Not streaming packets of silence.

remoting/host/audio_capturer_util.cc

Index: remoting/host/audio_capturer_util.cc
diff --git a/remoting/host/audio_capturer_util.cc b/remoting/host/audio_capturer_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f7ede98d0b0000c547b263d89bdce01858008e70
--- /dev/null
+++ b/remoting/host/audio_capturer_util.cc
@@ -0,0 +1,40 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/host/audio_capturer_util.h"
+
+#include <stdlib.h>
+
+#include "base/basictypes.h"
+#include "remoting/proto/audio.pb.h"
+
+namespace {
+const int kBytesPerSample = 2;
+const int kSilenceThreshold = 2;

[Sergey Ulanov, 2012/07/30 18:02:56]

Please add some comments to explain how that value was chosen (once you move it
to _win.cc)

[kxing, 2012/07/30 20:21:36]

Done.

+}  // namespace
+
+namespace remoting {
+
+bool IsValidSampleRate(int sample_rate) {
+  switch (sample_rate) {
+    case AudioPacket::SAMPLING_RATE_44100:
+    case AudioPacket::SAMPLING_RATE_48000:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsPacketOfSilence(const AudioPacket* packet) {
+  const int16* data = reinterpret_cast<const int16*>(packet->data().data());

[Sergey Ulanov, 2012/07/30 18:02:56]

You assume here that the packet is always two bytes per sample. Add
DCHECK(sizeof(int16), packet->bytes_per_sample);
That way you also don't need kBytesPerSample const - you can just use
sizeof(int16) instead.

[kxing, 2012/07/30 20:21:36]

Done.

+  int number_of_samples = packet->data().size() / kBytesPerSample;
+
+  for (int i = 0; i < number_of_samples; i++) {
+    if (abs(data[i]) > kSilenceThreshold)
+      return false;
+  }
+  return true;
+}
+
+}  // namespace remoting