media/audio/sounds/wav_audio_handler.h

   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 "base/time/time.h"
  10 #include "media/base/media_export.h"
  11
  12 namespace media {
  13
  14 class AudioBus;
  15
  16 // This class provides the input from wav file format.  See
  17 // https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
  18 class MEDIA_EXPORT WavAudioHandler {
  19  public:
  20   explicit WavAudioHandler(const base::StringPiece& wav_data);
  21   virtual ~WavAudioHandler();
  22
  23   // Returns true when cursor points to the end of the track.
  24   bool AtEnd(size_t cursor) const;
  25
  26   // Copies the audio data to |bus| starting from the |cursor| and in
  27   // the case of success stores the number of written bytes in
  28   // |bytes_written|. |bytes_written| should not be NULL.
  29   bool CopyTo(AudioBus* bus, size_t cursor, size_t* bytes_written) const;
  30
  31   // Accessors.
  32   const base::StringPiece& data() const { return data_; }
  33   uint16_t num_channels() const { return num_channels_; }
  34   uint32_t sample_rate() const { return sample_rate_; }
  35   uint16_t bits_per_sample() const { return bits_per_sample_; }
  36   uint32_t total_frames() const { return total_frames_; }
  37
  38   // Returns the duration of the entire audio chunk.
  39   base::TimeDelta GetDuration() const;
  40
  41  private:
  42   // Parses a chunk of wav format data. Returns the length of the chunk.
  43   int ParseSubChunk(const base::StringPiece& data);
  44
  45   // Parses the 'fmt' section chunk and stores |params_|.
  46   bool ParseFmtChunk(const base::StringPiece& data);
  47
  48   // Parses the 'data' section chunk and stores |data_|.
  49   bool ParseDataChunk(const base::StringPiece& data);
  50
  51   // Data part of the |wav_data_|.
  52   base::StringPiece data_;
  53
  54   uint16_t num_channels_;
  55   uint32_t sample_rate_;
  56   uint16_t bits_per_sample_;
  57   uint32_t total_frames_;
  58 };
  59
  60 }  // namespace media
  61
  62 #endif  // MEDIA_AUDIO_SOUNDS_WAV_AUDIO_HANDLER_H_