javazoom.jl.decoder.Equalizer Maven / Gradle / Ivy
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/*
* 11/19/04 1.0 moved to LGPL.
* 12/12/99 Initial version. [email protected]
*-----------------------------------------------------------------------
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*----------------------------------------------------------------------
*/
package javazoom.jl.decoder;
/**
* The Equalizer class can be used to specify
* equalization settings for the MPEG audio decoder.
*
* The equalizer consists of 32 band-pass filters.
* Each band of the equalizer can take on a fractional value between
* -1.0 and +1.0.
* At -1.0, the input signal is attenuated by 6dB, at +1.0 the signal is
* amplified by 6dB.
*
* @see Decoder
*
* @author MDM
*/
public final class Equalizer
{
/**
* Equalizer setting to denote that a given band will not be
* present in the output signal.
*/
static public final float BAND_NOT_PRESENT = Float.NEGATIVE_INFINITY;
static public final Equalizer PASS_THRU_EQ = new Equalizer();
private static final int BANDS = 32;
private final float[] settings = new float[BANDS];
/**
* Creates a new Equalizer instance.
*/
public Equalizer()
{
}
// private Equalizer(float b1, float b2, float b3, float b4, float b5,
// float b6, float b7, float b8, float b9, float b10, float b11,
// float b12, float b13, float b14, float b15, float b16,
// float b17, float b18, float b19, float b20);
public Equalizer(float[] settings)
{
setFrom(settings);
}
public Equalizer(EQFunction eq)
{
setFrom(eq);
}
public void setFrom(float[] eq)
{
reset();
int max = (eq.length > BANDS) ? BANDS : eq.length;
for (int i=0; i=0) && (band=0) && (band 1.0f)
return 1.0f;
if (eq < -1.0f)
return -1.0f;
return eq;
}
/**
* Retrieves an array of floats whose values represent a
* scaling factor that can be applied to linear samples
* in each band to provide the equalization represented by
* this instance.
*
* @return an array of factors that can be applied to the
* subbands.
*/
float[] getBandFactors()
{
float[] factors = new float[BANDS];
for (int i=0, maxCount=BANDS; i