Monkey's Audio

Overview

Monkey's Audio (also called APE or MAC) is a lossless compression format. The home page is http://www.monkeysaudio.com

Monkey's probably has the highest compression of all the lossless codecs, but it comes at a price - decoding is very CPU intensive, and not all compression levels are playable in realtime in Rockbox.

Monkey's audio has five compression modes, with each mode compressing to a smaller size, but significantly slower to decode than the previous one. -c2000 or -c3000 are a good compromise between compression size and decoding speed.

• -c1000 - "fast"
• -c2000 - "normal"
• -c3000 - "high"
• -c4000 - "extra high"
• -c5000 - "insane"

In addition, Monkey's Audio (currently at version 3.99) has been through many incompatible format changes in its life - most versions of the encoder produce files which are not decodable by earlier versions of the decoder.

Current Status

The Rockbox Monkey's Audio codec is in the early stages of development and has not yet been fullly optimised. Only v3.97 or later files are supported.

Rockbox supports APEv2 tags in Monkey's Audio files, but does not read (or skip) id3v2 tags, which some applications also add to APE files. If a file has an id3v2 tag, it won't work in Rockbox.

Performance

Approximate decoding speed on the various CPUs in Rockbox-supported DAPs are as follows:

Devices	SVN rev.	-c1000	-c2000	-c3000	-c4000	-c5000
iPod 1st Gen..3rd Gen (80MHz PortalPlayer PP5002)	r15305	64%	45%	30%	12%	2.2%
iPod 4th/5th Gen, iPod Mini/Nano, Iriver H10, Sansa (80MHz PortalPlayer 502x)	r15304	113%	75%	48%	18%	3.7%
Iriver H1x0/H300, iAudio X5/M5 (124 MHz ColdFire)	r15304	211%	148%	109%	46%	2.0% (1)
Gigabeat F (300MHz ARM)	r15205	456%	311%	207%	75%	17%
Gigabeat S (532MHz ARM, but clocked at approx 264MHz)	r17348	537%	360%	229%	84%	19%

1. 12% if the "insane" filter array is put into IRAM (only possible on iAudio X5/M5).

Note that a speed less than around 120% will not play without pausing in Rockbox.