JP2000032403A - Data transmission method, data transmitter and receiver thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply synchronize reproduction of main video and audio signals with reproduction of additional data, such as a still picture by defining a code denoting immediate production of an event to a packet position of time information, setting the code denoting immediate production of an event to a packet position of time information of even information of an event notice packet and transmitting the resulting packet. SOLUTION: A header denoting a stream event packet is placed to a head of a stream event packet. A first event name and time information in pairs are placed in succession to this header, and a succeeding event name and time information in pairs are placed in succession to the first pair. A plurality of the event names and the time information in pairs are consecutively connected. There may be which cannot be code as time information of this event which cannot set to a position of time information, such as ALL '1'. In this case, this is to mean 'immediately to generate an event'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission method, a data transmission apparatus, and a reception apparatus which are suitable for digital television broadcasting capable of transmitting additional data together with video and audio.

[0002]

2. Description of the Related Art A digital satellite broadcast is used to broadcast a music program on a main channel, search music data and artist information, and easily download the music to a data storage device. A music content distribution system has been proposed. In a program such as the music content distribution system, additional data such as text, a still image, and audio is transmitted as necessary together with normal video and audio. Then, on the transmitting side, so that it can handle such additional data of multimedia,
MHEG (Multimedia and Hypermedia Information Co
(ding Experts Group) A monomedia such as a still image or a sound is encoded using an authoring tool, and MHEG5 content is created together with a script for instructing a display procedure and the like. The created content is DSM-
CC (Digital Storage Media-Command and Control)
It is converted into a transport stream that can be multiplexed into a stream by an encoder, and transmitted.

[0003]

As described above, in the case of a broadcast in which multimedia additional data is transmitted together with the normal video and audio broadcast, the reproduction of the video and audio of the main channel and the static There are cases where it is desired to synchronize the reproduction of additional data such as images. In such a case, even if the additional data is simply transmitted simultaneously with the broadcast of the video and audio, the reproduction of the video and audio and the reproduction of the additional data are not always synchronized on the receiving side.

It is also conceivable that the time at which an event occurs is described in a script, and when the time at which the event occurs is reached, data reproduction is started.
As described above, if the event occurrence time is described in detail, it is possible to synchronize the reproduction of the main video and audio with the reproduction of the still image data added thereto.

[0005] However, in this case, if the accuracy of the time information to be transmitted is lower than the second accuracy, the burden on the transmitting side and the receiving side increases. In addition, the scheduled time of a program often changes due to a sports program, extraordinary news, or the like. When the time information for displaying and operating the additional data is described by the script, it is difficult to cope with such a change in the time of the program.

Accordingly, it is an object of the present invention to provide a data transmission method, a data transmission apparatus and a reception apparatus which can easily synchronize the reproduction of main video and audio with the reproduction of additional data such as still images. Is to do.

[0007]

According to the present invention, in a data transmission method for transmitting multimedia data, an event notification is constituted by time information and an event name, and an event is immediately generated at the position of the time information. When an event is to be generated immediately, a code indicating that an event is to be immediately generated is arranged and sent to the position of the time information in the event information of the event notification. .

[0008] With respect to the time information of a stream event composed of an event name and time information, one of the codes that cannot exist as time information (for example, ALL “1”) means “immediate event generation”. Defined. Therefore, when a stream event is sent with the time information set to, for example, ALL “1”, the event is immediately generated on the receiving side. Therefore, when it is desired to synchronize the display data with the video or audio, if the stream information is sent with the time information set to, for example, ALL “1” at a timing slightly before the timing at which the event is generated, the display data can be synchronized with the video or audio. Can be synchronized. Also,
On the receiving side, time management is not required.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The present invention uses, for example, digital satellite broadcasting to transmit ancillary data such as still images and texts together with a main television broadcast composed of moving images and audio, and converts necessary information into still images and texts on demand. It can be applied to interactive television that can be displayed by. FIG. 1 shows the configuration on the transmitting side of such an interactive television broadcast.

In FIG. 1, reference numeral 1 denotes an AV baseband system. The AV base video system 1 is a system for creating video and audio baseband signals of a main program. The AV baseband system 1 includes a plurality of VTRs, cart machines, and editing machines. The AV baseband system 1 outputs a moving image or audio baseband signal to be transmitted in a main program. This baseband signal is supplied to the AV encoder 2. In the AV encoder 2, for example, MPEG (Mo
The video data and the audio data are compression-encoded and converted into a packet stream of a fixed rate according to the two methods (ving Picture Experts Group).

Reference numeral 3 denotes an authoring system. In the authoring system 3, additional data such as still images and texts are produced. Then, the mono media such as the still image and the sound are encoded, and the MHEG5 content is created together with a script for instructing a display procedure and the like. The created content is converted so that it can be multiplexed into a stream by the DSM-CC encoder. The data transmission server 4 generates these data packets.

The service transmitted by the DSM-CC is provided by a service gateway. Objects included in the service gateway include directories, files, streams, stream events, and the like. Of these, directories are assignments of objects such as services and data and meaningful names, files are individual files such as still images, sounds, texts, etc., and streams are other data services and AV streams. The stream event includes an event name and time information. The output of the authoring system 3 is sent to the data sending server 4.

The video and audio packets of the main program from the encoder 2 and the packets from the data transmission server 4 are multiplexed by the multiplexer 5 to form a single high-speed data stream.

As a control system for synchronizing the video and audio of the main program, controlling the schedule, and synchronizing the additional data and controlling the schedule, a program scheduling system 7, a control system 8, and an internal clock 9 are provided. . When the timetable of the program is determined by the programming system 7, the schedule is set by the programming system 7. A control system 8 is provided in order to actually control each system in real time based on a schedule determined by the program scheduling system 7. The time information of the control system 8 is supplied from an internal clock 9.

The output of the multiplexer 5 is supplied to a modulation circuit 6. The modulation circuit 6 modulates the bit stream with, for example, QPSK (Quadrature Phase Shift Keying). The output of the modulation circuit 6 is frequency-converted to a predetermined carrier frequency (not shown), power-amplified, and transmitted.

As described above, in the transmission system of the interactive television to which the present invention is applied, the additional data is transmitted together with the main video and audio. Then, on the transmission side, a monomedia such as a still image or a sound is encoded using an MHEG authoring tool so that such multimedia additional data can be handled.
A script for instructing a display procedure and the like, and a stream event including an event name and time information, together with the MHEG5
Is created.

For example, as shown in FIG.
2A, while displaying the image P1 of the main program in the layout as shown in FIG. 2A, at time T1, as shown in FIG. 2B, in addition to the screen P1 of the main program, additional data Is displayed, and the still image P2 is continuously displayed until time T2.
As shown in FIG. 2C, it is assumed that display is performed such that the still image P2 disappears at time T2.

FIG. 3 shows an example of a script for generating such an event. As shown in FIG. 3, an event name when creating such display data is defined in the script, and a state transition (display data ON / OFF) corresponding to the event name is described.

At the same time, the time code of the video source is read, and time information corresponding to the event name is input. As a result, a list of pairs of event names and time information is generated. Information forming a pair of the event name and the time information is transmitted as a stream event packet.

FIG. 4 shows the structure of such a stream event packet. As shown in FIG. 4, a header indicating the stream event packet is provided at the head of the stream event packet. Following this header, a first pair of event name and time information is provided, and subsequently, a pair of next event name and time information is provided. A plurality of pairs of the event name and the time information can be continuously connected.

In the present invention, as will be described later, a code which cannot be used as time information of an event, for example, AL
L “1” may be provided at the position of the time information. In this case, this shall mean "immediately generate an event".

FIG. 5 shows the configuration of a digital television broadcast receiver that receives such an interactive television broadcast. In FIG. 5, a digital television broadcast signal is received by an antenna 21. The received signal from the antenna 21 is sent to the tuner circuit 22. The tuner circuit 22 includes a CPU (Cent
A frequency setting signal is supplied from a ral processing unit (27). In the tuner circuit 22, the carrier frequency of the received signal is set based on the frequency setting signal from the CPU 27.

The tuner circuit 22 includes a demodulation circuit for performing QPSK demodulation of the received signal, for example, and an error correction circuit for correcting an error in the received signal. The tuner circuit 12 demodulates the received signal and performs an error correction process.

The output of the tuner circuit 22 is supplied to a demultiplexer 23. The demultiplexer 23 refers to the packet identifier (PID) in the header of the packet,
Packets are sorted.

The main channel audio data packet is supplied to the audio decoder 24. The video data packet of the main channel is transmitted to the video decoder 25.
Supplied to

The audio decoder 24 expands the voice packet, and outputs a digital audio signal from the audio decoder 24. This digital audio signal is output from the output terminal 32.

The video decoder 25 expands a video signal compressed by the MPEG2 system and decodes a digital video signal. MP in video decoder 25
The video signal of the EG2 system is decoded, and the video decoder 25 outputs a digital video signal. This digital video signal is supplied to the video mixing circuit 26.

The packet of the additional data and the packet of the stream or the stream event are processed by the CPU 27. A ROM (Read Only Memory) 28 for storing programs and a RAM (Random Access Memory) 29 for a work area are connected to a bus 30 of the CPU 27.

The reproduced additional data is developed by the graphics processing section 31 and supplied to the video mixing circuit 26. In the video mixing circuit 26, the screen of the moving image from the video decoder 25 and the screen from the graphics processing unit 31 are combined. The output of the video mixing circuit 26 is output from the output terminal 33.

As described above, the MHEG5 script is used for the display control of the additional data, and the stream event is a pair of the event name and the time information. On the other hand, in the present invention, a code that cannot be used as time information of an event, for example, ALL “1” may be provided at the position of the time information. In this case,
It means "immediately generate an event."
Therefore, the CPU 27 determines that the time information
As soon as the stream event packet of "1" is received, the transmitting side shown in FIG. 1, which performs the process for generating the event, sends the image and sound of the main program and the additional data. When it is desired to synchronize the main image or sound with the display of the additional data, a stream event packet whose time information is ALL "1" is transmitted at a predetermined time earlier than the timing at which the synchronization is desired. Sent multiple times at intervals.

On the receiving side shown in FIG. 5, when a stream event packet having the time information of ALL "1" is received, the event is immediately generated according to the definition. This makes it possible to synchronize the image and sound of the main program with the display of the additional data.

That is, FIG. 6 shows a stream event sequence for realizing a stream corresponding to the event shown in FIG. As shown in FIG. 6A,
The video and audio streams of the main program are continuously transmitted. The packet of the additional data is shown in FIG.
, And the packet of the additional data has been captured in advance. Then, an event (Event1) is generated at the time T1, and the event (E1) is generated at the time T2.
vent2). Here, the event (Event1) turns on the display of the still image P2, and the event (Event2) turns off the display of the still image P2.

In this case, as shown in FIG. 6B, slightly before the time T1 at which the event (Event1) is generated,
A stream event packet SE1 whose event name is Event (Event1) and the time information is ALL "1"
-1 is sent. Then, the next event (Event
Until the start of 2), the event name is the event (Ev
ent1), the stream event packets SE1-2, SE1-3,... with the time information of ALL “1” are transmitted periodically and repeatedly. The stream packet S
E1-1, SE1-2, SE1-3,... Are the same packet.

Shortly before the time T2 when the event (Event2) is generated, the event name is changed to the event (Even2).
At t2), a stream event packet SE2-1 having the time information of ALL "1" is transmitted. Then, just before the next event starts (or until the end of the program)
The stream event packet SE2 whose event name is Event (Event2) and the time information is ALL “1”
. -2, SE2-3, ... are transmitted periodically and repeatedly.

On the receiving side, the stream event packet SE1-1 is received slightly before the time T1 at which the event (Event1) is generated. In the stream event packet SE1-1, the time information is indicated by ALL.
Since it is “1”, the event (Eve) is immediately performed when the stream event packet SE1-1 is received.
nt1) occurs. This event (Event1)
Turns on the still image data, an event occurs immediately when the stream event packet SE1-1 is received, and the display data is turned on as shown in FIG. 6D.

The stream event packet SE1
-1 is the time T at which the event (Event1) is generated
The reason why the data is sent slightly before 1 is to consider the processing time. Since there is such processing time, the stream event packet SE1-1 is sent to the event (Even
If the image is sent slightly before the time T1 at which the time t1) is generated, a still image is displayed just at the time T1. FIG. 6C
Is taken before the event occurs, the processing time of the display data is considered to be only the time required for developing the image, and can be regarded as substantially constant.

Next, a stream event packet SE2-1 is sent slightly before the time T2 when the event (Event2) is generated. Since the time information of the stream event packet SE2-1 is set to ALL "1", the stream event packet SE2-
Event 1 immediately after receiving 1 (Event2)
Occurs. Since this event (Event2) turns off the display data, the event occurs immediately when the stream event packet SE2-1 is received, and the still image data is turned off. Since there is a processing time for the display data, the processing of the data just ends at time T2, and the still image is deleted as shown in FIG. 6D.

As described above, the stream event packet for generating each event is sent to the receiver by a time required for processing the event data before the time at which each event is to be generated. Then, the additional data used for the event has been sent in advance, and has been taken into the receiver. Therefore, each event can be generated at a scheduled time.

The stream event packet is repeatedly sent until the start of the next event or until the end of the program. As described above, the reason why the same stream event packet is repeatedly transmitted is that the power is turned on to the receiver after the time of each defined event, or that a transition has been made from another channel to this channel. In this case, the display data is changed to a correct state.

In the above example, the event (Event1)
And (Event2), the time information is ALL
Although a stream event packet of "1" is sent, a stream event packet in which the event name and the event time information are described, and a stream event packet in which the event name and the time information are ALL "1" are sent as an event. You may make it distribute every time.

FIG. 7 shows a stream event packet in which the event name and the event time information are described, and a stream event packet in which the event name and the time information are all "1" are separately transmitted for each event. It is like that.

That is, in FIG. 7, the event (Eve
nt11) stream event packet SE11-
, SE11-2, SE11-3,... Turn on the display data at time T11, and the stream event packets SE11-1, SE11-2, SE11-.
"Time T1" is described in the time information of 3,.
On the other hand, the (Event 12) stream event packets SE12-1, SE12-2, SE12-3,...
The display data is turned off at time T12, and the stream packets SE12-1, SE12-2, SE1
In 2-3,..., The time information is set to ALL “1”.

In this case, as shown in FIG. 7B, stream event packets SE11-1, SE11-2, SE11-2
11-3,... Are periodically and repeatedly sent from before time T11 when the event (Event 11) occurs. Then, the time T at which the next event (Event 12) starts
Shortly before 12, a stream event packet SE12-1 of the event (Event 12) is sent, and then a similar stream event packet SE12-2,
Are sent periodically and repeatedly.

On the receiver side, before the time T11 at which the event occurs, the stream event packet SE1
1-1, SE11-2, SE11-3,... Are received. Stream event packets SE11-1, SE1
.., SE11-3,... Are all similar packets. This stream event packet SE11-1, S
The time information of E11-2, SE11-3,...
11 ". Therefore, the receiver side waits for the time T11.

At time T11, an event (Even
t11) occurs. This event (Event11)
Turns on the display data, so that the still image data is turned on at time T11 as shown in FIG. 7D.

Next, a stream event packet SE12-1 is sent slightly before the time T12 at which the event (Event 12) is generated. The time information of the stream event packet SE12-1 is ALL.
Since it is “1”, the event (Ev) is immediately performed when the stream event packet SE12-1 is received.
ent12) occurs. This event (Event1
Since 2) turns off the display data, an event (Event 12) occurs immediately when the stream event packet SE12-1 is received, and the display data is turned off. Since there is a processing time for the display data, FIG.
As shown in (5), the processing of the display data has just finished at time T12, and the still image based on the display data is deleted.

In this case as well, the stream event packet is repeatedly transmitted until the start of the next event or until the end of the program. As described above, the reason why the same stream event packet is repeatedly transmitted is, as described above, when the receiver is turned on after the time of each defined event, or when this channel is switched from another channel. This is because the display data is changed to a correct state when the display data has changed to.

When the time is described in the time information of the stream event packet, a definition is made such as "if the described time information has already passed the current time, an event is immediately generated". Keep it. By doing so, the time information of the stream event packet is described, and even if the current time is later than the time information, the event can be immediately generated.

In the above example, simple event processing for turning on / off one piece of additional data has been described. However, it is also possible to process a plurality of pieces of additional data. In this case, by treating events relating to the same additional data as a group, processing can be performed in the same manner as in the case of a simple sequence.

For example, as shown in FIG.
FIG. 8 shows the image P21 of the main program over T24.
As shown in FIG. 8B, the still image P22 is displayed at the time T21 as shown in FIG. 8B, and the still image P23 is further displayed at the time T22 as shown in FIG. At the time T23, only the still image P22 is erased, and as shown in FIG. 8E, the still image P23 is erased at the time T24, and only the main moving image P21 is continuously displayed.

As described above, when there are two events, that is, the event relating to the still image 22 and the event relating to the still image 23, the event relating to each additional data is considered as a group.

That is, in this case, there is an event related to the still picture P22 and an event related to the still picture P23. First, as an event of the group related to the still image P22, there is an event of turning on the still image 22 at time T21 and turning off the still image P21 at time T23. Still image P23
As an event of the group related to, there is an event that the still image 23 is turned on at the time T22 and the still image P23 is turned off at the time T24.

In order to realize the event related to the still image P22 of the first group, a stream event packet with an event name that turns on the still image P22 with the time information of ALL “1” is sent shortly before the time point T21. afterwards,
This stream event packet is transmitted periodically and repeatedly. Just before time T23, the time information is set to ALL.
A stream event packet with an event name that turns off the still image P22 at "1" is sent, and then this stream event packet is sent periodically and repeatedly.

In order to realize the event related to the still picture P23 of the next group, a stream event packet having an event name that turns on the still picture P23 with the time information set to ALL “1” is sent slightly before the time T22, Thereafter, the stream event packet is periodically and repeatedly transmitted. Just before time T24, the time information is ALL
A stream event packet with an event name that turns off the still image P23 at "1" is sent, and then this stream event packet is sent periodically and repeatedly.

As described above, when there is an event relating to a plurality of additional data, if grouping is performed for each data, it can be considered as in the case of one data. When a plurality of events are generated at the same time, it is not necessary to send the same in another packet, and a plurality of pieces of stream event information can be sent in one stream event packet.

FIG. 9 shows a stream event sequence for realizing a stream corresponding to the event shown in FIG. As shown in FIG. 9A, the video and audio streams of the main program are continuously transmitted. The packet of the additional data is sent as shown in FIG. 9C, and the packet of the additional data is captured in advance.

The event (EventG1-1) is an event for turning on the display of the still picture P22, and the event (EventG1-2) is an event for turning off the display of the still picture P22. Event (Event G2-1)
Is an event for turning on the display of the still image P23, and the event (Event G2-2) is an event for turning off the display of the still image P23.

In this case, as shown in FIG. 9B, the event name is slightly before the time point T21 at which the event (EventG1-1) is generated.
Then, a stream event packet SE21-1 whose time information is ALL "1" is transmitted. Then, the same stream event packet SE21-2, SE21-
3,... Are sent periodically and repeatedly.

Shortly before the time T22 at which the event (Event G2-1) is generated, the event name is the event (Event G2-1), and the time information is ALL.
A stream event packet of “1” is sent. At this time, the event name is the event (EventG1-1).
Therefore, it is necessary to continue sending a stream event packet whose time information is ALL “1”. Therefore, the stream event packet S in which these events are merged
E22-1, SE22-2, SE22-3, ... continue to be sent periodically.

A little before the time T23 when the event (EventG1-2) is generated, the event name is the event (EventG1-2), and the time information is ALL.
A stream event packet of “1” is sent. Here, it is necessary to continue sending a stream event whose event name is event (Event G2-1) and whose time information is ALL “1”. Therefore, stream event packets SE23-1 and S23-1 in which these events are merged
E23-2, SE23-3, ... continue to be sent periodically.

Shortly before the time T24 when the event (Event G2-2) is generated, the event name is the event (Event G2-2), and the time information is ALL.
A stream event packet of “1” is sent. Here, it is necessary to continue sending a stream event whose event name is Event (EventG1-2) and whose time information is ALL "1". Therefore, stream event packets SE24-1 and S24-1 in which these events are merged
E24-2, SE24-3,... Continue to be sent periodically.

As described above, the stream events are grouped according to the objects, for example, at time T2.
Even if this channel is entered between time 2 and time T23, event (EventG1-1) and event (Ev
entG2-1), the display of the still image P22 and the display of the still image P23 can both be turned on. In addition, if this channel is entered between time T23 and time T24, an event (Event G2-1)
And both events (EventG1-2)
As a result, the still image P23 can be displayed.

[0063]

According to the present invention, a stream event consisting of an event name and time information
One of the codes that cannot be used as time information (for example, A
LL “1”) is defined as “immediately generate an event”. For this reason, for example, the time information
When a stream event is sent as L "1", the event is immediately generated on the receiving side. Therefore, when it is desired to synchronize the display data with the video or audio, if the time information is set to, for example, ALL “1” at a timing slightly before the timing at which the event is generated and the stream event is sent, the display data is transmitted to the video or audio. Can be synchronized. For this reason, it is possible to easily synchronize the video and audio with the additional data, and it is possible to easily cope with a change in the program. On the receiving side, time management is not required.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transmission side of a system to which the present invention can be applied.

FIG. 2 is a schematic diagram used to describe an example of an event.

FIG. 3 is a schematic diagram used for explaining a script.

FIG. 4 is a schematic diagram illustrating a configuration of a stream event packet.

FIG. 5 is a block diagram showing a configuration of a receiving side of a system to which the present invention can be applied.

FIG. 6 is a timing chart used to describe an example of a stream event sequence.

FIG. 7 is a timing chart used to describe another example of a stream event sequence.

FIG. 8 is a schematic diagram used to describe another example of an event.

FIG. 9 is a timing chart used for explaining still another example of the stream event sequence.

[Explanation of symbols]

3 Authoring system, 4 Data transmission server, 7 Program organization system, 8 Control system, 9 Internal clock

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kenichi Murata, Inventor Kenichi Murata, 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Yasushi Katayama 6-35, Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F term (reference) 5C063 AA20 AB03 AB07 AB13 AC01 AC05 CA11 CA14 CA16 CA20 CA31

Claims (10)

[Claims] 1. A data transmission method for transmitting multimedia data, wherein an event notification is constituted by time information and an event name, and a code indicating that an event is immediately generated is defined at the position of the time information. A data transmission method in which when an event is to be generated immediately, a code indicating that the event is to be generated immediately is arranged and transmitted at the position of the time information in the event notification. 2. The data transmission method according to claim 1, wherein the code indicating that an event occurs immediately is selected from codes that cannot be used as the time information. 3. The data transmission method according to claim 1, wherein an event notification including a code indicating that the event is to be generated immediately is sent a predetermined data processing time before a timing at which the event is desired to be generated. 4. An event notification including a code indicating that an event is to be generated immediately is transmitted a predetermined data processing time before a timing at which an event is desired to be generated, and the same event notification is repeatedly transmitted at a predetermined cycle thereafter. 2. The data transmission method according to claim 1, wherein: 5. The data transmission method according to claim 4, wherein the same event notification is repeatedly transmitted at a predetermined cycle until the start of the next event. 6. The data transmission method according to claim 4, wherein the same event notification is repeatedly sent at a predetermined cycle until the end of the program. 7. The data transmission method according to claim 1, wherein the event notification including a code indicating that an event is immediately generated and the event notification describing the time information are sent together. 8. When there are a plurality of events, grouping is performed for each event for the same target data, and when simultaneously sending event information of a plurality of groups, a plurality of event information of each group is 2. The data transmission method according to claim 1, wherein the data is merged and transmitted as one event packet. 9. A means for transmitting an event notification including time information and an event name, and a means for transmitting an event notification in which a code indicating that an event is immediately generated is provided at the position of the time information. Data transmission device. 10. An event receiving means for receiving an event notification, and an event including a code for generating an event in accordance with the time information sent by the event notification upon receiving the event notification including the time information, and immediately generating the event. Means for generating the event immediately upon receiving the notification.