1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/media/webaudio/blink/HRTFPanner.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,115 @@
1.4 +/*
1.5 + * Copyright (C) 2010, Google Inc. All rights reserved.
1.6 + *
1.7 + * Redistribution and use in source and binary forms, with or without
1.8 + * modification, are permitted provided that the following conditions
1.9 + * are met:
1.10 + * 1. Redistributions of source code must retain the above copyright
1.11 + * notice, this list of conditions and the following disclaimer.
1.12 + * 2. Redistributions in binary form must reproduce the above copyright
1.13 + * notice, this list of conditions and the following disclaimer in the
1.14 + * documentation and/or other materials provided with the distribution.
1.15 + *
1.16 + * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
1.17 + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
1.18 + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
1.19 + * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
1.20 + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
1.21 + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
1.22 + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
1.23 + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.24 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
1.25 + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.26 + */
1.27 +
1.28 +#ifndef HRTFPanner_h
1.29 +#define HRTFPanner_h
1.30 +
1.31 +#include "FFTConvolver.h"
1.32 +#include "DelayBuffer.h"
1.33 +#include "mozilla/MemoryReporting.h"
1.34 +
1.35 +namespace mozilla {
1.36 +struct AudioChunk;
1.37 +}
1.38 +
1.39 +namespace WebCore {
1.40 +
1.41 +class HRTFDatabaseLoader;
1.42 +
1.43 +using mozilla::AudioChunk;
1.44 +
1.45 +class HRTFPanner {
1.46 +public:
1.47 + HRTFPanner(float sampleRate, mozilla::TemporaryRef<HRTFDatabaseLoader> databaseLoader);
1.48 + ~HRTFPanner();
1.49 +
1.50 + // chunk durations must be 128
1.51 + void pan(double azimuth, double elevation, const AudioChunk* inputBus, AudioChunk* outputBus);
1.52 + void reset();
1.53 +
1.54 + size_t fftSize() const { return m_convolverL1.fftSize(); }
1.55 +
1.56 + float sampleRate() const { return m_sampleRate; }
1.57 +
1.58 + int maxTailFrames() const;
1.59 +
1.60 + size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
1.61 +
1.62 +private:
1.63 + // Given an azimuth angle in the range -180 -> +180, returns the corresponding azimuth index for the database,
1.64 + // and azimuthBlend which is an interpolation value from 0 -> 1.
1.65 + int calculateDesiredAzimuthIndexAndBlend(double azimuth, double& azimuthBlend);
1.66 +
1.67 + mozilla::RefPtr<HRTFDatabaseLoader> m_databaseLoader;
1.68 +
1.69 + float m_sampleRate;
1.70 +
1.71 + // We maintain two sets of convolvers for smooth cross-faded interpolations when
1.72 + // then azimuth and elevation are dynamically changing.
1.73 + // When the azimuth and elevation are not changing, we simply process with one of the two sets.
1.74 + // Initially we use CrossfadeSelection1 corresponding to m_convolverL1 and m_convolverR1.
1.75 + // Whenever the azimuth or elevation changes, a crossfade is initiated to transition
1.76 + // to the new position. So if we're currently processing with CrossfadeSelection1, then
1.77 + // we transition to CrossfadeSelection2 (and vice versa).
1.78 + // If we're in the middle of a transition, then we wait until it is complete before
1.79 + // initiating a new transition.
1.80 +
1.81 + // Selects either the convolver set (m_convolverL1, m_convolverR1) or (m_convolverL2, m_convolverR2).
1.82 + enum CrossfadeSelection {
1.83 + CrossfadeSelection1,
1.84 + CrossfadeSelection2
1.85 + };
1.86 +
1.87 + CrossfadeSelection m_crossfadeSelection;
1.88 +
1.89 + // azimuth/elevation for CrossfadeSelection1.
1.90 + int m_azimuthIndex1;
1.91 + double m_elevation1;
1.92 +
1.93 + // azimuth/elevation for CrossfadeSelection2.
1.94 + int m_azimuthIndex2;
1.95 + double m_elevation2;
1.96 +
1.97 + // A crossfade value 0 <= m_crossfadeX <= 1.
1.98 + float m_crossfadeX;
1.99 +
1.100 + // Per-sample-frame crossfade value increment.
1.101 + float m_crossfadeIncr;
1.102 +
1.103 + FFTConvolver m_convolverL1;
1.104 + FFTConvolver m_convolverR1;
1.105 + FFTConvolver m_convolverL2;
1.106 + FFTConvolver m_convolverR2;
1.107 +
1.108 + mozilla::DelayBuffer m_delayLine;
1.109 +
1.110 + AudioFloatArray m_tempL1;
1.111 + AudioFloatArray m_tempR1;
1.112 + AudioFloatArray m_tempL2;
1.113 + AudioFloatArray m_tempR2;
1.114 +};
1.115 +
1.116 +} // namespace WebCore
1.117 +
1.118 +#endif // HRTFPanner_h
