content/browser/speech/audio_encoder.h

   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 <string>
   9
  10 #include "base/macros.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "content/browser/speech/audio_buffer.h"
  13 #include "third_party/flac/include/FLAC/stream_encoder.h"
  14
  15 namespace content{
  16 class AudioChunk;
  17
  18 // Provides a simple interface to encode raw audio using FLAC codec.
  19 class AudioEncoder {
  20  public:
  21   AudioEncoder(int sampling_rate, int bits_per_sample);
  22   ~AudioEncoder();
  23
  24   // Encodes |raw audio| to the internal buffer. Use
  25   // |GetEncodedDataAndClear| to read the result after this call or when
  26   // audio capture completes.
  27   void Encode(const AudioChunk& raw_audio);
  28
  29   // Finish encoding and flush any pending encoded bits out.
  30   void Flush();
  31
  32   // Merges, retrieves and clears all the accumulated encoded audio chunks.
  33   scoped_refptr<AudioChunk> GetEncodedDataAndClear();
  34
  35   std::string GetMimeType();
  36   int GetBitsPerSample();
  37
  38  private:
  39   AudioBuffer encoded_audio_buffer_;
  40
  41   FLAC__StreamEncoder* encoder_;
  42   bool is_encoder_initialized_;
  43
  44   DISALLOW_COPY_AND_ASSIGN(AudioEncoder);
  45 };
  46
  47 }  // namespace content
  48
  49 #endif  // CONTENT_BROWSER_SPEECH_AUDIO_ENCODER_H_