/* * Copyright (C) 2010, 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. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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 "config.h" #if ENABLE(WEB_AUDIO) #include "platform/audio/AudioUtilities.h" #include "wtf/Assertions.h" #include "wtf/MathExtras.h" namespace WebCore { namespace AudioUtilities { float decibelsToLinear(float decibels) { return powf(10, 0.05f * decibels); } float linearToDecibels(float linear) { // It's not possible to calculate decibels for a zero linear value since it would be -Inf. // -1000.0 dB represents a very tiny linear value in case we ever reach this case. ASSERT(linear); if (!linear) return -1000; return 20 * log10f(linear); } double discreteTimeConstantForSampleRate(double timeConstant, double sampleRate) { return 1 - exp(-1 / (sampleRate * timeConstant)); } size_t timeToSampleFrame(double time, double sampleRate) { return static_cast<size_t>(round(time * sampleRate)); } } // AudioUtilites } // WebCore #endif // ENABLE(WEB_AUDIO)