1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CONTENT_BROWSER_SPEECH_AUDIO_ENCODER_H_
6#define CONTENT_BROWSER_SPEECH_AUDIO_ENCODER_H_
7
8#include <list>
9#include <string>
10
11#include "base/basictypes.h"
12#include "base/memory/ref_counted.h"
13#include "content/browser/speech/audio_buffer.h"
14
15namespace content{
16class AudioChunk;
17
18// Provides a simple interface to encode raw audio using the various speech
19// codecs.
20class AudioEncoder {
21 public:
22  enum Codec {
23    CODEC_FLAC,
24    CODEC_SPEEX,
25  };
26
27  static AudioEncoder* Create(Codec codec,
28                              int sampling_rate,
29                              int bits_per_sample);
30
31  virtual ~AudioEncoder();
32
33  // Encodes |raw audio| to the internal buffer. Use
34  // |GetEncodedDataAndClear| to read the result after this call or when
35  // audio capture completes.
36  virtual void Encode(const AudioChunk& raw_audio) = 0;
37
38  // Finish encoding and flush any pending encoded bits out.
39  virtual void Flush() = 0;
40
41  // Merges, retrieves and clears all the accumulated encoded audio chunks.
42  scoped_refptr<AudioChunk> GetEncodedDataAndClear();
43
44  const std::string& mime_type() { return mime_type_; }
45  int bits_per_sample() { return bits_per_sample_; }
46
47 protected:
48  AudioEncoder(const std::string& mime_type, int bits_per_sample);
49  AudioBuffer encoded_audio_buffer_;
50
51 private:
52  std::string mime_type_;
53  int bits_per_sample_;
54
55  DISALLOW_COPY_AND_ASSIGN(AudioEncoder);
56};
57
58}  // namespace content
59
60#endif  // CONTENT_BROWSER_SPEECH_AUDIO_ENCODER_H_
61