media/base/audio_hardware_config.h

   1 // Copyright (c) 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_BASE_AUDIO_HARDWARE_CONFIG_H_
   6 #define MEDIA_BASE_AUDIO_HARDWARE_CONFIG_H_
   7
   8 #include "base/compiler_specific.h"
   9 #include "base/synchronization/lock.h"
  10 #include "media/audio/audio_parameters.h"
  11 #include "media/base/channel_layout.h"
  12 #include "media/base/media_export.h"
  13
  14 namespace media {
  15
  16 // Provides thread safe access to the audio hardware configuration.
  17 class MEDIA_EXPORT AudioHardwareConfig {
  18  public:
  19   AudioHardwareConfig(const media::AudioParameters& input_params,
  20                       const media::AudioParameters& output_params);
  21   virtual ~AudioHardwareConfig();
  22
  23   // Accessors for the currently cached hardware configuration.  Safe to call
  24   // from any thread.
  25   int GetOutputBufferSize() const;
  26   int GetOutputSampleRate() const;
  27   ChannelLayout GetOutputChannelLayout() const;
  28   int GetOutputChannels() const;
  29
  30   int GetInputSampleRate() const;
  31   ChannelLayout GetInputChannelLayout() const;
  32   int GetInputChannels() const;
  33
  34   media::AudioParameters GetInputConfig() const;
  35   media::AudioParameters GetOutputConfig() const;
  36
  37   // Allows callers to update the cached values for either input or output.  The
  38   // values are paired under the assumption that these values will only be set
  39   // after an input or output device change respectively.  Safe to call from
  40   // any thread.
  41   void UpdateInputConfig(const media::AudioParameters& input_params);
  42   void UpdateOutputConfig(const media::AudioParameters& output_params);
  43
  44   // For clients which don't need low latency, a larger buffer size should be
  45   // used to save power and CPU resources.
  46   int GetHighLatencyBufferSize() const;
  47
  48  private:
  49   // Cached values; access is protected by |config_lock_|.
  50   mutable base::Lock config_lock_;
  51   media::AudioParameters input_params_;
  52   media::AudioParameters output_params_;
  53
  54   DISALLOW_COPY_AND_ASSIGN(AudioHardwareConfig);
  55 };
  56
  57 }  // namespace media
  58
  59 #endif  // MEDIA_BASE_AUDIO_HARDWARE_CONFIG_H_