JP3509711B2 - Method for determining broadcast transfer rate of equipment with digital interface - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of managing connection between digital devices through a digital interface, and more particularly to a method of determining a broadcast transfer rate in a device having a digital interface such as IEEE 1394.

[0002]

2. Description of the Related Art In recent years, digital television (hereinafter referred to as DT
V), digital VCR, digital set-top box (hereinafter referred to as DSTB), and various digital devices have been developed, and the IEEE 1394 standard is being introduced for interfacing between these digital devices. This IEEE 1394 standard is based on "" IEEE 13
94-1995: Standard for a High
Performance Serial Bus ", I
EEE Standard Press, Decembe
r 1995 ”.

A system interconnected through a digital interface such as IEEE 1394 manages isochronous bit stream connection between digital devices according to the IEC 61883 standard. This I
The EC 61883 standard is based on "" Specification
no of Digital Interface forE
electronic Audio / Video Equi
pment ", Part 1, December 199
5, HD Digital VCR Conference
e ”and the like.

In the IEC 61883 standard, an input plug and an output plug are defined as an inlet and an outlet of a bit stream to each digital device, and the input plug and the output plug are oMPR (output master pl).
ug register), oPCR (output p
lug control register), iMPR
(Input master plug register
r), iPCR (input plug control)
register). Each digital device manages the connection by controlling the registers related to the input plug and the output plug. As shown in FIG. 1, the oPCR comprises on-line and broadcast co.
unter, point2point count
r, reserved, channel number
It consists of r, data rate, overhead ID, and payload area. And the oMPR is
As shown in FIG. 2, the data rate capabili
ity, broadcastchannel bas
e, extension field 1, extension
ion field 2, reserved, and num
It consists of the Ber of output plugs region.

[0005] Such a connection form between digital devices includes a point-to-point connection.
connection and broadcast connection (broa)
dcast connection). A point-to-point connection is a connection consisting of an output plug, an input plug, and a channel between them, where any digital device can set up that connection, and the device that set up the connection brakes the connection later. This releases the resources (channel, bandwidth) for that connection. The broadcast connection can be roughly divided into a broadcast-in connection and a broadcast-out connection. The broadcast-in connection is a connection between an input plug and a channel, and the broadcast-out connection is a connection between an output plug and a channel. Is a connection. The broadcast connection can actually be set only by the device that inputs and outputs the bit stream by this connection, and the braking and releasing of the connection can be set by any device on the network. At this time,
IMPR, oMPR, iPCR, oPC for all management including setting and releasing of point-to-point connection and broadcast connection
The RMI register is used, and the device that allocates and releases resources is the IRMI of the entire network system.
(Isochronous ResourceMana
The resources are allocated and released by communicating with the device that controls the (ger).

Referring to FIG. 3, in the system, a set top box (hereinafter referred to as STB) 110 which is a source device and a DTV which is a sink device are connected through an IEEE 1394 line. As shown in FIG. 1, two or more digital devices are connected to exchange data such as video,
Set up a broadcast connection that is an isochronous connection for data transfer between devices. That is, STB 1
When 10 sets a broadcast-out connection to a specific channel and the DTV 120 sets a broadcast-in connection to this channel, video data is transferred between the STB 110 and the DTV 120 via the specific channel. It At this time, the digital device must be allocated system resources, that is, channels and bandwidth, to be used for the broadcast connection. The channel is assigned a currently available number and its bandwidth is determined by the signal format and rate, and some additional information. Of these, the transfer rate has the strongest effect on the required bandwidth value.
When the transfer rate doubles, the bandwidth value to be allocated is halved. Therefore, in order to use the bandwidth of the entire network system efficiently, the transfer rate must be set to the maximum possible. Therefore, in point-to-point connection, the maximum transfer speed that can be supported between both devices is calculated. On the other hand, in the broadcast-out connection, since the other party is not determined, the lowest transfer rate (100 Mbps in the case of IEEE 1394) that all devices can support is used. For example, in a network system connected by IEEE 1394, the first device sets the broadcast out to exchange a bit stream between the first device supporting 200 Mbps and the second device supporting 400 Mbps, and the second device sets the broadcast out. If the device sets Broadcast-In, the transfer rate is actually 200 Mbps
And use only 150 Mbps bandwidth,
Since the first device sets the broadcast-out at 100 Mbps, the bandwidth is allocated to about 300 Mbps. Therefore, since the bandwidth varies depending on the transfer rate, the bandwidth of the entire network system cannot be used efficiently. Of course, the existing IEEE 1
Digital interface standards such as 394 do not mention any transfer rate for broadcast-out connections.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention, in a system in which a plurality of digital devices are connected to each other through a digital interface, that the signal format which one device is currently trying to output from the other device is It is an object of the present invention to provide a method for determining a broadcast transfer rate, which checks whether it is possible and determines the transfer rate of its own broadcast-out connection.

[0008]

In order to achieve the above object, the present invention provides a transfer rate when a device sets up a broadcast-out connection in a network system in which a plurality of devices are interconnected through a digital interface. (A) checking whether or not the certain device is compatible with the signal format to be output by itself and the signal format for each device connected to the network system, and If it is determined, among the steps of detecting the maximum transfer rate supported by each of the devices, (b) the maximum transfer rate supported by the certain device, and the maximum transfer rate detected in the step (a). Determining a minimum value as a transfer rate of the broadcast-out connection of the certain device. Is characterized by.

To achieve the above object, the present invention provides a method for determining a channel transfer rate when a device sets up a broadcast-out connection in a network system in which a plurality of devices are interconnected through a digital interface. And (a) detecting a maximum transfer rate that can be supported by the plurality of devices to which the certain device is connected, and (b) a maximum transfer rate supported by the certain device and the step. Determining the minimum value among the maximum transfer rates detected in (a) as the transfer rate of the broadcast-out connection of the certain device.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 4 is an example of a network system for explaining the broadcast transfer rate determination method according to the present invention.

Referring to FIG. 4, the first device 410 and the second device 410
Device 420, third device 430, fourth device 440 and fifth
Device 450 is connected to the IEEE 1394 interface. Each device supports a transfer rate of 200 Mbps to 400 Mbps, for example. That is,
The first device 410 is 200 Mbps (hereinafter, S200),
The second device 420 is 400 Mbps (hereinafter, S40
0), the third device 430 is S400, and the fourth device 440 is S400.
The 200 and the fifth device 450 support the transfer rate of S400. These devices set up a broadcast connection, which is an isochronous connection for data transfer, and exchange data. At this time, the fifth device 450 tries to set the broadcast-out connection to the specific channel. For the sake of convenience of explanation, the fifth device 450 may use an MPEG (Moving Picture E) connection via the broadcast-out connection.
xpert Group) Suppose you want to transfer data. The fifth device 450 determines the transfer rate of the broadcast-out connection by checking the compatibility between the signal format to be output by itself and the signal format for each device 410, 420, 430, 440.

FIG. 5 is a flow chart showing a method of determining a broadcast transfer rate of a device having a digital interface according to the present invention. Hereinafter, the method for determining the broadcast transfer rate of the device will be described with reference to FIGS. 4 and 5.

The fifth device 450 tries to transfer the MPEG data through the broadcast-out connection (51).
0). The fifth device 450 checks whether the first device 410, the second device 420, the third device 430, and the fourth device 440 currently connected to the network system can effectively receive the transferred MPEG format. That is, the fifth device 450 checks whether or not the signal format to be output by itself and the signal formats for the devices 410, 420, 430, 440 are compatible (520).

The fifth device 450 is one of the devices 410, 420, 430 currently connected to the network system.
When the 440 determines that it can effectively receive the signal format that it should output, each device 410, 420, 43
Detect the maximum transfer rate supported by 0, 440 (53
0).

The maximum transfer rate supported by the fifth device 450 detected in step 530 and each device 410, 4
The minimum value among the maximum transfer rates supported by 20, 430, and 440 is calculated and determined as the transfer rate of the broadcast-out connection of its own (540).

For example, the second device 420 and the third device 43
If 0 supports the MPEG format, the maximum transfer rate of all of these devices is S400, so the fifth device 450 sets the transfer rate of the broadcast-out connection to S400. In this case, the required bandwidth is reduced to 1/4 as compared with the existing case where S100 is simply set.

If the first device 410, the second device 420 and the third device 430 support the MPEG format, the maximum transfer rate of each of these devices is S20.
Since it is 0, S400, and S400, the fifth device 450 sets the transfer rate of the broadcast-out connection to S200, which is the minimum value. In this case, simply use S
The required bandwidth is halved compared to setting 100.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that modifications can be made by those skilled in the art within the spirit of the present invention. That is, a certain device may omit the process of checking whether the other device recognizes the signal format which the other device is currently trying to output and whether it can receive the signal format. That is, a certain device can simply check the maximum transfer rates of all currently connected devices, obtain the minimum value of these maximum transfer rates, and determine the minimum value as the transfer rate of its own broadcast-out connection.

On the other hand, the above-described embodiment of the present invention can be created by a computer-executable program. The program can be implemented by a general-purpose digital computer that operates the program from a medium used in the computer. The medium is a magnetic storage medium (eg, RO
M, floppy (registered trademark) disk, hard disk, etc., optically readable medium (eg, CD-ROM, DVD)
Etc.) and carrier waves (eg, transferred over the Internet).

[0021]

As described above, according to the present invention, the IE
In a network system in which a plurality of devices are connected through a digital interface such as EE 1394, when a certain device sets up a broadcast-out connection, the original purpose of the broadcast-out connection can be achieved, and at the same time, the bandwidth of all network systems can be achieved. The width can be used efficiently.

[Brief description of drawings]

FIG. 1 is a detailed diagram of oPCR according to a digital interface standard.

FIG. 2 is a detailed diagram of oMPR according to a digital interface standard.

FIG. 3 is a configuration diagram showing a network system in which a plurality of digital devices are mutually connected through a digital interface such as a general IEEE 1394.

FIG. 4 is an example of a network system for explaining a broadcast transfer rate determination method according to the present invention.

FIG. 5 is a flowchart showing a method of determining a broadcast transfer rate of a device having a digital interface according to the present invention.

[Explanation of symbols]

410 First device 420 Second device 430 Third device 440 Fourth device 450th equipment

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Claims (3)

(57) [Claims] 1. A method for determining a transfer rate when a device sets up a broadcast-out connection in a network system in which a plurality of devices are interconnected via a digital interface, the method comprising: If the compatibility between the signal format to be output by itself and the signal format for each device connected to the network system is checked, and it is determined that they are compatible, the maximum transfer speed supported by each device. And (b) the maximum value of the maximum transfer rate supported by the certain device and the maximum value of the maximum transfer rate detected in the step (a) as the transfer rate of the broadcast-out connection of the certain device. And a step of determining the channel transfer rate. 2. The transfer rate determining method according to claim 1, wherein the connection between the devices is an isochronous connection. 3. A method for determining a channel transfer rate when a device sets up a broadcast-out connection in a network system in which a plurality of devices are interconnected via a digital interface, the method comprising: Detecting a maximum transfer rate supported by the plurality of devices to which the device is connected; (b) a maximum transfer speed supported by the certain device; and a maximum transfer speed detected in the step (a). Determining the minimum value of the transfer rates as the transfer rate of the broadcast-out connection of the certain device.