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      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 AudioNode_h
     26 #define AudioNode_h
     27 
     28 #include "modules/EventTargetModules.h"
     29 #include "platform/audio/AudioBus.h"
     30 #include "wtf/Forward.h"
     31 #include "wtf/OwnPtr.h"
     32 #include "wtf/PassOwnPtr.h"
     33 #include "wtf/RefPtr.h"
     34 #include "wtf/Vector.h"
     35 
     36 #define DEBUG_AUDIONODE_REFERENCES 0
     37 
     38 namespace blink {
     39 
     40 class AudioContext;
     41 class AudioNodeInput;
     42 class AudioNodeOutput;
     43 class AudioParam;
     44 class ExceptionState;
     45 
     46 // An AudioNode is the basic building block for handling audio within an AudioContext.
     47 // It may be an audio source, an intermediate processing module, or an audio destination.
     48 // Each AudioNode can have inputs and/or outputs. An AudioSourceNode has no inputs and a single output.
     49 // An AudioDestinationNode has one input and no outputs and represents the final destination to the audio hardware.
     50 // Most processing nodes such as filters will have one input and one output, although multiple inputs and outputs are possible.
     51 
     52 class AudioNode : public RefCountedGarbageCollectedWillBeGarbageCollectedFinalized<AudioNode>, public EventTargetWithInlineData {
     53     DEFINE_EVENT_TARGET_REFCOUNTING_WILL_BE_REMOVED(RefCountedGarbageCollected<AudioNode>);
     54     DEFINE_WRAPPERTYPEINFO();
     55     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(AudioNode);
     56 public:
     57     enum { ProcessingSizeInFrames = 128 };
     58 
     59     AudioNode(AudioContext*, float sampleRate);
     60     virtual ~AudioNode();
     61     // dispose() is called just before the destructor. This must be called in
     62     // the main thread, and while the graph lock is held.
     63     virtual void dispose();
     64     static unsigned instanceCount() { return s_instanceCount; }
     65 
     66     AudioContext* context() { return m_context.get(); }
     67     const AudioContext* context() const { return m_context.get(); }
     68 
     69     enum NodeType {
     70         NodeTypeUnknown,
     71         NodeTypeDestination,
     72         NodeTypeOscillator,
     73         NodeTypeAudioBufferSource,
     74         NodeTypeMediaElementAudioSource,
     75         NodeTypeMediaStreamAudioDestination,
     76         NodeTypeMediaStreamAudioSource,
     77         NodeTypeJavaScript,
     78         NodeTypeBiquadFilter,
     79         NodeTypePanner,
     80         NodeTypeConvolver,
     81         NodeTypeDelay,
     82         NodeTypeGain,
     83         NodeTypeChannelSplitter,
     84         NodeTypeChannelMerger,
     85         NodeTypeAnalyser,
     86         NodeTypeDynamicsCompressor,
     87         NodeTypeWaveShaper,
     88         NodeTypeEnd
     89     };
     90 
     91     enum ChannelCountMode {
     92         Max,
     93         ClampedMax,
     94         Explicit
     95     };
     96 
     97     NodeType nodeType() const { return m_nodeType; }
     98     String nodeTypeName() const;
     99     void setNodeType(NodeType);
    100 
    101     // This object has been connected to another object. This might have
    102     // existing connections from others.
    103     // This function must be called after acquiring a connection reference.
    104     void makeConnection();
    105     // This object will be disconnected from another object. This might have
    106     // remaining connections from others.
    107     // This function must be called before releasing a connection reference.
    108     void breakConnection();
    109 
    110     // Can be called from main thread or context's audio thread.  It must be called while the context's graph lock is held.
    111     void breakConnectionWithLock();
    112 
    113     // The AudioNodeInput(s) (if any) will already have their input data available when process() is called.
    114     // Subclasses will take this input data and put the results in the AudioBus(s) of its AudioNodeOutput(s) (if any).
    115     // Called from context's audio thread.
    116     virtual void process(size_t framesToProcess) = 0;
    117 
    118     // No significant resources should be allocated until initialize() is called.
    119     // Processing may not occur until a node is initialized.
    120     virtual void initialize();
    121     virtual void uninitialize();
    122 
    123     bool isInitialized() const { return m_isInitialized; }
    124 
    125     unsigned numberOfInputs() const { return m_inputs.size(); }
    126     unsigned numberOfOutputs() const { return m_outputs.size(); }
    127 
    128     AudioNodeInput* input(unsigned);
    129     AudioNodeOutput* output(unsigned);
    130 
    131     // Called from main thread by corresponding JavaScript methods.
    132     virtual void connect(AudioNode*, unsigned outputIndex, unsigned inputIndex, ExceptionState&);
    133     void connect(AudioParam*, unsigned outputIndex, ExceptionState&);
    134     virtual void disconnect(unsigned outputIndex, ExceptionState&);
    135 
    136     virtual float sampleRate() const { return m_sampleRate; }
    137 
    138     // processIfNecessary() is called by our output(s) when the rendering graph needs this AudioNode to process.
    139     // This method ensures that the AudioNode will only process once per rendering time quantum even if it's called repeatedly.
    140     // This handles the case of "fanout" where an output is connected to multiple AudioNode inputs.
    141     // Called from context's audio thread.
    142     void processIfNecessary(size_t framesToProcess);
    143 
    144     // Called when a new connection has been made to one of our inputs or the connection number of channels has changed.
    145     // This potentially gives us enough information to perform a lazy initialization or, if necessary, a re-initialization.
    146     // Called from main thread.
    147     virtual void checkNumberOfChannelsForInput(AudioNodeInput*);
    148 
    149 #if DEBUG_AUDIONODE_REFERENCES
    150     static void printNodeCounts();
    151 #endif
    152 
    153     // tailTime() is the length of time (not counting latency time) where non-zero output may occur after continuous silent input.
    154     virtual double tailTime() const = 0;
    155     // latencyTime() is the length of time it takes for non-zero output to appear after non-zero input is provided. This only applies to
    156     // processing delay which is an artifact of the processing algorithm chosen and is *not* part of the intrinsic desired effect. For
    157     // example, a "delay" effect is expected to delay the signal, and thus would not be considered latency.
    158     virtual double latencyTime() const = 0;
    159 
    160     // propagatesSilence() should return true if the node will generate silent output when given silent input. By default, AudioNode
    161     // will take tailTime() and latencyTime() into account when determining whether the node will propagate silence.
    162     virtual bool propagatesSilence() const;
    163     bool inputsAreSilent();
    164     void silenceOutputs();
    165     void unsilenceOutputs();
    166 
    167     void enableOutputsIfNecessary();
    168     void disableOutputsIfNecessary();
    169 
    170     unsigned long channelCount();
    171     virtual void setChannelCount(unsigned long, ExceptionState&);
    172 
    173     String channelCountMode();
    174     void setChannelCountMode(const String&, ExceptionState&);
    175 
    176     String channelInterpretation();
    177     void setChannelInterpretation(const String&, ExceptionState&);
    178 
    179     ChannelCountMode internalChannelCountMode() const { return m_channelCountMode; }
    180     AudioBus::ChannelInterpretation internalChannelInterpretation() const { return m_channelInterpretation; }
    181 
    182     // EventTarget
    183     virtual const AtomicString& interfaceName() const OVERRIDE FINAL;
    184     virtual ExecutionContext* executionContext() const OVERRIDE FINAL;
    185 
    186     void updateChannelCountMode();
    187 
    188     virtual void trace(Visitor*) OVERRIDE;
    189 
    190 protected:
    191     // Inputs and outputs must be created before the AudioNode is initialized.
    192     void addInput();
    193     void addOutput(AudioNodeOutput*);
    194 
    195     // Called by processIfNecessary() to cause all parts of the rendering graph connected to us to process.
    196     // Each rendering quantum, the audio data for each of the AudioNode's inputs will be available after this method is called.
    197     // Called from context's audio thread.
    198     virtual void pullInputs(size_t framesToProcess);
    199 
    200     // Force all inputs to take any channel interpretation changes into account.
    201     void updateChannelsForInputs();
    202 
    203 private:
    204     volatile bool m_isInitialized;
    205     NodeType m_nodeType;
    206     Member<AudioContext> m_context;
    207     float m_sampleRate;
    208     HeapVector<Member<AudioNodeInput> > m_inputs;
    209     HeapVector<Member<AudioNodeOutput> > m_outputs;
    210 
    211     double m_lastProcessingTime;
    212     double m_lastNonSilentTime;
    213 
    214     volatile int m_connectionRefCount;
    215 
    216     bool m_isDisabled;
    217 
    218 #if DEBUG_AUDIONODE_REFERENCES
    219     static bool s_isNodeCountInitialized;
    220     static int s_nodeCount[NodeTypeEnd];
    221 #endif
    222     static unsigned s_instanceCount;
    223 
    224     // The new channel count mode that will be used to set the actual mode in the pre or post
    225     // rendering phase.
    226     ChannelCountMode m_newChannelCountMode;
    227 protected:
    228     unsigned m_channelCount;
    229     ChannelCountMode m_channelCountMode;
    230     AudioBus::ChannelInterpretation m_channelInterpretation;
    231 };
    232 
    233 } // namespace blink
    234 
    235 #endif // AudioNode_h
    236