Source API

Version: 1.0.0

Status:

Source interface for Thunder framework.

(Defined with IBluetoothAudio::ISource in IBluetoothAudio.h)

Table of Contents

• Introduction
• Description
• Properties
• Notifications

Introduction

Scope

This document describes purpose and functionality of the Source interface (version 1.0.0). It includes detailed specification about its properties provided and notifications sent.

Case Sensitivity

All identifiers of the interfaces described in this document are case-sensitive. Thus, unless stated otherwise, all keywords, entities, properties, relations and actions should be treated as such.

Acronyms, Abbreviations and Terms

The table below provides and overview of acronyms used in this document and their definitions.

Acronym	Description
API	Application Programming Interface
HTTP	Hypertext Transfer Protocol
JSON	JavaScript Object Notation; a data interchange format
JSON-RPC	A remote procedure call protocol encoded in JSON

The table below provides and overview of terms and abbreviations used in this document and their definitions.

Term	Description
callsign	The name given to an instance of a plugin. One plugin can be instantiated multiple times, but each instance the instance name, callsign, must be unique.

References

Ref ID	Description
HTTP	HTTP specification
JSON-RPC	JSON-RPC 2.0 specification
JSON	JSON specification
Thunder	Thunder API Reference

Description

Source JSON-RPC interface.

This interface uses legacy lowercase naming convention. With the next major release the naming convention will change to camelCase.

Properties

The following properties are provided by the Source interface:

BluetoothAudio Source interface properties:

Property	R/W	Description
source::state	read-only	Current state of the source device
source::device	read-only	Bluetooth address of the source device
source::type	read-only	Type of the audio source device
source::codec	read-only	Properites of the currently used codec
source::drm	read-only	Properties of the currently used DRM scheme
source::stream	read-only	Properites of the currently transmitted audio stream

source::state ^property

Provides access to the current state of the source device.

This property is read-only.

Value

Name	Type	M/O	Description
(property)	string	mandatory	Current state of the source device (must be one of the following: Connected, ConnectedBad, ConnectedRestricted, Connecting, Disconnected, Ready, Streaming, Unassigned)

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.source::state"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": "Disconnected"
}

source::device ^property

Provides access to the bluetooth address of the source device.

This property is read-only.

Value

Name	Type	M/O	Description
(property)	string	mandatory	Bluetooth address of the source device

Errors

Message	Description
ERROR_ILLEGAL_STATE	No source device is currently connected

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.source::device"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": "..."
}

source::type ^property

Provides access to the type of the audio source device.

This property is read-only.

Value

Name	Type	M/O	Description
(property)	string	mandatory	Type of the audio source device (must be one of the following: Microphone, Mixer, Player, Tuner, Unknown)

Errors

Message	Description
ERROR_ILLEGAL_STATE	No source device is currently connected

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.source::type"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": "Player"
}

source::codec ^property

Provides access to the properites of the currently used codec.

This property is read-only.

Value

Name	Type	M/O	Description
(property)	object	mandatory	Properites of the currently used codec
(property).codec	string	mandatory	Audio codec used (must be one of the following: LC-SBC)
(property).settings	opaque object	mandatory	Codec-specific audio quality preset, compression profile, etc

Errors

Message	Description
ERROR_ILLEGAL_STATE	No source device is not connected or sink is not yet configured

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.source::codec"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": {
    "codec": "LC-SBC",
    "settings": {}
  }
}

source::drm ^property

Provides access to the properties of the currently used DRM scheme.

This property is read-only.

Value

Name	Type	M/O	Description
(property)	object	mandatory	Properties of the currently used DRM scheme
(property).drm	string	mandatory	Content protection scheme used (must be one of the following: DTCP, SCMS-T)
(property).settings	opaque object	mandatory	DRM-specific content protection level, encoding rules, etc

Errors

Message	Description
ERROR_ILLEGAL_STATE	No source device is connected or sink is not yet configured

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.source::drm"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": {
    "drm": "SCMS-T",
    "settings": {}
  }
}

source::stream ^property

Provides access to the properites of the currently transmitted audio stream.

This property is read-only.

Value

Name	Type	M/O	Description
(property)	object	mandatory	Properites of the currently transmitted audio stream
(property).samplerate	integer	mandatory	Sample rate in Hz
(property).bitrate	integer	mandatory	Target bitrate in bits per second (eg. 320000)
(property).channels	integer	mandatory	Number of audio channels
(property).resolution	integer	mandatory	Sampling resolution in bits per sample
(property).isresampled	boolean	mandatory	Indicates if the source stream is being resampled by the stack to match sink capabilities

Errors

Message	Description
ERROR_ILLEGAL_STATE	No source device is connected or sink is not yet configured

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.source::stream"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": {
    "samplerate": 44100,
    "bitrate": 0,
    "channels": 2,
    "resolution": 16,
    "isresampled": false
  }
}

Notifications

Notifications are autonomous events triggered by the internals of the implementation and broadcasted via JSON-RPC to all registered observers. Refer to [Thunder] for information on how to register for a notification.

The following events are provided by the Source interface:

BluetoothAudio Source interface events:

Notification	Description
source::statechanged	Signals audio source state change

source::statechanged ^notification

Signals audio source state change.

Notification Parameters

Name	Type	M/O	Description
params	object	mandatory	...
params.state	string	mandatory	Changed BluetoothAudio State (must be one of the following: Connected, ConnectedBad, ConnectedRestricted, Connecting, Disconnected, Ready, Streaming, Unassigned)

Example

Registration

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.register",
  "params": {
    "event": "source::statechanged",
    "id": "myid"
  }
}

Notification

{
  "jsonrpc": "2.0",
  "method": "myid.source::statechanged",
  "params": {
    "state": "Disconnected"
  }
}

The client ID parameter is passed within the notification designator, i.e. <client-id>.source::statechanged.