NationMaster - Encyclopedia: WavPack

WavPack is a free, open source lossless audio compression format developed by David Bryant. Software engineering (SE) is the profession concerned with specifying, designing, developing and maintaining software applications by applying technologies and practices from computer science, project management, and other fields. ... A software release refers to the creation and availability of a new version of a computer software product. ... April 10 is the 100th day of the year in the Gregorian calendar (101st in leap years). ... 2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... A cross-platform (or platform independent) programming language, software application or hardware device works on more than one system platform (e. ... An audio codec is a computer program that compresses/decompresses digital audio data according to a given audio file format or streaming audio format. ... An encoder is a device used to encode a signal (such as a bitstream) or data into a form that is acceptable for transmission or storage. ... A software license is a legal agreement which may take the form of a proprietary or gratuitous license as well as a memorandum of contract between a producer and a user of computer software. ... The BSD daemon BSD licenses represent a family of a permissive free software licenses. ... This page as shown in the AOL 9. ... Lossless data compression is a class of data compression algorithms that allow the original data to be reconstructed exactly from the compressed data. ...

Features

WavPack compression (.WV files) can compress (and restore) 8, 16, 24 & 32-bit float audio files in the .WAV file format. It also supports multichannel streams and high frequency sampling rates. Like other lossless compression schemes the data reduction varies with the source, but it is generally between 30% and 70% for typical popular music and somewhat better than that for classical music and other sources with greater dynamic range. WAV (or WAVE), short for Waveform audio format, is a Microsoft and IBM audio file format standard for storing audio on PCs. ... Multichannel is a term used in telecommunication. ... The sampling frequency or sampling rate defines the number of samples per second taken from a continuous signal to make a discrete signal. ...

WavPack also incorporates a unique "hybrid" mode that provides all the advantages of lossless compression with an additional bonus. Instead of creating a single file, this mode creates both a relatively small, high-quality lossy file that can be used all by itself, and a "correction" file that (when combined with the lossy file) provides full lossless restoration. For some users, this means never having to choose between lossless and lossy compression.

Summary

Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ... The BSD license is a permissive license and is one of the most widely used free software licenses. ... Streaming media is media that is consumed (heard or viewed) (mostly in the form of clips) while it is being delivered. ... ID3 is a metadata container most often used in conjunction with the MP3 audio file format. ... APEv2 tags are used to add metadata, such as the title, artist, or track number, to digital audio files. ... The Resource Interchange File Format (RIFF) is a generic meta-format for storing data in tagged chunks. ... Replay Gain is a proposed standard published on July 12, 2001 to normalize the perceived loudness of computer audio formats such as MP3 and Ogg Vorbis. ... A cue sheet, or cue file, is an ASCII (plain text) file that specifies how the tracks of a compact disc should be laid out. ... In cryptography, MD5 (Message-Digest algorithm 5) is a widely-used cryptographic hash function with a 128-bit hash value. ...

History

David Bryant started development on WavPack in mid-1998, with the release of version 1.0. This first version compressed and decompressed audio losslessly, nothing else, but by then it already featured one of the best efficiency vs. speed ratio among lossless encoders.

Very soon after the release of version 1.0, Bryant released v. 2.0, which featured lossy encoding (using only quantization of prediction residue for data reduction - no psychoacoustic masking model was applied to the stream). Psychoacoustics is the study of subjective human perception of sounds. ...

In 1999, the developer released version 3.0, which featured novelties such as a fast mode (with reduced compression ratio), compression of raw (headerless) PCM audio files, and error detection using a 32-bit cyclic redundancy check. 4-bit PCM of a signal (red) Pulse-code modulation (PCM) is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a digital (usually binary) code. ... A cyclic redundancy check (CRC) is a type of hash function used to produce a checksum â€“ a small, fixed number of bits â€“ against a block of data, such as a packet of network traffic or a block of a computer file. ...

WavPack development is still going on, and a major feature added in late 3.x versions is the hybrid mode, where the encoder generates a lossy file + a correction file, so that both can be decompressed back to the original PCM stream.

WavPack 4 has been recently released. It included important changes, such as fast seeking, multichannel support, high resolution audio support, etc., turning it into one of the most full featured and modern lossless audio compressors. The latest stable version of the 4.x branch is 4.31; a Linux/OSX-specific bugfix resulted in a 4.32 version for these operating systems but no quality-related changes.

Bryant has recently released alpha versions previewing the forthcoming version 4.4 of WavPack, including new features such as improved handling of mono or almost-mono audio data and a redesigned quality system which offers very similar compression with greatly-improved efficiency. [1]

Support

Software

Winamp is a multimedia player made by Nullsoft and eventually acquired by America Online. ... foobar2000 is a freeware audio player for Windows 2000 or higher developed by Peter Pawlowski, a former freelance contractor for Nullsoft. ... Windows Media Player (WMP) is a digital media player and media library application developed by Microsoft that is used for playing audio, video and images on personal computers running the Microsoft Windows operating system, as well as on Pocket PC and Windows Mobile-based devices. ... XMMSs default appearance The X Multimedia System (XMMS) is a free audio player very similar to Winamp, that runs on many Unix-like operating systems. ... Adobe Audition (formerly Cool Edit Pro) is a digital audio editor computer program from Adobe Systems featuring both a multitrack, non-destructive mix/edit environment and a destructive-approach waveform editing view that has been referred to as the Swiss army knife of digital audio. ... Nero Burning ROM is a popular optical disc authoring program for Microsoft Windows and Linux by Nero AG, formerly Ahead Software. ... Exact Audio Copy, or often simply EAC, is a proprietary freeware, for non-commercial use, CD ripping program for Microsoft Windows. ... â€¹ The template below has been proposed for deletion. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... FreeDOS (formerly Free-DOS and PD-DOS) is an operating system for IBM PC compatible computers. ... DR-DOS is a PC DOS-compatible operating system for IBM PC-compatible personal computers, originally developed by Gary Kildalls Digital Research and derived from CP/M-86. ... Winamp is a multimedia player made by Nullsoft and eventually acquired by America Online. ... KSP (KSP Sound Player or Kalliope Sound Player) is a free audio player for Windows which is developed and distributed by Kalliope s. ... FFmpeg is a set of free computer programs that can record, convert and stream digital audio and video. ... VLC is a three-letter abbreviation with multiple meanings, as described below: VLC media player Visible Light Communications technology Valencia Airport - IATA airport code VLC Variable Length Coding This page concerning a three-letter acronym or abbreviation is a disambiguation pageâ€”a list of articles associated with the same title. ... MPlayer is a free media player with support for more multimedia formats than any other media player. ... xine (officially pronounced zinny) is a multimedia playback engine for Unix released under the GNU General Public License. ... Amarok (formerly known as amaroK or AmaroK) is an audio player application for KDE, which is released independantly from the kmultimedia package, and away from the central release cycle of KDE. It is now thought to be the most popular KDE-based audio player because of its extensive feature...

Hardware

Rockbox is a free software / open source operating system for digital audio players (DAPs). ...

Technology

To ensure high-speed operation, WavPack uses a very simple predictor that is implemented entirely in integer math. In its "fast" mode the prediction is simply the arithmetic extrapolation of the previous two samples. For example, if the previous two samples were -10 and 20, then the prediction would be 50. For the default mode a simple adaptive factor is added to weigh the influence of the earlier sample on the prediction. In our example the resulting prediction could then vary between 20 for no influence to 50 for full influence. This weight factor is constantly updated based on the audio data's changing spectral characteristics, which is why it is called "adaptive".

The prediction generated is then subtracted from the actual sample to be encoded to generate the error value. In mono mode this value is sent directly to the coder. However, stereo signals tend to have some correlation between the two channels that can be further exploited. Therefore, two error values are calculated that represent the difference and average of the left and right error values. In the "fast" mode of operation these two new values are simply sent to the coder instead of the left and right values. In the default mode, the difference value is always sent to the coder along with one of the other three values (average, left, or right). An adaptive algorithm continuously determines the most efficient of the three to send based on the changing balance of the channels. Label for 2. ...

The developer has developed a unique data encoder for WavPack that he believes is better than Rice coding in two different areas. It is impossible to encode more efficiently than Rice coding because it represents the optimal bit coding (sometimes known as the Huffman code) for this type of data. WavPack's encoder is slightly less efficient than this, but only by about 0.15 bits/sample (or less than 1% for 16-bit data). The first advantage of WavPack's coder is that it does not require the data to be buffered ahead of encoding, instead it converts each sample directly to bitcodes. This is more computationally efficient and it is better in some applications where coding delay is critical. The second advantage is that it is easily adaptable to lossy encoding because all significant bits (except the implied "one" MSB) are transmitted directly. In this way it is possible to only transmit, for example, the 3 most significant bits (with sign) of each sample. In fact, it is possible to transmit only the sign and implied MSB for each sample with an average of only 3.65 bits/sample. Golomb coding is a form of entropy coding invented by Solomon W. Golomb that is optimal for alphabets following geometric distributions, that is, when small values are vastly more common than large values. ... In computer science, Huffman coding is an entropy encoding algorithm used for data compression that finds the optimal system of encoding strings based on the relative frequency of each character. ... The binary representation of decimal 149, with the MSB highlighted. ...

This coding scheme is used to implement the "lossy" mode of WavPack. In the "fast" mode the output of the non-adaptive decorrelator is simply rounded to the nearest codable value for the specified number of bits. In the default mode the adaptive decorrelator is used (which reduces the average noise about 1 dB) and also both the current and the next sample are considered in choosing the better of the two available codes (which reduces noise another 1 dB). The decibel (dB) is a measure of the ratio between two quantities, and is used in a wide variety of measurements in acoustics, physics and electronics. ...

The developer has decided to not use any floating-point arithmetic in WavPack's data path because he believes that integer operations are less susceptible to subtle chip to chip variations that could corrupt the lossless nature of the compression, the Pentium floating point bug being a blatant example of this. It is possible that a lossless compressor that used floating-point math could generate different output when running on that faulty Pentium. Even disregarding actual bugs, floating-point math is complicated enough that there could be subtle differences between "correct" implementations that could cause trouble for this type of application. To further ensure confidence in the integrity of WavPack's compression, the encoder includes a 32-bit error detection code to the generated streams. This article or section is in need of attention from an expert on the subject. ... The integers consist of the positive natural numbers (1, 2, 3, â€¦), their negatives (âˆ’1, âˆ’2, âˆ’3, ...) and the number zero. ...

WavPack source code is very portable. It has been compiled on several Unices (Linux, Mac OS X, Solaris, FreeBSD, OpenBSD, NetBSD, Compaq Tru64, HP-UX...) as well as Windows, DOS, Palm OS, and OpenVMS. It works on many architectures, including x86, ARM, PowerPC, AMD64, IA-64, SPARC, DEC Alpha, PA-RISC, MIPS and Motorola 68k. Linux (also known as GNU/Linux) is a Unix-like computer operating system. ... Mac OS X (IPA pronunciation: ) is a line of proprietary, graphical operating systems developed, marketed, and sold by Apple Computer, the latest of which is pre-loaded on all currently shipping Macintosh computers. ... Solaris is a computer operating system developed by Sun Microsystems. ... FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4. ... OpenBSD is a freely available Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Unix derivative developed at the University of California, Berkeley. ... NetBSD is a freely redistributable, open source version of the Unix-like BSD computer operating system. ... Tru64 is HPs (formerly Compaq; formerly DEC) 64-bit UNIX for the Alpha AXP platform. ... HP-UX (Hewlett Packard UniX) is Hewlett-Packards proprietary implementation of the Unix operating system. ... Microsoft Windows is a family of operating systems by Microsoft. ... â€¹ The template below has been proposed for deletion. ... Palm OS is a compact operating system developed and licensed by PalmSource, Inc. ... OpenVMS (Open Virtual Memory System or just VMS) is the name of a high-end computer server operating system that runs on the VAX and Alpha family of computers developed by Digital Equipment Corporation of Maynard, Massachusetts (now owned by Hewlett-Packard), and more recently on Hewlett-Packard systems built... x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ... The current version of the article or section reads more like an advertisement than an encyclopedic article. ... IBM PowerPC 601 Microprocessor PowerPC is a RISC microprocessor architecture created by the 1991 Appleâ€“IBMâ€“Motorola alliance, known as AIM. Originally intended for personal computers, PowerPC CPUs have since become popular embedded and high-performance processors as well. ... AMD64 Logo AMD64 (also x86-64 or x64) is a 64-bit microprocessor architecture and corresponding instruction set designed by Advanced Micro Devices. ... In computing, IA-64 (or ia64, short for Intel Architecture-64) is a 64-bit processor architecture developed in cooperation by Intel and Hewlett-Packard, implemented by processors such as Itanium and Itanium 2. ... Sun UltraSPARC II Microprocessor Sun UltraSPARC T1 (Niagara 8 Core) SPARC (Scalable Processor ARChitecture) is a pure big-endian RISC microprocessor instruction set architecture originally designed in 1985 by Sun Microsystems. ... DEC Alpha AXP 21064 Microprocessor The DEC Alpha, also known as the Alpha AXP, is a 64-bit RISC microprocessor originally developed and fabricated by Digital Equipment Corp (DEC). ... PA-RISC is a microprocessor architecture developed by Hewlett-Packards Systems & VLSI Technology Operation. ... A MIPS R4400 microprocessor made by Toshiba. ... The Motorola 680x0/0x0/m68k/68k/68K family of CISC microprocessor CPU chips were 32-bit from the start, and were the primary competition for the Intel x86 family of chips. ...

See also

FLAC, an acronym for Free Lossless Audio Codec, is a popular file format for audio data compression. ... True Audio (abbreviated TTA) is a free, simple real-time lossless audio codec, based on adaptive prognostic filters which has shown satisfactory results comparing to majority of modern analogs. ... Monkeyâ€™s Audio is a lossless audio compression codec. ... Meridian Lossless Packing is a proprietary lossless compression technique for compressing PCM audio data. ...

External links

Categories: Computer file formats | Audio codecs | Free audio software | Free multimedia codecs, containers, and splitters | Lossless compression algorithms This article or section does not cite its references or sources. ... Bold text Wiktionary has related dictionary definitions, such as: compressor, compression inthe wkjhrlfidhb;g/df == Compressor may refer to: Gas compressor, a mechanical device that compresses a gas e. ... Format has several meanings; did you mean: Disk formatting — the process of preparing a disk for use File format — various ways information is encoded in computing Format — a command in the Common Lisp programming language Radio format — the musical style and programming philosophy of a radio... Video compression refers to making a digital video signal use less data, without noticeably reducing the quality of the picture. ... ISO has many meanings: Iso is the stem of the Latin transliteration of the Greek word Î¯ÏƒÎ¿Ï‚ (Ãsos, meaning equal). The iso- prefix in English derives from this and means equality or similarity. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ... MPEG-1 defines a group of Audio and Video (AV) coding and compression standards agreed upon by MPEG (Moving Picture Experts Group). ... MPEG-2 is the designation for a group of coding and compression standards for Audio and Video (AV), agreed upon by MPEG (Moving Picture Experts Group), and published as the ISO/IEC 13818 international standard. ... MPEG-4 is a standard used primarily to compress audio and video (AV) digital data. ... H.264, MPEG-4 Part 10, or AVC, for Advanced Video Coding, is a digital video codec standard which is noted for achieving very high data compression. ... The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ... H.261 is an 1990 ITU video coding standard originally designed for transmission over ISDN lines on which data rates are multiples of 64 kbit/s. ... H.262 is an ITU-T digital video coding standard. ... H.263 is a video codec designed by the ITU-T as a low-bitrate encoding solution for videoconferencing. ... H.264, MPEG-4 Part 10, or AVC, for Advanced Video Coding, is a digital video codec standard which is noted for achieving very high data compression. ... The Society of Motion Picture and Television Engineers or SMPTE (pronounced simptee or sometimes sumptee) is a US professional association of engineers. ... VC-1 is the informal name of the SMPTE 421M video codec standard. ... TrueMotion VP7 is a video codec developed by On2 Technologies as a successor to earlier efforts such as VP3, VP5 and TrueMotion VP6. ... RealVideo is a proprietary video format developed by RealNetworks. ... Windows Media Video (WMV) is a generic name for the set of video codec technologies developed by Microsoft. ... Indeo Video (commonly known now simply as Indeo) is a video codec developed by Intel in 1992. ... Motion JPEG (M-JPEG) is an informal name for multimedia formats where each video frame or interlaced field of a digital video sequence is separately compressed as a JPEG image. ... Theora is a video codec being developed by the Xiph. ... Dirac is a prototype algorithm for the encoding and decoding (see codec) of raw video. ... Audio compression is a form of data compression designed to reduce the size of audio files. ... ISO has many meanings: Iso is the stem of the Latin transliteration of the Greek word Î¯ÏƒÎ¿Ï‚ (Ãsos, meaning equal). The iso- prefix in English derives from this and means equality or similarity. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ... The Moving Picture Experts Group or MPEG is a working group of ISO/IEC charged with the development of video and audio encoding standards. ... MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a popular digital audio encoding and lossy compression format, designed to greatly reduce the amount of data required to represent audio, yet still sound like a faithful reproduction of the original uncompressed audio to most listeners. ... MPEG-1 Audio Layer II (MP2, sometimes Musicam) is an audio codec defined by ISO/IEC 11172-3. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... MPEG-4 Part 3 (formally ISO/IEC 14496-3) is, as the name suggests, the third part of the ISO/IEC MPEG-4 international standard. ... The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ... G.711 is an ITU-T standard for audio companding. ... G.722 is a ITU-T standard wideband speech codec operating at 32-64 kbit/s. ... G.722. ... Adaptive Multi Rate - WideBand or AMR-WB is a speech coding standard developed after the AMR using same technology like ACELP. The codec provides excellent speech quality due to wider speech bandwidth of 50 - 7000 Hz compared to narrowband speech codecs which in general are optimized for POTS wireline quality... This article is in need of attention from an expert on the subject. ... G.723. ... G.726 is ITU-T speech codec operating at bit rates of 16-40 kbit/s. ... G.728 is a ITU-T standard for speech coding operating at 16 kbit/s. ... G.729 From Wikipedia, the free encyclopedia You have new messages (changes). ... G.729 is an audio data compression algorithm for voice that compresses voice audio in chunks of 10 milliseconds. ... FLAC, an acronym for Free Lossless Audio Codec, is a popular file format for audio data compression. ... The Internet Low Bit Rate Codec (iLBC) is a royalty free narrowband speech codec, developed by Global IP Sound (GIPS). ... RealAudio is a proprietary audio format developed by RealNetworks. ... Windows Media Audio (WMA) is a proprietary compressed audio file format developed by Microsoft. ... SHN (Shorten) is a file format used to losslessly compress CD-quality audio files (44. ... Speex is a free software speech codec that claims to be unencumbered by patent restrictions. ... Musepack or MPC is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160-180 kbit/s. ... Vorbis is an open and free lossy audio compression codec project headed by the Xiph. ... ATRAC (Adaptive TRansform Acoustic Coding) is a family of proprietary audio compression algorithms used to store information on MiniDiscs and other Sony-branded audio players. ... Dolby Digital is the marketing name for a series of lossy audio compression technologies by Dolby Laboratories. ... Image compression is the application of data compression on digital images. ... ISO has many meanings: Iso is the stem of the Latin transliteration of the Greek word Î¯ÏƒÎ¿Ï‚ (Ãsos, meaning equal). The iso- prefix in English derives from this and means equality or similarity. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ... The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ... In computing, JPEG(pronounced JAY-peg; IPA: ) is a commonly used standard method of compression for photographic images and not for movie files for which MPEG compression is used. ... JPEG 2000 is a wavelet-based image compression standard. ... faldfjajsldfkja;sdfkja;dkjfasdf;j ... JBIG is a lossless image compression standard from the Joint Bi-level Image Experts Group, standardized as ISO/IEC standard 11544 and as ITU-T recommendation T.82. ... JBIG2 is an image compression standard for bi-level images, developed by the Joint Bi-level Image Experts Group. ... An example of a GIF image. ... A PNG image with an 8-bit transparency channel (top). ... Tagged Image File Format (abbreviated TIFF) is a file format for mainly storing images, including photographs and line art. ... PCX is an image file format that uses a simple form of run-length encoding (a type of lossless compression algorithm). ... Truevisions TGA File Format, often referred to as TARGA File Format, is a raster graphics file format. ... // Bitmap File Overview . ... Windows Media Photo (WMPhoto), a part of the Windows Media family, is a high compression still image format for continuous tone photographic images, developed by Andrew Gordon of Microsoft. ... ILBM is a subtype of the Interchange File Format used for storing picture data. ... A container format is a computer file format that can contain various types of data, compressed by means of standardized codecs. ... The Au file format is a simple audio file format that consists of a header of 6 32-bit words and then the data (high-order byte comes first). ... Audio Interchange File Format (AIFF) is an audio file format standard used for storing sound data on personal computers. ... WAV (or WAVE), short for Waveform audio format, is a Microsoft and IBM audio file format standard for storing audio on PCs. ... NUT is a patent-free, multimedia container format originally conceived by a few MPlayer and FFmpeg developers that were dissatisfied with the limitations of all currently available multimedia container formats such as AVI or Matroska. ... Material eXchange Format (MXF) is a container format for professional digital video and audio media defined by a set of SMPTE standards. ... Matroska (common file extensions being . ... OGG can refer to several items: Ogg is a multimedia bitstream container, used for audio and video files, especially Vorbis audio files. ... Ogg Media (OGM), meaning Ogg Media File, is a container format (for video, audio and subtitle streams). ... MPEG-4 Part 14, formally, ISO/IEC 14496-14:2003, is a multimedia container format standard specified as a part of MPEG-4. ... QuickTime is a multimedia framework developed by Apple Computer, capable of handling various formats of digital video, media clips, sound, text, animation, music, and several types of interactive panoramic images. ... RealMedia is a multimedia container format created by RealNetworks. ... To meet Wikipedias content policies, the external links section for this article may require cleanup. ... Audio Video Interleave, known by its acronym AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of the Video for Windows technology. ... Advanced Systems Format (formerly Advanced Streaming Format) is Microsofts proprietary digital audio/digital video container format, especially meant for streaming media. ... 3GP is a multimedia container format defined by the Third Generation Partnership Project (3GPP) for use on 3G mobile phones. ...

Contents

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