduces file sizes significantly before degradation is noticed by the end-user. Even when noticeable by the user, further data reduction may be desirable (e.g., for real-time communication or to reduce transmission times or storage needs). The most widely used lossy compression algorithm is the discrete cosine transform (DCT), first published by N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metadata
Metadata (or metainformation) is "data that provides information about other data", but not the content of the data itself, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata – the descriptive information about a resource. It is used for discovery and identification. It includes elements such as title, abstract, author, and keywords. * Structural metadata – metadata about containers of data and indicates how compound objects are put together, for example, how pages are ordered to form chapters. It describes the types, versions, relationships, and other characteristics of digital materials. * Administrative metadata – the information to help manage a resource, like resource type, and permissions, and when and how it was created. * Reference metadata – the information about the contents and quality of Statistical data type, statistical data. * Statistical metadata – also called process data, may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subtitles
Subtitles are texts representing the contents of the audio in a film, television show, opera or other audiovisual media. Subtitles might provide a transcription or translation of spoken dialogue. Although naming conventions can vary, captions are subtitles that include written descriptions of other elements of the audio, like music or sound effects. Captions are thus especially helpful to deaf or hard-of-hearing people. Subtitles may also add information that is not present in the audio. Localizing subtitles provide cultural context to viewers. For example, a subtitle could be used to explain to an audience unfamiliar with sake that it is a type of Japanese wine. Lastly, subtitles are sometimes used for humor, as in '' Annie Hall'', where subtitles show the characters' inner thoughts, which contradict what they were saying in the audio. Creating, delivering, and displaying subtitles is a complicated and multi-step endeavor. First, the text of the subtitles needs to be wri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video
Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems, which, in turn, were replaced by flat-panel displays of several types. Video systems vary in display resolution, Display aspect ratio, aspect ratio, refresh rate, color capabilities, and other qualities. Analog and digital variants exist and can be carried on a variety of media, including radio broadcasts, magnetic tape, optical discs, Video file format, computer files, and Streaming media, network streaming. Etymology The word ''video'' comes from the Latin verb ''video,'' meaning to see or ''videre''. And as a noun, "that which is displayed on a (television) screen," History Analog video Video developed from facsimile systems developed in the mid-19th century. Early mecha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound
In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the brain. Only acoustic waves that have frequency, frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges, allowing some to even hear ultrasounds. Definition Sound is defined as "(a) Oscillation in pressure, stress, particle displacement, particle velocity, etc., propagated in a medium with internal forces (e.g., elastic or viscous), or the superposition of such propagated oscillation. (b) Auditory sen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
