NAME
Audio::Ofa - Perl interface to libofa, an Acoustig Fingerprinting
library
VERSION
This is version 1.01
SYNOPSIS
This module provides a direct interface to libofa. For not-so-lowlevel
and more practical assistance with audio fingerprints see
Audio::Ofa::Util.
use Audio::Ofa qw(ofa_get_version ofa_create_print);
SUBROUTINES
ofa_get_version
Retrieves the version of the installed libofa. Returns a string like
0.9.3.
ofa_create_print(data, byteOrder, size, sRate, stereo)
From the libofa source code comments:
data: a buffer of 16-bit samples in interleaved format (if stereo), i.e. L,R,L,R, etc.
This buffer is destroyed during processing.
Ideally, this buffer should contain the entire song to be analyzed, but the process will only
need the first 2min + 10sec + any silence prepending the actual audio. Since the precise silence
interval will only be known after a couple of processing steps, the caller must make adequate
allowance for this. Caveat emptor.
byteOrder: OFA_LITTLE_ENDIAN, or OFA_BIG_ENDIAN - indicates the byte
order of the data being passed in.
size: the size of the buffer, in number of samples.
sRate: the sample rate of the signal. This can be an arbitrary rate, as long as it can be expressed
as an integer (in samples per second). If this is different from 44100, rate conversion will
be performed during preprocessing, which will add significantly to the overhead.
stereo: 1 if there are left and right channels stored, 0 if the data is mono
On success, a valid text representation of the fingerprint is returned.
One should note that "size" is the byte length of "data" divided by 2
(as in 2 bytes as in 16 bit), regardless of "stereo".
The XS code will throw an exception if "size" is too large, to prevent a
buffer overread.
CONSTANTS
OFA_LITTLE_ENDIAN
OFA_BIG_ENDIAN
SEE ALSO
Audio::Ofa::Util provides utilities to read audio files and to look up
audio fingerprints at MusicDNS.
<
http://en.wikipedia.org/wiki/Audio_fingerprint> - The Wikipedia article
about acoustic fingerprints.
LICENSE
This module is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License (GPL) as published by
the Free Software Foundation (
http://www.fsf.org/); either version 2 of
the License, or (at your option) any later version.