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Codec Listening Test
A codec listening test is a scientific study designed to compare two or more lossy audio codecs, usually with respect to perceived fidelity or compression efficiency. Most tests take the form of a double-blind comparison. Commonly used methods are known as " ABX" or "ABC/HR" or "MUSHRA". There are various software packages available for individuals to perform this type of testing themselves with minimal assistance. Testing methods ABX test In an ABX test, the listener has to identify an unknown sample X as being A or B, with A (usually the original) and B (usually the encoded version) available for reference. The outcome of a test must be statistically significant. This setup ensures that the listener is not biased by his/her expectations, and that the outcome is not likely to be the result of chance. If sample X cannot be determined reliably with a low p-value in a predetermined number of trials, then the null hypothesis cannot be rejected and it cannot be proved that t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for scientific reasoning is tens of thousands of years old. The earliest written records in the history of science come from Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age and later by the efforts of Byzantine Greek scholars who brought Greek m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Musepack
Musepack or MPC is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160–180 (manual set allows bitrates up to 320) kbit/s. It was formerly known as MPEGplus, MPEG+ or MP+. Development of MPC was initiated in 1997 by Andree Buschmann and later assumed by Frank Klemm, and as of 2004 is maintained by the Musepack Development Team (MDT) with assistance from Buschmann and Klemm. Encoders and decoders are available for Microsoft Windows, Linux and Mac OS X, and plugins for several third-party media players available from the Musepack website, licensed under the GNU Lesser General Public License (LGPL) or BSD licenses, and an extensive list of programs supporting the format. Technical details Musepack was developed using the MP2 codec as a starting point, but many features have since been added, including: * subband selectable M/S encoding (as in AAC) * Huffman coding (as in MP3 and AAC, but more efficient). S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITunes
iTunes () is a software program that acts as a media player, media library, mobile device management utility, and the client app for the iTunes Store. Developed by Apple Inc., it is used to purchase, play, download, and organize digital multimedia, on personal computers running the macOS and Windows operating systems, and can be used to rip songs from CDs, as well as play content with the use of dynamic, smart playlists. Options for sound optimizations exist, as well as ways to wirelessly share the iTunes library. Originally announced by Apple CEO Steve Jobs on January 9, 2001, iTunes' original and main focus was music, with a library offering organization and storage of Mac users' music collections. With the 2003 addition of the iTunes Store for purchasing and downloading digital music, and a version of the program for Windows, it became a ubiquitous tool for managing music and configuring other features on Apple's line of iPod media players, which extended to the iPh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LAME
Lame or LAME may refer to: Music * "Lame" (song) by Unwritten Law * ''Lame'' (album) by Iame People * Ibrahim Lame (born 1953), Nigerian educator and politician * Jennifer Lame (), American film editor * Quintín Lame (1880–1967), Colombian rebel * Lame Kodra, pen name of Sejfulla Malëshova (1900–1971), Albanian politician and writer Technology * LAME, audio encoding computer software * Lame (armor), a single plate of a suit of armour * Lame (kitchen tool), a blade for scoring bread loaves * Licensed Aircraft Maintenance Engineer (''LAME'' or ''L-AME''), professional title and qualification Other uses * A limp or lameness, a leg impairment ** Lameness (equine) in horses **Any physical disability (by extension) * Lame language, a Nigerian, Bantoid dialect cluster See also * Lamé (other) * List of people known as the Lame * Lago delle Lame, a lake in Liguria, Italy * Lamer, hacker slang term * Lamestream media In journalism, mainstream media (MSM) is a te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nero Digital
Nero Digital is a brand name applied to a suite of MPEG-4-compatible video and audio compression codecs developed by Nero AG of Germany and Ateme of France. The audio codecs are integrated into the ''Nero Digital Audio+'' audio encoding tool for Microsoft Windows, and the audio & video codecs are integrated into Nero's ''Recode'' DVD ripping software. Nero certifies certain DVD player/recorder devices as Nero Digital compatible, and licenses the codec technology to integrated circuit manufacturers. The video codecs were developed by Ateme, and according to an interview with Nero AG developer Ivan Dimkovic, the audio codecs are improved versions of Dimkovic's older ''PsyTEL AAC Encoder''. The audio codec is now available as a free stand-alone package called Nero AAC Codec. Functionality Nero Digital can generate streams in the 3GP/MPEG-4 Part 14 () container format and includes two video and two audio codecs: * ASP (one of about 20 profiles defined in MPEG-4 Part 2) * AVC (also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QuickTime
QuickTime is an extensible multimedia framework developed by Apple Inc., capable of handling various formats of digital video, picture, sound, panoramic images, and interactivity. Created in 1991, the latest Mac version, QuickTime X, is available for Mac OS X Snow Leopard up to macOS Mojave. Apple ceased support for the Windows version of QuickTime in 2016, and ceased support for QuickTime 7 on macOS in 2018. As of Mac OS X Lion, the underlying media framework for QuickTime, QTKit, was deprecated in favor of a newer graphics framework, AVFoundation, and completely discontinued as of macOS Catalina. Overview QuickTime is bundled with macOS. QuickTime for Microsoft Windows is downloadable as a standalone installation, and was bundled with Apple's iTunes prior to iTunes 10.5, but is no longer supported and therefore security vulnerabilities will no longer be patched. Already, at the time of the Windows version's discontinuation, two such zero-day vulnerabilities (both of whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant Bitrate
Constant bitrate (CBR) is a term used in telecommunications, relating to the quality of service. Compare with variable bitrate. When referring to codecs, constant bit rate encoding means that the rate at which a codec's output data should be consumed is constant. CBR is useful for streaming multimedia content on limited capacity channels since it is the maximum bit rate that matters, not the average, so CBR would be used to take advantage of all of the capacity. CBR is not optimal for storing data as it may not allocate enough data for complex sections (resulting in degraded quality); and if it maximizes quality for complex sections, it will waste data on simple sections. The problem of not allocating enough data for complex sections could be solved by choosing a high bitrate to ensure that there will be enough bits for the entire encoding process, though the size of the file at the end would be proportionally larger. Most coding schemes such as Huffman coding or run-length en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Source Software
Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Open-source software may be developed in a collaborative public manner. Open-source software is a prominent example of open collaboration, meaning any capable user is able to participate online in development, making the number of possible contributors indefinite. The ability to examine the code facilitates public trust in the software. Open-source software development can bring in diverse perspectives beyond those of a single company. A 2008 report by the Standish Group stated that adoption of open-source software models has resulted in savings of about $60 billion per year for consumers. Open source code can be used for studying and allows capable end users to adapt software to their personal needs in a similar way user scripts a ... [...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] |
Mp3PRO
mp3PRO is an unmaintained proprietary audio compression codec that combines the MP3 audio format with the spectral band replication (SBR) compression method. At the time it was developed it could reduce the size of a stereo MP3 by as much as 50% while maintaining the same relative quality. This works, fundamentally, by discarding the higher half of the frequency range and algorithmically replicating that information while decoding. The technology behind SBR was developed by the former Swedish company Coding Technologies AB (acquired by Dolby Laboratories in 2007) in the late 1990s. It was included in their MPEG-2 AAC derived codec aacPlus, which would later be standardized as MPEG-4 HE-AAC. Thomson Multimedia (now Technicolor SA) licensed the technology and used it to extend the MP3 format, for which they held patents, hoping to also extend its profitable lifetime. This was released as mp3PRO in 2001. It was originally claimed that mp3PRO files were compatible with existing MP3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QDesign
QDesign Corporation was a developer of digital audio compression technologies. The company's MP2 and MP3 technologies were used in professional audio and broadcast automation systems as well as multimedia and video production systems. QDesign developed a music codec, originally known as LBpack. QDesign licensed the initial version of the codec and created the official audio compression in Apple Computer's QuickTime v3. The personal version comes with QuickTime Pro and allows encoding at bitrates up to 48 kbit/s. The professional version allows bitrates up to 128 kbit/s. Apple steered away from proprietary codecs in QuickTime like Sorenson Video and QDesign, and focused on standards like (MPEG-4 MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related t ...). In recent years, usage of QDMC (= ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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