1 /*
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15  *     from this software without specific prior written permission.
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28 
29 #ifndef ReverbConvolverStage_h
30 #define ReverbConvolverStage_h
31 
32 #include "AudioArray.h"
33 #include "FFTFrame.h"
34 #include <wtf/OwnPtr.h>
35 
36 namespace WebCore {
37 
38 class ReverbAccumulationBuffer;
39 class ReverbConvolver;
40 class FFTConvolver;
41 
42 // A ReverbConvolverStage represents the convolution associated with a sub-section of a large impulse response.
43 // It incorporates a delay line to account for the offset of the sub-section within the larger impulse response.
44 class ReverbConvolverStage {
45 public:
46     // renderPhase is useful to know so that we can manipulate the pre versus post delay so that stages will perform
47     // their heavy work (FFT processing) on different slices to balance the load in a real-time thread.
48     ReverbConvolverStage(float* impulseResponse, size_t responseLength, size_t reverbTotalLatency, size_t stageOffset, size_t stageLength,
49                          size_t fftSize, size_t renderPhase, size_t renderSliceSize, ReverbAccumulationBuffer* accumulationBuffer);
50 
51     // WARNING: framesToProcess must be such that it evenly divides the delay buffer size (stage_offset).
52     void process(float* source, size_t framesToProcess);
53 
54     void processInBackground(ReverbConvolver* convolver, size_t framesToProcess);
55 
56     void reset();
57 
58     // Useful for background processing
inputReadIndex()59     int inputReadIndex() const { return m_inputReadIndex; }
60 
61 private:
62     FFTFrame m_fftKernel;
63     OwnPtr<FFTConvolver> m_convolver;
64 
65     AudioFloatArray m_preDelayBuffer;
66 
67     ReverbAccumulationBuffer* m_accumulationBuffer;
68     int m_accumulationReadIndex;
69     int m_inputReadIndex;
70 
71     size_t m_preDelayLength;
72     size_t m_postDelayLength;
73     size_t m_preReadWriteIndex;
74     size_t m_framesProcessed;
75 
76     AudioFloatArray m_temporaryBuffer;
77 
78     size_t m_impulseResponseLength;
79 };
80 
81 } // namespace WebCore
82 
83 #endif // ReverbConvolverStage_h
84