Traverso/cvs/traverso/src/common/Mixer.h

/*
    Copyright (C) 2005-2006 Remon Sijrier 
 
    This file is part of Traverso
 
    Traverso is free software; you can redistribute it and/or modify
    it under the terms of the GNU 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 General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
 
    $Id: Mixer.h,v 1.2 2007/10/27 17:57:15 r_sijrier Exp $
*/

#ifndef TRAVERSO_MIXER_H
#define TRAVERSO_MIXER_H

#include "defines.h"
#include <cmath>


static inline float f_max(float x, float a)
{
        x -= a;
        x += fabsf (x);
        x *= 0.5f;
        x += a;

        return (x);
}

// This is for VU : db = 20 * log ( sample / MaxSample )
static inline float dB_to_scale_factor (float dB)
{
        // examples :
        // dB = 0    will return 1.0
        // db = -6.0 will return 0.5
        // db = -inf will return 0.0
        return dB > -120.0f ? ::pow(10.0f, dB * 0.05f) : 0.0f;
}


static inline float coefficient_to_dB (float coeff)
{
        // examples :
        // coeff = 1.0 will return 0 dB
        // coeff = 0.5 will return -6 dB
        // coeff = 0.0 will return -infinite dB
        if (coeff < 0.000001f)          //Should be (coeff == 0), but this will do...
                return (-120.0f);       //Should be minus infinity, but it will do for busMonitor purposes
        return 20.0f * log10 (coeff);
}


float default_compute_peak                      (const audio_sample_t*  buf, nframes_t nsamples, float current);
void  default_apply_gain_to_buffer              (audio_sample_t*  buf, nframes_t nframes, float gain);
void  default_mix_buffers_with_gain             (audio_sample_t*  dst, const audio_sample_t*  src, nframes_t nframes, float gain);
void  default_mix_buffers_no_gain               (audio_sample_t*  dst, const audio_sample_t*  src, nframes_t nframes);


#if defined (ARCH_X86) && defined (SSE_OPTIMIZATIONS)

extern "C"
{
        /* SSE functions */
        float x86_sse_compute_peak              (const audio_sample_t*  buf, nframes_t nsamples, float current);
        void  x86_sse_apply_gain_to_buffer      (audio_sample_t*  buf, nframes_t nframes, float gain);
        void  x86_sse_mix_buffers_with_gain     (audio_sample_t*  dst, const audio_sample_t*  src, nframes_t nframes, float gain);
        void  x86_sse_mix_buffers_no_gain       (audio_sample_t*  dst, const audio_sample_t*  src, nframes_t nframes);
}
#endif

#if defined (__APPLE__)  && defined (BUILD_VECLIB_OPTIMIZATIONS)

float veclib_compute_peak              (const audio_sample_t* buf, nframes_t nsamples, float current);
void  veclib_apply_gain_to_buffer      (audio_sample_t* buf, nframes_t nframes, float gain);
void  veclib_mix_buffers_with_gain     (audio_sample_t* dst, const audio_sample_t* src, nframes_t nframes, float gain);
void  veclib_mix_buffers_no_gain       (audio_sample_t* dst, const audio_sample_t* src, nframes_t nframes);

#endif

class Mixer
{
public:
        typedef float (*compute_peak_t)                 (const audio_sample_t* , nframes_t, float);
        typedef void  (*apply_gain_to_buffer_t)         (audio_sample_t* , nframes_t, float);
        typedef void  (*mix_buffers_with_gain_t)        (audio_sample_t* , const audio_sample_t* , nframes_t, float);
        typedef void  (*mix_buffers_no_gain_t)          (audio_sample_t* , const audio_sample_t* , nframes_t);

        static compute_peak_t           compute_peak;
        static apply_gain_to_buffer_t   apply_gain_to_buffer;
        static mix_buffers_with_gain_t  mix_buffers_with_gain;
        static mix_buffers_no_gain_t    mix_buffers_no_gain;
};

#endif


//eof

---