WO2006130931A1

WO2006130931A1 - Networked audio system

Info

Publication number: WO2006130931A1
Application number: PCT/AU2006/000808
Authority: WO
Inventors: Leonard Charles Layton; Chi-Chen Cheng; Chih-Ching Chiang
Original assignee: C-Media Electronics, Inc.
Priority date: 2005-06-10
Filing date: 2006-06-09
Publication date: 2006-12-14

Abstract

A method of providing audio streaming capabilities in a networked environment, the method comprising the steps of: on a first hardware device rendering an audio applications audio output to a virtual software driver device to produce a first output audio stream suitable for rendering on a second audio hardware playback device; outputting the first output audio stream across a network to matching second audio hardware playback device; rendering the emitted the first output audio stream at the second audio playback device.

Description

TITLE: NETWORKED AUDIO SYSTEM

Field of the Invention

[0001] The present invention relates to the field of audio stream distribution in a networked environment and, in particular, discloses an efficient mechanism for implementation of networked audio streams.

Background of the Invention

[0002] Many audio devices are adapted to play digital audio information. For example, CD players, home theatre environments and personal computers are often equipped with audio capabilities. A personal computer for instance may be equipped with a sound card which is designed to play a downloaded audio stream. Traditionally, such devices have operated in a standalone manner. Operation in a standalone manner is often inefficient. This is especially the case where sophisticated processing of the audio is involved. For example, a sophisticated processing capability in a PC may operate on an audio stream so as to produce a complex audio format providing, for example, surround sound capabilities for the audio. However, these capabilities are more localised to a particular device. An environment may contain many audio playback devices and where the sophisticated processing is restricted to one of the devices and therefore is a consequential inefficient use of audio resources.

Summary of the Invention [0003] In accordance with a first aspect of the present invention, there is provided a method of providing audio streaming capabilities in a networked environment, the method comprising the steps of: on a first hardware device, rendering an audio applications audio output to a virtual software driver device to produce a first output audio stream suitable for rendering on a second audio hardware playback device; outputting the first output audio stream across a network to a matching second audio hardware playback device; rendering the emitted the first output audio stream at the second audio playback device.

[0004] The network can comprise a wireless network. The first hardware device can comprise a Personal Computer having digital signal processing capabilities. The first output audio stream can be in a surround sound format. [0005] In accordance with a further aspect of the present invention, there is provided a method of providing audio streaming capabilities in a networked environment, the method comprising the steps of: on a first hardware device, rendering a series of audio applications audio output to a corresponding virtual software driver device to produce a corresponding series of audio streams; mixing predetermined audio streams together in accordance with the output requirements for a series of audio output devices located at a series of dispersed locations so as to produce a series of mixed audio streams; outputting the mixed audio streams first output audio stream across a network to a corresponding series of audio hardware playback devices; [0006] The method can also include the step of further providing on the hardware device a user interface for altering the playback characteristics of at least the second audio playback device.

[0007] hi accordance with another aspect of the present invention, there is provided a method of providing audio streaming capabilities in a networked environment, the method comprising the steps of: (a) on a first hardware device rendering an audio applications audio output to a virtual software driver device to produce a first series of output audio streams suitable for rendering on a second series of audio hardware playback devices; (b) outputting the first series of output audio streams across a network to matching second audio hardware playback devices; and (c) rendering the emitted first series of output audio streams at corresponding ones of said second audio playback devices.

[0008] In accordance with another aspect of the present invention, there is provided a method of providing audio streaming capabilities in a networked environment, the method comprising the steps of: (a) forming an audio cluster by clustering together a series of audio output devices; (b) presenting a uniform virtual interface for rendering audio to said cluster; (c) virtually rendering audio for playback on said cluster by said virtual interface; and (d) dispatching said virtually rendered audio for playback by said cluster.

Brief description of the Drawings [0009] Preferred and other embodiments of the present invention will now be described with reference to the accompanying drawings in which: [0010] Fig. 1 illustrates an operational environment of the preferred embodiment; [0011] Fig. 2 illustrates schematically one form of the preferred embodiment; [0012] Fig. 3 illustrates the process of mixing audio application streams in the preferred embodiment;

[0013] Fig. 4 illustrates the process of a control interface on a personal computer controlling a audio device; and

[0014] Fig. 5 illustrates a standard formatting utilised in the preferred embodiment.

Description of Preferred and Other Embodiments

[0015] The preferred embodiment provides for a networked audio technology which is designed to provide for a high performance, robust way for personal computer users to stream audio content from their computer to other devices over wired or wireless networks.

[0016] The preferred embodiment has been designed to provide an audio streaming system which is low cost, simple to use, robust, high quality, real time streaming, variable latency and buffer trade off, interoperability with existing content applications and decoders, and has remote control and user interface remote operation capabilities. [0017] Turning initially to Fig. 1, there is illustrated an operational environment of the preferred embodiment 10, wherein a master computer which can comprise a portable computer 11 or standalone device 12 communicates with a series of audio devices over a wireless network. These devices can optionally include an access point 13 with audio capabilities, a wireless audio receiver box 14 which outputs to a series of speakers; a home theatre system 15 having wireless audio steaming capabilities; a set of wireless speakers 16; a stereo system 17 having built in wireless audio capabilities. Any of the latest wireless standard for device communication can be used. [0018] Turning now to Fig. 2, there is illustrated the operational software environment of the preferred embodiment. In this environment, a PC e.g. 21 or 22 is utilised to control the audio output device e.g. 23. The PC e.g. 21 includes a Graphical User Interface arrangement 25 for overall control. The audio media for output by the device 26 is also assumed to have been provided in addition to a web browsing environment 27. [0019] The Graphical User Interface 25 is utilised to set up how the remote device is to output its audio stream. This can include volume controls, directional controls etc. The various values for control are output to an overall audio driver 29 which also takes as an input the base material. The audio driver 29 is assumed to include internal digital signal processing capabilities 30 for rendering the audio stream received 26 in accordance with the control information received from the Graphical User Interface 25. The driver 29 recreates the required output audio stream and formats it for transmission over the wireless network. This is then transmitted over the wireless network to the relevant device 23. The audio stream information is received by the device's receiver firmware 32 and subsequently output by the device. It is also assumed that the device 23 has a remote server configuration interface 33 for configuring the device 23 over the wireless network via, for example, web browser 27. [0020] The driver 29 therefore acts as a virtual device driver that masquerades as a local audio hardware device on the computer 21 however it sends its audio data over the wireless network to the remote device 23. The output audio stream from diver 29 could also be sent to other local or real audio hardware devices.

[0021] As device 23 can receive multiple audio streams, virtual multi-streaming is possible with multiple device drivers mixing and routing. This allows the computer 21 to emulate complex behaviours in software and rout the audio to a simpler device 23 using a low level highly efficient protocol.

[0022] A simple Graphical User Interface can also be provided on the device 21 for remote control of the audio devices located on the network. The network audio driver 29 can provide an interface identical in behaviour to a standard audio device driver but provide communication to remote audio hardware over a communications network. [0023] Whereas prior PC audio systems normally consisted of single input and output paths for audio, the preferred embodiment provides a wireless multi-stream capability allowing multiple streams to be supported simultaneously and independently routed to different hardware and or mixed with other streams in a local or remote manner. This can be advantageous. For example, it may be desirable to have all audio streams locally on speakers attached directly to a PC. Some sounds such as that from a music audio application may be routed to another room. Listeners in the other room really do not wish to be bothered by other audio events such as error sounds etc. coming from the PC. By use of the preferred embodiment, these audio streams can be distinguished. Such an arrangement is illustrated in Fig. 3 wherein two applications 40, 41 are running on a host computer. The application 41 may provide an output stream that is high quality music. The output stream is forwarded to a device driver 43 which may provide surround sound capability. The application 40 provides an output audio stream which is forwarded to device driver 44. Hardware device 45 receives only the output stream from device driver 43. Hardware device 46 receives both output streams which are firstly mixed by mixer 47.

[0024] The preferred embodiment also allows for more intelligent routing and adaptive behaviour in audio devices. Previous PC audio systems provide simple, static behaviour and ignore signals from users that represent intentions with respect to audio functions. EG: A user has audio playing from a USB speaker system, the User connects headphones to front panel of PC, the PC should mute USB speakers an re-route audio to the front panel [0025] Behavioural rules and audio/acoustic relationships

[0026] User can specify the acoustical relationships of audio devices (such as their physical locations in the same room).

[0027] Behavioural rules can be specified to enable 'smart' convenient and intuitive behaviours to be implemented in response to user's actions. [0028] Audio devices that are physically connected to different PCs or network nodes can be logically grouped into a single 'meta-device' or a 'cluster' to enable smart behaviour to be implemented across the collection of devices. For example, a user connects headphones to a PC that is acting as a server for audio that is being played over a network to a set of networked speakers. The user can selectively enable a behavioural rule that will mute the speakers when the headphones are connected.

[0029] As the audio driver 29 of Fig. 2 can be implemented in software on a PC this represents an opportunity to present a standard device discovery interface to an overall network. The device driver 29 can act as a virtual UPNP device even though the connected audio devices may not have UPNP capabilities. The abstraction of audio to the virtual device driver also allows the abstraction of the control interface for different classes of audio playback and recording product. Graphical interpretations of user interfaces can be stored on the device so that the drivers do not need to be preloaded on the control end product. Such an arrangement is illustrated schematically in Fig. 4 wherein an audio receiver 50 is controlled from a PC device 51 with a user interface 52 being present to the user for overall system control.

[0030] More complex arrangements are possible. The remote interface 12 functions of audio visual products can be provided where the user interface can be remotely controlled from any client. This allows for device abstraction and separate encoding, for example, XML coding of device characteristics. An example of this encoding is illustrated in Fig. 5.

[0031] This allows for the set up of a wireless audio device without having to connect it physically to the PC. The audio device can become a client on the user's pre-existing wireless network. There is a need to tell the wireless device the name of the network and also install the security key, if any, into it. The PC will also be a client of the wireless network (a peer to the device). The process for registration of the wireless device can proceed by the following steps:

I . The device is turned on for the first time by the user 2. The device starts up initially as an "access point" - i.e. a wireless network hub & is set to a specific network name (e..g "Network A")

3. The user installs the software on a PC in reasonable proximity (wireless network range) to the device

4. The PC software sets the PC's wireless network name to the same as the device's default network e.g. "Network A" above. (The PC's current wireless network name is stored)

5. The PC software then searches for a wireless audio node on that network

6. PC connects to that wireless audio node (the device)

7. PC configures the device as follows: 8. -The device scans for other wireless networks in the area and the user is presented with a list of networks to choose from -The user selects their wireless network

-IF there is a security key required, the user is prompted to enter it -The device is restarted as a client, with the user-defined wireless network name and security key entered.

9. The PC's wireless network name is then switched back to the original one it was before step 4.

10. The device is now a client on the network and is a peer of the PC.

I 1. The PC can connect to the device and stream audio [0032] The preferred embodiments thereby provides for a simplified audio interface in a complex audio environment. [0033] The forgoing describes preferred forms of the present invention. Modifications, obvious to those skilled in the art can be made thereto without departing from the scope of the invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

1. A method of providing audio streaming capabilities in a networked environment, the method comprising the steps of:

(a) on a first hardware device rendering an audio application's audio output to a virtual software driver device to produce a first output audio stream suitable for rendering on a second audio hardware playback device;

(b) outputting the first output audio stream across a network to matching second audio hardware playback device;

(c) rendering the emitted said first output audio stream at said second audio playback device.

2. A method as claimed in any previous claim wherein said network comprises a wireless network.

3. A method as claimed in any previous claim wherein said first hardware device comprises a Personal Computer having digital signal processing capabilities.

4. A method as claimed in any previous claim wherein said first output audio stream is in a surround sound format.

5. A method of providing audio streaming capabilities in a networked environment, the method comprising the steps of: on a first hardware device rendering a series of audio application's audio output to a corresponding virtual software driver device to produce a corresponding series of audio streams; mixing predetermined audio streams together in accordance with the output requirements for a series of audio output devices located at a series of dispersed locations so as to produce a series of mixed audio streams; outputting the mixed audio streams first output audio stream across a network to a corresponding series of audio hardware playback devices;

6. A method as claimed in any previous claim further providing on said hardware device a user interface for altering the playback characteristics of at least said second audio playback device. 7. A method as claimed in any previous claim further comprising the initial step of: [Amended Page] mixing local and remote audio streams.

9. A method of providing audio streaming capabilities in a networked environment, the method comprising the steps of:

(a) on a first hardware device rendering an audio applications audio output to a virtual software driver device to produce a first series of output audio streams suitable for rendering on a second series of audio hardware playback devices;

(b) outputting the first series of output audio streams across a network to matching second audio hardware playback devices;

(c) rendering the emitted first series of output audio streams at corresponding ones of said second audio playback devices.

10. A method as claimed in claim 9 wherein said first hardware device acts as a virtual UPnP device.

11. A method of providing audio streaming capabilities in a networked environment, the method comprising the steps of: (a) forming an audio cluster by clustering together a series of audio output devices;

(b) presenting a uniform virtual interface for rendering audio to said cluster;

(c) virtually rendering audio for playback on said cluster by said virtual interface;

(d) dispatching said virtually rendered audio for playback by said cluster.

12. A method as claimed in claim 11 further comprising the step of adding on demand, new audio output devices to the cluster.

13. A method of providing audio streaming capabilities substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.