JPH1132280A - Hypermedia retrieval system for interactive tv system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make data other than video data readable, in advance by allowing a terminal to inquire about a bit rate of video data received by itself of a server and checking whether or not there is a room for advanced read of a still image by the terminal itself, so as to utilize effectively a channel while the video data are being transferred. SOLUTION: A user selects and depresses a button using an entry section 201 and decides on a node required next. An instruction issue section 205 generates an instruction based thereon and sends the instruction to a hypermedia server 131 via a network section 203. When the node on request is video data, the hypermedia server 131 transfers the request to a video data transmission server 111, the video data transmission server 111 sends the video data on request to the terminal and a display section 202 in the terminal displays the data. A period for delivery of the video data is utilized effectively to advance- read menu data stored in a storage section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a hypermedia search system for displaying menus on an interactive TV capable of delivering video data via a network.

[0002]

2. Description of the Related Art Information media and their use procedures have a predetermined relationship, and an information medium configured so that a user can interactively use these information / use procedure sets is provided. It is called hypermedia. Generally, a script language is used to describe the relationship of hypermedia information on a terminal device. As an example of a script language, there is MHEG defined in ISO / IEC13522-1. MHEG describes each scenario of multimedia information, procedures, operations, etc., and its combination as independent and collective information, and encodes those objects to describe a scenario for producing a multimedia hypermedia title. I do.

Specifically, the MHEG defines a user interface on the screen of the terminal device and, at the same time, defines an identifier of a menu screen corresponding to a next node to be read next when a button on the screen is selected. Then, in the terminal, the next node requested next is determined based on the information input by the user and the definition of the script, and the instruction issuing unit issues a request to the server. The terminal device obtains a new menu or video data by sending the command to the server. A look-ahead function in a hypertext system in which data on a node is limited to text is disclosed in
No. 0926. When the next display of each node is predicted, the menu can be displayed in a short time by pre-reading in advance.
As one of the protocol specifications for a terminal and a multimedia server that is physically remote on the network, DSMCC (Digital Storage Me
dia-Command and Control). DSMCC is used especially in VOD (Video on Demand) systems, where data such as menus, text, still images, and videos held by the server can be seen as an abstract object for the terminal device. it can. The terminal can obtain menu data or video data by requesting the object. When this is used in combination with MHEG, even if the next node of MHEG is on a remote server, the user can obtain the next node without being aware that each data exists in a remote place. . Taking Movie on Demand as an example, an application server that holds the application itself as a logical server, a directory server that holds a database of movie titles and provides menus to terminal devices, and a user that holds video data and There is a stream server that distributes the requested video data. These servers are allowed to exist in physically different network environments. Generally, the server storing the menu data and the server storing the video data are different, and the throughput of the line between the terminal and the video data is large, but the line between the terminal and the server storing the menu data is large. Throughput can be small. The operation procedure of the terminal device for accessing these servers is as follows. The terminal device first reads, for example, the Movie on Demand application itself from the application server. Next, the loaded application requests a list of services from the directory server in the form of an MHEG script. The user selects a service from the list and issues a menu request for the service to the server. Hereinafter, the user repeatedly makes selections and requests from the menu, and finally obtains video data. A method of prefetching data obtained via a network and efficiently transferring the data is disclosed in
No. 7-73085.

[0004]

When the node of the hypermedia is video data, it is impossible to pre-read the node itself because of the large amount of data. Further, since the video data is reproduced in real time, the time occupying the line is longer than that of the text transfer. The first invention of the present invention provides a method of prefetching data other than video data by effectively using a line while video data is being transferred.

[0005] In addition, menu display in a terminal device using the DSMCC protocol is generally not a text but a still image. In DSMCC, one terminal device accesses a plurality of physically different servers in communication between servers. Therefore, there are various types of networks between the terminal device and each server,
The transmission speed of the network between the server that distributes a certain menu screen and the terminal may be low. If image data is sent using the line, it takes time to transfer the still image of the menu. Even if the selection is predicted, in the case of a menu request using image data through a network with a low transmission speed, it takes time to read ahead. The second invention of the present invention provides a method for quickly displaying a menu with still images even on a slow communication line.

[0006]

According to the DSMCC rules, there is always a server that manages the resources of the network to which the terminal is connected. The terminal inquires the server of the bit rate of the video data received by the terminal, and checks whether the terminal itself can afford to pre-read still images. Then, pre-reading is performed while the terminal is reproducing video data.

If the line throughput between the terminal and the server is low, a node that has a link where the next node is video data in a server that provides a menu cannot have still image data. Instead, a characteristic scene used as a menu in the video data has an offset value indicating the byte in the video data, and the terminal receives a menu screen display request from the user. Requires a server-specific scene that holds the video.

[0008]

FIG. 2 shows an environment to which the present invention is applied. The following are connected to the network 101. The video data transmitting devices 111, 112, and 113 are devices that can transmit video data that can be randomly accessed to some extent in response to an external request. Terminal device
Reference numerals 121, 122, and 123 denote devices having a function of allowing a user to input an instruction to a server, and to reproduce and display video or still image data transmitted from the server. The hypermedia servers 131, 132, and 133 hold still image data and text data for displaying a menu used by a user to search for target data. Further, the hypermedia server also holds a relationship between a plurality of menus. The terminal requests data one after another by following this relationship, and in response thereto, the hypermedia server has a function of sending the next menu to the terminal. The relationship between the menus is maintained in the form of a script. By making a request, the terminal first downloads the script, then interprets the script, gets the user's request at the same time, and makes the next request to the hypermedia server.

FIG. 1 is a block diagram showing a terminal device and a hypermedia server in the hypermedia search system of the present invention. The input unit 201 in the terminal is a device such as a mouse to which a user can give an instruction. The display unit 202 is for showing a still image or video data to a user. Network section 203
Is an interface for communicating with a hypermedia server and a video data transmission device. Control unit 208
Is a part having a function for performing the information search of the present invention. Each part in the control unit will be described in the description of FIG. Further, each unit in the hypermedia server will be described when describing FIGS. 4, 5, and 6.

FIG. 3A shows a state in which the terminal device of the hypermedia search system to which the present invention is applied reads a script given from the hypermedia server and displays a menu corresponding to a node of the hypermedia system. ing. Each button 302, 30 of the menu 301
In 3, 304 and 305, in addition to the title name, a link to the next menu requested next when this button is selected is defined as an attribute.
Are connected. This link continues and eventually leads to video data 316, 317, 318, 319. In the figure,
The shaded area indicates the menu actually displayed on the display unit of the terminal. FIG. 3A shows a state in which only the still image data of the displayed menu exists in the storage unit.

FIG. 3B shows a state where the menu corresponding to the next node is read. If there is room in the storage unit, the menu 301 before that is not discarded and is kept stored. Each button 312, 313, 31 of the loaded menu 311
4, 315 are linked to video data 316, 317, 318, 319.

FIG. 4A shows a data flow in a hypermedia search system to which the present invention is applied. First, it is assumed that the terminal unit is reading a script describing the menu link structure generated by the node pointer management unit 210 in the hypermedia server. In that script, each button in the menu has a pointer to the next node and the user
By selecting a button using 207, the next required node is determined. Based on this, the instruction issuing unit 205
Generates a command, and sends the command to the hypermedia server via the network unit 203. If the next requested node is video data, the hypermedia server forwards the request to the video data transmission device 111, and the video data transmission device sends the requested video data to the terminal, and a display unit in the terminal. Displayed at 202.

Next, the prefetch function in the hypermedia search system, which is the first invention of the present invention, will be described. FIG. 3C shows a state in which the user selects the button 312 in the state of FIG. 3B and requests video data. However, since the image data is not read at once but is read over time, this diagram shows a state during the reading. In the example of FIG.
The pre-reading of another menu data 306 pointed to by one button on the initially read menu is performed simultaneously with the reading of the video data 316.

FIG. 4B shows the data flow in the terminal at this time. The process up to the point where the terminal requests the next node from the server according to the user's instruction, receives the video data, and displays it on the display unit is the same as the case of (a).
Here, at the same time, the instruction issuing unit 205 determines, based on the fact that the current request is a request for video data,
Command to perform prefetching. The look-ahead section first,
The maximum bit rate of the video data currently being delivered is obtained from the bit rate management unit 411 in the hypermedia server. The look-ahead unit knows the limit bit rate that the terminal can receive, and requests the look-ahead data within a range in which the total bit rate of the data currently received keeps the limit bit rate. The prefetch command is sent to the hypermedia server, and the menu data is stored in the storage unit 204. As a result, prefetching can be performed by effectively utilizing the time during which the video data is being delivered and the surplus network resources.

FIG. 5A shows a list of menu attributes held by the hypermedia server. Each button holds a title name, a pointer to the next node, whether the node is a still image or video data, and a bit rate if the node is video data. The terminal queries the contents of this table to the hypermedia server, so that when receiving video data,
It is possible to know the bit rate of the video data.

As a method of determining which menu is prefetched, the following method can be considered. As shown in FIG.
The hypermedia server has a table for each user, in which a personal database for each user who is currently using and an index of popularity not depending on the user are stored in a history database unit 212 in the hypermedia server. A look-ahead priority is calculated by adding a certain weight to each of them and adding them. This calculation is performed for each button of all the menus held in the storage unit in the terminal, and the one determined to have the highest priority is read ahead. As personal information for each user, values such as the frequency of actual selection in the past and how close to the favorite genre given by the individual,
It is updated and stored as data each time it is actually selected.
The overall popularity applies this value to all users.
Each time the hypermedia server performs prefetching, it compares the prefetching priority attached to the menu in the storage unit, selects the largest one, and informs the terminal.

Next, a menu display using video data in the hypermedia search system according to the second invention of the present invention will be described. FIG. 3 (d) shows that when a certain menu is displayed, only a few frames of the picture data 316, 317, 318, 319 linked from each button of the menu are read out, and are read as a menu. Indicates that it is displayed. FIG. 4C shows the flow of data in the terminal at this time. The process up to the point where the terminal requests the next node from the server according to the user's instruction, receives the video data, and displays it on the display unit is the same as the case of (a). However, when the line throughput between the terminal and the hypermedia server is small, the server does not send the still image data but sends only the text data. When the next node is video data, the server of the hypermedia search system of the present invention includes, in addition to a text representing a menu and a pointer to the next node, several scenes that can be used as a menu in the video data of the next node. An offset value such as the byte position of the data is given to the terminal as information.

When the terminal determines that the menu data is text data and video data of the next node indicated by the menu button, the terminal sends the received offset value to the still image requesting unit 206. Therefore, only a few scenes are newly requested from the video data transmitting apparatus, and the obtained several scenes are used for the menu screen. Thus, even when the throughput of the line with the hypermedia server is small, the terminal can quickly display the menu with the still image.

FIG. 5B shows the attributes of the menu held by the hypermedia server when the menu data consists of text data. As in (a), each button shows the title name, the pointer to the next node, whether the node is a still image or video data, and the bit rate if the node is video data. I have. Further, with respect to the video data, offset values of several scenes that can be used for the menu screen in the video data are stored. By receiving the contents of this table from the hypermedia server, the terminal can request several scenes of the menu from the video data transmission device when receiving the menu data of the text data. FIG. 7 shows an algorithm for performing the prefetching and menu display of the present invention described above in the hypermedia system terminal device. The terminal first reads a script for displaying an initial menu from the hypermedia server (702), and displays the menu based on the script (703). When the menu is based on text data (704),
Request several scenes of the video used for the menu to the video transmission device based on the offset value obtained from the hypermedia server (705), and display a menu of still images based on the data. (703). When the received data is not text data but video data (7
In step 06), while displaying video data (707), pre-reading is performed in the procedure described below. First, it is checked whether there is enough throughput to receive a still image while reading video data (708). If possible, the capacity of the storage unit for storing prefetched data is checked next (709). If that is possible, search the history data in the storage unit (71
0), prefetching is executed (711) and saved (712).

[0020]

According to the present invention, prefetching can be performed by effectively utilizing the time during which video data is being delivered and the surplus network resources. Further, even when the throughput of the line with the hypermedia server is small, the terminal can quickly display the menu using the still image.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an environment to which the present invention is applied.

FIG. 2 is a block diagram of a terminal device and a hypermedia server in the hypermedia search system of the present invention.

FIG. 3A is a diagram showing the structure of hypermedia data in the hypermedia search system of the present invention. (2) A diagram showing the structure of the hypermedia data when the hypermedia search system terminal device of the present invention reads another menu data. (3) A diagram showing the structure of hypermedia data when the hypermedia search system terminal device of the present invention pre-reads a still image. (4) Diagram showing the structure of hypermedia data when the hypermedia search system terminal device of the present invention reads several still images from the video data transmission device.

FIG. 4 shows (1) a data flow in the hypermedia search system terminal device of the present invention. (2) shows a data flow when the hypermedia search system terminal device of the present invention pre-reads a still image. FIG. (3) A diagram showing a data flow when the hypermedia search system terminal device of the present invention reads several still images from the video data transmission device.

FIG. 5A is a diagram showing the contents of data held by a node when the node is still image data in the hypermedia search system of the present invention. (2) A diagram showing the contents of data held by a node when the node is text data in the hypermedia search system of the present invention.

FIG. 6 is a diagram showing the contents of data held for a user for prefetching in the hypermedia search system of the present invention.

FIG. 7 is a diagram showing an algorithm for the hypermedia search system terminal device of the present invention to prefetch and display menu data.

[Explanation of symbols]

301: menu actually displayed among the stored menu data, 302, 303, 304, 305, 306, 307, 309, 31
0,312,313,314,315… button on menu, 308,311… menu, 316,317,318,319… video data

Claims (2)

[Claims] 1. A unit of information is a node, and means for logically connecting the plurality of nodes includes:
In a hypermedia search system in which information on the next node to be connected is stored and the server sends the next node connected to a certain node to the terminal device in response to a request from the terminal, the server uses the bit of each video data held The terminal has means for managing a rate, the terminal determines whether its own state is a state displaying still image data or a state displaying video data, and a means for reading data from a plurality of lines. Means to know the maximum bit rate that can be received,
A hypermedia search system comprising: means for inquiring of a server about an available capacity of a line used by a server and, if there is a blank portion, a means for prefetching another still image using the blank portion. 2. A means for making a unit of information a node, and means for logically connecting the plurality of nodes;
In a hypermedia search system in which information on the next node to be connected is stored, and the server sends the next node connected to a certain node to the terminal device in response to a request from the terminal, the server uses the next Has a means for storing whether the data is video data, and, when the next node is video data, means for storing, as an attribute, an offset value of a characteristic scene in the video data as an attribute in a node name. A hypermedia search system comprising: means for displaying a menu composed of still images on a terminal by reading a scene specified by the offset value from a server that delivers video when displaying a node list.