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