1 /* 2 * Copyright (C) 2010, Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY 17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23 */ 24 25 #ifndef AudioResampler_h 26 #define AudioResampler_h 27 28 #include "AudioBus.h" 29 #include "AudioResamplerKernel.h" 30 #include "AudioSourceProvider.h" 31 #include <wtf/OwnPtr.h> 32 #include <wtf/Vector.h> 33 34 namespace WebCore { 35 36 // AudioResampler resamples the audio stream from an AudioSourceProvider. 37 // The audio stream may be single or multi-channel. 38 // The default constructor defaults to single-channel (mono). 39 40 class AudioResampler { 41 public: 42 AudioResampler(); 43 AudioResampler(unsigned numberOfChannels); ~AudioResampler()44 ~AudioResampler() { } 45 46 // Given an AudioSourceProvider, process() resamples the source stream into destinationBus. 47 void process(AudioSourceProvider*, AudioBus* destinationBus, size_t framesToProcess); 48 49 // Resets the processing state. 50 void reset(); 51 52 void configureChannels(unsigned numberOfChannels); 53 54 // 0 < rate <= MaxRate 55 void setRate(double rate); rate()56 double rate() const { return m_rate; } 57 58 static const double MaxRate; 59 60 private: 61 double m_rate; 62 Vector<OwnPtr<AudioResamplerKernel> > m_kernels; 63 OwnPtr<AudioBus> m_sourceBus; 64 }; 65 66 } // namespace WebCore 67 68 #endif // AudioResampler_h 69