audio/include/AudioGain.h

	AudioGain.h revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
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/*
 * Copyright (c) 1993-2001 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#ifndef _MULTIMEDIA_AUDIOGAIN_H
#define _MULTIMEDIA_AUDIOGAIN_H

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <AudioTypePcm.h>

#ifdef __cplusplus
extern "C" {
#endif

// Class to handle gain calculations

// Define bits for AudioGain::Process() type argument
#define AUDIO_GAIN_INSTANT  (1)     // Gain for level meter
#define AUDIO_GAIN_WEIGHTED (2)     // Gain for agc


class AudioGain {
protected:

static const double LoSigInstantRange;  // normalization constants
static const double HiSigInstantRange;
static const double NoSigWeight;
static const double LoSigWeightRange;
static const double HiSigWeightRange;
static const double PeakSig;
static const double DCtimeconstant;     // DC offset time constant

    AudioTypePcm    float_convert;      // used in signal processing
    unsigned    clipcnt;        // clip counter
    Double      DCaverage;      // weighted DC offset
    Double      instant_gain;       // current (instantaneous) gain
    Double      weighted_peaksum;   // peak weighted sum
    Double      weighted_sum;       // running sum of squares
    Double      weighted_avgsum;    // accumulated sums to averages
    unsigned    weighted_cnt;       // number of sums to average
    double      *gain_cache;        // weighted gains
    Double      gain_cache_size;    // number of cached gains

protected:
    // Internal processing methods

    // filter DC bias
    virtual void process_dcfilter(
        AudioBuffer*);
    // calculate instant gain
    virtual void process_instant(
        AudioBuffer*);
    // calculate weighted gain
    virtual void process_weighted(
        AudioBuffer*);

public:
        AudioGain();            // Constructor
    virtual ~AudioGain();           // Destructor

    // TRUE if conversion ok
    virtual Boolean CanConvert(
        const AudioHdr&) const; // type to check against

    // Process new audio data
    virtual AudioError Process(
        AudioBuffer*, int);     // buffer destroyed if not referenced!
    virtual double InstantGain();   // Get most recent gain
    virtual double WeightedGain();  // Get current weighted gain
    virtual double WeightedPeak();  // Get peak weighted gain
    virtual Boolean Clipped();  // TRUE if peak since last check
    virtual void Flush();       // Reset state
};

#ifdef __cplusplus
}
#endif

#endif /* !_MULTIMEDIA_AUDIOGAIN_H */