JP2005122619A - Client device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate to take a target file out of one of a plurality of server devices. <P>SOLUTION: This client device is provided with a communication block 32 which is connected to the plurality of server devices through a network, a memory 44 which stores information for identifying a server device used last, and a control circuit 40. The control circuit 40 makes a connection with a server device when the information for identifying the server device used last is stored in the memory 44 and the server device that the stored information indicate makes a response. When the information for identifying the server device used last is not stored in the memory 44 and a server device other than the device that the stored information indicates makes a response, a connection with the server making the response is made and information for identifying the server device making the response is stored in the memory 44 as information for identifying the server device used last. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a client device.

  For example, in order to be able to enjoy audio contents such as music in each room in the home, a network system may be constructed as shown in FIG. At this time, audio contents are prepared in the server device, and a client function is added to the audio device to form a network audio device.

  If such a network system is constructed, audio content can be distributed from the server device to each network audio device (client device), so that music or the like can be heard in each room.

  In such a network audio system, when distributing digital audio data from the server device to the client device, it is conceivable to use TCP / IP as the protocol. This TCP / IP has spread with the development of the Internet, but it can withstand the transmission of digital audio data from the viewpoint of transmission speed and reliability, and the cable can be extended up to 100m, Audio content can be distributed anywhere in the home.

  In consideration of the communication band, a plurality of digital audio data can be transmitted at a time as long as the transmission is equivalent to digital audio data. You can also enjoy separate music at the same time. In addition, since the audio content is prepared in the server device, a large number of audio contents can be prepared and managed in an integrated manner.

For example, there are the following prior art documents.
Japanese Patent Laid-Open No. 2001-109877

  For the sake of simplicity, assume that four servers 11 to 14 and one network audio device 20 constitute a network audio system as shown in FIG. In this case, it is assumed that the server 11 stores, for example, five directories A to E and 12 files 1 to 12 in a tree structure (hierarchical structure) as shown in FIG. Similarly, it is assumed that a plurality of directories and a plurality of files are also stored in a tree structure in the other servers 12 to 14. If the digital audio data is music data, for example, the digital audio data for one song constitutes one file.

Then, when the network audio device 20 takes out the target digital audio data (file) from the servers 11 to 14 and reproduces music or the like, the user needs to perform the following operation. That is,
(A) Select a server storing a target file from the servers 11 to 14.
(B) Select the directory that stores the target file from the server tree selected in (A).
(C) Select the target file from the directory selected in (B).
(D) Stream the file selected in (C).
However, it is cumbersome to operate in four steps in this way. Especially, if you make a mistake in the selection of the server in (A), it will be the objective no matter how many operations in (B) and (C). I can't find the file.

  The present invention is intended to solve such problems.

In this invention,
A client device that constructs a network system with a plurality of server devices,
A communication block connected to the plurality of server devices through a network;
Among the plurality of server devices, a memory for storing information for identifying a server device used last time,
Control circuit,
The control circuit is
When using any of the plurality of server devices, request connection to the plurality of server devices through the communication block,
When the information for identifying the server device used last time is stored in the memory and there is a response from the server device indicated by the stored information, the connection with the server device is established. Done
When the information for identifying the server device used last time is not stored in the memory and there is a response from a server device other than the server device indicated by the stored information, the response is While connecting to the server device that was
Information identifying the server device that has responded is stored in the memory as information identifying the previously used server device.

  According to the present invention, among the plurality of server devices, the server device is preferentially connected to the server device used last time, and thereafter, if the operations in the items (B) to (D) are performed, the target content can be obtained from the server device. It can be taken out.

  Further, when the server device used last time is not registered in the client device, the client device is connected to the server device that responded first, so that the content stored in the server device that responded first can be used. it can. At the next use, the server device that responded first is preferentially connected.

  Furthermore, since it is possible to change any valid server device among the plurality of server devices to a server device that is preferentially connected, the following (B) to (D) The target content can be taken out simply by performing the operation.

1 UPnP (R) Here, UPnP (R), which is one of protocol groups that can be used in a network audio system, will be described.

1-1 Configuration of UPnP (R) To play audio content using UPnP (R), it is necessary to comply with the UPnP (R) AV equipment and service regulations called UPnP (R) AV architecture. UPnP (R) AV equipment based on UPnP (R) AV architecture
Media server: A device that provides audio content Control point: Operation system, control terminal Media renderer: Audio signal processing system, audio playback device Therefore, the server in FIG. 4 constitutes a media server, and the network audio device (client) constitutes a control point and a media renderer.

1-2 UPnP (R) Function UPnP (R) is one of communication functions composed of IP, TCP, UDP, etc. on a network such as Ethernet (registered trademark). It is a group of protocols that enable devices to easily authenticate each other and provide services and execute the services provided.

For this reason, UPnP® has a protocol stack as shown in FIG. The UPnP (R) device has the following six functions (1) to (6). That is,
(1) Addressing
A function for UPnP® devices to obtain an IP address on the IEEE 802 network. DHCP or automatic acquisition is used.
(2) Discovery
Function to detect UPnP (R) devices. This is performed after addressing, and the control point can detect the UPnP (R) device to be controlled.
The protocol used here is SSDP. When each device is connected to the IEEE 802 network, it multicasts a message for notifying its own devices and services on the IEEE 802 network.
The control point can know what device is connected to the IEEE 802 network by receiving the multicast message.
(3) Description (Description)
Function to know the details of the function of the counterpart device. A device description URL is described in the SSDP packet output from the control target device discovered by the control point by the discovery. The control point can acquire more detailed device information of the device from the device description by accessing the URL.
This device information includes icon information, model name, producer name, product name, service description in which detailed information on the service of the device is described, and the like. The control point can know the access method to the target from these device descriptions and service descriptions. The device description and service description are expressed in XML.
(4) Control
Function to control the other device. This control is roughly divided into two types, “Action” and “Query”. The action is performed by a method defined in the action information of the service description. By executing the action (Invoke), the control point can operate the target.
The query is used to retrieve the value of device information (stateVariable) of the service description. In the control, a transport protocol called SOAP is used, and XML is used as the expression.
(5) Eventing
A function that notifies the other device of the situation. This eventing is used to notify the control point from the target when the value of the device information is changed. The control point can know the variable held by the target from the device information by analyzing the service description for the target, and can receive a notification from the target when the variable is changed.
In eventing, a transport protocol called GENA is used, and XML is used as its expression.

(6) Presentation
The ability to publish your own functions. This presentation is used to provide the user with control means using a user interface. By accessing the presentation URL described in the device description, a presentation page described in HTML can be obtained. This function makes it possible to prepare an application on the target.

1-3 Functions of Media Server A function called CDS is indispensably incorporated in the media server, and notifies the control point how content is stored in the media server. There are two abstracted objects in CDS called “containers” and “items”. Simply put,
Item: Content or its file.
Container: Group when items are grouped. directory.
It is. These containers and items always have a tree structure (hierarchical structure), and the tree of FIG. 6 is an example.

  The control point can obtain URLs (links on which information is written) of each content by acquiring tree information having a tree structure as shown in FIG. 6 from the media server, for example. In addition, when information of desired content (item) can be acquired, operations such as playback and stop of the content can be performed using a function called AV transport of the media server.

2. Network Audio Machine (Client) Here, a network audio machine will be described, but the network audio system uses the above-described UPnP®.

2-1. Configuration of Network Audio Machine In FIG. 1, reference numeral 20 denotes an example of a network audio machine, and the network audio machine 20 includes a media renderer 30 and a control point 40. The media renderer 30 is an audio signal processing system. In this example, the media renderer 30 includes an RJ-45 modular jack 31, a communication block 32, an equalizer 33, a D / A converter 34, and output amplifiers 35L and 35R. Is done.

  In this case, the modular plug 61 is inserted into the modular jack 31, and the network audio device 20 is connected to the media server 20 through the plug 61 and the LAN cable 62, and further through, for example, a network using Ethernet (registered trademark) as shown in FIG. 11 to 14 are connected.

  The communication block 32 is an LSI for realizing network communication, and analyzes packets transmitted and received by TCP / IP, and performs content selection, search, and audio signal reproduction control. Therefore, the communication block 32 is connected to the media server through the modular jack 31 and receives the content sent from the server.

  Furthermore, the equalizer 33 is for performing selection of an input signal and equalizing processing for the selected signal. Therefore, the equalizer 33 is connected to the communication block 32 and supplied with digital audio data, and an analog audio signal is supplied to the A / D converter 38 through the analog input terminals 37L and 37R, and its A / D conversion output is supplied. It is supplied to the equalizer 33. A digital audio signal is supplied to the equalizer 33 through the digital input terminal 39.

  Then, the equalizer 33 selects the signal supplied thereto, performs equalizing processing, and supplies the equalizing output to the D / A converter 34. The D / A converter 34 D / A converts the digital signal supplied thereto into left and right channel analog audio signals L and R, and the output amplifiers 35L and 35R output the D / A conversion result audio signal. L and R are supplied to the speakers 63L and 63R through the output terminals 36L and 36R.

  On the other hand, the control point 40 is a control system of the network audio machine 20, and is constituted by a microcomputer, for example. Therefore, the control point 40 includes a CPU 41 that executes various programs, a ROM 42 in which the programs are written, a RAM 43 for a work area, and a nonvolatile memory 44 that holds various data when the power is turned off. These memories 42 to 44 are connected to the CPU 41 through the system bus 49.

  Further, in the ROM 42, for example, a routine 100 as shown in FIG. 2 is prepared as a part of the program executed by the CPU 41. This routine 100 is for realizing processing corresponding to the item (A) for a plurality of media servers. Although details of the routine 100 will be described later, in FIG. 2, the routine 100 shows only a portion related to the present invention.

  Furthermore, the control point 40 has an operation key 45 and a display 47 as a user interface. In this case, the operation key 45 is constituted by a non-locking type push switch, and the display 47 is constituted by a fluorescent display tube or an LCD. The key 45 is connected to the system bus 49 through the interface 46, and the display 47 is connected to the system bus 49 through the display controller 48.

  Further, the system bus 49 is connected to the communication block 32 through the interface 51, and various data and commands are exchanged between the control point (microcomputer) 40 and the communication block 32.

  A system bus 49 is connected to the equalizer 33 through the interface 52, and the equalizer 33 is controlled by the control point 40. As a result of this control, the digital audio data obtained from each of the communication block 32, the A / D converter 38 and the input terminal 39 is selected by the equalizer 33, and the selected digital audio data is as described above. The equalizing process is executed at the same time.

  When digital audio data is sent from one of the media servers 11 to 14, it is processed and extracted by the communication block 32, equalized by the equalizer 33, and then analog audio by the D / A converter 34. D / A conversion into signals L and R is performed. The audio signals L and R are supplied to the speakers 63L and 63R through the amplifiers 35L and 35R and output as sound.

2-2 Selection of Media Server This is a process corresponding to the item (A) and is realized by the routine 100. Therefore, the user performs only operations (B) to (D).

  Here, the network audio system of FIG. 5 will be described as an example. In the following description, among the media servers 11 to 14 in FIG. 5, the media server 13 is referred to as “previous media server”. Here, the “previous media server” refers to the media server used for file retrieval (reproduction of digital audio data) last time among the media servers 11 to 14. In addition, the previous media server 13 is registered in the network audio device 20 by storing information for identifying it, for example, information such as MAC in the memory 44.

  When the network audio device 20 makes a connection request to the media servers 11 to 14, the processing of the CPU 41 starts from step 101 of the routine 100. Next, in step 102, the detection of the media servers 11 to 14 is performed. In order to give a time limit, a time-out timer is set, and then in step 103, the discovery message of item (2) is multicast to the media servers 11-14.

  Subsequently, in step 111, it is determined whether or not the previous media server is registered in the network audio device 20. In this case, since the media server 13 is registered in the network audio device 20 as the previous media server, the process proceeds from step 111 to step 112. In this step 112, from the previous media server 13 for the multicast in step 103, Check whether there is a response.

  If there is no response, the process proceeds from step 112 to step 113. In this step 113, it is checked whether or not the timeout timer set in step 102 has timed out. Return to 112. Therefore, thereafter, steps 112 and 113 are repeated until the timeout timer times out.

  If there is a response from the previous media server 13 during this repetition period, this response is detected in step 112, and the process proceeds from step 112 to step 114. In step 114, the network audio device 20 and the previous media are detected. A connection with the server 13 is made, and the connection is displayed on the display 47, and then the routine 100 is terminated at step 126.

  Therefore, after that, if the user executes the items (B) to (D) with respect to the previous media server 13, the user can take out digital audio data such as the target music, and stream the music. Can do.

  However, when there is no response from the previous media server 13 during the repetition period of steps 112 and 113, the timeout timer times out, so the process proceeds from step 113 to step 115. The message “Could not be connected” is displayed on the display 47, and then the routine 100 is terminated at step 126.

  On the other hand, if the previous media server is not registered in step 111, the process proceeds from step 111 to step 122, and in this step 122, as in step 112, from other media servers 11, 12, and 14. If there is no response, the process proceeds from step 122 to step 123. In this step 123, it is checked whether or not the timeout timer set in step 102 has timed out. Returns from step 123 to step 122. Therefore, thereafter, steps 122 and 123 are repeated until the timeout timer times out.

  If there is a response from any of the other media servers 11, 12, 14 during this repetition period, this response is detected by step 122, and the process proceeds from step 122 to step 124. The media server that responds first is registered in the memory 44, for example, as the previous media server. Thereafter, the process proceeds from step 124 to step 114 to connect to the media server that responded first, and display on the display 47 that the connection to the media server that responded first was made. Thus, the routine 100 is terminated.

  Therefore, after that, if the user executes the items (B) to (D) for the media server that responds first, the user can take out the digital audio data such as the target music and stream the music. Can be played.

  However, when there is no response from the media servers 11, 12, and 14 in the repetition period of steps 122 and 123, the timeout timer times out, so the process proceeds from step 123 to step 125. In this step 125, for example, “valid server” Is not connected ”message is displayed on the display 47, and then the routine 100 is terminated at step 126.

  Thus, according to the routine 100, the network audio device 20 is preferentially connected to the media server 13 used last time among the media servers 11 to 14, and thereafter the operations of the items (B) to (D) are performed. The target digital audio data is extracted from the media server 13, and the digital audio data is transmitted to the network audio device 20 through the network in a streaming format. Therefore, according to the network audio device 20 described above, the user can listen to music stored in the media server 13 used last time without performing selection of the media server only by performing the operations of the items (B) to (D). Can do.

  When the media server 13 used last time is not registered in the network audio device 20, the network audio device 20 is connected to the media server that responded first, so that the music stored in the media server that responded first is stored. You can listen to them. At the next use, the media server that responded first is preferentially connected.

2-3 Previous Media Server Change In the case of the routine 100 shown in FIG. 2, when the network audio device 20 requests connection to the media servers 11 to 14, if the previous media server 13 is valid, the network audio device 20 is always connected to the previous media server 13. Therefore, even if it is desired to play back digital audio data stored in other media servers 11, 12, and 14, it cannot be played back.

  The routine 200 shown in FIG. 3 is a case where it is possible to connect to other media servers 11, 12, and 14 by changing the information of the previous media server.

  That is, in the network audio device 20, when the previous change of the media server is requested, the processing of the CPU 41 starts from step 201 of the routine 200. Next, in step 202, the time limit is given to the detection of the media servers 11 to 14. A timeout timer is set, and then in step 203, the discovery message of item (2) is multicast to the media servers 11-14.

  Subsequently, in step 211, the presence / absence of a response from the media servers 11 to 14 for the multicast in step 203 is checked. If there is no response, the process proceeds from step 211 to step 212. The timed-out timer is checked to see if it has timed out, and if not timed out, the process returns from step 212 to step 211. Therefore, thereafter, Steps 211 and 212 are repeated until the timeout timer times out.

  If there is a response from any of the media servers 11 to 14 during this repetition period, this response is detected in step 211, and the process proceeds from step 211 to step 213. In step 213, the media server that has responded Is registered in the media server list, and then the process proceeds to step 212. Therefore, if there is a media server that has responded from the time of multicast in step 203 to the time-out of the timeout timer set in step 202, all of the media servers are registered in the media server list. .

  When the time-out timer elapses, the process proceeds from step 212 to step 221, where it is checked whether a media server is registered in the media server list. If the media server is registered as a result of this check, the process proceeds from step 221 to step 222. In this step 222, the media set in the previous media server from among the media servers registered in the media server list. Let the user select a server.

  When the user selects a media server to be set as the previous media server from the list of media servers, the process proceeds from step 222 to step 223. In step 223, the media server selected by the user in step 222 is changed to the previous media server. The media server is registered in the memory 44, and then the routine 200 is terminated at step 224.

  In step 221, when the media server is not registered in the media server list, the process proceeds from step 221 to step 224, and the routine 200 is terminated.

  Therefore, according to the routine 200, any valid media server among the media servers 11 to 14 can be changed to a media server to be preferentially connected. By simply performing operations (B) to (D) on the media server, it is possible to retrieve the target file and play music or the like.

3 Summary According to the network audio device 20 described above, the media servers 11 to 14 are preferentially connected to the media server 13 used last time. Therefore, if the operations (B) to (D) are performed thereafter, The target digital audio data can be extracted from the media server 13.

  Therefore, the music stored in the media server 13 used last time can be listened to only by performing the operations in the items (B) to (D). For example, even if playback is stopped while listening to music, the music can be heard seamlessly from the next time during the next playback.

  When the media server 13 used last time is not registered in the network audio device 20, the network audio device 20 is connected to the media server that responded first, so that the music stored in the media server that responded first is stored. You can listen to them. At the next use, the media server that responded first is preferentially connected.

  Furthermore, any valid media server among the media servers 11 to 14 can be changed to a media server to be preferentially connected. Henceforth, (B) to (D) The target file can be taken out and music etc. can be reproduced just by performing the operation of item).

4. Others In the above description, the audio content is extracted from the media server. However, the present invention can be applied if the target content is extracted from a plurality of media servers. Also, in routine 100, routine 200 can be executed following step 115, or the timeout timer can be restarted before proceeding to step 122.

  Further, in step 122 of the routine 100, the presence / absence of a response from a specific media server is checked. If there is a response, the process proceeds from step 122 to step 124. If there is no response, the process proceeds from step 123 to step 123. Proceed to 125.

  In the above description, UPnP (R) is used as a protocol. The tree structure of directories (containers) and files (items) in the media server can be transmitted to the network audio device 20 through the network, Jini (R), HAVi (R), or the like can be used as long as playback or stop can be instructed. Furthermore, when the communication block 32 has a software processing capability, the communication block 32 can execute part or all of the routines 100 and 200.

[List of abbreviations]
A / D: Analog to Digital
AV: Audio and Visual
CDS: Contents Directory Service
CE: Consumer Electronics
CPU: Central Processing Unit
D / A: Digital to Analog
DHCP: Dynamic Host Configuration Protocol
GENA: General Event Notification Architecture
HAVi (R): Home Audio / Video interoperability (R)
HTML: Hyper Text Markup Language
IEEE: Institute of Electrical and Electronics Engineers
IP: Internet Protocol
LAN: Local Area Network
LCD: Liquid Crystal Display
MAC: Media Access Control address
RAM: Random Access Memory
ROM: Read Only Memory
SOAP: Simple Object Access Protocol
SSDP: Simple Service Discovery Protocol
TCP: Transmission Control Protocol
TCP / IP: Transmission Control Protocol / Internet Protocol
UDP: User Datagram Protocol
UPnP (R): Universal Plug and Play (R)
URL: Uniform Resource Locator
XML: eXtensible Markup Language

It is a systematic diagram showing one embodiment of the present invention. It is a flowchart which shows one form of the process sequence which can be used for this invention. It is a flowchart which shows the other form of the process sequence which can be used for this invention. It is a figure which shows a server client system. It is a figure which shows a server client system. It is a figure for demonstrating this invention. It is a figure which shows the protocol stack of UPnP (R).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Network audio machine, 30 ... Media renderer, 31 ... Modular jack, 32 ... Communication block, 33 ... Equalizer, 34 ... D / A converter, 35L and 35R ... Output amplifier, 40 ... Control point, 41 ... CPU, 42 ... ROM, 43 ... RAM, 44 ... nonvolatile memory, 45 ... operation keys, 47 ... display, 61 ... modular plug, 62 ... LAN cable, 63L and 63R ... speaker

Claims (4)

A client device that constructs a network system with a plurality of server devices,
A communication block connected to the plurality of server devices through a network;
Among the plurality of server devices, a memory for storing information for identifying a server device used last time,
Control circuit,
The control circuit is
When using any of the plurality of server devices, request connection to the plurality of server devices through the communication block,
When the information for identifying the server device used last time is stored in the memory and there is a response from the server device indicated by the stored information, the connection with the server device is established. Done
When the information for identifying the server device used last time is not stored in the memory and there is a response from a server device other than the server device indicated by the stored information, the response is While connecting to the server device that was
A client device in which information for identifying a server device that has responded is stored in the memory as information for identifying the previously used server device. The client device according to claim 1,
The control circuit is
When the information for identifying the server device used last time is not stored in the memory and there is a response from a server device other than the server device indicated by the stored information, the response is Connect to the first server device and
A client device in which information for identifying a server device with the first response is stored in the memory as information for identifying the previously used server device. The client device according to claim 1,
The control circuit is
When information identifying the server device used last time is not stored in the memory, and when there is a response from a specific server device other than the server device indicated by the stored information, While connecting to a specific server device,
A client device in which information for identifying the specific server device is stored in the memory as information for identifying the server device used last time. In the client device according to claim 1, claim 2, or claim 3,
A client device configured to change information that is stored in the memory and that identifies the server device that has responded to information that identifies another server device among the plurality of server devices.

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