tomwalters@268: // Copyright 2006-2010, Thomas Walters
tomwalters@268: //
tomwalters@268: // AIM-C: A C++ implementation of the Auditory Image Model
tomwalters@268: // http://www.acousticscale.org/AIMC
tomwalters@268: //
tomwalters@318: // Licensed under the Apache License, Version 2.0 (the "License");
tomwalters@318: // you may not use this file except in compliance with the License.
tomwalters@318: // You may obtain a copy of the License at
tomwalters@268: //
tomwalters@318: //     http://www.apache.org/licenses/LICENSE-2.0
tomwalters@268: //
tomwalters@318: // Unless required by applicable law or agreed to in writing, software
tomwalters@318: // distributed under the License is distributed on an "AS IS" BASIS,
tomwalters@318: // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
tomwalters@318: // See the License for the specific language governing permissions and
tomwalters@318: // limitations under the License.
tomwalters@268: 
tomwalters@268: /*! \file
tomwalters@277:  *  \brief ERB calculations
tomwalters@268:  */
tomwalters@268: 
tomwalters@268: /*! \author: Thomas Walters <tom@acousticscale.org>
tomwalters@268:  *  \date 2010/01/23
tomwalters@296:  *  \version \$Id$
tomwalters@268:  */
tomwalters@268: 
tomwalters@283: #ifndef AIMC_SUPPORT_ERBTOOLS_H_
tomwalters@283: #define AIMC_SUPPORT_ERBTOOLS_H_
tomwalters@268: 
tomwalters@287: #include <cmath>
tomwalters@268: 
tomwalters@268: namespace aimc {
tomwalters@268: class ERBTools {
tomwalters@268:  public:
tomwalters@268:   static float Freq2ERB(float freq) {
tomwalters@268:     return 21.4f * log10(4.37f * freq / 1000.0f + 1.0f);
tomwalters@268:   }
tomwalters@268: 
tomwalters@268:   static float Freq2ERBw(float freq) {
tomwalters@268:     return 24.7f * (4.37f * freq / 1000.0f + 1.0f);
tomwalters@268:   }
tomwalters@277: 
tomwalters@277:   static float ERB2Freq(float erb) {
tomwalters@277:     return (pow(10, (erb / 21.4f)) - 1.0f) / 4.37f * 1000.0f;
tomwalters@277:   }
tomwalters@268: };
tomwalters@268: }
tomwalters@268: 
tomwalters@283: #endif  // AIMC_SUPPORT_ERBTOOLS_H_