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 /*

  * Copyright (C) 2010 Google Inc. All rights reserved.

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  *     from this software without specific prior written permission.

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 #include "HRTFElevation.h"

 #include "speex/speex_resampler.h"

 #include "mozilla/PodOperations.h"

 #include "AudioSampleFormat.h"

 #include "IRC_Composite_C_R0195-incl.cpp"

 using namespace std;

 using namespace mozilla;

 namespace WebCore {

 const int elevationSpacing = irc_composite_c_r0195_elevation_interval;

 const int firstElevation = irc_composite_c_r0195_first_elevation;

 const int numberOfElevations = MOZ_ARRAY_LENGTH(irc_composite_c_r0195);

 const unsigned HRTFElevation::NumberOfTotalAzimuths = 360 / 15 * 8;

 const int rawSampleRate = irc_composite_c_r0195_sample_rate;

 // Number of frames in an individual impulse response.

 const size_t ResponseFrameSize = 256;

 size_t HRTFElevation::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const

 {

     size_t amount = aMallocSizeOf(this);

     amount += m_kernelListL.SizeOfExcludingThis(aMallocSizeOf);

     for (size_t i = 0; i < m_kernelListL.Length(); i++) {

         amount += m_kernelListL[i]->sizeOfIncludingThis(aMallocSizeOf);

     }

     return amount;

 }

 size_t HRTFElevation::fftSizeForSampleRate(float sampleRate)

 {

     // The IRCAM HRTF impulse responses were 512 sample-frames @44.1KHz,

     // but these have been truncated to 256 samples.

     // An FFT-size of twice impulse response size is used (for convolution).

     // So for sample rates of 44.1KHz an FFT size of 512 is good.

     // We double the FFT-size only for sample rates at least double this.

     // If the FFT size is too large then the impulse response will be padded

     // with zeros without the fade-out provided by HRTFKernel.

     MOZ_ASSERT(sampleRate > 1.0 && sampleRate < 1048576.0);

     // This is the size if we were to use all raw response samples.

     unsigned resampledLength =

         floorf(ResponseFrameSize * sampleRate / rawSampleRate);

     // Keep things semi-sane, with max FFT size of 1024 and minimum of 4.

     // "size |= 3" ensures a minimum of 4 (with the size++ below) and sets the

     // 2 least significant bits for rounding up to the next power of 2 below.

     unsigned size = min(resampledLength, 1023U);

     size |= 3;

     // Round up to the next power of 2, making the FFT size no more than twice

     // the impulse response length.  This doubles size for values that are

     // already powers of 2.  This works by filling in 7 bits to right of the

     // most significant bit.  The most significant bit is no greater than

     // 1 << 9, and the least significant 2 bits were already set above.

     size |= (size >> 1);

     size |= (size >> 2);

     size |= (size >> 4);

     size++;

     MOZ_ASSERT((size & (size - 1)) == 0);

     return size;

 }

 nsReturnRef<HRTFKernel> HRTFElevation::calculateKernelForAzimuthElevation(int azimuth, int elevation, SpeexResamplerState* resampler, float sampleRate)

 {

     int elevationIndex = (elevation - firstElevation) / elevationSpacing;

     MOZ_ASSERT(elevationIndex >= 0 && elevationIndex <= numberOfElevations);

     int numberOfAzimuths = irc_composite_c_r0195[elevationIndex].count;

     int azimuthSpacing = 360 / numberOfAzimuths;

     MOZ_ASSERT(numberOfAzimuths * azimuthSpacing == 360);

     int azimuthIndex = azimuth / azimuthSpacing;

     MOZ_ASSERT(azimuthIndex * azimuthSpacing == azimuth);

     const int16_t (&impulse_response_data)[ResponseFrameSize] =

         irc_composite_c_r0195[elevationIndex].azimuths[azimuthIndex];

     // When libspeex_resampler is compiled with FIXED_POINT, samples in

     // speex_resampler_process_float are rounded directly to int16_t, which

     // only works well if the floats are in the range +/-32767.  On such

     // platforms it's better to resample before converting to float anyway.

 #ifdef MOZ_SAMPLE_TYPE_S16

 #  define RESAMPLER_PROCESS speex_resampler_process_int

     const int16_t* response = impulse_response_data;

     const int16_t* resampledResponse;

 #else

 #  define RESAMPLER_PROCESS speex_resampler_process_float

     float response[ResponseFrameSize];

     ConvertAudioSamples(impulse_response_data, response, ResponseFrameSize);

     float* resampledResponse;

 #endif

     // Note that depending on the fftSize returned by the panner, we may be truncating the impulse response.

     const size_t resampledResponseLength = fftSizeForSampleRate(sampleRate) / 2;

     nsAutoTArray<AudioDataValue, 2 * ResponseFrameSize> resampled;

     if (sampleRate == rawSampleRate) {

         resampledResponse = response;

         MOZ_ASSERT(resampledResponseLength == ResponseFrameSize);

     } else {

         resampled.SetLength(resampledResponseLength);

         resampledResponse = resampled.Elements();

         speex_resampler_skip_zeros(resampler);

         // Feed the input buffer into the resampler.

         spx_uint32_t in_len = ResponseFrameSize;

         spx_uint32_t out_len = resampled.Length();

         RESAMPLER_PROCESS(resampler, 0, response, &in_len,

                           resampled.Elements(), &out_len);

         if (out_len < resampled.Length()) {

             // The input should have all been processed.

             MOZ_ASSERT(in_len == ResponseFrameSize);

             // Feed in zeros get the data remaining in the resampler.

             spx_uint32_t out_index = out_len;

             in_len = speex_resampler_get_input_latency(resampler);

             out_len = resampled.Length() - out_index;

             RESAMPLER_PROCESS(resampler, 0, nullptr, &in_len,

                               resampled.Elements() + out_index, &out_len);

             out_index += out_len;

             // There may be some uninitialized samples remaining for very low

             // sample rates.

             PodZero(resampled.Elements() + out_index,

                     resampled.Length() - out_index);

         }

         speex_resampler_reset_mem(resampler);

     }

 #ifdef MOZ_SAMPLE_TYPE_S16

     nsAutoTArray<float, 2 * ResponseFrameSize> floatArray;

     floatArray.SetLength(resampledResponseLength);

     float *floatResponse = floatArray.Elements();

     ConvertAudioSamples(resampledResponse,

                         floatResponse, resampledResponseLength);

 #else

     float *floatResponse = resampledResponse;

 #endif

 #undef RESAMPLER_PROCESS

     return HRTFKernel::create(floatResponse, resampledResponseLength, sampleRate);

 }

 // The range of elevations for the IRCAM impulse responses varies depending on azimuth, but the minimum elevation appears to always be -45.

 //

 // Here's how it goes:

 static int maxElevations[] = {

         //  Azimuth

         //

     90, // 0  

     45, // 15 

     60, // 30 

     45, // 45 

     75, // 60 

     45, // 75 

     60, // 90 

     45, // 105 

     75, // 120 

     45, // 135 

     60, // 150 

     45, // 165 

     75, // 180 

     45, // 195 

     60, // 210 

     45, // 225 

     75, // 240 

     45, // 255 

     60, // 270 

     45, // 285 

     75, // 300 

     45, // 315 

     60, // 330 

     45 //  345 

 };

 nsReturnRef<HRTFElevation> HRTFElevation::createBuiltin(int elevation, float sampleRate)

 {

     if (elevation < firstElevation ||

         elevation > firstElevation + numberOfElevations * elevationSpacing ||

         (elevation / elevationSpacing) * elevationSpacing != elevation)

         return nsReturnRef<HRTFElevation>();

     // Spacing, in degrees, between every azimuth loaded from resource.

     // Some elevations do not have data for all these intervals.

     // See maxElevations.

     static const unsigned AzimuthSpacing = 15;

     static const unsigned NumberOfRawAzimuths = 360 / AzimuthSpacing;

     static_assert(AzimuthSpacing * NumberOfRawAzimuths == 360,

                   "Not a multiple");

     static const unsigned InterpolationFactor =

         NumberOfTotalAzimuths / NumberOfRawAzimuths;

     static_assert(NumberOfTotalAzimuths ==

                   NumberOfRawAzimuths * InterpolationFactor, "Not a multiple");

     HRTFKernelList kernelListL;

     kernelListL.SetLength(NumberOfTotalAzimuths);

     SpeexResamplerState* resampler = sampleRate == rawSampleRate ? nullptr :

         speex_resampler_init(1, rawSampleRate, sampleRate,

                              SPEEX_RESAMPLER_QUALITY_DEFAULT, nullptr);

     // Load convolution kernels from HRTF files.

     int interpolatedIndex = 0;

     for (unsigned rawIndex = 0; rawIndex < NumberOfRawAzimuths; ++rawIndex) {

         // Don't let elevation exceed maximum for this azimuth.

         int maxElevation = maxElevations[rawIndex];

         int actualElevation = min(elevation, maxElevation);

         kernelListL[interpolatedIndex] = calculateKernelForAzimuthElevation(rawIndex * AzimuthSpacing, actualElevation, resampler, sampleRate);

         interpolatedIndex += InterpolationFactor;

     }

     if (resampler)

         speex_resampler_destroy(resampler);

     // Now go back and interpolate intermediate azimuth values.

     for (unsigned i = 0; i < NumberOfTotalAzimuths; i += InterpolationFactor) {

         int j = (i + InterpolationFactor) % NumberOfTotalAzimuths;

         // Create the interpolated convolution kernels and delays.

         for (unsigned jj = 1; jj < InterpolationFactor; ++jj) {

             float x = float(jj) / float(InterpolationFactor); // interpolate from 0 -> 1

             kernelListL[i + jj] = HRTFKernel::createInterpolatedKernel(kernelListL[i], kernelListL[j], x);

         }

     }

     return nsReturnRef<HRTFElevation>(new HRTFElevation(&kernelListL, elevation, sampleRate));

 }

 nsReturnRef<HRTFElevation> HRTFElevation::createByInterpolatingSlices(HRTFElevation* hrtfElevation1, HRTFElevation* hrtfElevation2, float x, float sampleRate)

 {

     MOZ_ASSERT(hrtfElevation1 && hrtfElevation2);

     if (!hrtfElevation1 || !hrtfElevation2)

         return nsReturnRef<HRTFElevation>();

     MOZ_ASSERT(x >= 0.0 && x < 1.0);

     HRTFKernelList kernelListL;

     kernelListL.SetLength(NumberOfTotalAzimuths);

     const HRTFKernelList& kernelListL1 = hrtfElevation1->kernelListL();

     const HRTFKernelList& kernelListL2 = hrtfElevation2->kernelListL();

     // Interpolate kernels of corresponding azimuths of the two elevations.

     for (unsigned i = 0; i < NumberOfTotalAzimuths; ++i) {

         kernelListL[i] = HRTFKernel::createInterpolatedKernel(kernelListL1[i], kernelListL2[i], x);

     }

     // Interpolate elevation angle.

     double angle = (1.0 - x) * hrtfElevation1->elevationAngle() + x * hrtfElevation2->elevationAngle();

     return nsReturnRef<HRTFElevation>(new HRTFElevation(&kernelListL, static_cast<int>(angle), sampleRate));

 }

 void HRTFElevation::getKernelsFromAzimuth(double azimuthBlend, unsigned azimuthIndex, HRTFKernel* &kernelL, HRTFKernel* &kernelR, double& frameDelayL, double& frameDelayR)

 {

     bool checkAzimuthBlend = azimuthBlend >= 0.0 && azimuthBlend < 1.0;

     MOZ_ASSERT(checkAzimuthBlend);

     if (!checkAzimuthBlend)

         azimuthBlend = 0.0;

     unsigned numKernels = m_kernelListL.Length();

     bool isIndexGood = azimuthIndex < numKernels;

     MOZ_ASSERT(isIndexGood);

     if (!isIndexGood) {

         kernelL = 0;

         kernelR = 0;

         return;

     }

     // Return the left and right kernels,

     // using symmetry to produce the right kernel.

     kernelL = m_kernelListL[azimuthIndex];

     int azimuthIndexR = (numKernels - azimuthIndex) % numKernels;

     kernelR = m_kernelListL[azimuthIndexR];

     frameDelayL = kernelL->frameDelay();

     frameDelayR = kernelR->frameDelay();

     int azimuthIndex2L = (azimuthIndex + 1) % numKernels;

     double frameDelay2L = m_kernelListL[azimuthIndex2L]->frameDelay();

     int azimuthIndex2R = (numKernels - azimuthIndex2L) % numKernels;

     double frameDelay2R = m_kernelListL[azimuthIndex2R]->frameDelay();

     // Linearly interpolate delays.

     frameDelayL = (1.0 - azimuthBlend) * frameDelayL + azimuthBlend * frameDelay2L;

     frameDelayR = (1.0 - azimuthBlend) * frameDelayR + azimuthBlend * frameDelay2R;

 }

 } // namespace WebCore