media/audio/cras/cras_input.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 MEDIA_AUDIO_CRAS_CRAS_INPUT_H_
   6 #define MEDIA_AUDIO_CRAS_CRAS_INPUT_H_
   7
   8 #include <cras_client.h>
   9
  10 #include <string>
  11
  12 #include "base/compiler_specific.h"
  13 #include "media/audio/agc_audio_stream.h"
  14 #include "media/audio/audio_io.h"
  15 #include "media/audio/audio_parameters.h"
  16 #include "media/base/media_export.h"
  17
  18 namespace media {
  19
  20 class AudioManagerCras;
  21
  22 // Provides an input stream for audio capture based on CRAS, the ChromeOS Audio
  23 // Server.  This object is not thread safe and all methods should be invoked in
  24 // the thread that created the object.
  25 class MEDIA_EXPORT CrasInputStream : public AgcAudioStream<AudioInputStream> {
  26  public:
  27   // The ctor takes all the usual parameters, plus |manager| which is the
  28   // audio manager who is creating this object.
  29   CrasInputStream(const AudioParameters& params,
  30                   AudioManagerCras* manager,
  31                   const std::string& device_id);
  32
  33   // The dtor is typically called by the AudioManager only and it is usually
  34   // triggered by calling AudioOutputStream::Close().
  35   ~CrasInputStream() override;
  36
  37   // Implementation of AudioInputStream.
  38   bool Open() override;
  39   void Start(AudioInputCallback* callback) override;
  40   void Stop() override;
  41   void Close() override;
  42   double GetMaxVolume() override;
  43   void SetVolume(double volume) override;
  44   double GetVolume() override;
  45   bool IsMuted() override;
  46
  47  private:
  48   // Handles requests to get samples from the provided buffer.  This will be
  49   // called by the audio server when it has samples ready.
  50   static int SamplesReady(cras_client* client,
  51                           cras_stream_id_t stream_id,
  52                           uint8* samples,
  53                           size_t frames,
  54                           const timespec* sample_ts,
  55                           void* arg);
  56
  57   // Handles notification that there was an error with the playback stream.
  58   static int StreamError(cras_client* client,
  59                          cras_stream_id_t stream_id,
  60                          int err,
  61                          void* arg);
  62
  63   // Reads one or more buffers of audio from the device, passes on to the
  64   // registered callback. Called from SamplesReady().
  65   void ReadAudio(size_t frames, uint8* buffer, const timespec* sample_ts);
  66
  67   // Deals with an error that occured in the stream.  Called from StreamError().
  68   void NotifyStreamError(int err);
  69
  70   // Convert from dB * 100 to a volume ratio.
  71   double GetVolumeRatioFromDecibels(double dB) const;
  72
  73   // Convert from a volume ratio to dB.
  74   double GetDecibelsFromVolumeRatio(double volume_ratio) const;
  75
  76   // Non-refcounted pointer back to the audio manager.
  77   // The AudioManager indirectly holds on to stream objects, so we don't
  78   // want circular references.  Additionally, stream objects live on the audio
  79   // thread, which is owned by the audio manager and we don't want to addref
  80   // the manager from that thread.
  81   AudioManagerCras* const audio_manager_;
  82
  83   // Size of frame in bytes.
  84   uint32 bytes_per_frame_;
  85
  86   // Callback to pass audio samples too, valid while recording.
  87   AudioInputCallback* callback_;
  88
  89   // The client used to communicate with the audio server.
  90   cras_client* client_;
  91
  92   // PCM parameters for the stream.
  93   const AudioParameters params_;
  94
  95   // True if the stream has been started.
  96   bool started_;
  97
  98   // ID of the playing stream.
  99   cras_stream_id_t stream_id_;
 100
 101   // Direction of the stream.
 102   const CRAS_STREAM_DIRECTION stream_direction_;
 103
 104   // Index of the CRAS device to stream input from.
 105   int pin_device_;
 106
 107   // True if the stream is a system-wide loopback stream.
 108   bool is_loopback_;
 109
 110   scoped_ptr<AudioBus> audio_bus_;
 111
 112   DISALLOW_COPY_AND_ASSIGN(CrasInputStream);
 113 };
 114
 115 }  // namespace media
 116
 117 #endif  // MEDIA_AUDIO_CRAS_CRAS_INPUT_H_