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/*
* 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.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE 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 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.
*/
#ifndef AudioBus_h
#define AudioBus_h
#include "AudioChannel.h"
#include <wtf/Noncopyable.h>
#include <wtf/PassOwnPtr.h>
#include <wtf/Vector.h>
namespace WebCore {
// An AudioBus represents a collection of one or more AudioChannels.
// The data layout is "planar" as opposed to "interleaved".
// An AudioBus with one channel is mono, an AudioBus with two channels is stereo, etc.
class AudioBus {
WTF_MAKE_NONCOPYABLE(AudioBus);
public:
enum {
ChannelLeft = 0,
ChannelRight = 1,
ChannelCenter = 2, // center and mono are the same
ChannelMono = 2,
ChannelLFE = 3,
ChannelSurroundLeft = 4,
ChannelSurroundRight = 5,
};
enum {
LayoutCanonical = 0
// Can define non-standard layouts here
};
// allocate indicates whether or not to initially have the AudioChannels created with managed storage.
// Normal usage is to pass true here, in which case the AudioChannels will memory-manage their own storage.
// If allocate is false then setChannelMemory() has to be called later on for each channel before the AudioBus is useable...
AudioBus(unsigned numberOfChannels, size_t length, bool allocate = true);
// Tells the given channel to use an externally allocated buffer.
void setChannelMemory(unsigned channelIndex, float* storage, size_t length);
// Channels
unsigned numberOfChannels() const { return m_channels.size(); }
AudioChannel* channel(unsigned channel) { return m_channels[channel].get(); }
const AudioChannel* channel(unsigned channel) const { return const_cast<AudioBus*>(this)->m_channels[channel].get(); }
AudioChannel* channelByType(unsigned type);
// Number of sample-frames
size_t length() const { return m_length; }
// Sample-rate : 0.0 if unknown or "don't care"
double sampleRate() const { return m_sampleRate; }
void setSampleRate(double sampleRate) { m_sampleRate = sampleRate; }
// Zeroes all channels.
void zero();
// Returns true if the channel count and frame-size match.
bool topologyMatches(const AudioBus &sourceBus) const;
// Creates a new buffer from a range in the source buffer.
// 0 may be returned if the range does not fit in the sourceBuffer
static PassOwnPtr<AudioBus> createBufferFromRange(AudioBus* sourceBuffer, unsigned startFrame, unsigned endFrame);
// Scales all samples by the same amount.
void scale(double scale);
// Master gain for this bus - used with sumWithGainFrom() below
void setGain(double gain) { m_busGain = gain; }
double gain() { return m_busGain; }
void reset() { m_isFirstTime = true; } // for de-zippering
// Assuming sourceBus has the same topology, copies sample data from each channel of sourceBus to our corresponding channel.
void copyFrom(const AudioBus &sourceBus);
// Sums the sourceBus into our bus with unity gain.
// Our own internal gain m_busGain is ignored.
void sumFrom(const AudioBus &sourceBus);
// Copy or sum each channel from sourceBus into our corresponding channel.
// We scale by targetGain (and our own internal gain m_busGain), performing "de-zippering" to smoothly change from *lastMixGain to (targetGain*m_busGain).
// The caller is responsible for setting up lastMixGain to point to storage which is unique for every "stream" which will be summed to this bus.
// This represents the dezippering memory.
void copyWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain);
void sumWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain);
// Returns maximum absolute value across all channels (useful for normalization).
float maxAbsValue() const;
// Makes maximum absolute value == 1.0 (if possible).
void normalize();
static PassOwnPtr<AudioBus> loadPlatformResource(const char* name, double sampleRate);
protected:
AudioBus() { };
void processWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain, bool sumToBus);
void processWithGainFromMonoStereo(const AudioBus &sourceBus, double* lastMixGain, double targetGain, bool sumToBus);
size_t m_length;
Vector<OwnPtr<AudioChannel> > m_channels;
int m_layout;
double m_busGain;
bool m_isFirstTime;
double m_sampleRate; // 0.0 if unknown or N/A
};
} // WebCore
#endif // AudioBus_h
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