commit 65e56dba534976efddd623c0cb57c5c211387beb
author bjornv@webrtc.org <bjornv@webrtc.org> Tue Sep 30 09:31:28 2014 +0000
committer bjornv@webrtc.org <bjornv@webrtc.org> Tue Sep 30 09:31:28 2014 +0000
tree c42649f26e025e2ff48327945d6325b2c8446b4b
parent 23ec8372a66de8ca3eed82b5827f56e1a14a5f0a

audio_processing/aecm: Added help function for calculating log of energy

The same operation of calculating log of the energy was executed four times. This CL adds a help function LogOfEnergyInQ8() for that.

BUG=N/A
TESTED=locally on linux and trybots
R=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/22819004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7331 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_processing/aecm/aecm_core.c

diff --git a/webrtc/modules/audio_processing/aecm/aecm_core.c b/webrtc/modules/audio_processing/aecm/aecm_core.c
index 72a1108..61d4c0b 100644
--- a/webrtc/modules/audio_processing/aecm/aecm_core.c
+++ b/webrtc/modules/audio_processing/aecm/aecm_core.c
@@ -709,6 +709,20 @@
   return (int16_t)(((a << zeros) & 0x7FFFFFFF) >> 23);
 }
 
+// Calculates and returns the log of |energy| in Q8. The input |energy| is
+// supposed to be in Q(|q_domain|).
+static int16_t LogOfEnergyInQ8(uint32_t energy, int q_domain) {
+  static const int16_t kLogLowValue = PART_LEN_SHIFT << 7;
+  int16_t log_energy_q8 = kLogLowValue;
+  if (energy > 0) {
+    int zeros = WebRtcSpl_NormU32(energy);
+    int16_t frac = ExtractFractionPart(energy, zeros);
+    // log2 of |energy| in Q8.
+    log_energy_q8 += ((31 - zeros) << 8) + frac - (q_domain << 8);
+  }
+  return log_energy_q8;
+}
+
 // WebRtcAecm_CalcEnergies(...)
 //
 // This function calculates the log of energies for nearend, farend and estimated
@@ -735,13 +749,11 @@
 
     int i;
 
-    int16_t zeros, frac;
     int16_t tmp16;
     int16_t increase_max_shifts = 4;
     int16_t decrease_max_shifts = 11;
     int16_t increase_min_shifts = 11;
     int16_t decrease_min_shifts = 3;
-    static const int16_t kLogLowValue = PART_LEN_SHIFT << 7;
 
     // Get log of near end energy and store in buffer
 
@@ -750,17 +762,7 @@
             sizeof(int16_t) * (MAX_BUF_LEN - 1));
 
     // Logarithm of integrated magnitude spectrum (nearEner)
-    tmp16 = kLogLowValue;
-    if (nearEner)
-    {
-        zeros = WebRtcSpl_NormU32(nearEner);
-        frac = ExtractFractionPart(nearEner, zeros);
-        // log2 in Q8
-        tmp16 += ((31 - zeros) << 8) + frac;
-        tmp16 -= aecm->dfaNoisyQDomain << 8;
-    }
-    aecm->nearLogEnergy[0] = tmp16;
-    // END: Get log of near end energy
+    aecm->nearLogEnergy[0] = LogOfEnergyInQ8(nearEner, aecm->dfaNoisyQDomain);
 
     WebRtcAecm_CalcLinearEnergies(aecm, far_spectrum, echoEst, &tmpFar, &tmpAdapt, &tmpStored);
 
@@ -771,40 +773,15 @@
             sizeof(int16_t) * (MAX_BUF_LEN - 1));
 
     // Logarithm of delayed far end energy
-    tmp16 = kLogLowValue;
-    if (tmpFar)
-    {
-        zeros = WebRtcSpl_NormU32(tmpFar);
-        frac = ExtractFractionPart(tmpFar, zeros);
-        // log2 in Q8
-        tmp16 += ((31 - zeros) << 8) + frac;
-        tmp16 -= far_q << 8;
-    }
-    aecm->farLogEnergy = tmp16;
+    aecm->farLogEnergy = LogOfEnergyInQ8(tmpFar, far_q);
 
     // Logarithm of estimated echo energy through adapted channel
-    tmp16 = kLogLowValue;
-    if (tmpAdapt)
-    {
-        zeros = WebRtcSpl_NormU32(tmpAdapt);
-        frac = ExtractFractionPart(tmpAdapt, zeros);
-        //log2 in Q8
-        tmp16 += ((31 - zeros) << 8) + frac;
-        tmp16 -= (RESOLUTION_CHANNEL16 + far_q) << 8;
-    }
-    aecm->echoAdaptLogEnergy[0] = tmp16;
+    aecm->echoAdaptLogEnergy[0] = LogOfEnergyInQ8(tmpAdapt,
+                                                  RESOLUTION_CHANNEL16 + far_q);
 
     // Logarithm of estimated echo energy through stored channel
-    tmp16 = kLogLowValue;
-    if (tmpStored)
-    {
-        zeros = WebRtcSpl_NormU32(tmpStored);
-        frac = ExtractFractionPart(tmpStored, zeros);
-        //log2 in Q8
-        tmp16 += ((31 - zeros) << 8) + frac;
-        tmp16 -= (RESOLUTION_CHANNEL16 + far_q) << 8;
-    }
-    aecm->echoStoredLogEnergy[0] = tmp16;
+    aecm->echoStoredLogEnergy[0] =
+        LogOfEnergyInQ8(tmpStored, RESOLUTION_CHANNEL16 + far_q);
 
     // Update farend energy levels (min, max, vad, mse)
     if (aecm->farLogEnergy > FAR_ENERGY_MIN)