79 lines
2.7 KiB
C++
79 lines
2.7 KiB
C++
|
/*
|
||
|
* Copyright (C) 2011 Google Inc. All rights reserved.
|
||
|
*
|
||
|
* Redistribution and use in source and binary forms, with or without
|
||
|
* modification, are permitted provided that the following conditions
|
||
|
* are met:
|
||
|
*
|
||
|
* 1. Redistributions of source code must retain the above copyright
|
||
|
* notice, this list of conditions and the following disclaimer.
|
||
|
* 2. Redistributions in binary form must reproduce the above copyright
|
||
|
* notice, this list of conditions and the following disclaimer in the
|
||
|
* documentation and/or other materials provided with the distribution.
|
||
|
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
|
||
|
* its contributors may be used to endorse or promote products derived
|
||
|
* from this software without specific prior written permission.
|
||
|
*
|
||
|
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
|
||
|
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
||
|
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
||
|
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
|
||
|
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
||
|
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
||
|
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
||
|
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
||
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||
|
*/
|
||
|
|
||
|
#include "ZeroPole.h"
|
||
|
|
||
|
#include <cmath>
|
||
|
#include <float.h>
|
||
|
|
||
|
namespace WebCore {
|
||
|
|
||
|
void ZeroPole::process(const float *source, float *destination, int framesToProcess)
|
||
|
{
|
||
|
float zero = m_zero;
|
||
|
float pole = m_pole;
|
||
|
|
||
|
// Gain compensation to make 0dB @ 0Hz
|
||
|
const float k1 = 1 / (1 - zero);
|
||
|
const float k2 = 1 - pole;
|
||
|
|
||
|
// Member variables to locals.
|
||
|
float lastX = m_lastX;
|
||
|
float lastY = m_lastY;
|
||
|
|
||
|
for (int i = 0; i < framesToProcess; ++i) {
|
||
|
float input = source[i];
|
||
|
|
||
|
// Zero
|
||
|
float output1 = k1 * (input - zero * lastX);
|
||
|
lastX = input;
|
||
|
|
||
|
// Pole
|
||
|
float output2 = k2 * output1 + pole * lastY;
|
||
|
lastY = output2;
|
||
|
|
||
|
destination[i] = output2;
|
||
|
}
|
||
|
|
||
|
// Locals to member variables. Flush denormals here so we don't
|
||
|
// slow down the inner loop above.
|
||
|
if (lastX == 0.0f && lastY != 0.0f && fabsf(lastY) < FLT_MIN) {
|
||
|
// Flush future values to zero (until there is new input).
|
||
|
lastY = 0.0;
|
||
|
// Flush calculated values.
|
||
|
for (int i = framesToProcess; i-- && fabsf(destination[i]) < FLT_MIN; ) {
|
||
|
destination[i] = 0.0f;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
m_lastX = lastX;
|
||
|
m_lastY = lastY;
|
||
|
}
|
||
|
|
||
|
} // namespace WebCore
|