Index: content/renderer/media/media_stream_audio_level_calculator.h |
diff --git a/content/renderer/media/media_stream_audio_level_calculator.h b/content/renderer/media/media_stream_audio_level_calculator.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..1440d2bff2cdf33e825bc3b9b65cf79f47dbe247 |
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+++ b/content/renderer/media/media_stream_audio_level_calculator.h |
@@ -0,0 +1,42 @@ |
+// Copyright 2014 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. |
+ |
+#ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_ |
+#define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_ |
+ |
+#include "base/threading/thread_checker.h" |
+ |
+namespace content { |
+ |
+// This class is used by the WebRtcLocalAudioTrack to calculate the level of |
+// the audio signal. And the audio level will be eventually used by the volume |
+// animation UI. |
+// The algorithm used by this class is the same as how it is done in |
+// third_party/webrtc/voice_engine/level_indicator.cc. |
+class MediaStreamAudioLevelCalculator { |
+ public: |
+ MediaStreamAudioLevelCalculator(); |
+ ~MediaStreamAudioLevelCalculator(); |
+ |
+ // Calculates the signal level of the audio data. |
+ // Returns the level of bars that the volume animation UI uses for |
+ // presenting the energy level of the audio data. |
+ int Calculate(const int16* audio_data, int number_of_channels, |
+ int number_of_frames); |
+ |
+ private: |
+ // Used to DCHECK that the constructor and Calculate() are always called on |
+ // the same audio thread. Note that the destructor will be called on a |
+ // different thread, which can be either the main render thread or a new |
+ // audio thread where WebRtcLocalAudioTrack::OnSetFormat() is called. |
+ base::ThreadChecker thread_checker_; |
+ |
+ int counter_; |
+ int max_amplitude_; |
+ int level_; |
+}; |
+ |
+} // namespace content |
+ |
+#endif // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_ |