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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 #include "config.h"
     26 
     27 #if ENABLE(WEB_AUDIO)
     28 
     29 #include "modules/webaudio/AudioBasicProcessorNode.h"
     30 
     31 #include "platform/audio/AudioBus.h"
     32 #include "platform/audio/AudioProcessor.h"
     33 #include "modules/webaudio/AudioContext.h"
     34 #include "modules/webaudio/AudioNodeInput.h"
     35 #include "modules/webaudio/AudioNodeOutput.h"
     36 
     37 namespace blink {
     38 
     39 AudioBasicProcessorNode::AudioBasicProcessorNode(AudioContext* context, float sampleRate)
     40     : AudioNode(context, sampleRate)
     41 {
     42     addInput();
     43     addOutput(AudioNodeOutput::create(this, 1));
     44 
     45     // The subclass must create m_processor.
     46 }
     47 
     48 AudioBasicProcessorNode::~AudioBasicProcessorNode()
     49 {
     50     ASSERT(!isInitialized());
     51 }
     52 
     53 void AudioBasicProcessorNode::trace(Visitor* visitor)
     54 {
     55     visitor->trace(m_processor);
     56     AudioNode::trace(visitor);
     57 }
     58 
     59 void AudioBasicProcessorNode::dispose()
     60 {
     61     uninitialize();
     62     AudioNode::dispose();
     63 }
     64 
     65 void AudioBasicProcessorNode::initialize()
     66 {
     67     if (isInitialized())
     68         return;
     69 
     70     ASSERT(processor());
     71     processor()->initialize();
     72 
     73     AudioNode::initialize();
     74 }
     75 
     76 void AudioBasicProcessorNode::uninitialize()
     77 {
     78     if (!isInitialized())
     79         return;
     80 
     81     ASSERT(processor());
     82     processor()->uninitialize();
     83 
     84     AudioNode::uninitialize();
     85 }
     86 
     87 void AudioBasicProcessorNode::process(size_t framesToProcess)
     88 {
     89     AudioBus* destinationBus = output(0)->bus();
     90 
     91     if (!isInitialized() || !processor() || processor()->numberOfChannels() != numberOfChannels())
     92         destinationBus->zero();
     93     else {
     94         AudioBus* sourceBus = input(0)->bus();
     95 
     96         // FIXME: if we take "tail time" into account, then we can avoid calling processor()->process() once the tail dies down.
     97         if (!input(0)->isConnected())
     98             sourceBus->zero();
     99 
    100         processor()->process(sourceBus, destinationBus, framesToProcess);
    101     }
    102 }
    103 
    104 // Nice optimization in the very common case allowing for "in-place" processing
    105 void AudioBasicProcessorNode::pullInputs(size_t framesToProcess)
    106 {
    107     // Render input stream - suggest to the input to render directly into output bus for in-place processing in process() if possible.
    108     input(0)->pull(output(0)->bus(), framesToProcess);
    109 }
    110 
    111 // As soon as we know the channel count of our input, we can lazily initialize.
    112 // Sometimes this may be called more than once with different channel counts, in which case we must safely
    113 // uninitialize and then re-initialize with the new channel count.
    114 void AudioBasicProcessorNode::checkNumberOfChannelsForInput(AudioNodeInput* input)
    115 {
    116     ASSERT(context()->isAudioThread() && context()->isGraphOwner());
    117 
    118     ASSERT(input == this->input(0));
    119     if (input != this->input(0))
    120         return;
    121 
    122     ASSERT(processor());
    123     if (!processor())
    124         return;
    125 
    126     unsigned numberOfChannels = input->numberOfChannels();
    127 
    128     if (isInitialized() && numberOfChannels != output(0)->numberOfChannels()) {
    129         // We're already initialized but the channel count has changed.
    130         uninitialize();
    131     }
    132 
    133     if (!isInitialized()) {
    134         // This will propagate the channel count to any nodes connected further down the chain...
    135         output(0)->setNumberOfChannels(numberOfChannels);
    136 
    137         // Re-initialize the processor with the new channel count.
    138         processor()->setNumberOfChannels(numberOfChannels);
    139         initialize();
    140     }
    141 
    142     AudioNode::checkNumberOfChannelsForInput(input);
    143 }
    144 
    145 unsigned AudioBasicProcessorNode::numberOfChannels()
    146 {
    147     return output(0)->numberOfChannels();
    148 }
    149 
    150 double AudioBasicProcessorNode::tailTime() const
    151 {
    152     return m_processor->tailTime();
    153 }
    154 
    155 double AudioBasicProcessorNode::latencyTime() const
    156 {
    157     return m_processor->latencyTime();
    158 }
    159 
    160 } // namespace blink
    161 
    162 #endif // ENABLE(WEB_AUDIO)
    163