HRTF panner should handle the case of no loaded HRTF database

third_party/WebKit/Source/platform/audio/HRTFPanner.cpp

 /*
  * Copyright (C) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 99 matching lines @@
     double desiredAzimuthIndexFloat = azimuth / angleBetweenAzimuths;
     int desiredAzimuthIndex = static_cast<int>(desiredAzimuthIndexFloat);
     azimuthBlend = desiredAzimuthIndexFloat - static_cast<double>(desiredAzimuthIndex);
 
     // We don't immediately start using this azimuth index, but instead approach this index from the last index we rendered at.
     // This minimizes the clicks and graininess for moving sources which occur otherwise.
     desiredAzimuthIndex = clampTo(desiredAzimuthIndex, 0, numberOfAzimuths - 1);
     return desiredAzimuthIndex;
 }
 
-void HRTFPanner::pan(double desiredAzimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
+void HRTFPanner::pan(double desiredAzimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation channelInterpretation)
 {
     unsigned numInputChannels = inputBus ? inputBus->numberOfChannels() : 0;
 
     bool isInputGood = inputBus &&  numInputChannels >= 1 && numInputChannels <= 2;
     ASSERT(isInputGood);
 
     bool isOutputGood = outputBus && outputBus->numberOfChannels() == 2 && framesToProcess <= outputBus->length();
     ASSERT(isOutputGood);
 
     if (!isInputGood || !isOutputGood) {
         if (outputBus)
             outputBus->zero();
         return;
     }
 
     HRTFDatabase* database = m_databaseLoader->database();
-    ASSERT(database);
     if (!database) {
-        outputBus->zero();
+        outputBus->copyFrom(*inputBus, channelInterpretation);
         return;
     }
 
     // IRCAM HRTF azimuths values from the loaded database is reversed from the panner's notion of azimuth.
     double azimuth = -desiredAzimuth;
 
     bool isAzimuthGood = azimuth >= -180.0 && azimuth <= 180.0;
     ASSERT(isAzimuthGood);
     if (!isAzimuthGood) {
         outputBus->zero();
@@ skipping 135 matching lines @@
             } else if (m_crossfadeIncr < 0 && fabs(m_crossfadeX) < -m_crossfadeIncr) {
                 // We've fully made the crossfade transition from 2 -> 1.
                 m_crossfadeSelection = CrossfadeSelection1;
                 m_crossfadeX = 0;
                 m_crossfadeIncr = 0;
             }
         }
     }
 }
 
-void HRTFPanner::panWithSampleAccurateValues(double* desiredAzimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
+void HRTFPanner::panWithSampleAccurateValues(double* desiredAzimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation channelInterpretation)
 {
     // Sample-accurate (a-rate) HRTF panner is not implemented, just k-rate.  Just grab the current
     // azimuth/elevation and use that.
     //
     // We are assuming that the inherent smoothing in the HRTF processing is good enough, and we
     // don't want to increase the complexity of the HRTF panner by 15-20 times.  (We need to cmopute
     // one output sample for each possibly different impulse response.  That N^2.  Previously, we
     // used an FFT to do them all at once for a complexity of N/log2(N).  Hence, N/log2(N) times
     // more complex.)
-    pan(desiredAzimuth[0], elevation[0], inputBus, outputBus, framesToProcess);
+    pan(desiredAzimuth[0], elevation[0], inputBus, outputBus, framesToProcess, channelInterpretation);
 }
 
 double HRTFPanner::tailTime() const
 {
     // Because HRTFPanner is implemented with a DelayKernel and a FFTConvolver, the tailTime of the HRTFPanner
     // is the sum of the tailTime of the DelayKernel and the tailTime of the FFTConvolver, which is MaxDelayTimeSeconds
     // and fftSize() / 2, respectively.
     return MaxDelayTimeSeconds + (fftSize() / 2) / static_cast<double>(sampleRate());
 }
 
 double HRTFPanner::latencyTime() const
 {
     // The latency of a FFTConvolver is also fftSize() / 2, and is in addition to its tailTime of the
     // same value.
     return (fftSize() / 2) / static_cast<double>(sampleRate());
 }
 
 } // namespace blink