Add opus audio codec support in remoting

remoting/codec/audio_encoder_opus.h

+// 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.
+
+#ifndef REMOTING_CODEC_AUDIO_ENCODER_OPUS_H_
+#define REMOTING_CODEC_AUDIO_ENCODER_OPUS_H_
+
+#include "remoting/codec/audio_encoder.h"
+
+#include "remoting/proto/audio.pb.h"
+
+struct OpusEncoder;
+
+namespace media {
+class AudioBus;
+class MultiChannelResampler;
+}  // namespace media
+
+namespace remoting {
+
+class AudioPacket;
+
+class AudioEncoderOpus : public AudioEncoder {
+ public:
+  AudioEncoderOpus();
+  virtual ~AudioEncoderOpus();
+
+  // AudioEncoder interface.
+  virtual scoped_ptr<AudioPacket> Encode(
+      scoped_ptr<AudioPacket> packet) OVERRIDE;
+
+ private:
+  void InitEncoder();
+  void DestroyEncoder();
+  bool ResetForPacket(AudioPacket* packet);
+
+  void FetchBytesToResampler(media::AudioBus* audio_bus);
+
+  int sampling_rate_;
+  AudioPacket::Channels channels_;
+  OpusEncoder* encoder_;
+
+  int frame_size_;
+  scoped_ptr<media::MultiChannelResampler> resampler_;
+  scoped_array<char> resample_buffer_;
+  scoped_ptr<media::AudioBus> resampler_bus_;
+
+  // Used to pass packet to the FetchBytesToResampler() callback.
+  const char* resampling_data_;
+  int resampling_data_size_;
+  int resampling_data_pos_;
+
+  // Left-over unencoded samples from the previous AudioPacket.
+  scoped_array<int16> leftover_buffer_;
+  int leftover_buffer_size_;
+  int leftover_samples_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioEncoderOpus);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_CODEC_AUDIO_ENCODER_OPUS_H_