XDSP 包絡概觀

#define ROUND_UP_TO_16BYTE_ALIGNED(x) (((x) + (15)) & ~(0xF))

// XDspActivationParameters::impulseResponseLengthInFloats is the impulse response length of each channel in case of stereo IR
uint32_t irLengthInComplexes = XDspActivationParameters::impulseResponseLengthInFloats/2;  
uint32_t numFilterBlocks = irLengthInComplexes/XDspActivationParameters::blockFrameCount;

// Round up the envelope size to the nearest multiple of 16 bytes. Additional values resulting from the rounding will be ignored.
// envelopeGainCount represents the number of gain values an envelope buffer holds. In case of a stereo impulse response filter,
// this is the number of gain values per channel.
uint32_t envelopeLengthInBytes = ROUND_UP_TO_16BYTE_ALIGNED(numFilterBlocks * sizeof(float));
uint32_t envelopeGainCount = envelopeSize / sizeof(float)  

// Account for left and right channel envelopes in case of stereo impulse response
if (stereoImpulseRespone)
{
    envelopeLengthInBytes = envelopeLengthInBytes * 2;
}

XDspSubmitCommand(...)/XDspSubmitCommandWithEnvelope(.., nullptr, ...);  // _envelopeState = Off;  
XDspSubmitCommand(...)/XDspSubmitCommandWithEnvelope(.., nullptr, ...);  // _envelopeState = Off;  
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XDspSubmitCommandWithEnvelope(..., envelopeBuffer1, ...); // _envelopeState = Engaged with envelopeBuffer1  
XDspSubmitCommandWithEnvelope(..., envelopeBuffer1, ...); // _envelopeState = Engaged with envelopeBuffer1  
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XDspSubmitCommandWithEnvelope(..., envelopeBuffer2, ...); // _envelopeState = Engaged with envelopeBuffer2  
XDspSubmitCommandWithEnvelope(..., envelopeBuffer2, ...); // _envelopeState = Engaged with envelopeBuffer2  
::::::::::::::::::::::  
XDspSubmitCommand(...)/XDspSubmitCommandWithEnvelope(.., nullptr, ...);  // _envelopeState = Off;  
XDspSubmitCommand(...)/XDspSubmitCommandWithEnvelope(.., nullptr, ...);  // _envelopeState = Off;  
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