Musepack

Introduction

Musepack is a lossy audio compression scheme created by Andree Buschmann. He started work on the codec in 1998 (then called MP+) because he was unsatisfied with the audio quality of MP3 codecs at the time. It is strongly based on the MPEG-1 Layer-2 (MP2) algorithms, with 32 subbands of the same bandwidth, but with several significant improvements. Musepack is optimized for "transparency". The format doesn't compete well at lower, 'streaming' bitrates such as 32/48/64kbps. This is due to MPC being a subband codec as well as the fact that very little optimization has gone into such low bitrates. However, as can be seen in various 128kbit/s listening tests (see below), despite the fact that MPC has been optimized little for such bitrates it is in the same class of other modern competitors such as AAC and (Ogg) Vorbis.

Pros

• Suffers from different "problem cases" than most other formats (less pre-echo)
• Very fast encoding/decoding
• Designed to be very good by default at --standard setting.
• Open source
• Portable playback by Pocket-PCs, Palm OS-based and Windows CE/Windows Mobile-based devices, even Smartphones/Tablets, see Program Overview
• Portable playback on digital audio players with Rockbox support, see http://www.rockbox.org
• Support & development forum at https://forum.musepack.net/

Cons

• Marginal support (yet) on portable players
• No support for sampling rates above 48khz

Technical details

Supported input formats

• channels: 1 to 8
• bit depths: 1 to 32 bit linear PCM
• sample rates: 32kHz, 37.8kHz, 44.1kHz, 48kHz (44.1 and 48 are highly tuned)
• WAV, raw PCM, a lot of lossless compressed audio formats like FLAC, LPAC, APE, OptimFROG, SZIP and Shorten (SHN)

Encoder Functions

MPC Encoder Functions

Links

User oriented links

• Musepack.net - a general info, news and software site.
• Users' HowTo MPC guide at HydrogenAudio
• EAC and Musepack

Technical links

• Specifications
• Source code
• reference: Frank Klemm mirror

Listening test involving MPC

• Listening Tests page
• Nine different audio encoders 100-pass recompression test
• Codec listening test + results on Wikipedia.org
• ff123's 128kbit/s group listening test
• ff123's second 128kbit/s group listening test
• rjamorim's 128kbit/s test

Please note that some of these tests, while valid, used encoder versions which have now been superseded. You should make your own decision about the comparative quality of MPC, listening to clips of music in the style you prefer.

Also note that these are tests at low bitrates; an area where MPC is not particularly optimized. The encoder was designed by the author to be very good at the --standard setting, thus little to no low bitrate tuning has gone into the codec, opposite to that of AAC, (Ogg) Vorbis, WMA and others which focus more on this region. However, as can be seen in the various listening test pages, MPC competes surprisingly well with the rest of them.