Avoiding overflow in cross correlation in NetEq.

webrtc/modules/audio_coding/neteq/background_noise.cc

Index: webrtc/modules/audio_coding/neteq/background_noise.cc
diff --git a/webrtc/modules/audio_coding/neteq/background_noise.cc b/webrtc/modules/audio_coding/neteq/background_noise.cc
index 7e7a6325e97ad18071570f0381cbee5df26cd67e..50911a56269debf417b1a530b2ea17c63f9e0ba6 100644
--- a/webrtc/modules/audio_coding/neteq/background_noise.cc
+++ b/webrtc/modules/audio_coding/neteq/background_noise.cc
@@ -17,6 +17,7 @@
 
 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
 #include "webrtc/modules/audio_coding/neteq/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq/cross_correlation.h"
 #include "webrtc/modules/audio_coding/neteq/post_decode_vad.h"
 
 namespace webrtc {
@@ -169,15 +170,10 @@ int16_t BackgroundNoise::ScaleShift(size_t channel) const {
 
 int32_t BackgroundNoise::CalculateAutoCorrelation(
     const int16_t* signal, size_t length, int32_t* auto_correlation) const {
-  int16_t signal_max = WebRtcSpl_MaxAbsValueW16(signal, length);
-  int correlation_scale = kLogVecLen -
-      WebRtcSpl_NormW32(signal_max * signal_max);
-  correlation_scale = std::max(0, correlation_scale);
-
   static const int kCorrelationStep = -1;
-  WebRtcSpl_CrossCorrelation(auto_correlation, signal, signal, length,
-                             kMaxLpcOrder + 1, correlation_scale,
-                             kCorrelationStep);
+  const int correlation_scale =
+      CrossCorrelationWithAutoShift(auto_correlation, signal, signal, length,
+                                    kMaxLpcOrder + 1, kCorrelationStep);
 
   // Number of shifts to normalize energy to energy/sample.
   int energy_sample_shift = kLogVecLen - correlation_scale;