extensions/common/api/audio.idl

// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// The <code>chrome.audio</code> API is provided to allow users to
// get information about and control the audio devices attached to the
// system. This API is currently only implemented for ChromeOS.
namespace audio {

  dictionary OutputDeviceInfo {
    // The unique identifier of the audio output device.
    DOMString id;
    // The user-friendly name (e.g. "Bose Amplifier").
    DOMString name;
    // True if this is the current active device.
    boolean isActive;
    // True if this is muted.
    boolean isMuted;
    // The output volume ranging from 0.0 to 100.0.
    double volume;
  };

  dictionary InputDeviceInfo {
    // The unique identifier of the audio input device.
    DOMString id;
    // The user-friendly name (e.g. "USB Microphone").
    DOMString name;
    // True if this is the current active device.
    boolean isActive;
    // True if this is muted.
    boolean isMuted;
    // The input gain ranging from 0.0 to 100.0.
    double gain;
  };

  dictionary AudioDeviceInfo {
    // The unique identifier of the audio device.
    DOMString id;
    // True for input device; false for output device.
    boolean isInput;
    // Type of the device, including "INTERNAL_SPEAKER", "INTERNAL_MIC",
    // "HEADPHONE", "USB", "BLUETOOTH", "HDMI", "MIC", "KEYBOARD_MIC",
    // "AOKR", and "OTHER".
    DOMString deviceType;
    // The user-friendly name (e.g. "USB Microphone").
    DOMString displayName;
    // Device name.
    DOMString deviceName;
    // True if this is the current active device.
    boolean isActive;
    // True if this is muted.
    boolean isMuted;
    // The sound level of the device, volume for output, gain for input.
    long level;
    // The stable/persisted device id string when available.
    DOMString? stableDeviceId;
  };

  dictionary DeviceProperties {
    // True if this is muted.
    boolean isMuted;
    // If this is an output device then this field indicates the output volume.
    // If this is an input device then this field is ignored.
    double? volume;
    // If this is an input device then this field indicates the input gain.
    // If this is an output device then this field is ignored.
    double? gain;
  };

  callback GetInfoCallback = void(OutputDeviceInfo[] outputInfo,
                                  InputDeviceInfo[] inputInfo);
  callback SetActiveDevicesCallback = void();
  callback SetPropertiesCallback = void();

  interface Functions {
    // Gets the information of all audio output and input devices.
    static void getInfo(GetInfoCallback callback);

  // Sets the active devices to the devices specified by |ids|.
  // It can pass in the "complete" active device id list of either input
  // devices, or output devices, or both. If only input device ids are passed
  // in, it will only change the input devices' active status, output devices will
  // NOT be changed; similarly for the case if only output devices are passed.
  // If the devices specified in |new_active_ids| are already active, they will
  // remain active. Otherwise, the old active devices will be de-activated
  // before we activate the new devices with the same type(input/output).
    static void setActiveDevices(DOMString[] ids,
                                 SetActiveDevicesCallback callback);

    // Sets the properties for the input or output device.
    static void setProperties(DOMString id,
                              DeviceProperties properties,
                              SetPropertiesCallback callback);
     };

  interface Events {
    // Fired when anything changes to the audio device configuration.
    static void onDeviceChanged();

    // Fired when sound level changes for an active audio device.
    // |id|: id of the audio device.
    // |level|: new sound level of device(volume for output, gain for input).
    static void OnLevelChanged(DOMString id, long level);

    // Fired when the mute state of the audio input or output changes.
    // |isInput|: true indicating audio input; false indicating audio output.
    // |isMuted|: new value of mute state.
    static void OnMuteChanged(boolean isInput, boolean isMuted);

    // Fired when audio devices change, either new devices being added, or
    // existing devices being removed.
    // |devices|: List of all present audio devices after the change.
    static void OnDevicesChanged(AudioDeviceInfo[] devices);
  };
};