Reland: Drop the 16kHz sample rate restriction on AECM and zero out higher bands

webrtc/modules/audio_processing/echo_control_mobile_impl.cc

Index: webrtc/modules/audio_processing/echo_control_mobile_impl.cc
diff --git a/webrtc/modules/audio_processing/echo_control_mobile_impl.cc b/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
index f2df5f79849f7fb98a85022506c4cceb26423588..7c6760d666e44179e980348eb84ae0679f09a330 100644
--- a/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
+++ b/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
@@ -206,6 +206,12 @@ int EchoControlMobileImpl::ProcessCaptureAudio(AudioBuffer* audio) {
 
       handle_index++;
     }
+    for (size_t band = 1u; band < audio->num_bands(); ++band) {
+      memset(audio->split_bands(i)[band],
+             0,
+             audio->num_frames_per_band() *
+                 sizeof(audio->split_bands(i)[band][0]));
+    }
   }
 
   return AudioProcessing::kNoError;
@@ -313,8 +319,8 @@ int EchoControlMobileImpl::Initialize() {
     }
   }
 

[peah-webrtc, 2016/03/11 11:34:39]

Regarding proc_split_sample_rate_hz(), can that ever be higher than 16 kHz?
Furthermore, can that be anything other than 16 kHz?

[aluebs-webrtc, 2016/03/11 13:27:05]

As it is today, it is always 16kHz except when the sample_rate is 8kHz, then the
split_sample_rate is also 8kHz.

[peah-webrtc, 2016/03/11 21:37:28]

We really need to change the names of these functions. In my mind, split rate
relates to the rate of the split signal. And the 8 and 16 kHz are not split so
then the name is quite misleading.

[aluebs-webrtc, 2016/03/14 17:30:40]

I agree it probably can have a better name, but the rename should be done in a
separate CL.

-  if (apm_->proc_sample_rate_hz() > AudioProcessing::kSampleRate16kHz) {
-    LOG(LS_ERROR) << "AECM only supports 16 kHz or lower sample rates";
+  if (apm_->proc_split_sample_rate_hz() > AudioProcessing::kSampleRate16kHz) {
+    LOG(LS_ERROR) << "AECM only supports 16 kHz or lower split sample rates";
     return AudioProcessing::kBadSampleRateError;
   }
 
@@ -370,7 +376,7 @@ int EchoControlMobileImpl::InitializeHandle(void* handle) const {
   rtc::CritScope cs_capture(crit_capture_);
   assert(handle != NULL);
   Handle* my_handle = static_cast<Handle*>(handle);
-  if (WebRtcAecm_Init(my_handle, apm_->proc_sample_rate_hz()) != 0) {
+  if (WebRtcAecm_Init(my_handle, apm_->proc_split_sample_rate_hz()) != 0) {
     return GetHandleError(my_handle);
   }
   if (external_echo_path_ != NULL) {