diff src/Modules/SAI/ModuleSAI.cc @ 0:582cbe817f2c

- Initial add of support code and modules. Not everything is working yet.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Modules/SAI/ModuleSAI.cc	Fri Feb 12 12:31:23 2010 +0000
@@ -0,0 +1,261 @@
+// Copyright 2006-2010, Thomas Walters
+//
+// AIM-C: A C++ implementation of the Auditory Image Model
+// http://www.acousticscale.org/AIMC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+/*! \file
+ *  \brief SAI module
+ */
+
+/*
+ * \author Thomas Walters <[e-mail]>
+ * \date created 2007/08/29
+ * \version \$Id: ModuleSAI.cc 4 2010-02-03 18:44:58Z tcw $
+ */
+#include <math.h>
+
+#include "Modules/SAI/ModuleSAI.h"
+
+ModuleSAI::ModuleSAI(Parameters *parameters) : Module(parameters) {
+  module_description_ = "Stabilised auditory image";
+  module_name_ = "sai2007";
+  module_type_ = "sai";
+  module_id_ = "$Id: ModuleSAI.cc 4 2010-02-03 18:44:58Z tcw $";
+
+  min_delay_ms_ = parameters_->DefaultFloat("sai.min_delay_ms", 0.0f);
+  max_delay_ms_ = parameters_->DefaultFloat("sai.max_delay_ms", 35.0f);
+  strobe_weight_alpha_ = parameters_->DefaultFloat("sai.strobe_weight_alpha",
+                                                   0.5f);
+  buffer_memory_decay_ = parameters_->DefaultFloat("sai.buffer_memory_decay",
+                                                   0.03f);
+  frame_period_ms_ = parameters_->DefaultFloat("sai.frame_period_ms", 20.0f);
+
+  min_strobe_delay_index_ = 0;
+  max_strobe_delay_index_ = 0;
+  sai_decay_factor_ = 0.0f;
+  max_concurrent_strobes_ = 0;
+  output_frame_period_ms_ = 0.0f;
+  last_output_frame_time_ms_ = 0.0f;
+}
+
+bool ModuleSAI::InitializeInternal(const SignalBank &input) {
+  // The SAI output bank must be as long as the SAI's Maximum delay.
+  // One sample is added to the SAI buffer length to account for the
+  // zero-lag point
+  int sai_buffer_length = 1 + Round(input.sample_rate() * max_delay_ms_);
+
+  // Make an output SignalBank with the same number of channels and centre
+  // frequencies as the input, but with a different buffer length
+  if (!output_.Initialize(input.channel_count(),
+                          sai_buffer_length,
+                          input.sample_rate());) {
+    LOG_ERROR("Failed to create output buffer in SAI module");
+    return false;
+  }
+  for (int i = 0; i < input.channel_count(); ++i ) {
+    output_.set_centre_frequency(i, input.get_centre_frequency(i));
+  }
+
+  // sai_temp_ will be initialized to zero
+  if (!sai_temp_.Initialize(output_)) {
+    LOG_ERROR("Failed to create temporary buffer in SAI module");
+    return false;
+  }
+
+  last_output_time_ms_ = 0.0f;
+
+  frame_period_samples_ = Round(input.sample_rate()
+                                * frame_period_ms_ / 1000.0f);
+
+  min_strobe_delay_idx_ = Round(input.sample_rate() * min_delay_ms_ / 1000.0f);
+  max_strobe_delay_idx_ = Round(input.sample_rate() * max_delay_ms_ / 1000.0f);
+
+  // Make sure we don't go past the output buffer's upper bound
+  if (max_strobe_delay_idx_ > output_.buffer_length()))
+    max_strobe_delay_idx_ = output_.buffer_length();
+
+  // Define decay factor from time since last sample (see ti2003)
+  sai_decay_factor_ = pow(0.5f, 1.0f / (buffer_memory_decay_
+                                        * input.sample_rate()));
+
+  // Maximum strobes that can be active at the same time within maxdelay.
+  //! \todo Choose this value in a more principled way
+  max_concurrent_strobes_ = Round(1000.0f * max_delay_ * 5);
+
+  // Precompute strobe weights
+  strobe_weights_.resize(max_concurrent_strobes_);
+  for (int n = 0; n < max_concurrent_strobes_; ++n) {
+    strobe_weights_[n] = pow(1.0f / (n + 1)), strobe_weight_alpha_);
+  }
+
+  // Active Strobes
+  active_strobes_.Resize(input.channel_count());
+  for (int i = 0; i < input.channel_count(); ++i) {
+    active_strobes_[i].Create(max_concurrent_strobes_);
+  }
+  next_strobes_.resize(input.channel_count(), 0);
+
+  return true;
+}
+
+void ModuleSAI::Reset() {
+}
+
+void ModuleSAI::Process(const SignalBank &input) {
+  int s;
+  int c;
+  int output_buffer_length = output_.buffer_length();
+
+  // Reset the next strobe times
+  next_strobes_.clear();
+  next_strobes_.resize(output_.channel_count(), 0);
+
+  // Offset the times on the strobes from the previous buffer
+  for (c = 0; c < input.channel_count(), ++c) {
+    active_strobes_[c].shiftStrobes(input.buffer_length());
+  }
+
+  // Make sure only start time is transferred to the output
+  output_.set_start_time(input.start_time());
+
+  // Loop over samples to make the SAI
+  for (s = 0; s < input_buffer_length; ++s) {
+    float decay_factor = pow(sai_decay_factor_, fire_counter_);
+    // Loop over channels
+    for (c = 0; c < input.channel_count(); ++c) {
+      // Local convenience variables
+      StrobeList &active_strobes = active_strobes_[c];
+      float centre_frequency = input.get_centre_frequency(c);
+      int next_strobe = next_strobes_[c];
+
+      // 1. Update strobes
+      // If we are up to or beyond the next strobe...
+      if (next_strobe < input.strobe_count(c)) {
+        if (s == pSigIn->getStrobe(iNextStrobe)) {
+          //A new strobe has arrived
+          // if there aren't already too many strobes active...
+          if ((active_strobes.getStrobeCount() + 1) < max_concurrent_strobes_) {
+            // ...add the active strobe to the list of current strobes
+            // calculate the strobe weight
+            float weight = 1.0f;
+            if (active_strobes.getStrobeCount() > 0) {
+              int last_strobe = active_strobes.getTime(
+                active_strobes.getStrobeCount());
+
+              // If the strobe occured within 10 impulse-response
+              // cycles of the previous strobe, then lower its weight
+              weight = (s - iLastStrobe) / input.sample_rate()
+                       * centre_frequency / 10.0f;
+              if (weight > 1.0f)
+                weight = 1.0f;
+            }
+            pActiveStrobes->addStrobe(iCurrentSample, weight);
+            iNextStrobe++;
+          } else {
+            // We have a problem
+            aimASSERT(0);
+          }
+
+          // 2. Having updated the strobes, we now need to update the
+          // strobe weights
+          float total_strobe_weight = 0.0f;
+          for (int si = 1; si <= pActiveStrobes->getStrobeCount(); ++si) {
+            total_strobe_weight += (pActiveStrobes->getWeight(si) 
+              * m_pStrobeWeights[pActiveStrobes->getStrobeCount() - si]);
+          }
+          for (int si = 1; si <= pActiveStrobes->getStrobeCount(); ++si) {
+            active_strobes.setWorkingWeight(si,(active_strobes.getWeight(si)
+              * strobe_weights_[active_strobes.getStrobeCount() - si])
+                / total_strobe_weight);
+          }
+        }
+      }
+
+      // remove inactive strobes...
+      while (pActiveStrobes->getStrobeCount() > 0) {
+        // Get the time of the first strobe (ordering of strobes is
+        // from one, not zero)
+        int iStrobeTime = pActiveStrobes->getTime(1);
+        int iDelay = iCurrentSample - iStrobeTime;
+        // ... do we now need to remove this strobe?
+        if (iDelay > m_maxStrobeDelayIdx)
+          pActiveStrobes->deleteFirstStrobe();
+        else
+          break;
+          // Since the strobes are ordered, we don't need to go
+          // beyond the first still-active strobe
+      }
+
+      // 3. Loop over active strobes
+      for (int si = 1; si <= pActiveStrobes->getStrobeCount(); si++) {
+        // 3.1 Add effect of active strobe at correct place in the SAI buffer
+        // Calculate the time from the strobe event to 'now': iDelay
+        int iStrobeTime = pActiveStrobes->getTime(si);
+        int iDelay = iCurrentSample - iStrobeTime;
+
+        // If the delay is greater than the (user-set)
+        // minimum strobe delay, the strobe can be used
+        if (iDelay >= m_minStrobeDelayIdx && iDelay < m_maxStrobeDelayIdx) {
+          // The value at be added to the SAI
+          float sig = pSigIn->getSample(iCurrentSample, audCh);
+
+          // Weight the sample correctly
+          sig *= pActiveStrobes->getWorkingWeight(si);
+
+          // Adjust the weight acording to the number of samples until the
+          // next output frame
+          sig *= fDecayFactor;
+
+          // Update the temporary SAI buffer
+          pSigOut->setSample(iDelay, audCh,
+                             pSigOut->getSample(iDelay, audCh)+sig);
+        }
+      }
+
+      m_pNextStrobes[bankCh]=iNextStrobe;
+
+    } // End loop over channels
+
+
+    //Check to see if we need to output an SAI frame this sample
+    if (m_iFireCounter-- == 0) {
+      // Decay the SAI by the correct amount and add the current output frame
+      float decay = pow(sai_decay_factor_, fire_period_samples_);
+
+      for (c = 0; c < input.channel_count(); ++c) {
+        for (int i = 0; i < output_.buffer_length(); ++i) {
+          output_.set_sample(c, i, sai_temp_[c][i] + output_[c][i] * decay);
+        }
+      }
+
+      // Zero the temporary signal
+      for (int ch = 0; ch < sai_temp_.channel_count(); ++ch) {
+        for (int i = 0; i < sai_temp_.buffer_length(); ++i) {
+          sai_temp_.set_sample(ch, i, 0.0f);
+        }
+      }
+
+      m_iFireCounter=m_iFirePeriodSamples-1;
+
+      // Make sure the start time is transferred to the output
+      m_pOutputData->setStartTime(m_pInputData->getSignal(0)->getStartTime()+(SIGNAL_SAMPLE)((float)iCurrentSample*1000.0f/(float)m_pInputData->getSamplerate()));
+      PushOutput();
+    }
+  } // End loop over samples
+}
+
+ModuleSAI::~ModuleSAI() {
+}