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 *
8 * 1.  Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 * 2.  Redistributions in binary form must reproduce the above copyright
11 *     notice, this list of conditions and the following disclaimer in the
12 *     documentation and/or other materials provided with the distribution.
13 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 *     its contributors may be used to endorse or promote products derived
15 *     from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef AudioBus_h
30#define AudioBus_h
31
32#include "platform/audio/AudioChannel.h"
33#include "wtf/Noncopyable.h"
34#include "wtf/PassOwnPtr.h"
35#include "wtf/ThreadSafeRefCounted.h"
36#include "wtf/Vector.h"
37
38namespace blink {
39
40// An AudioBus represents a collection of one or more AudioChannels.
41// The data layout is "planar" as opposed to "interleaved".
42// An AudioBus with one channel is mono, an AudioBus with two channels is stereo, etc.
43class PLATFORM_EXPORT AudioBus : public ThreadSafeRefCounted<AudioBus> {
44    WTF_MAKE_NONCOPYABLE(AudioBus);
45public:
46    enum {
47        ChannelLeft = 0,
48        ChannelRight = 1,
49        ChannelCenter = 2, // center and mono are the same
50        ChannelMono = 2,
51        ChannelLFE = 3,
52        ChannelSurroundLeft = 4,
53        ChannelSurroundRight = 5,
54    };
55
56    enum {
57        LayoutCanonical = 0
58        // Can define non-standard layouts here
59    };
60
61    enum ChannelInterpretation {
62        Speakers,
63        Discrete,
64    };
65
66    // allocate indicates whether or not to initially have the AudioChannels created with managed storage.
67    // Normal usage is to pass true here, in which case the AudioChannels will memory-manage their own storage.
68    // If allocate is false then setChannelMemory() has to be called later on for each channel before the AudioBus is useable...
69    static PassRefPtr<AudioBus> create(unsigned numberOfChannels, size_t length, bool allocate = true);
70
71    // Tells the given channel to use an externally allocated buffer.
72    void setChannelMemory(unsigned channelIndex, float* storage, size_t length);
73
74    // Channels
75    unsigned numberOfChannels() const { return m_channels.size(); }
76
77    AudioChannel* channel(unsigned channel) { return m_channels[channel].get(); }
78    const AudioChannel* channel(unsigned channel) const { return const_cast<AudioBus*>(this)->m_channels[channel].get(); }
79    AudioChannel* channelByType(unsigned type);
80    const AudioChannel* channelByType(unsigned type) const;
81
82    // Number of sample-frames
83    size_t length() const { return m_length; }
84
85    // resizeSmaller() can only be called with a new length <= the current length.
86    // The data stored in the bus will remain undisturbed.
87    void resizeSmaller(size_t newLength);
88
89    // Sample-rate : 0.0 if unknown or "don't care"
90    float sampleRate() const { return m_sampleRate; }
91    void setSampleRate(float sampleRate) { m_sampleRate = sampleRate; }
92
93    // Zeroes all channels.
94    void zero();
95
96    // Clears the silent flag on all channels.
97    void clearSilentFlag();
98
99    // Returns true if the silent bit is set on all channels.
100    bool isSilent() const;
101
102    // Returns true if the channel count and frame-size match.
103    bool topologyMatches(const AudioBus &sourceBus) const;
104
105    // Creates a new buffer from a range in the source buffer.
106    // 0 may be returned if the range does not fit in the sourceBuffer
107    static PassRefPtr<AudioBus> createBufferFromRange(const AudioBus* sourceBuffer, unsigned startFrame, unsigned endFrame);
108
109
110    // Creates a new AudioBus by sample-rate converting sourceBus to the newSampleRate.
111    // setSampleRate() must have been previously called on sourceBus.
112    // Note: sample-rate conversion is already handled in the file-reading code for the mac port, so we don't need this.
113    static PassRefPtr<AudioBus> createBySampleRateConverting(const AudioBus* sourceBus, bool mixToMono, double newSampleRate);
114
115    // Creates a new AudioBus by mixing all the channels down to mono.
116    // If sourceBus is already mono, then the returned AudioBus will simply be a copy.
117    static PassRefPtr<AudioBus> createByMixingToMono(const AudioBus* sourceBus);
118
119    // Scales all samples by the same amount.
120    void scale(float scale);
121
122    void reset() { m_isFirstTime = true; } // for de-zippering
123
124    // Copies the samples from the source bus to this one.
125    // This is just a simple per-channel copy if the number of channels match, otherwise an up-mix or down-mix is done.
126    void copyFrom(const AudioBus& sourceBus, ChannelInterpretation = Speakers);
127
128    // Sums the samples from the source bus to this one.
129    // This is just a simple per-channel summing if the number of channels match, otherwise an up-mix or down-mix is done.
130    void sumFrom(const AudioBus& sourceBus, ChannelInterpretation = Speakers);
131
132    // Copy each channel from sourceBus into our corresponding channel.
133    // We scale by targetGain (and our own internal gain m_busGain), performing "de-zippering" to smoothly change from *lastMixGain to (targetGain*m_busGain).
134    // The caller is responsible for setting up lastMixGain to point to storage which is unique for every "stream" which will be applied to this bus.
135    // This represents the dezippering memory.
136    void copyWithGainFrom(const AudioBus &sourceBus, float* lastMixGain, float targetGain);
137
138    // Copies the sourceBus by scaling with sample-accurate gain values.
139    void copyWithSampleAccurateGainValuesFrom(const AudioBus &sourceBus, float* gainValues, unsigned numberOfGainValues);
140
141    // Returns maximum absolute value across all channels (useful for normalization).
142    float maxAbsValue() const;
143
144    // Makes maximum absolute value == 1.0 (if possible).
145    void normalize();
146
147    static PassRefPtr<AudioBus> loadPlatformResource(const char* name, float sampleRate);
148
149protected:
150    AudioBus() { };
151
152    AudioBus(unsigned numberOfChannels, size_t length, bool allocate);
153
154    void speakersCopyFrom(const AudioBus&);
155    void discreteCopyFrom(const AudioBus&);
156    void speakersSumFrom(const AudioBus&);
157    void discreteSumFrom(const AudioBus&);
158    void speakersSumFrom5_1_ToMono(const AudioBus&);
159
160    size_t m_length;
161    Vector<OwnPtr<AudioChannel> > m_channels;
162    int m_layout;
163    float m_busGain;
164    OwnPtr<AudioFloatArray> m_dezipperGainValues;
165    bool m_isFirstTime;
166    float m_sampleRate; // 0.0 if unknown or N/A
167};
168
169} // namespace blink
170
171#endif // AudioBus_h
172