Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services. In digital broadcasting systems, the analog audio signal is digitized, compressed using an audio coding format such as AAC+ (MDCT) or MP2, and transmitted using a digital modulation scheme. The aim is to increase the number of radio programs in a given spectrum, to improve the audio quality, to eliminate fading problems in mobile environments, to allow additional datacasting services, and to decrease the transmission power or the number of transmitters required to cover a region.
Modern interconnect standards for digital video include HDMI, DisplayPort, Digital Visual Interface (DVI) and serial digital interface (SDI). Digital video can be copied with no degradation in quality. In contrast, when analog sources are copied, they experience generation loss. Digital video can be stored on digital media such as Blu-ray Disc, on computer data storage or streamed over the Internet to end users who watch content on a desktop computer screen or a digital smart TV. In everyday practice, digital video content such as TV shows and movies also includes a digital audio soundtrack. The basis for digital video cameras are metal-oxide-semiconductor (MOS) image sensors.
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, MP3.com 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. In December 1999, Napster was sued by several recording companies and lost in A&M Records, Inc. v. Napster, Inc..
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.
ISOISO standardInternational Organisation for Standardisation
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.
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 (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.
file extensionextensionfile extensions
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.
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 clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of energy, via the photon energy equation (E=hν), with one hertz equivalent to h joules. The hertz is defined as one cycle per second.
bandwidthnetwork bandwidthInternet bandwidth
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.
LSP is an important technology for speech synthesis and coding, and in the 1990s was adopted by almost all international speech coding standards as an essential component, contributing to the enhancement of digital speech communication over mobile channels and the internet worldwide. In 1981, he was appointed as Chief of the Speech and Acoustics Research Section at NTT. He left this position in 1984 to take a professorship in communications theory and signal processing at Nagoya University. He currently teaches at Meijo University. Itakura's work on spectral and formant estimation laid the foundation for much of the early progress in speech signal processing.
University of NagoyaNagoyaNagoya Imperial University
Nagoya University, abbreviated to Meidai, is a Japanese national university located in Chikusa-ku, Nagoya. It was the last Imperial University in Japan and among the National Seven Universities. It is the 3rd highest ranked higher education institution in Japan (72nd worldwide).
. * US Patent 4,472,832: Digital speech coder * From “Harmonic Telegraph” to Cellular Phones – Bishnu Atal talks about the history of telecom invention and his role in pushing cell phone technology (Aug 23, 2016 at USC, event, book) New Jersey Inventors of the Year. IEEE Signal Processing Society Speech Technical Committee (STC) newsletter. Voice Communication Between Humans and Machines.
Manfred SchroederSchroederSchroeder, Manfred R.
Audio Engineering Society fellow and Gold medalist (1972). Member of the United States National Academy of Engineering (1979), for "founding the statistical theory of wave propagation in multi-mode media and contributions to speech coding and acoustics". Fellow of the American Academy of Arts and Sciences (1986). Helmholtz Medal of the German Acoustical Society. 1975 Max Planck Society appointed foreign scientific member. New York Academy of Sciences member 1978. Rayleigh Medal 1984 and 1987.
Adaptive predictive coding (APC) is a narrowband analog-to-digital conversion that uses a one-level or multilevel sampling system in which the value of the signal at each sampling instant is predicted according to a linear function of the past values of the quantized signals. APC is related to linear predictive coding (LPC) in that both use adaptive predictors. However, APC uses fewer prediction coefficients, thus requiring a higher sampling rate than LPC.
video sharingvideo hosting servicevideo-sharing
The most important compression algorithm that enabled practical video hosting and streaming is the discrete cosine transform (DCT), a lossy compression technique first proposed by Nasir Ahmed in 1972. The DCT algorithm is the basis for the first practical video coding format, H.261, in 1988. It was followed by more popular DCT-based video coding formats, most notably the MPEG video standards from 1991 onwards. The modified discrete cosine transform (MDCT) is also the basis for the MP3 audio compression format introduced in 1994, and later the Advanced Audio Coding (AAC) format in 1999. The first Internet video hosting site was ShareYourWorld.com.
bit streambyte streambinary sequence
Bit-stream access. Bitstream format. Byte-oriented protocol. MPEG Elementary stream. Reliable byte stream. Stream (computing). Stream processing. Traffic flow (computer networking).
Mii ChannelForecast ChannelNews 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.
CD rippingripperA list of other CD Rippers
Another term used for the process of ripping Audio-CDs is Digital Audio Extraction (DAE). As an intermediate step, some ripping programs save the extracted audio in a lossless format such as WAV, FLAC, or even raw PCM audio. The extracted audio can then be encoded with a lossy codec like MP3, Vorbis, WMA or AAC. The encoded files are more compact and are suitable for playback on digital audio players. They may also be played back in a media player program on a computer. Most ripping programs will assist in tagging the encoded files with metadata. The MP3 file format, for example, allows tags with title, artist, album and track number information.
transparenttransparencydata compression transparency
However, a double-blind comparison could still yield claims of perceived differences and thus lack of transparency, even though such claims would be in error. * * "Transparency", Hydrogen Audio Wiki Codec listening test. 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.
H.264H.264/MPEG-4 AVCMPEG-4 AVC
Each version represents changes relative to the next lower version that is integrated into the text. |} The H.264 video format has a very broad application range that covers all forms of digital compressed video from low bit-rate Internet streaming applications to HDTV broadcast and Digital Cinema applications with nearly lossless coding. With the use of H.264, bit rate savings of 50% or more compared to MPEG-2 Part 2 are reported. For example, H.264 has been reported to give the same Digital Satellite TV quality as current MPEG-2 implementations with less than half the bitrate, with current MPEG-2 implementations working at around 3.5 Mbit/s and H.264 at only 1.5 Mbit/s.
Nintendo WiiWii MiniSensor Bar
An SD card can also be used to create customized in-game music from stored MP3 files (as first shown in Excite Truck) and music for the slide-show feature of the Photo Channel. Version 1.1 of the Photo Channel removed MP3 playback in favor of AAC support. At the Nintendo Fall Press Conference in October 2008, Satoru Iwata announced that Wii owners would have the option to download WiiWare and Virtual Console content directly onto an SD card. The option would offer an alternative to "address the console's insufficient memory storage". The announcement stated that it would be available in Japan in spring 2009; Nintendo made the update available on March 25.
SilverlightSilverlight 3Microsoft Silverlight 2.0
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".
Zune MarketplaceZuneZune Pass
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, ALAC, 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.