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Codec Listening Test
A codec listening test is a scientific Experiment, study designed to compare two or more lossy sound reproduction, 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 test, 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 their 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 rej ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific
Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into twoor threemajor branches: the natural sciences, which study the physical world, and the social sciences, which study individuals and societies. While referred to as the formal sciences, the study of logic, mathematics, and theoretical computer science are typically regarded as separate because they rely on deductive reasoning instead of the scientific method as their main methodology. Meanwhile, applied sciences are disciplines that use scientific knowledge for practical purposes, such as engineering and medicine. The history of science spans the majority of the historical record, with the earliest identifiable predecessors to modern science dating to the Bronze Age in Egypt and Mesopotamia (). Their contributions to mathematics, astronomy, and medicine entered and shaped the Greek natural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows Media Audio
Windows Media Audio (WMA) is a series of audio codecs and their corresponding audio coding formats developed by Microsoft. It is a proprietary technology that forms part of the Windows Media framework. Audio encoded in WMA is stored in a digital container format called Advanced Systems Format (ASF). WMA consists of four distinct codecs. The original WMA codec, known simply as ''WMA'', was conceived as a competitor to the popular MP3 and RealAudio codecs. ''WMA Pro'', a newer and more advanced codec, supports multichannel and high-resolution audio. A lossless codec, ''WMA Lossless'', compresses audio data without loss of audio fidelity (the regular WMA format is lossy). ''WMA Voice'', targeted at voice content, applies compression using a range of low bit rates. Development history The first WMA codec was based on earlier work by Henrique Malvar and his team which was transferred to the Windows Media team at Microsoft. Malvar was a senior researcher and manager of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FAAC
FAAC (Freeware Advanced Audio Coder) is a software project which includes the Advanced Audio Coding, AAC data compression, encoder FAAC and Audio decoder, decoder FAAD2. It supports MPEG-2 AAC as well as MPEG-4 AAC. It supports several MPEG-4 Audio object types (LC, Main, LTP for encoding and Spectral band replication, SBR, Parametric Stereo, PS, ER, LD for decoding), file formats (ADTS AAC, raw AAC, MP4), multichannel and gapless encoding/decoding and MP4 metadata tags. The encoder and decoder is compatible with standard-compliant audio applications using one or more of these object types and facilities. It also supports Digital Radio Mondiale. FAAC and FAAD2, being distributed in C (programming language), C source code form, can be compiled on various platforms and are distributed free of charge. FAAD2 is free software. FAAC contains some code which is published as Free Software, but as a whole it is only distributed under a proprietary license. FAAC was originally written by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITunes
iTunes is a media player, media library, and mobile device management (MDM) utility developed by Apple. 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 playing content from dynamic, smart playlists. It includes options for sound optimization and wirelessly sharing iTunes libraries. iTunes was announced by Apple CEO Steve Jobs on January 9, 2001. Its 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 Windows version of the program, it became an ubiquitous tool for managing music and configuring other features on Apple's line of iPod media players, which extended to the iPhone and iPad upon their introduction. From 2005 on, Apple expanded its core music features with s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LAME
LAME is a software encoder that converts digital audio into the MP3 audio coding format. LAME is a free software project that was first released in 1998 and has incorporated many improvements since then, including an improved psychoacoustic model. The LAME encoder outperforms early encoders like L3enc and possibly the "gold standard encoder" MP3enc, both marketed by Fraunhofer. LAME was required by some programs released as free software in which LAME was linked for MP3 support. This avoided including LAME itself, which used patented techniques, and so required patent licenses in some countries. All relevant patents have since expired, and LAME is now bundled with Audacity. History The name LAME is a recursive acronym for "LAME Ain't an MP3 Encoder". Around mid-1998, Mike Cheng created LAME 1.0 as a set of modifications against the 8Hz-MP3 encoder source code. After some quality concerns were raised by others, he decided to start again from scratch based on the dist10 ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QuickTime
QuickTime (or QuickTime Player) is an extensible multimedia architecture created by Apple, which supports playing, streaming, encoding, and transcoding a variety of digital media formats. The term ''QuickTime'' also refers to the QuickTime Player front-end media player application, which is built-into macOS, and was formerly available for Windows. QuickTime was created in 1991, when the concept of playing digital video directly on computers was "groundbreaking." QuickTime could embed a number of advanced media types, including panoramic images (called QuickTime VR) and Adobe Flash. Over the 1990s, QuickTime became a dominant standard for digital multimedia, as it was integrated into many websites, applications, and video games, and adopted by professional filmmakers. The QuickTime File Format became the basis for the MPEG-4 standard. During its heyday, QuickTime was notably used to create the innovative ''Myst'' and '' Xplora1'' video games, and to exclusively distribute mo ... [...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 enc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Source Software
Open-source software (OSS) is Software, computer software that is released under a Open-source license, license in which the copyright holder grants users the rights to use, study, change, and Software distribution, 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 online collaboration, 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 2024 estimate of the value of open-source software to firms is $8.8 trillion, as firms would need to spend 3.5 times the amount they currently do without the use of open source software. Open-source code can be used for studying and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprietary Software
Proprietary software is computer software, software that grants its creator, publisher, or other rightsholder or rightsholder partner a legal monopoly 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 their freedoms. Proprietary software is a subset of non-free software, a term defined in contrast to free and open-source software; non-commercial licenses such as CC BY-NC are not deemed proprietary, but are non-free. Proprietary software may either be closed-source software or source-available software. Types Origin Until the late 1960s, computers—especially large and expensive mainframe computers, machines in specially air-conditioned computer rooms—were usually leased to customers rather than Sales, sold. Service and all software available ... [...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] |
