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comparison: content/media/webaudio/blink/HRTFElevation.cpp

content/media/webaudio/blink/HRTFElevation.cpp

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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 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "HRTFElevation.h"
30
31 #include "speex/speex_resampler.h"
32 #include "mozilla/PodOperations.h"
33 #include "AudioSampleFormat.h"
34
35 #include "IRC_Composite_C_R0195-incl.cpp"
36
37 using namespace std;
38 using namespace mozilla;
39
40 namespace WebCore {
41
42 const int elevationSpacing = irc_composite_c_r0195_elevation_interval;
43 const int firstElevation = irc_composite_c_r0195_first_elevation;
44 const int numberOfElevations = MOZ_ARRAY_LENGTH(irc_composite_c_r0195);
45
46 const unsigned HRTFElevation::NumberOfTotalAzimuths = 360 / 15 * 8;
47
48 const int rawSampleRate = irc_composite_c_r0195_sample_rate;
49
50 // Number of frames in an individual impulse response.
51 const size_t ResponseFrameSize = 256;
52
53 size_t HRTFElevation::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
54 {
55 size_t amount = aMallocSizeOf(this);
56
57 amount += m_kernelListL.SizeOfExcludingThis(aMallocSizeOf);
58 for (size_t i = 0; i < m_kernelListL.Length(); i++) {
59 amount += m_kernelListL[i]->sizeOfIncludingThis(aMallocSizeOf);
60 }
61
62 return amount;
63 }
64
65 size_t HRTFElevation::fftSizeForSampleRate(float sampleRate)
66 {
67 // The IRCAM HRTF impulse responses were 512 sample-frames @44.1KHz,
68 // but these have been truncated to 256 samples.
69 // An FFT-size of twice impulse response size is used (for convolution).
70 // So for sample rates of 44.1KHz an FFT size of 512 is good.
71 // We double the FFT-size only for sample rates at least double this.
72 // If the FFT size is too large then the impulse response will be padded
73 // with zeros without the fade-out provided by HRTFKernel.
74 MOZ_ASSERT(sampleRate > 1.0 && sampleRate < 1048576.0);
75
76 // This is the size if we were to use all raw response samples.
77 unsigned resampledLength =
78 floorf(ResponseFrameSize * sampleRate / rawSampleRate);
79 // Keep things semi-sane, with max FFT size of 1024 and minimum of 4.
80 // "size |= 3" ensures a minimum of 4 (with the size++ below) and sets the
81 // 2 least significant bits for rounding up to the next power of 2 below.
82 unsigned size = min(resampledLength, 1023U);
83 size |= 3;
84 // Round up to the next power of 2, making the FFT size no more than twice
85 // the impulse response length. This doubles size for values that are
86 // already powers of 2. This works by filling in 7 bits to right of the
87 // most significant bit. The most significant bit is no greater than
88 // 1 << 9, and the least significant 2 bits were already set above.
89 size |= (size >> 1);
90 size |= (size >> 2);
91 size |= (size >> 4);
92 size++;
93 MOZ_ASSERT((size & (size - 1)) == 0);
94
95 return size;
96 }
97
98 nsReturnRef<HRTFKernel> HRTFElevation::calculateKernelForAzimuthElevation(int azimuth, int elevation, SpeexResamplerState* resampler, float sampleRate)
99 {
100 int elevationIndex = (elevation - firstElevation) / elevationSpacing;
101 MOZ_ASSERT(elevationIndex >= 0 && elevationIndex <= numberOfElevations);
102
103 int numberOfAzimuths = irc_composite_c_r0195[elevationIndex].count;
104 int azimuthSpacing = 360 / numberOfAzimuths;
105 MOZ_ASSERT(numberOfAzimuths * azimuthSpacing == 360);
106
107 int azimuthIndex = azimuth / azimuthSpacing;
108 MOZ_ASSERT(azimuthIndex * azimuthSpacing == azimuth);
109
110 const int16_t (&impulse_response_data)[ResponseFrameSize] =
111 irc_composite_c_r0195[elevationIndex].azimuths[azimuthIndex];
112
113 // When libspeex_resampler is compiled with FIXED_POINT, samples in
114 // speex_resampler_process_float are rounded directly to int16_t, which
115 // only works well if the floats are in the range +/-32767. On such
116 // platforms it's better to resample before converting to float anyway.
117 #ifdef MOZ_SAMPLE_TYPE_S16
118 # define RESAMPLER_PROCESS speex_resampler_process_int
119 const int16_t* response = impulse_response_data;
120 const int16_t* resampledResponse;
121 #else
122 # define RESAMPLER_PROCESS speex_resampler_process_float
123 float response[ResponseFrameSize];
124 ConvertAudioSamples(impulse_response_data, response, ResponseFrameSize);
125 float* resampledResponse;
126 #endif
127
128 // Note that depending on the fftSize returned by the panner, we may be truncating the impulse response.
129 const size_t resampledResponseLength = fftSizeForSampleRate(sampleRate) / 2;
130
131 nsAutoTArray<AudioDataValue, 2 * ResponseFrameSize> resampled;
132 if (sampleRate == rawSampleRate) {
133 resampledResponse = response;
134 MOZ_ASSERT(resampledResponseLength == ResponseFrameSize);
135 } else {
136 resampled.SetLength(resampledResponseLength);
137 resampledResponse = resampled.Elements();
138 speex_resampler_skip_zeros(resampler);
139
140 // Feed the input buffer into the resampler.
141 spx_uint32_t in_len = ResponseFrameSize;
142 spx_uint32_t out_len = resampled.Length();
143 RESAMPLER_PROCESS(resampler, 0, response, &in_len,
144 resampled.Elements(), &out_len);
145
146 if (out_len < resampled.Length()) {
147 // The input should have all been processed.
148 MOZ_ASSERT(in_len == ResponseFrameSize);
149 // Feed in zeros get the data remaining in the resampler.
150 spx_uint32_t out_index = out_len;
151 in_len = speex_resampler_get_input_latency(resampler);
152 out_len = resampled.Length() - out_index;
153 RESAMPLER_PROCESS(resampler, 0, nullptr, &in_len,
154 resampled.Elements() + out_index, &out_len);
155 out_index += out_len;
156 // There may be some uninitialized samples remaining for very low
157 // sample rates.
158 PodZero(resampled.Elements() + out_index,
159 resampled.Length() - out_index);
160 }
161
162 speex_resampler_reset_mem(resampler);
163 }
164
165 #ifdef MOZ_SAMPLE_TYPE_S16
166 nsAutoTArray<float, 2 * ResponseFrameSize> floatArray;
167 floatArray.SetLength(resampledResponseLength);
168 float *floatResponse = floatArray.Elements();
169 ConvertAudioSamples(resampledResponse,
170 floatResponse, resampledResponseLength);
171 #else
172 float *floatResponse = resampledResponse;
173 #endif
174 #undef RESAMPLER_PROCESS
175
176 return HRTFKernel::create(floatResponse, resampledResponseLength, sampleRate);
177 }
178
179 // The range of elevations for the IRCAM impulse responses varies depending on azimuth, but the minimum elevation appears to always be -45.
180 //
181 // Here's how it goes:
182 static int maxElevations[] = {
183 // Azimuth
184 //
185 90, // 0
186 45, // 15
187 60, // 30
188 45, // 45
189 75, // 60
190 45, // 75
191 60, // 90
192 45, // 105
193 75, // 120
194 45, // 135
195 60, // 150
196 45, // 165
197 75, // 180
198 45, // 195
199 60, // 210
200 45, // 225
201 75, // 240
202 45, // 255
203 60, // 270
204 45, // 285
205 75, // 300
206 45, // 315
207 60, // 330
208 45 // 345
209 };
210
211 nsReturnRef<HRTFElevation> HRTFElevation::createBuiltin(int elevation, float sampleRate)
212 {
213 if (elevation < firstElevation ||
214 elevation > firstElevation + numberOfElevations * elevationSpacing ||
215 (elevation / elevationSpacing) * elevationSpacing != elevation)
216 return nsReturnRef<HRTFElevation>();
217
218 // Spacing, in degrees, between every azimuth loaded from resource.
219 // Some elevations do not have data for all these intervals.
220 // See maxElevations.
221 static const unsigned AzimuthSpacing = 15;
222 static const unsigned NumberOfRawAzimuths = 360 / AzimuthSpacing;
223 static_assert(AzimuthSpacing * NumberOfRawAzimuths == 360,
224 "Not a multiple");
225 static const unsigned InterpolationFactor =
226 NumberOfTotalAzimuths / NumberOfRawAzimuths;
227 static_assert(NumberOfTotalAzimuths ==
228 NumberOfRawAzimuths * InterpolationFactor, "Not a multiple");
229
230 HRTFKernelList kernelListL;
231 kernelListL.SetLength(NumberOfTotalAzimuths);
232
233 SpeexResamplerState* resampler = sampleRate == rawSampleRate ? nullptr :
234 speex_resampler_init(1, rawSampleRate, sampleRate,
235 SPEEX_RESAMPLER_QUALITY_DEFAULT, nullptr);
236
237 // Load convolution kernels from HRTF files.
238 int interpolatedIndex = 0;
239 for (unsigned rawIndex = 0; rawIndex < NumberOfRawAzimuths; ++rawIndex) {
240 // Don't let elevation exceed maximum for this azimuth.
241 int maxElevation = maxElevations[rawIndex];
242 int actualElevation = min(elevation, maxElevation);
243
244 kernelListL[interpolatedIndex] = calculateKernelForAzimuthElevation(rawIndex * AzimuthSpacing, actualElevation, resampler, sampleRate);
245
246 interpolatedIndex += InterpolationFactor;
247 }
248
249 if (resampler)
250 speex_resampler_destroy(resampler);
251
252 // Now go back and interpolate intermediate azimuth values.
253 for (unsigned i = 0; i < NumberOfTotalAzimuths; i += InterpolationFactor) {
254 int j = (i + InterpolationFactor) % NumberOfTotalAzimuths;
255
256 // Create the interpolated convolution kernels and delays.
257 for (unsigned jj = 1; jj < InterpolationFactor; ++jj) {
258 float x = float(jj) / float(InterpolationFactor); // interpolate from 0 -> 1
259
260 kernelListL[i + jj] = HRTFKernel::createInterpolatedKernel(kernelListL[i], kernelListL[j], x);
261 }
262 }
263
264 return nsReturnRef<HRTFElevation>(new HRTFElevation(&kernelListL, elevation, sampleRate));
265 }
266
267 nsReturnRef<HRTFElevation> HRTFElevation::createByInterpolatingSlices(HRTFElevation* hrtfElevation1, HRTFElevation* hrtfElevation2, float x, float sampleRate)
268 {
269 MOZ_ASSERT(hrtfElevation1 && hrtfElevation2);
270 if (!hrtfElevation1 || !hrtfElevation2)
271 return nsReturnRef<HRTFElevation>();
272
273 MOZ_ASSERT(x >= 0.0 && x < 1.0);
274
275 HRTFKernelList kernelListL;
276 kernelListL.SetLength(NumberOfTotalAzimuths);
277
278 const HRTFKernelList& kernelListL1 = hrtfElevation1->kernelListL();
279 const HRTFKernelList& kernelListL2 = hrtfElevation2->kernelListL();
280
281 // Interpolate kernels of corresponding azimuths of the two elevations.
282 for (unsigned i = 0; i < NumberOfTotalAzimuths; ++i) {
283 kernelListL[i] = HRTFKernel::createInterpolatedKernel(kernelListL1[i], kernelListL2[i], x);
284 }
285
286 // Interpolate elevation angle.
287 double angle = (1.0 - x) * hrtfElevation1->elevationAngle() + x * hrtfElevation2->elevationAngle();
288
289 return nsReturnRef<HRTFElevation>(new HRTFElevation(&kernelListL, static_cast<int>(angle), sampleRate));
290 }
291
292 void HRTFElevation::getKernelsFromAzimuth(double azimuthBlend, unsigned azimuthIndex, HRTFKernel* &kernelL, HRTFKernel* &kernelR, double& frameDelayL, double& frameDelayR)
293 {
294 bool checkAzimuthBlend = azimuthBlend >= 0.0 && azimuthBlend < 1.0;
295 MOZ_ASSERT(checkAzimuthBlend);
296 if (!checkAzimuthBlend)
297 azimuthBlend = 0.0;
298
299 unsigned numKernels = m_kernelListL.Length();
300
301 bool isIndexGood = azimuthIndex < numKernels;
302 MOZ_ASSERT(isIndexGood);
303 if (!isIndexGood) {
304 kernelL = 0;
305 kernelR = 0;
306 return;
307 }
308
309 // Return the left and right kernels,
310 // using symmetry to produce the right kernel.
311 kernelL = m_kernelListL[azimuthIndex];
312 int azimuthIndexR = (numKernels - azimuthIndex) % numKernels;
313 kernelR = m_kernelListL[azimuthIndexR];
314
315 frameDelayL = kernelL->frameDelay();
316 frameDelayR = kernelR->frameDelay();
317
318 int azimuthIndex2L = (azimuthIndex + 1) % numKernels;
319 double frameDelay2L = m_kernelListL[azimuthIndex2L]->frameDelay();
320 int azimuthIndex2R = (numKernels - azimuthIndex2L) % numKernels;
321 double frameDelay2R = m_kernelListL[azimuthIndex2R]->frameDelay();
322
323 // Linearly interpolate delays.
324 frameDelayL = (1.0 - azimuthBlend) * frameDelayL + azimuthBlend * frameDelay2L;
325 frameDelayR = (1.0 - azimuthBlend) * frameDelayR + azimuthBlend * frameDelay2R;
326 }
327
328 } // namespace WebCore

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