Changed OLA window for neteq. Old code didnt work well with 48khz

webrtc/modules/audio_coding/neteq/normal.cc

Index: webrtc/modules/audio_coding/neteq/normal.cc
diff --git a/webrtc/modules/audio_coding/neteq/normal.cc b/webrtc/modules/audio_coding/neteq/normal.cc
index 3dee39a8bc54e0ed2e176b80f64b83e0f9a9d40d..44a5a779fd3dbb4f64d01b879bcc414e73594fcc 100644
--- a/webrtc/modules/audio_coding/neteq/normal.cc
+++ b/webrtc/modules/audio_coding/neteq/normal.cc
@@ -130,23 +130,20 @@ int Normal::Process(const int16_t* input,
 
       // Interpolate the expanded data into the new vector.
       // (NB/WB/SWB32/SWB48 8/16/32/48 samples.)
-      RTC_DCHECK_LT(fs_shift, 3);  // Will always be 0, 1, or, 2.
-      increment = 4 >> fs_shift;
-      int fraction = increment;
-      // Don't interpolate over more samples than what is in output. When this
-      // cap strikes, the interpolation will likely sound worse, but this is an
-      // emergency operation in response to unexpected input.
-      const size_t interp_len_samples =
-          std::min(static_cast<size_t>(8 * fs_mult), output->Size());
-      for (size_t i = 0; i < interp_len_samples; ++i) {
-        // TODO(hlundin): Add 16 instead of 8 for correct rounding. Keeping 8
-        // now for legacy bit-exactness.
-        RTC_DCHECK_LT(channel_ix, output->Channels());
-        RTC_DCHECK_LT(i, output->Size());
+      int win_length = ola_win_length_ ;

[hlundin-webrtc, 2017/03/23 11:41:50]

int -> size_t

[squashingskak, 2017/03/27 10:24:59]

Acknowledged.

+      int16_t win_slope_Q14 = ola_win_slope_Q14_;
+      int16_t win_up_Q14 = win_slope_Q14;

[hlundin-webrtc, 2017/03/23 11:41:51]

Move declaration of win_up_Q14 to after the if statement, when the initial value
is known.

[squashingskak, 2017/03/27 10:24:59]

Acknowledged.

+      assert(channel_ix < output->Channels());

[hlundin-webrtc, 2017/03/23 11:41:50]

RTC_DCHECK_LT(channel_ix, output->Channels());

[squashingskak, 2017/03/27 10:24:59]

Acknowledged.

+      if(win_length > (int)output->Size()){

[hlundin-webrtc, 2017/03/23 11:41:51]

Don't cast; both sides should be size_t. Also, when casting, use static_cast
instead.

[squashingskak, 2017/03/27 10:24:59]

Acknowledged.

+        win_length = length;
+        win_slope_Q14 = (1 << 14)/length;

[hlundin-webrtc, 2017/03/23 11:41:51]

Add spaces on both sides of /

[squashingskak, 2017/03/27 10:24:59]

Acknowledged.

+        win_up_Q14 = win_slope_Q14;
+      }
+      for (int i = 0; i < win_length; i++) {

[hlundin-webrtc, 2017/03/23 11:41:51]

size_t i

[squashingskak, 2017/03/27 10:24:59]

Acknowledged.

         (*output)[channel_ix][i] =
-            static_cast<int16_t>((fraction * (*output)[channel_ix][i] +
-                (32 - fraction) * expanded[channel_ix][i] + 8) >> 5);
-        fraction += increment;
+        (win_up_Q14 * (*output)[channel_ix][i] +
+          ((1 << 14) - win_up_Q14) * expanded[channel_ix][i] + (1 << 13)) >> 14;
+        win_up_Q14 += win_slope_Q14;
       }

[hlundin-webrtc, 2017/03/23 11:41:51]

After this for loop, we expect the value of win_up_Q14 to be 1<<14. I'd usually
recommend documenting this by adding a DCHECK. But the problem in this case is
that the increment is not exact for 48000 Hz. How far off from 1<<14 will we end
up in that case?

[squashingskak, 2017/03/27 10:24:59]

1 << 14 / 48 = 341. 341 * 48 = 16384 = 1<< 14 - 16

[hlundin-webrtc, 2017/03/27 10:44:27]

OK. Please, add a DCHECK.
if (fs_hz_ == 48000) {
  RTC_DCHECK_EQ(win_up_Q14, (1 << 14) - 16);
} else {
  RTC_DCHECK_EQ(win_up_Q14, 1 << 14);
}

     }
   } else if (last_mode == kModeRfc3389Cng) {
@@ -171,15 +168,18 @@ int Normal::Process(const int16_t* input,
     }
     // Interpolate the CNG into the new vector.
     // (NB/WB/SWB32/SWB48 8/16/32/48 samples.)
-    RTC_DCHECK_LT(fs_shift, 3);  // Will always be 0, 1, or, 2.
-    int16_t increment = 4 >> fs_shift;
-    int16_t fraction = increment;
-    for (size_t i = 0; i < static_cast<size_t>(8 * fs_mult); i++) {
-      // TODO(hlundin): Add 16 instead of 8 for correct rounding. Keeping 8 now
-      // for legacy bit-exactness.
-      (*output)[0][i] = (fraction * (*output)[0][i] +
-          (32 - fraction) * cng_output[i] + 8) >> 5;
-      fraction += increment;
+    int win_length = ola_win_length_;

[hlundin-webrtc, 2017/03/23 11:41:50]

All the above comments that apply here.

[squashingskak, 2017/03/27 10:24:59]

Acknowledged.

+    int16_t win_slope_Q14 = ola_win_slope_Q14_;
+    int16_t win_up_Q14 = win_slope_Q14;
+    if(win_length > (int)kCngLength){
+        win_length = (int)kCngLength;
+        win_slope_Q14 = (1 << 14)/kCngLength;
+        win_up_Q14 = win_slope_Q14;
+    }
+    for (int i = 0; i < win_length; i++) {
+        (*output)[0][i] = (win_up_Q14 * (*output)[0][i] +
+            ((1 << 14) - win_up_Q14) * cng_output[i] + (1 << 13)) >> 14;
+        win_up_Q14 += win_slope_Q14;
     }
   } else if (external_mute_factor_array[0] < 16384) {
     // Previous was neither of Expand, FadeToBGN or RFC3389_CNG, but we are