annotate src/Support/ERBTools.h @ 611:0fbaf443ec82

Carfac C++ revision 3, indluding more style improvements. The output structs are now classes again, and have separate storage methods for each output structure along with flags in the Run and RunSegment methods to allow for only storing NAPs if desired.

// Copyright 2006-2010, Thomas Walters
//
// AIM-C: A C++ implementation of the Auditory Image Model
// http://www.acousticscale.org/AIMC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/*! \file
 *  \brief ERB calculations
 */

/*! \author: Thomas Walters <[e-mail]>
 *  \date 2010/01/23
 *  \version \$Id$
 */

#ifndef AIMC_SUPPORT_ERBTOOLS_H_
#define AIMC_SUPPORT_ERBTOOLS_H_

#include <cmath>

namespace aimc {
class ERBTools {
 public:
  static float Freq2ERB(float freq) {
    return 21.4f * log10(4.37f * freq / 1000.0f + 1.0f);
  }

  static float Freq2ERBw(float freq) {
    return 24.7f * (4.37f * freq / 1000.0f + 1.0f);
  }

  static float ERB2Freq(float erb) {
    return (pow(10, (erb / 21.4f)) - 1.0f) / 4.37f * 1000.0f;
  }
};
}

#endif  // AIMC_SUPPORT_ERBTOOLS_H_