273d2e81f7
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7656 a1c6a512-1295-4272-9138-f99709370657
46 lines
1.6 KiB
Text
46 lines
1.6 KiB
Text
Library: libffmpegFLAC
|
|
Imported: 2005-10-26 by Dave Chapman
|
|
|
|
This directory contains a FLAC decoder based on the flac.c (and a small
|
|
number of other files) from the ffmpeg project.
|
|
|
|
LICENSING INFORMATION
|
|
|
|
ffmpeg is licensed under the Lesser GNU General Public License and the
|
|
file flac.c is Copyright 2003 Alex Beregszaszi.
|
|
|
|
IMPORT DETAILS
|
|
|
|
The decoder is based on ffmpeg-cvs from 26 October 2005.
|
|
|
|
The file libavcodec/flac.c was renamed to decoder.c and all ffmpeg
|
|
related code was removed. It was also heavily modified to remove
|
|
debugging information and unused experiemental code.
|
|
|
|
It was also changed to provide output as 32-bit integers (with the
|
|
data left-shifted to 28 bit accuracy). The original flac.c provided
|
|
16-bit output.
|
|
|
|
In order to minimise memory usage, a small number of hard-coded limits
|
|
are present in decoder.h - mainly limiting the supported blocksize
|
|
(number of samples in a frame) to 4608. This is the default value
|
|
used by the reference FLAC encoder at all standard compression
|
|
settings.
|
|
|
|
|
|
TESTING
|
|
|
|
A test program is contained in the file main.c and this should compile
|
|
in any Unix-like environment using the command "make -f Makefile.test".
|
|
|
|
Running "test file.flac" will decode the audio data to a WAV file
|
|
called "test.wav" in the current directory. This has been tested with
|
|
16-bit and 24-bit mono and stereo FLAC files.
|
|
|
|
This can be used to test the accuracy of the decoder by comparing the
|
|
md5sum of the WAV file produced by this decoder with a WAV file
|
|
produced by the official libFLAC decoder.
|
|
|
|
This test program could be extended to perform an internal md5sum
|
|
calculation and comparing that against the md5sum stored in the FLAC
|
|
file's header.
|