Musepack or MPC is an

open source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...

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 In telecommunications, data transfer rate is the average number of bits ( bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mu ...

. 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 Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

and

Mac OS X macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

, and plugins for several third-party media players available from the Musepack website, licensed under the

GNU Lesser General Public License The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own ...

(LGPL) or

BSD licenses BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD lice ...

, and an extensive list of programs supporting the format.

Technical details

Musepack was developed using the

MP2 MP2 or MP-2 may refer to: Aviation * The second terminal of Marseille Provence Airport * Chyetverikov ARK-3 flying-boat Firearms * German Army designation for the Uzi * MP-2 machine pistol Science * MP 2, an abbreviation for a zone during t ...

codec as a starting point, but many features have since been added, including: * subband selectable M/S encoding (as in

AAC AAC may refer to: Aviation * Advanced Aircraft, a company from Carlsbad, California * Airborne aircraft carrier, a type of aircraft * Alaskan Air Command, a radar network * American Aeronautical Corporation, a company from Port Washington, New ...

) *

Huffman coding In computer science and information theory, a Huffman code is a particular type of optimal prefix code that is commonly used for lossless data compression. The process of finding or using such a code is Huffman coding, an algorithm developed by ...

(as in

MP3 MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III) is a coding format for digital audio developed largely by the Fraunhofer Society in Germany under the lead of Karlheinz Brandenburg. It was designed to greatly reduce the amount ...

and AAC, but more efficient). Since SV8 the bitstream is compressed by highly optimized canonical huffman tables that yields 2% smaller files and faster decoding * noise substitution techniques (as in ATSC A-52 and

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 ...

AAC V2) * pure variable bitrate between 0 and 1300 kbit/s (when needed) The

psychoacoustic Psychoacoustics is the branch of psychophysics involving the scientific study of the perception of sound by the human auditory system. It is the branch of science studying the psychological responses associated with sound including noise, speech, ...

model of MPC is based on MPEG ISO model 2, but is extended by CVD (clear voice detection). The quantization algorithm of the MPC encoder performs spectral shaping of the noise, called ''

adaptive noise shaping Adaptation, in biology, is the process or trait by which organisms or population better match their environment Adaptation may also refer to: Arts * Adaptation (arts), a transfer of a work of art from one medium to another ** Film adaptation, a ...

'' (ANS), in order to overcome the low frequency resolution of the

polyphase quadrature filter Polyphase may refer to: * Polyphase matrix, in signal processing * Polyphase system, in electrical engineering * Polyphase quadrature filter * Polyphasic sleep {{Disambig ...

bands. MPC uses the

APEv2 tag APE tags comprise one extant convention used to store information (metadata) about a given digital audio file. Each APE tag constitutes a discrete element that describes a single attribute of the file's contents. Each consists of a key/value p ...

metadata Metadata (or metainformation) is "data that provides information about other data", but not the content of the data itself, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive ...

container. Musepack is mainly optimized for transparent encoding at the "--standard" preset (175-185 kbit/s). Very few optimisations have been made at lower bitrates (like 128 kbit/s). Nevertheless, various listening tests have been conducted in which Musepack has performed well at both lower and higher bitrates.

Features

* Container-independent format. An SV8 MPC is a container file for a Musepack stream. Raw stream encoding is possible. * Packetized stream allows muxing into audio and video containers (e.g. MKA/MKV,

NUT Nut often refers to: * Nut (fruit), fruit composed of a hard shell and a seed * Nut (food), a dry and edible fruit or seed, including but not limited to true nuts * Nut (hardware), fastener used with a bolt Nut, NUT or Nuts may also refer to: A ...

). * Sample-accurate, fast seeking independent of file length. * Sample-accurate cutting. Application included in download package (mpccut) allows losslessly cutting stream segments based on selected start/end samples. * Chapters. Chapter editor (mpcchap) included, for embedding chapters into MPC files. * No internal clipping. * Streamable.

Test results

Despite being optimized for 100% transparency at moderately high bitrates, MPC has also scored highly on many 128 kbit/s tests. In May 2004, a series of

double-blind In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expec ...

listening tests (as reported on Slashdot) suggested that Musepack and

Ogg Vorbis Vorbis is a free and open-source software project headed by the Xiph.Org Foundation. The project produces an audio coding format and software reference encoder/decoder (codec) for lossy audio compression, libvorbis. Vorbis is most common ...

(which was the 1.1 "aoTuV" fork at the time) were the two best available codecs for high-quality audio compression at bitrates around 128 kbit/s, beating

, WMA, and

ATRAC Adaptive Transform Acoustic Coding (ATRAC) is a family of proprietary audio compression algorithms developed by Sony. MiniDisc was the first commercial product to incorporate ATRAC, in 1992. ATRAC allowed a relatively small disc like MiniDisc t ...

. Listening tests of MPC: * 2004 – rjamorim's second 128 kbit/s group listening test – between 14 and 27 listeners. MPC and Vorbis tied for first. * 2003 – rjamorim's first 128 kbit/s group listening test – between 14 and 29 listeners. AAC, MPC, Vorbis, and WMA tied for first. * 2002 – ff123's second 128 kbit/s group listening test * 2001 – ff123's 128 kbit/s group listening test

Hardware and software support

Devices supporting

The Core Pocket Media Player The Core Pocket Media Player (TCPMP) is a software media player which operates on portable devices and Windows-based PCs. It is discontinued, but still available from the official mirror site. Supported operating systems include Palm OS, Symbi ...

can play MPC. This includes devices running

Palm OS Palm OS (also known as Garnet OS) is a discontinued mobile operating system initially developed by Palm, Inc., for personal digital assistants (PDAs) in 1996. Palm OS was designed for ease of use with a touchscreen-based graphical user interface. ...

Symbian Symbian is a discontinued mobile operating system (OS) and computing platform designed for smartphones. It was originally developed as a proprietary software OS for personal digital assistants in 1998 by the Symbian Ltd. consortium. Symbian OS ...

OS,

Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

Windows CE Windows CE, later known as Windows Embedded CE and Windows Embedded Compact, is a discontinued operating system developed by Microsoft for mobile and embedded devices. It was part of the Windows Embedded family and served as the software foun ...

and

Windows Mobile Windows Mobile is a discontinued mobile operating system developed by Microsoft for smartphones and personal digital assistants (PDA). Designed to be the portable equivalent of the Windows desktop OS in the emerging Mobile device, mobile/port ...

(

Pocket PC A Pocket PC (P/PC, PPC) is a class of personal digital assistant (PDA) that runs the Windows Mobile operating system, which is based on Windows Embedded Compact, Windows CE/Windows Embedded Compact, and that has some of the abilities of modern ...

). All devices with software audio decoding that are supported by

Rockbox Rockbox is a free and open-source software replacement for the OEM firmware in various forms of digital audio players (DAPs) with an original kernel. It offers an alternative to the player's operating system, in many cases without removing the o ...

, including older revisions of

iPod The iPod is a series of portable media players and multi-purpose mobile devices that were designed and marketed by Apple Inc. from 2001 to 2022. The iPod Classic#1st generation, first version was released on November 10, 2001, about mon ...

, can also play Musepack files. Playback on

Roku Roku ( ) is a brand of consumer electronics that includes streaming players, smart TVs (and their operating systems), as well as a free TV streaming service. The brand is owned by Roku, Inc., an American company. As of 2024, Roku is the U ...

Photobridge HD is supported with a plugin. There is a plethora of media players for Android supporting Musepack (among them is the ported Rockbox media player). Musepack distributes the ''libmpcdec'' library for decoding MPC content. Various plugins have been developed, using that library, including for the

XMMS X Multimedia System (XMMS) is an audio player for Unix-like systems released under a free software license. History XMMS was originally written as ''x11amp'' by Peter and Mikael Alm in November 1997. The player was made to resemble Winamp, which ...

player (on

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

). Asunder and Jack! The Knife allows ripping Audio CD tracks directly into Musepack files.

References

External links

*
Software supporting Musepack

Hydrogen Audio Wiki's article on Musepack
{{Compression software implementations Free audio codecs Open formats