Musepack

Musepack , shortened MPC , is a algorithm of audio Compression (see also “codec”) with loss S.

Development

Andree Buschmann initiated in 1997 the development of Musepack. The development will be taken again later by Franck Klemm. Currently, Musepack Development TEAM (MDT) ensures the development, with the assistance of Frank Klemm.
Musepack is free and Open Source. Thus, the development is opened with all.

Characteristics

Quality, speed

Musepack is conceived to produce an encoding known as " transparent" (i.e. indifférenciable of the original file) atsampling rates ranging between 160 and 180 kilobits/second.
the compression and the decompression of Musepack are carried out very quickly. The achievable ones are particularly swift on architectures X86, PowerPC, ARM or Sparc, in particular the decoding part through the library libmpcdec (under license BSD). Nevertheless, on more exotic platforms, such as those supported by Rockbox, this advantage is less due to the absence of optimizations Assembleur.

Free licenses

principal source code: license GNU LGPL
library of decoding, libmpcdec : license BSD (less restrictive than license GNU LGPL)

Portability

Because of its portability, Musepack can be used on many operating systems, for the encoding as for decoding: Microsoft Windows, Linux, Mac OS X, etc
Of many software manages Musepack, nativement or via plugins: Foobar2000, Winamp, Nero, Hearing/Cool Edict, Exact Audio Copy, CDex, etc the official site provides a detailed list of this software.

Format of the metadata (or " tags")

Musepack uses the tags with the APEv2 format nativement; the tags ID3v1 are also supported, but disadvised; the tags ID3v2 are to be proscribed (many problems cause)

Extension of file

The audio files obtained with Musepack carry the extension " .mpc ". One can also meet the extensions " .mpp " or " .mp+ ", but that is very rare. Indeed, Musepack was before called MPEGplus, MPEG+ or even MP+.

Encoding

Software

Under Microsoft Windows, the encoding in Musepack is carried out with mppenc.exe, a utility in line of order. This one can be used in 3 different ways:

such as it is, in line of order
since a specific GUI, for example MuseDrop
called by an external software: Exact Audio Copy, CDex…

Operation is similar on the others operating systems.

Parameters

General information

An encoding is carried out with the following order:

mppenc.exe N input.wav

" n" is the factor of quality (see below). If the option " --quality n" is not specified, the default setting, that is to say " --quality 5" , is used.

" output.mpc" is the name of the file obtained. If this option is not specified, it is the name of the input file which is used, with the extension " .mpc " (here, we would obtain " input.mpc").

Adjustment of quality

It is advised to choose like factor of quality an entirety ranging between 5 and 7. That is to say:

--quality 5 (before --standard): bitrate of approximately 170 kbps, variable between 142 and 184 kbps
--quality 6 (before --xtreme): bitrate of approximately 200 kbps, variable between 168 and 212 kbps
--quality 7 (before --insane): bitrate of approximately 220 kbps

In the near total of the cases, the profile " standard" cause only few audible deteriorations of the audio signal. The demanding audiophiles can use the profiles " xtreme" and " insane". Such profiles can also prove to be useful if the file is réencodé thereafter.

Musepack is not conceived for the profiles lower than " standard" (for example " --quality 4" , that is to say " --radio"). However, its performances with such profiles remain rather good.

Prevention of the " clipping"

The option " --xlevel" is an option allowing to avoid the " clipping" (saturation of the aural signal). Since the version 1.15s of mppenc, this option is activated by defect. It is not necessary thus more to add it to the line of order.

Example

These 2 lines produce the same result:

mppenc.exe --quality 7 musique.wav musique.mpc

mppenc.exe --insane musique.wav

See too

Internal bonds

External bonds

Official site of Musepack
Site of project MPC of Frank Klemm
Guide MPC on Hydrogenaudio
FreeMPC - a free software for conversion of MPC into MP3 and MPC into WAV
Xcfa - a software of extraction and audio conversion free under license GNU/GPL. For the GNU/Linux platforms.

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