wav_audio_handler.h revision 0f1bc08d4cfcc34181b0b5cbf065c40f687bf740 
1// Copyright 2013 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 MEDIA_AUDIO_SOUNDS_WAV_AUDIO_HANDLER_H_
6#define MEDIA_AUDIO_SOUNDS_WAV_AUDIO_HANDLER_H_
7
8#include "base/strings/string_piece.h"
9#include "media/base/media_export.h"
10
11namespace media {
12
13class AudioBus;
14
15// This class provides the input from wav file format.  See
16// https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
17class MEDIA_EXPORT WavAudioHandler {
18 public:
19  explicit WavAudioHandler(const base::StringPiece& wav_data);
20  virtual ~WavAudioHandler();
21
22  // Returns true when cursor points to the end of the track.
23  bool AtEnd(size_t cursor) const;
24
25  // Copies the audio data to |bus| starting from the |cursor| and in
26  // the case of success stores the number of written bytes in
27  // |bytes_written|. |bytes_written| should not be NULL.
28  bool CopyTo(AudioBus* bus, size_t cursor, size_t* bytes_written) const;
29
30  int size() const { return data_.size(); }
31  uint16 num_channels() const { return num_channels_; }
32  uint32 sample_rate() const { return sample_rate_; }
33  uint32 byte_rate() const { return byte_rate_; }
34  uint16 bits_per_sample() const { return bits_per_sample_; }
35
36 private:
37  // Parses a chunk of wav format data. Returns the length of the chunk.
38  int ParseSubChunk(const base::StringPiece& data);
39
40  // Parses the 'fmt' section chunk and stores |params_|.
41  bool ParseFmtChunk(const base::StringPiece& data);
42
43  // Parses the 'data' section chunk and stores |data_|.
44  bool ParseDataChunk(const base::StringPiece& data);
45
46  // Data part of the |wav_data_|.
47  base::StringPiece data_;
48
49  uint16 num_channels_;
50  uint32 sample_rate_;
51  uint32 byte_rate_;
52  uint16 bits_per_sample_;
53  int bytes_per_sample_;
54  int bytes_per_frame_;
55};
56
57}  // namespace media
58
59#endif  // MEDIA_AUDIO_SOUNDS_WAV_AUDIO_HANDLER_H_
60