youtube.comYouTube channelYouTuber
The default video stream is encoded in the VP9 format with stereo Opus audio; if VP9/WebM is not supported in the browser/device or the browser's user agent reports Windows XP, then H.264/MPEG-4 AVC video with stereo AAC audio is used instead. From 2008 to 2017, users could add "annotations" to their videos—such as pop-up text messages and hyperlinks. These functions were notably used as the basis for interactive videos, which used hyperlinks to other videos to achieve branching elements.

Digital radio

digitalDABdigital transmission
Digital Audio Broadcasting (DAB), also known as Eureka 147, has been adopted by around 20 countries worldwide. It is based on the MPEG-1 Audio Layer II audio coding format and this has been co-ordinated by the WorldDMB. WorldDMB announced in November 2006 that DAB would be adopting the HE-AACv2 audio coding format, also known as eAAC+. Also being adopted are the MPEG Surround format, and stronger error correction coding called Reed-Solomon coding. The update has been named DAB+. Receivers that support the new DAB standard began being released during 2007 with firmware updated available for some older receivers.

File sharing

The mp3 encoding, which was standardized in 1991 and substantially reduced the size of audio files, grew to widespread use in the late 1990s. In 1998, and Audiogalaxy were established, the Digital Millennium Copyright Act was unanimously passed, and the first mp3 player devices were launched. In June 1999, Napster was released as an unstructured centralized peer-to-peer system, requiring a central server for indexing and peer discovery. It is generally credited as being the first peer-to-peer file sharing system. Gnutella, eDonkey2000, and Freenet were released in 2000, as and Napster were facing litigation.


.wavWAVEwave file
The RIFF format acts as a "wrapper" for various audio coding formats. Though a WAV file can contain compressed audio, the most common WAV audio format is uncompressed audio in the linear pulse code modulation (LPCM) format. LPCM is also the standard audio coding format for audio CDs, which store two-channel LPCM audio sampled at 44,100 Hz with 16 bits per sample. Since LPCM is uncompressed and retains all of the samples of an audio track, professional users or audio experts may use the WAV format with LPCM audio for maximum audio quality. WAV files can also be edited and manipulated with relative ease using software.

International Organization for Standardization

ISOInternational Organization for Standardization (ISO)ISO standard
The first document that is produced for example for audio and video coding standards is called a verification model (VM) (previously also called a "simulation and test model"). When a sufficient confidence in the stability of the standard under development is reached, a working draft (WD) is produced. This is in the form of a standard but is kept internal to working group for revision. When a working draft is sufficiently solid and the working group is satisfied that it has developed the best technical solution to the problem being addressed, it becomes committee draft (CD). If it is required, it is then sent to the P-members of the TC/SC (national bodies) for ballot.

International Electrotechnical Commission

IECInternational Electrotechnical Commission (IEC)(IEC)
The International Electrotechnical Commission (IEC; in French: Commission électrotechnique internationale) is an international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology". IEC standards cover a vast range of technologies from power generation, transmission and distribution to home appliances and office equipment, semiconductors, fibre optics, batteries, solar energy, nanotechnology and marine energy as well as many others.

Audio Interchange File Format

Audio Interchange File Format (AIFF) is an audio file format standard used for storing sound data for personal computers and other electronic audio devices. The format was developed by Apple Inc. in 1988 based on Electronic Arts' Interchange File Format (IFF, widely used on Amiga systems) and is most commonly used on Apple Macintosh computer systems. The audio data in most AIFF files is uncompressed pulse-code modulation (PCM). This type of AIFF file uses much more disk space than lossy formats like MP3—about 10 MB for one minute of stereo audio at a sample rate of 44.1 kHz and a bit depth of 16 bits.


Some of the unit's most common uses are in the description of sine waves and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the speeds at which computers and other electronics are driven. The hertz is defined as one cycle per second. The International Committee for Weights and Measures defined the second as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom" and then adds: "It follows that the hyperfine splitting in the ground state of the caesium 133 atom is exactly 9 192 631 770 hertz, ν(hfs Cs) = 9 192 631 770 Hz."

Filename extension

file extensionextensionextensions
In many Internet protocols, such as HTTP and MIME email, the type of a bitstream is stated as the media type, or MIME type, of the stream, rather than a filename extension. This is given in a line of text preceding the stream, such as Content-type: text/plain. There is no standard mapping between filename extensions and media types, resulting in possible mismatches in interpretation between authors, web servers, and client software when transferring files over the Internet.

Bandwidth (computing)

bandwidthnetwork bandwidthbandwidths
A bit stream's bandwidth is proportional to the average consumed signal bandwidth in hertz (the average spectral bandwidth of the analog signal representing the bit stream) during a studied time interval. Channel bandwidth may be confused with useful data throughput (or goodput). For example, a channel with x bps may not necessarily transmit data at x rate, since protocols, encryption, and other factors can add appreciable overhead. For instance, much internet traffic uses the transmission control protocol (TCP), which requires a three-way handshake for each transaction.

Wii Menu

News ChannelMii ChannelNintendo Channel
The update replaced MP3 support with support for MPEG-4 encoded audio files encoded with AAC in the .m4a extension. Wii owners who updated to version 1.1 can revert to version 1.0 by deleting it from the channels menu in the data management setup. Consoles released after December 10, 2007 will come with the version 1.1 update pre-installed, and cannot be downgraded to version 1.0. Owners of Japanese systems can download a "Revert to Photo Channel 1.0" Channel from the Wii Shop Channel if they wish to do so.


HLS, HTTP Live Streaming. IFF. ISO base media file format (including QuickTime, 3GP and MP4). Matroska (including WebM). Maxis XA. MPEG-DASH. MPEG program stream. MPEG transport stream (including AVCHD). MXF, Material eXchange Format, SMPTE 377M. MSN Webcam stream. NUT. Ogg. OMA. RL2. Segment, for creating segmented video streams. Smooth Streaming. TXD. WTV. IETF RFCs. FTP. Gopher. HTTP. HTTPS. RTP. RTSP. SCTP. SDP. SRTP. TCP. TLS. UDP. UDP-Lite. IETF I-Ds:. HLS. SFTP (via libssh). Microsoft OSP. CIFS/SMB (via libsmbclient). MMS over TCP (MS-MMSP) and MMS over HTTP (MS-WMSP). Pro-MPEG Forum:.

Transparency (data compression)

transparenttransparencydata compression transparency
*Codec listening test * "Transparency", Hydrogen Audio Wiki Bosi, Marina; Richard E. Goldberg. Introduction to digital audio coding and standards. Springer, 2003. ISBN: 1-4020-7357-7. Cvejic, Nedeljko; Tapio Seppänen. Digital audio watermarking techniques and technologies: applications and benchmarks. Idea Group Inc (IGI), 2007. ISBN: 1-59904-513-3. Pohlmann, Ken C. Principles of digital audio. McGraw-Hill Professional, 2005. ISBN: 0-07-144156-5. Spanias, Andreas; Ted Painter; Venkatraman Atti. Audio signal processing and coding. Wiley-Interscience, 2007. ISBN: 0-471-79147-4. Syed, Mahbubur Rahman. Multimedia technologies: concepts, methodologies, tools, and applications, Volume 3.

H.264/MPEG-4 AVC

Switching slices, called SP and SI slices, allowing an encoder to direct a decoder to jump into an ongoing video stream for such purposes as video streaming bit rate switching and "trick mode" operation. When a decoder jumps into the middle of a video stream using the SP/SI feature, it can get an exact match to the decoded pictures at that location in the video stream despite using different pictures, or no pictures at all, as references prior to the switch.

Microsoft Silverlight

SilverlightMicrosoft Silverlight 2.0Microsoft Silverlight runtime for IE
Silverlight supports H.264 video, Advanced Audio Coding, Windows Media Video (WMV), Windows Media Audio (WMA), and MPEG Layer III (MP3) media content across all supported browsers without requiring Windows Media Player, the Windows Media Player ActiveX control, or Windows Media browser plug-ins. Because Windows Media Video 9 is an implementation of the Society of Motion Picture and Television Engineers (SMPTE) VC-1 standard, Silverlight also supports VC-1 video. According to the end user license agreement VC-1 and H.264 are only licensed for the "personal and non-commercial use of a consumer".


Sony CorporationSony BMG MusicSony Music
In 1987 Sony launched the 4 mm DAT or Digital Audio Tape as a new digital audio tape standard. In 1979, the Walkman brand was introduced, in the form of the world's first portable music player using the compact cassette format. Sony introduced the MiniDisc format in 1992 as an alternative to Philips DCC or Digital Compact Cassette and as a successor to the compact cassette. Since the introduction of MiniDisc, Sony has attempted to promote its own audio compression technologies under the ATRAC brand, against the more widely used MP3. Until late 2004, Sony's Network Walkman line of digital portable music players did not support the MP3 standard natively.


Nintendo WiiWii miniZii
Audio DSP. 18 W when switched on. 9.6 W in standby with WiiConnect24 standby connection. 1.3 W in standby.

Zune software

ZuneWindows MobileZune Marketplace
The Xbox 360 offers movie and music video downloads, as well as Zune Pass streaming. Zune devices, Windows Phone devices and the Microsoft Kin phones permit the download and streaming of music; Windows Phone devices additionally allow the download of applications. Purchases are made in the Microsoft Points currency, which can also be used to purchase content from Xbox Live and Games for Windows Live marketplaces. The exchange rate is one United States dollar to 80 Microsoft points. Most music tracks are priced at 79 points or 99 points. This works out to US$0.9875 or US$1.24 per song.


MusicBee is a freeware media player for playback and organization of audio files on Microsoft Windows, built using the BASS (audio library) audio library. * Comparison of audio player software Audio playback: MP3, AAC, M4A, MPC, OGG, FLAC, APE, Opus, TAK (audio format), WavPack, WMA, WAV, MIDI, MOD, UMX, XM. CDDA support: playback and ripping (CD-Text-capable) of audio CDs. Tracks can be ripped (in fast or secure mode), as individual files or as a single album with embedded cuesheet. Synchronization: ability to sync content from local libraries with external devices (including iOS 3.0-based and earlier), and import libraries from iTunes and Windows Media Player.

Advanced Systems Format

Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming media. ASF is part of the Media Foundation framework. ASF is based on serialized objects which are essentially byte sequences identified by a GUID marker. The format does not specify how (i.e. with which codec) the video or audio should be encoded; it just specifies the structure of the video/audio stream. This is similar to the function performed by the QuickTime, AVI, or Ogg container formats.

Gapless playback

Optimal solutions: Alternative or partial solutions: * XMMS2 – has native support for gapless MP3 / Ogg Vorbis and FLAC * Segue, the technique in classical music * MP3 players: Buyer Beware, a description of gapless playback in digital audio players Musepack. Ogg Vorbis. Speex. Opus. LAME-encoded MP3 can be gapless with players that support the LAME Mp3 info tag. AAC in MP4 encoded with Nero Digital from Nero AG can be gapless with foobar2000, latest XMMS2, and iTunes through 11.4.


Microsoft CorporationMSMicrosoft Corp.
Microsoft Corporation (MS) is an American multinational technology company with headquarters in Redmond, Washington. It develops, manufactures, licenses, supports and sells computer software, consumer electronics, personal computers, and related services. Its best known software products are the Microsoft Windows line of operating systems, the Microsoft Office suite, and the Internet Explorer and Edge web browsers. Its flagship hardware products are the Xbox video game consoles and the Microsoft Surface lineup of touchscreen personal computers. As of 2016, it is the world's largest software maker by revenue, and one of the world's most valuable companies.

Real-Time Messaging Protocol

RTMPFlash RTMPReal Time Messaging Protocol (RTMP)
At a higher level, the RTMP encapsulates MP3 or AAC audio and FLV1 video multimedia streams, and can make remote procedure calls (RPCs) using the Action Message Format. Any RPC services required are made asynchronously, using a single client/server request/response model, such that real-time communication is not required. RTMP sessions may be encrypted using either of two methods: In RTMP Tunneled (RTMPT), RTMP data is encapsulated and exchanged via HTTP, and messages from the client (the media player, in this case) are addressed to port 80 (the default for HTTP) on the server.

Adaptive Transform Acoustic Coding

ATRACATRAC3Adaptive Transform Acoustic Coding (ATRAC)
In a test conducted by an independent firm, but financed by Sony, it was concluded that ATRAC3plus at 64 kbit/s is equal in subjective sound quality to an obsolete MP3 encoder at 128 kbit/s. Performance against modern high quality MP3 encoders was not evaluated. ATRAC Advanced Lossless is a "scalable" lossless audio codec that records a lossy ATRAC3 or ATRAC3plus stream, and supplements it with a stream of correction information stored within the file itself that allows the original signal to be reproduced, if desired.

Squeezebox (network music player)

SqueezeboxSliMP3Squeezebox and Transporter
Features included optional 802.11g Wi-Fi, native support for more audio formats (FLAC, WMA, Ogg), upgraded 320×32 pixel greyscale bitmap VFD display, visualizers, bitmapped fonts. This model has infrared remote control, analog outputs, volume control, headphone jack, coaxial and optical digital outputs. The Squeezebox2 supports numerous audio formats including MP3, Windows Media Audio, Musepack, Monkey's Audio, Apple Lossless, FLAC, Shorten, WAV, AIFF, Ogg Vorbis, and unencrypted AAC.