JPH10190736A - Synchronizing method/device for network data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To synchronize data on a network. SOLUTION: A node 1 adds the same data marks to data transmitted at the same timing and transmits them to plural channels. Data on respective channels are received by corresponding nodes and corresponding processings are executed in the respective nodes. Data transmitted from the respective nodes are inputted to a node 4 being a time aligner and are stored in buffers corresponding to the respective channels. When data to which the same data marks are added are received from all the channels, data are transmitted to a node 5. Thus, timing can be adjusted even if data of the respective channels arrive at the node 4 at different time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for synchronizing network data.

[0002]

2. Description of the Related Art Generally, when handling multimedia data such as image data, audio data, and musical sound data, it is required to synchronize and output these data. As a technique therefor, a time stamp is added to data, and various data are synchronized by referring to the time stamp. An example of such a timestamp is SMPTE
Time codes are known. This is SMTPE (So
ciety of Motion Picture and Television Engineers)
Is a time code defined by the above, and an address consisting of 80 bits in one frame of video data (when ○○○
(Composed of a time code and user bits displayed in the form of ○ minutes, ○ seconds, and ○○ frames), which are used for editing processing and synchronous running of a plurality of materials and devices.

In recent years, various multimedia devices and A
With the advancement of digitalization of V devices, it has been proposed to configure a multimedia system by mutually connecting a plurality of multimedia related devices using a network such as IEEE1394.

[0004]

When data that requires precise timing reference, such as digital sound data, digital video data, or performance data, is transmitted using a network as described above, such data must be transmitted. It is necessary to guarantee reproducibility on the time axis.

For example, in a multimedia system configured by connecting a plurality of nodes each having a unique function through a network, in order to perform predetermined processing on data generated by a certain node, The generated data is transferred to another node via a plurality of paths so as to pass through a node that executes a corresponding process. Therefore, each data arrives at the output node with a different delay time due to the processing time at the node in each path, and it is not possible to guarantee the reproducibility of the data on the time axis.

This will be described in more detail with reference to FIG. In the example shown in this figure, node 1 (1
The four nodes 1) to 4 (14) are IEEE13
It is assumed that they are connected by 94. As described above, various devices for configuring the system can be nodes. Here, for example, it is assumed that, for example, a tone generator is configured as a whole, and node 1 is a tone generator and node 2 is a tone generator. , An effector for adding vibrato, a node 3 is an effector for performing panning on a musical tone, and a node 4 is a mixer for mixing each musical tone signal.

[0007] In the musical tone generating apparatus thus configured, a plurality of musical tones are output at predetermined timings (frames) from the node 1 which is the tone generator, and these musical tones are output as they are. It is assumed that there are, for example, four types, one added with vibrato, one panned, and one further panned after adding vibrato. In this case, the tone generator of the node 1 outputs each type of musical tone to a network channel corresponding to each of the four types of musical tone processing.

The other nodes such as node 2, node 3 and node 4 each have a preset network channel to be received by themselves, and receive data from each of the channels received from the network. The data of the channel to be fetched is subjected to predetermined processing, for example, vibrato, panning, mixing and the like. Then, if necessary, the data for which the processing has been completed is transmitted to the network again.

FIG. 7 shows an example of the arrangement of each channel on the network. As shown, packets corresponding to each channel are arranged on the time axis with a predetermined gap therebetween. Each packet is composed of an arbitration unit 21 and a data packet 23 to which a data prefix unit 22 and a data end unit 24 are added before and after the arbitration unit 21. The packet may be either a packet obtained by isochronous transfer or a normal packet.

In the tone generating apparatus in which each component is connected by a network as described above, the node 1
The tone generator of which the effect processing is not performed among the generated musical sound data is transmitted directly from the node 1 to the node 4 which is a mixer via, for example, the first channel ch1 of the network (A14). Further, the musical tone to be subjected to the reverb processing is transmitted to the node 2 which is a reverb processing unit via, for example, the second channel (A12). Further, the tone to be panned is transmitted to the node 3 that executes the panning process, for example, via the third channel ch3 (A13).

The reverb processing unit of the node 2 determines that the tone data (A12) of the second channel ch2 in the network is received by itself, reads the tone data, and performs a predetermined reverb process. Then, among the tones subjected to the reverb processing, those to be further panned are sent to the fourth channel ch4 and sent to the node 3 which is a panning processing unit (A123). In addition, the tone which is not subjected to panning is transmitted to the node 4, which is the mixer (A124). The tone data to be transmitted to the node 4 is transmitted using, for example, the channel ch5.

The panning processing unit of the node 3 converts the tone data (A13) sent from the node 1 through the channel ch3 and the tone data (A123) sent from the node 2 through the channel ch4,
It determines that the tone is to be processed by itself, receives these tone data, and performs a predetermined panning process. The tone data received from the channel ch4 and subjected to panning is transmitted to the node 4 via the channel ch6 (A1234).
The tone received through the channel 3 and subjected to the panning process is transmitted to the node 4 through the channel ch7 (A134).

As described above, the tone generated at the node 1 reaches the mixer at the node 4 through the following four routes. (1) Music data (A1) directly transmitted through channel ch1
4), (2) ch5 data (A124) subjected to reverb processing in node 2, and (3) ch6 data (A1234) subjected to reverb processing in node 2 and further subjected to panning processing in node 3. ),
And (4) the data (A134) of ch7 that has been subjected to the panning processing in the node 3.

As described above, the tone data generated at the node 1, which is the sound source, reaches the mixer of the node 4 through different paths, but the execution time for each processing at the nodes 2 and 3 is different. Therefore, even if the musical tone is generated from the node 1 at the same timing, the time at which the musical tone arrives at the node 4 which is the mixer differs depending on the path through which the musical tone passes. Here, assuming that the time required for the processing in the node 2 is a2 and the time required for the processing in the node 3 is a3, the data passing through the routes (2), (3) and (4) is The data passing through the route arrives at the node 4 with a delay of a2, a2 + a3, and a3, respectively. As a result, a timing shift occurs at the time of addition in the mixer of the node 4.

In the above description, the difference in the arrival time of data passing through each route is based on the processing delay time at each node. However, in reality, the timing at which each node sends data to the network depends on the traffic. Because it may fluctuate depending on the degree of congestion, and the processing time at each node is not always a fixed time,
In many cases, the difference between the arrival times does not become a constant value.

Accordingly, an object of the present invention is to solve such a problem and to enable data that has passed through a plurality of routes on a network to reach a predetermined node in synchronization.

[0017]

In order to achieve the above object, a method for synchronizing network data according to the present invention is a method for synchronizing data transferred on a network to which a plurality of nodes are connected. A node that sends a plurality of data required to be taken adds a predetermined data mark to the plurality of data and sends the data to the network, and a node that receives data from the network refers to the data mark. Thereby, the plurality of received data are synchronized.

Further, the network data synchronizer of the present invention is a synchronizer for a plurality of data transferred on a network to which a plurality of nodes are connected, and is included in data received from the network. Based on the data mark, a plurality of received data to which the same data mark is added are synchronized. The network node has a function of the network data synchronization device.

[0019]

FIG. 1 shows a configuration example of an embodiment of a network system to which a network data synchronization method of the present invention is applied. In this figure, 1 is the first
, And as described above, for example, a sound source device. Reference numeral 2 denotes a second node, and reference numeral 3 denotes a third node, which are, for example, a reverb processing unit and a panning processing unit, respectively, as described above. Reference numeral 4 denotes a fourth node, which is a synchronization device (time aligner) for synchronizing data on the network.
The details of this time aligner will be described later. Reference numeral 5 denotes a fifth node, which is, for example, a mixer.

In the network configured as described above, the first node 1 sends out the musical sound data to the corresponding channel at each timing time (frame). A data mark indicating the transmission timing is added and transmitted. As the data mark, a frame number or time stamp data for specifying the frame is used.

As in the case of FIG. 6 described above, data (for example, musical tone data) transmitted from the node 1 at the same timing is subjected to predetermined processing at each node through different paths. The time alignment of the node 4 is reached. That is, as in the case of FIG. 6, the node 4 receives (1) data (A14) directly input from the node 1 and (2) input data to the node 2 from the node 1, Data (A124) input after being subjected to processing (for example, reverb processing). (3) After being input from the node 1 to the node 2 and subjected to, for example, the reverb processing at the node 2, the node 3 And data (A1234) subjected to predetermined processing (for example, panning processing) at the node 3 and (4) input from the node 1 to the node 3 and subjected to, for example, panning processing at the node 3. After input (A134)
Are input.

FIG. 2 is a diagram showing timings at which data output simultaneously from the node 1 arrives at the node 4 via respective paths. Among the data input to the node 4, the data that arrives earliest is the data (A14) of (1) described above. Assuming that the time required for the processing in the node 2 is a2 and the time required for the processing in the node 3 is a3, as shown in the figure, the data (A124) of (2) is longer than the data of A14 by a time a.
Arrived two delays later, the data of (4) (A134)
Arrives with a delay of time a3, and the data (A1234) of (3) arrives with a delay of time a2 + a3.

The time aligner of the node 4 synchronizes data arriving with such different delay times, aligns the timing of data arriving from each path, and
It is sent to node 5 which is a mixer. This time aligner is provided with a buffer for storing received data for each channel to be synchronized. When received data with the same data mark is received for all target channels, the buffer is stored. It operates to sequentially output the data of each channel with the same data mark. Thus, although the data is output from the node 1 at the same timing, the data arrives with different delay times, respectively, with the same timing, and can be transmitted to the node 5 which is a mixer, for example.

The operation of each node in the network system configured as described above will be further described with reference to FIGS. FIG. 3 shows a node 1 transmitting data.
5 is a flowchart for explaining the operation of FIG. As shown in this figure, the node 1 generates a data packet by adding the same data mark to transmission data to be transmitted in the same frame (S11), and transmits the data packet to the corresponding channel (S12). That is, the data packet transmitted directly to the node 4 is, for example, channel 1, node 2
The data packet to be transmitted to channel 2 and node 3
For example, a data packet to be transmitted is transmitted using channel 3 and a packet to which the same data mark is added is transmitted.

FIG. 4 is a flowchart showing the operation of a general receiving node, for example, the nodes 2, 3, and 5.
As shown in this figure, each receiving node receives data of each channel (step S21), and then,
It is determined whether the received data is data to be processed in the own device (S22). This can be performed by comparing the channel that received the data with the channel of the processing target data set in advance in this node. As a result of the determination, when the received data is data to be processed by the own device, predetermined data processing is performed on the data, for example, when the node is the node 2, reverb processing is performed, and the node 3 is processed. At this time, a panning process is performed, and the processed data is sent to the network (S23). If it is determined in step S22 that the received data is not the processing data of the own device, the processing for the data of the channel is terminated without executing any processing (S24).

FIG. 5 is a flowchart for explaining the operation of the time aligner (node 4). This time aligner has a channel (synchronization channel) to which the timing should be synchronized by the user or the like in advance.
Is set. As shown in the figure, in the time aligner, data is received (S31), and it is determined whether the received data is a channel corresponding to a preset synchronization channel (S32). If the result of this determination is that the currently received channel does not correspond to the synchronization channel, no processing is performed (S3).
5).

On the other hand, if the received channel is a channel corresponding to a preset synchronization channel, the flow advances to step S33 to check the data mark included in the received packet, It is determined whether or not the data packets to which the same data mark has been added are stored in all the buffers of the synchronization channel. If the result of this determination is YES, that is, if the currently received channel is the data that has arrived last among the data marked with the same data mark, the process proceeds to step S34, where the data is stored in the buffer of the synchronous channel. Are output in ascending order of channel number. As a result, the data arrived at the time aligner via the various paths and having the same data mark can be output to the node 5 at the same timing.

On the other hand, when packets with the data mark are not available for all synchronization channels,
The result of determination in step S33 is NO, and the received data is stored in the buffer for the channel (S3
6). Note that, depending on the magnitude of the delay time, the packet of the channel transmitted in the next frame may arrive before all the packets of a certain frame have arrived. It is configured so that packets can be stored in units. In this way, in the time aligner, the timing of packets arriving at different timings can be aligned.

In the above example, the node 4 has been described as having only the function of the time aligner. However, the present invention is not limited to this, and a normal node may have the function of the time aligner. Can also.
For example, the function of the time aligner described above may be included in the node 5. However, it is desirable that the "time aligner" is placed immediately before the output node.

Further, in the above-described example, it has been described that a channel for transmitting data to be received at the node is set in each node in advance. However, the present invention is not limited to this. Data for designating a destination node of the data may be included, and each node may determine the data to determine whether the data is data to be received.

Further, in the above example, the IEEE
Although a network connected by E1394 has been described as an example, the present invention can be applied to a network configured with other interfaces. Furthermore, in the above-described example, a description has been given of a musical sound generator as an example, but the present invention is not limited to this, and data or synchronization necessary to guarantee reproducibility on a time axis is taken over a network. Obviously, the present invention can be similarly applied to transmitting data that needs to be transmitted.

[0032]

As described above, according to the method and apparatus for synchronizing network data of the present invention, it is possible to synchronize data that needs to be time-synchronized and has passed through a plurality of paths on a network. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of an embodiment of a network system to which a network data synchronization method of the present invention is applied.

FIG. 2 is a diagram for explaining a timing at which data arrives.

FIG. 3 is a flowchart illustrating the operation of a node that sends data.

FIG. 4 is a flowchart for explaining the operation of the receiving node.

FIG. 5 is a flowchart illustrating the operation of the synchronization device.

FIG. 6 is a diagram illustrating an example of a conventional network system.

FIG. 7 is a diagram illustrating an example of a data channel in a network.

[Explanation of symbols]

1 to 5, 11 to 14 nodes, 21 arbitration section, 22 data prefix section, 23 data packet, 24 data end section

Claims (3)

[Claims] 1. A method for synchronizing data transferred on a network to which a plurality of nodes are connected, wherein the node transmitting a plurality of data required to be synchronized includes:
A predetermined data mark is added to the plurality of data and transmitted to the network, and the node receiving the data from the network synchronizes the plurality of received data by referring to the data mark. A method for synchronizing network data. 2. A device for synchronizing a plurality of data transferred on a network to which a plurality of nodes are connected, wherein the same data mark is provided based on a data mark included in data received from the network. A synchronization device for network data, wherein a plurality of reception data to which a symbol is added is synchronized. 3. A node connected to a network, the node having a function of the network data synchronization device according to claim 2.