Integrate Intelligibility with APM

webrtc/modules/audio_processing/audio_buffer.cc

Index: webrtc/modules/audio_processing/audio_buffer.cc
diff --git a/webrtc/modules/audio_processing/audio_buffer.cc b/webrtc/modules/audio_processing/audio_buffer.cc
index 04dcaea799d60af6bbc48d899e9ded8134d6ce03..405b0c833c35bfb3b908249985ba093bc64ee92b 100644
--- a/webrtc/modules/audio_processing/audio_buffer.cc
+++ b/webrtc/modules/audio_processing/audio_buffer.cc
@@ -436,20 +436,27 @@ void AudioBuffer::DeinterleaveFrom(AudioFrame* frame) {
 }
 
 void AudioBuffer::InterleaveTo(AudioFrame* frame, bool data_changed) const {
-  assert(proc_num_frames_ == output_num_frames_);
-  assert(num_channels_ == num_input_channels_);
-  assert(frame->num_channels_ == num_channels_);
-  assert(frame->samples_per_channel_ == proc_num_frames_);
   frame->vad_activity_ = activity_;
-
   if (!data_changed) {
     return;
   }
 
-  Interleave(data_->ibuf()->channels(),
-             proc_num_frames_,
-             num_channels_,
-             frame->data_);
+  assert(proc_num_frames_ == output_num_frames_);
+  assert(frame->num_channels_ == num_channels_ || num_channels_ == 1);
+  assert(frame->samples_per_channel_ == proc_num_frames_);
+
+  if (frame->num_channels_ == num_channels_) {
+    Interleave(data_->ibuf()->channels(), proc_num_frames_, num_channels_,
+               frame->data_);
+  } else {
+    // Copy single AudioBuffer channel into all AudioFrame channels
+    int16_t* channel_ptr_copies[frame->num_channels_];
+    for (int i = 0; i < frame->num_channels_; ++i) {
+      channel_ptr_copies[i] = data_->ibuf()->channels()[0];
+    }
+    Interleave(channel_ptr_copies, proc_num_frames_, num_channels_,
+               frame->data_);
+  }
 }
 
 void AudioBuffer::CopyLowPassToReference() {