rockbox

History

Andrew Mahone e76f30a57c Improvements to specialized dividers for APE codec: * Use Newton-Raphson divider on ARMv5e and ARMv6, about 7% speedup on Gigabeat S. * On ARMv4 targets using IRAM, remove insane filter buffer from IRAM, fill available IRAM with LUT of reciprocals for small divisors - speedup varies according to target and available IRAM, APE normal sample is approx. 109% RT on e200. * Rename apps/codecs/lib/udiv32_armv4.S to apps/codecs/lib/udiv32_arm.S, which includes dividers for all ARM targets specialized for APE. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24354 a1c6a512-1295-4272-9138-f99709370657		2010-01-28 02:28:52 +00:00
..
libdemac	Improvements to specialized dividers for APE codec:	2010-01-28 02:28:52 +00:00
COPYING
demac.c	Fix handling of 8 bit mono and stereo APE files, and also optimise 16 and 24 bit output in the standalone decoder a bit.	2008-12-21 01:29:36 +00:00
libdemac.make	Silence warning from 'ar' if the archive had to be created.	2009-03-01 09:04:15 +00:00
Makefile	Fix decoding of stereo frames with silence in only one channel. * Make the standalone decoder contain debugging information.	2008-12-21 23:49:02 +00:00
README
wavwrite.c	Make it compile again on linux...	2008-11-16 17:44:59 +00:00
wavwrite.h	Calculate watermark from bitrate and harddisk spinup time.	2009-01-10 21:10:56 +00:00

README

demac - a decoder for Monkey's Audio files.

Introduction

demac is an implementation in portable ANSI C of a decoder for the
Monkey's Audio lossless compression format.  It has the following
features:

  * Open source (GNU GPL)
  * Written in portable ANSI C
  * Designed for use on low memory and embedded devices.  All internal
    buffers are statically declared - the core library doesn't require 
    malloc/free.  This has the disadvantage that the library isn't 
    re-entrant.


Compatibility


libdemac is still in the early stages of development but has been
relatively well tested with v3.99 files at all compression levels.

v3.97 files have received less testing - 16-bit files seem to work,
but 24-bit files are causing problems in the range decoder.

Files earlier than v3.97 are not supported by libdemac, but support
might be added in the future.


Source Code

The source code in this directory is structured as follows:

demac/Makefile - Makefile for the standalone demac decoder
demac/demac.c - Simple standalone test program to decoder an APE file to WAV
demac/wavwrite.[ch] - Helper functions for demac.c
demac/libdemac/Makefile - A Makefile for use in Rockbox
demac/libdemac/*.[ch] - The main libdemac code


Latest Version

The latest version of demac and libdemac can always be found in the
"apps/codecs/demac/" directory in the Rockbox source.  You can check
this out from svn with the command:

svn co svn://svn.rockbox.org/rockbox/trunk/apps/codecs/demac demac

Or browse the source code online here:

http://svn.rockbox.org/viewvc.cgi/trunk/apps/codecs/demac



Acknowledgements

Thanks to Matt. T. Ashland for writing Monkey's Audio.  His website
can be found here: http://www.monkeysaudio.com


Copyright and license


libdemac is (C) 2007 Dave Chapman and is licensed under the GNU
GPL. See the COPYING file in this directory.

The exception is the majority of rangecoding.h, which is (C) 1997,
1998, 1999, 2000 Michael Schindler and is also licensed under the GPL.
See that source file for full details.