JP3505378B2 - Data switching device, data switching method, and receiving device - Google Patents

Description

Detailed Description of the Invention

[0001]

[Field of the Invention The invention is a system for communication and broadcasting, a data switching apparatus and a method for transmitting by selecting one of the plurality of received data, the receiving equipment to receive the transmitted data it relates to.

[0002]

2. Description of the Related Art MPE which is ISO / IEC standard as a standard for handling digital multimedia data
There is a G-2 transport stream. Video, audio, data, etc. are multiplexed in this transport stream. The receiving device can play back video and audio by receiving and decoding this transport stream.

When an arbitrary one is selected from a plurality of transport streams and is switched to another transport stream, the switching method is "ISO /
IEC13818-1 "splicing (spli
cing) method is shown.

According to this method, information of a switchable point (splice point) is multiplexed in a transport stream received by a device for splicing, and the device for splicing detects and switches the point. The receiving device that receives the switched stream normally decodes the stream.

FIG. 8 shows "ISO / IEC13818-
2 is a diagram showing a transport stream syntax of "1". FIG. In the figure, the numbers at the bottom of each field are
It is a bit indicating the length of the field.

FIG. 9 shows "ISO / IEC13818-
1] is a diagram showing an example of a transport stream when information regarding splicing described in “1” is multiplexed.

In the figure, reference numerals 200 and 300 denote received data in the transport stream format received by the data switching device. Also, from 201 to 211, and 3
01 to 311 are transport stream packets included in the reception data 200 and the reception data 300, respectively. Further, 250 and 350 are splice information indicating points where the received data 200 and the received data 300 can be spliced, respectively.

As shown in FIG. 8, the reception data 200 and 300 are formed by connecting transport stream packets having a fixed length of 188 bytes separated for each medium. The coding unit of the data of each media extends over a plurality of transport stream packets, and the transport stream packet that ends with the last data of the coding unit has "ISO / IEC
8138, the splicing point flag, which is one of the "5 flags" shown in the third row of FIG. 8, is set to "1", and the fourth row of FIG. The "splicing countdown" of the eye is set to "0".

This is information regarding splicing that splicing (switching) may be performed immediately after this transport stream packet. That is, this corresponds to the splice information 250 and 350.

Received data 200 to received data 300
F) When performing splicing, that is, when switching, the splicing device is the splicing information 25.
Transport packets up to transport packet 207 in which 0 is multiplexed are output from received data 200, and then transport packet 304 in which splice information 350 is multiplexed.
The received data 300 is output from the transport packet 305 next to.

In splicing, by storing the coding unit of the media data in this way, the receiving device that receives the spliced transport stream can normally receive and decode.

[0012]

In the conventional digital data switching system as described above, the information to be handled must be multiplexed with the data to be handled, and the data that does not contain the information is used for the switching. There was a problem that I could not do it.

Also, the device for switching data cannot switch data at points other than the switchable points indicated by the received data, and there is a problem that the degree of freedom in switching is small.

If the data is simply switched, the receiving device continuously receives different data, so that the new data is regarded as a continuation of the old data, a decoding error occurs, and it takes time to recover it. There was a problem that it would take.

The present invention has been made in order to solve the above-mentioned problems, and data can be switched at an arbitrary point by using a data string in which special information for switching is not multiplexed. An object of the present invention is to obtain a data switching device and method capable of performing the same.

Further, according to the present invention , a decoding error is required at the time of data switching.
The purpose of the present invention is to obtain a receiver that does not cause the error .

[0017]

The data switching according to the present invention
The conversion device uses the encoded first, second and third data strings.
Select at least two data strings from
Generate 1 multiplexed data string as 3rd multiplexed data string
Then select at least two other data columns to
The duplicated second multiplexed data string is added to the third multiplexed data string.
Of the first multiplexed data sequence and the first multiplexed data sequence.
Switching showing data string switching between two multiplexed data strings
It inserts information .

Further, the data switching device according to the present invention is
The first, second and third data strings are converted to MPEG-2 format.
It is a port stream .

Further, the data switching device according to the present invention is
The switching information may disturb synchronization between data strings .

Further, the data switching device according to the present invention is
The switching information is transferred to the MPEG-2 transport stream.
It is a packet .

Further, the data switching device according to the present invention is
As for the switching information, a PA in which information on the program before switching does not exist
It is T.

The data switching apparatus according to the present invention, the switching
Exchange information, media multiplex information of the data string before switching exists
Not a PMT .

Further, the data switching method according to the present invention, one of data to receive a plurality of data strings in which a plurality of transmitting device transmits to each coding, the receiving device switches the plurality of data sequence received A data switching method for transmitting a string , wherein switching information indicating switching of the data string is provided between a data string before switching and a data string after switching when switching the plurality of data strings. It is inserted independently of the data string before and after switching.

The data switching method according to the present invention is
The above data string is defined by ISO / IEC13818-1
The MPEG-2 transport stream is used.

The data switching method according to the present invention is
The switching information disturbs synchronization between data strings .

The data switching method according to the present invention is
The switching information is specified by ISO / IEC13818-1
MPEG-2 Transport Stream Package
It is a thing. In addition, the data
The conversion method is to convert the switching information into ISO / IEC13818.
-1 MPEG-2 Transport Stream
The PAT of the ream packet and the contents of the PAT are switched.
The information about the previous program does not exist. Well
Also, the data switching method according to the present invention provides the switching information.
Is defined by ISO / IEC13818-1
PMT of PEG-2 transport stream packet
The content of the PMT is the media of the data string before switching.
This is because there is no multiple information .

Furthermore, the receiving apparatus according to the present invention, multiple
Data inserted between a data string before switching and a data string after switching when a number of data strings are switched, independently of the data strings before and after the switching. The column is received by the media separation unit, and this media separation is performed.
When the section receives the switching information, the buffer control section
The decoding unit is initialized to decode the data string after switching, which follows the switching information. Furthermore, the receiving device according to the present invention has a plurality of receiving buffers for temporarily accumulating the received data string when decoding the received bit string, and when the switching information is received, after the switching information, the switching The data string is stored in a receiving buffer different from the receiving buffer that has stored the data string before switching received before the switching information, and the data after switching following the switching information in the another receiving buffer. The data string before switching, which is accumulated in the reception buffer, is decoded until the amount of data that can be normally decoded is accumulated in the string.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. A digital data switching system according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4. 1 is a block diagram showing the configuration of a digital data switching system according to a first embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the data switching device of the digital data switching system according to the first embodiment. FIG. 3 is a diagram showing a configuration of a data string output from the data switching device of the digital data switching system according to the first embodiment.
Further, FIG. 4 is a block diagram showing the configuration of the receiving device of the digital data switching system according to the first embodiment. In each figure, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, reference numerals 10 and 20 denote a transmitter for transmitting encoded data of a plurality of media, 10D.
And 20D are data strings transmitted by the transmitters 10 and 20. For example, the data string 10D includes all media of video, audio, and data, or two media or one of those media, and the data string 20D
Is also the same. Further, 40 is a plurality of transmitters 10 and 2
A data switching device which receives data strings 10D and 20D from 0 and selectively transfers one data string from the data strings, 40
D is a data string selected and output by the data switching device 40, and 50 is a receiving device as a receiving means for receiving and decoding the data string 40D from the data switching device 40.

In FIG. 2, 41 is a switching information generator for outputting switching information, and 42 is a plurality of data strings 10D, 20.
D is a selector that selects one from the switching information generated by the switching information generator 41 and outputs it as a data string 40D.

In FIG. 4, reference numeral 51 is a media separation unit that analyzes the data string 40D and separates each media such as video, audio and data, and 52 and 53 receive data of only the corresponding media from the media separation unit 51. This is a media decoder that performs decoding by decoding. For example, the media decoder 52 is for video and the media decoder 53 is for audio. If the data string 40D includes only one type of media, for example, video, one media decoder (for video) is enough.

Further, in the figure, reference numerals 521 and 531 denote buffer control units for analyzing data input to a buffer described later and controlling the buffer, and 522 and 532 are buffers 523 and 5 for temporarily storing media data.
A decoding unit 33 receives data from the buffer 522 or 532 and decodes the data at the decoding timing.

Next, the operation of the first embodiment will be described with reference to the drawings. As shown in FIG. 1, the transmission devices 10 and 20 transmit data strings 10D and 20D that are a plurality of encoded media data. The data strings 10D and 20D are, for example, “ISO / IEC138
18-1 ”is an MPEG-2 transport stream.

The data switching device 40 comprises a plurality of transmitting devices 1.
One data string is selected from the data strings 10D and 20D sent from Nos. 0 and 20 and sent as the data string 40D. Here, when switching the data string 10D and the data string 20D, "switching information" is inserted between the two data strings.

In FIG. 1, data strings 10D and 20D to be selected.
, But there may be any number of two or more.

The receiving device 50 can display various media by receiving and decoding the data string 40D selected by the data switching device 40.

In other words, when the data switching device 40 switches from the data string 10D to 20D, the receiving device 50 performs the data switching by the "switching information" inserted in the data string 40D. Can be recognized.

As shown in FIG. 2, the data switching device 40
Selects the data string 10D from one certain transmission device 10 by the selector 42 and transmits it as the data string 40D. Next, when changing the data string to be selected from 10D to 20D, the data switching device 40 once outputs the "switching information" output from the switching information generating device 41 by the selector 42.
Is selected and output as a data string 40D. Then, the data switching device 40 selects another data string 20D and outputs it as the data string 40D.

FIG. 3 is a diagram for explaining the data string 40D transmitted when the data switching device 40 performs the switching operation. In the figure, immediately after the data string 10D, "switching information" 41D follows, and further another data string 20D follows. In the above description, an example is shown in which the data string 10D is switched to the data string 20D, but the data string 20D is switched to the data string 10D in the same manner.

This "switching information" 41D is received by the receiving device 50.
Anything can be used as long as it can recognize that the switching has been performed by receiving this.

Hereinafter, the data strings 10D and 20D are MPE defined by, for example, "ISO / IEC13818-1".
An example of “switching information” in the case of a G-2 transport stream will be described. The data strings 10D, 2
OD may be a synchronous stream other than the MPEG-2 transport stream.

In the data strings 10D and 20D, as shown in the second row of FIG. 8, a hexadecimal number "47" which is a "sync byte" is multiplexed at the beginning of each transport packet. Therefore, as the "switching information" 41D, this synchronization byte "47" in hexadecimal is used as another numerical value, for example, "0"
Pseudo transport stream packets that have been desynchronized by changing to "0", "10", or "48" are used. In addition,
This pseudo transport stream packet, that is, the "switching information" 41D does not have to be 188 bytes. The receiving device 50 can recognize that the switching has been performed due to the loss of synchronization.

In order to multiplex the "switching information" 41D without breaking the synchronization of the transport stream, the "switching information" 41D is "ISO / IEC13818-1".
It must be an MPEG-2 transport stream packet defined by Then, if the data can be understood by the receiving device 50, the data switching device 40 transmits the transport stream packet by including the "unique data" indicating the switching, so that the receiving device 50 is out of synchronization with the transport stream. Without causing
It can be recognized that the switching has been performed.

That is, the "switching information" 41D is a transport stream packet in which the "sync byte" is a hexadecimal number "47", and a field other than the "sync byte" is "unique data" indicating switching. Is.

Further, in order to recognize the switching without using "unique data", "ISO / IEC13818-
By using the "management information" defined in "1" to indicate that the data to be received is temporarily lost, the receiving device 50 detects the discontinuity of the data and recognizes that the data has been switched. it can. This "management information" is one of the "payload" data, as with video and audio.

As "management information", "PAT: Program
Association Table "can be used. This "P
Since "AT" indicates the information (PMT) of the program (program) to be multiplexed in the transport stream, "PAT" in which there is no program multiplexed in the data string 10D before the switching should be the "switching information" 41D. Then, the receiving device 50 recognizes that the corresponding program has disappeared, and thereafter, the program cannot be received until the program information of "PAT" included in the new data string 20D is received, and the data string is switched. Can be recognized.

As another "management information", "PMT: Prog
ram Map Table "can be used. This "PM
Since "T" is program information and indicates information of each medium to be multiplexed in the transport stream, "PMT" in which there is no media information multiplexed in the data string 10D before switching is referred to as "switching information" 41D. As a result, the receiving device 50 recognizes that the data of the corresponding medium is lost, and thereafter, the "PM" included in the new data string 20D is included.
The media data cannot be received until the media information of “T” is received, and it can be recognized that the data string has been switched.

As described above, the "switching information" 41D can make the receiving device 50 recognize that the data string has been switched.

Next, the operation of the receiving apparatus will be described.
When the data string 40D is received, the media separating unit 51 of the receiving device 50 analyzes it and separates and transfers only the data of the portion corresponding to the media decoder 52 to which the data corresponds. The data input to the media decoder 52 is temporarily stored in the buffer 5 via the buffer controller 521.
It is stored in 22. The decoding unit 523 receives the data from the buffer 522 and decodes the data.

When the decoding section 523 continues decoding at regular intervals, it is necessary to receive data to be decoded at regular intervals.
However, if the data is variable-length coded or there is a possibility that the required amount of data cannot be transferred to the decoding unit 523 due to the delay of the transmission path, the buffer 522 is provided and the data is accumulated to some extent, Can be prevented from running out of data. Also, the buffer control unit 5
21 analyzes the media data and controls the amount of data to be stored in the buffer 522.

Decoding of media data is independently performed by each of the media decoders 52 and 53. In FIG. 4, there are two media decoders 52 and 53, the number of which depends on the number of media types.

When the data string 40D includes the "switching information" 41D, the media separating section 51 causes the "switching information" 4D.
1D is detected and each media decoder 52, 53 is notified of that fact.

Only the media decoder 52 will be described below, but the media decoder 53 also performs the same operation. In the media decoder 52, the buffer control unit 521 causes the buffer 52
2 is cleared, and the decryption unit 523 initializes. Then, the system for properly decoding the data input thereafter is prepared.
Then, when the media decoder 52 receives new data, the media decoder 52 performs a normal decoding operation after detecting the synchronization of the media data and the frame.

In this way, the receiving device 50 can quickly decode the data after switching when receiving the data string 40D including the "switching information" 41D.

Embodiment 2. A digital data switching system according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of a receiver of the digital data switching system according to the second embodiment of the present invention. The rest of the configuration is similar to that of the first embodiment.

In FIG. 5, reference numeral 51 denotes a media separation unit for analyzing the data string 40D and separating the data for each media, 52A.
Reference numerals 53A and 53A denote media decoders that receive and decode only the data of the corresponding media from the media separation unit 51.

Also, in the figure, 521A and 521
B is a buffer control unit 522A and 522 that analyzes the data input to the buffer described later and controls the buffer.
B is a buffer for temporarily storing media data, 52
A decoding unit 3 receives data from the buffer 522A or 522B and decodes the data at the decoding timing. For example, in MPEG-2 video data and the like, since the data is temporarily stored in the buffer and then decoding is started,
Since it takes time to start decoding after receiving the data, two buffers are provided so that the old data string can be decoded during the waiting time.

Further, in the figure, reference numeral 524 is a buffer 522A having a plurality of data from the media separation unit 51,
A selector 525 for switching to input to any of 522B is a selector for switching to output data from any of the plurality of buffers 522A and 522B and input to the decoding unit 523. The media decoder 53A also has the same configuration and operation as the media decoder 52A.

Next, the operation of the receiver 50A will be described. When the data string 40D is received, the media separation unit 5
1 analyzes the data and separates and transfers only the data of the portion corresponding to the media decoder 52A to which the data corresponds. The data input to the media decoder 52A is
One of the plurality of buffers 522A and 522B is selected by the selector 524 and accumulated. Here, it is assumed that the buffer 522A is selected. The buffer 522A selected by the selector 524 is also selected by the selector 525, the data accumulated in the buffer 522A is transferred to the decoding unit 523, and the decoding unit 523 performs decoding.

When the data string 40D includes "switching information" 41D, the media separating section 51 determines that "switching information".
41D is detected and the media decoders 52A and 53A are notified accordingly. The media decoder 52A switches the selector 524 and accumulates the data to be subsequently received in another buffer 522B. At this time, the selector 525 is not switched, and the data is transferred to the decoding unit 523 from the same buffer 522A as before. The decoding unit 523 continues decoding using old data as long as there is data in the buffer 522A that has been used before.

The buffer 522B in which new data is accumulated via the buffer control unit 521B continues to accumulate until some data is accumulated. "ISO / IEC1381
In the case of MPEG video data defined by "8-2", the time for which the data is continuously accumulated corresponds to the value indicated by "vbv de1ay".

The buffer control unit 521B analyzes such information from the media data, initializes the decoding unit 523 when an appropriate amount of data is accumulated in the buffer 522B,
The selector 525 is switched to the output of the buffer 522B. As a result, the new data (after switching) stored in the buffer 522B is decoded by the decoding unit 523.

If data remains in the buffer 522A, the buffer is cleared for the next use.

If there is no data accumulated in the buffer 522A before an appropriate amount of data is accumulated in the buffer 522B, the decoding unit 523 stops the decoding operation. When an appropriate amount of data is stored in the buffer 522B, the selector 525 is switched to the output of the buffer 522B. The decoding unit 523 receives the data from the buffer 522B and restarts the decoding operation.

As described above, each time the "switching information" 41D is received, the buffers 522A and 522B used by the selector 524 and the selector 525 are switched to perform decoding.
Since old and new data will not be mixed, no decoding error will occur at the time of switching. In addition, since old data can be decoded until new data is accumulated in the decodable data amount buffer, for example, the displayed information is the decoding unit 52.
When set to 3, there is less interruption during switching.

Third Embodiment A digital data switching system according to Embodiment 3 of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is a block diagram showing the configuration of a digital data switching system according to the third embodiment of the present invention. Further, FIG. 7 shows the third embodiment.
It is a figure which shows the structure of the data sequence which is the output of the data switching device of the digital data switching system which concerns on FIG.

In FIG. 6, reference numerals 10, 20 and 30 denote transmission devices for transmitting encoded data of a plurality of media,
10D, 20D and 30D are transmitters 10, 20 and 3
0 is a data string to be transmitted, 40A is a plurality of transmitting devices 10,
A data switching device that receives data strings 10D, 20D, 30D from 20, 30 and selects a data string or a plurality of data strings from the data strings, multiplexes and transfers the data, 40
Da is a data string multiplexed by the data switching device 40A,
50B is a data string 40Da from the data switching device 40A.
Is a receiving device as a receiving means for receiving and decoding.

Next, the operation of the digital data switching system according to the third embodiment will be described. The data switching device 40A selects a plurality of data strings or a part of the data strings from the data strings 10D, 20D, 30D sent from the plurality of transmitters 10, 20, 30 and multiplexes them to transmit as a data string 40Da. To do. Although there are only three data strings 10D, 20D, and 30D to be selected in FIG. 6,
It can be any number. Also, when changing the selected data string, "switching information" is inserted between the two data strings.

The receiving device 50B is a data switching device 40A.
When the data column selected by is changed,
It can be recognized that the data is switched by the "switching information" inserted in the data string 40Da.

FIG. 7 shows a data string 40 transmitted when the data string to be multiplexed is changed by the data switching device 40A.
It is a figure for demonstrating Da. In the figure, at first, the data sequence 10D and the data sequence 20D are time-division multiplexed and are output as the data sequence 40Da. However, when the data sequence selected for multiplexing is changed from 20D to 30D, the "switching information" 41D is displayed. Has been inserted. At this time, the "switching information" 41D indicates that the data string is changed from 20D to 30D.

[0071]

As described above, the data switching device according to the present invention has the first, second and third encoded data.
Select at least two data strings from the data string and multiplex
The first multiplexed data string that has been set is the third multiplexed data string
And then select at least two other data columns
The second multiplexed data string that has been multiplexed by
And the first multiplexed data string
Shows switching of the data stream to and from the second multiplexed data stream.
Since the switching information is inserted , the receiving device can recognize that the data string has been switched, and the switched data can be quickly decoded.

Further, the data switching device according to the present invention is
As described above, the first, second and third data
Since the stream is an MPEG-2 transport stream , the receiving device can recognize that the data stream has been switched, and the switched data can be promptly decoded.

Further, the data switching device according to the present invention is
As described above, the switching information is set to the same value between the data strings.
Since the period is disturbed, it is possible for the receiving device to recognize that the data string has been switched, and it is possible to promptly decode the switched data.

Further, the data switching device according to the present invention is
As described above, the switching information is converted into MPEG-2 format.
Since the transport stream packet is used , the receiving device can recognize that the data sequence has been switched, and the switched data can be quickly decoded.

Further, the data switching device according to the present invention is
As explained above, the switching information is set to the program before switching.
Since the PAT has no information , the receiving device can recognize that the data string has been switched, and thus the switched data can be quickly decoded.

As described above, the data switching device according to the present invention stores the switching information in the data string before switching.
Since the PMT does not include the media multiplex information , the receiving device can recognize that the data string has been switched, and the switched data can be quickly decoded.

[0077] The data switching method is in accordance with the present invention, or as described, to receive a plurality of data strings in which a plurality of transmitting device transmits to each marks <br/> Goka, a plurality of data sequence received To switch one data
A data switching method when transmitting data sequence, said plurality
The switching information indicating the switching of the data string is inserted between the data string before the switching and the data string after the switching when the data string is switched independently of the data string before and after the switching. The device can recognize that the data string has been switched, and the data after switching can be promptly decoded.

The data switching method according to the present invention is
As described above , the above data string is converted to ISO / IEC
MPEG-2 transformer specified by 13818-1
Since the port stream is used, the receiving device can recognize that the data string has been switched, and the switched data can be quickly decoded.

The data switching method according to the present invention is
As described above, the switching information is set to the same value between the data strings.
Since the period is disturbed, it is possible for the receiving device to recognize that the data string has been switched, and it is possible to promptly decode the switched data.

The data switching method according to the present invention is
As described above, the switching information is set to ISO / IEC
MPEG-2 transformer specified by 13818-1
It is a port stream packet. Also, this
The data switching method according to the invention of claim 1,
MPEG-specified by O / IEC13818-1
2 PAT of transport stream packet
The content of the PAT does not have information on the program before switching.
It is what Further, the data switching method according to the present invention
The method uses the switching information as ISO / IEC13818-1.
MPEG-2 transport stream defined by
Packet PMT, and the content of the PMT before switching
Since the media multiplex information of the data string does not exist , the receiving device can recognize that the data string has been switched, and the switched data can be quickly decoded.

Further, as described above, the receiving device according to the present invention shows the switching of the data string between the data string before the switching and the data string after the switching when switching the plurality of data strings. the switching information is received the data string is inserted independently of the data sequence after before and the changeover in the media demultiplexing unit, when the media demultiplexing unit receives the switching information, the initial buffer controller decoder The data string after conversion is decoded after the above conversion information. Furthermore, the receiving device according to the present invention has a plurality of receiving buffers for temporarily accumulating the received data string when decoding the received bit string, and when the switching information is received, after the switching information, the switching The data string is stored in a receiving buffer different from the receiving buffer that has stored the data string before switching received before the switching information, and the data after switching following the switching information in the another receiving buffer. The data string before switching, which is stored in the reception buffer, is decoded until the string is normally stored up to the amount of data that can be decoded, so that the receiving device can recognize that the data string has been switched, and The data can be quickly decrypted.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a digital data switching system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a data switching device of the digital data switching system according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a data string of the data switching device of the digital data switching system according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a receiver of the digital data switching system according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a receiver of the digital data switching system according to the second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a digital data switching system according to Embodiment 3 of the present invention.

FIG. 7 is a diagram showing a data string of the data switching device of the digital data switching system according to the third embodiment of the present invention.

[Fig. 8] Fig. 8 is a diagram illustrating a transport stream syntax of "ISO / IEC13818-1".

FIG. 9 is a diagram showing a data string of a data switching device of a conventional digital data switching system.

[Explanation of symbols]

10, 20, 30 Transmitter, 10D, 20D, 30D
Data string, 40, 40A data switching device, 40D,
40 Da data string, 41 switching information generator, 41D
Switching information, 42 selector, 50, 50A, 50B
Receiving device, 51 media separating unit, 52, 52A, 53,
53A media decoder.

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-9-139677 (JP, A) JP-A-8-181994 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 29/00 H04N 7/24

Claims (14)

(57) [Claims] 1. A first multiplexed data sequence in which at least two data sequences are selected from the encoded first, second and third data sequences and multiplexed to generate a first multiplexed data sequence as a third multiplexed data sequence. Then, at least another two data strings are selected and multiplexed to generate a second multiplexed data string as the third multiplexed data string, and the first multiplexed data string and the second multiplexed data string are generated. 2. A data switching device, characterized in that switching information indicating switching of a data string is inserted between the data string and the multiplexed data string. 2. The first, second and third data strings are:
The data switching device according to claim 1, wherein the data switching device is an MPEG-2 transport stream. 3. The switching information according to claim 1, wherein the switching information disturbs synchronization between data strings.
The data switching device described. 4. The data switching device according to claim 3, wherein the switching information is an MPEG-2 transport stream packet. 5. The data switching device according to claim 4, wherein the switching information is a PAT in which information of a program before switching does not exist. 6. The data switching device according to claim 4, wherein the switching information is a PMT in which media multiplex information of a data string before switching does not exist. 7. A plurality of transmitting apparatus receives a plurality of data sequence transmitted by encoding each data switching method in transmitting one data stream to the receiving apparatus by switching the plurality of data sequence received The switching information indicating the switching of the data string between the data string before switching and the data string after switching when switching the plurality of data strings is independent from the data strings before and after the switching. A data switching method characterized in that the data is inserted by inserting. 8. The data string is ISO / IEC138.
The data switching method according to claim 7, which is an MPEG-2 transport stream defined in 18-1. 9. The switching information according to claim 7, wherein the switching information disturbs synchronization between data strings.
Described data switching method. 10. The switching information is ISO / IEC13.
8. An MPEG-2 transport stream packet defined by 818-1.
Alternatively, the data switching method according to claim 8. 11. The switching information is ISO / IEC13.
11. The data switching method according to claim 10, wherein the PAT is an MPEG-2 transport stream packet specified by 818-1, and the content of the PAT does not include information on a program before switching. 12. The switching information is ISO / IEC13.
11. The data switching method according to claim 10, wherein the PMT is an MPEG-2 transport stream packet specified by 818-1, and the content of the PMT does not include media multiplex information of a data stream before switching. . 13. Between a data string before switching and a data string after switching when switching a plurality of data strings, switching information indicating switching of the data string is independent of the data strings before and after the switching. When the media separation section receives the switching information, the buffer control section initializes the decoding section and outputs the data string after switching following the switching information when the media separation section receives the switching information. A receiving device characterized by decoding. 14. A plurality of reception buffers for temporarily accumulating a received data string when decoding a received bit string, wherein when the switching information is received, the data string after switching following the switching information is the above-mentioned The data string received before the switching information before switching is stored in a receiving buffer different from the receiving buffer in which the data string after switching following the switching information is normally decoded in the other receiving buffer. 14. The receiving apparatus according to claim 13, wherein the data string before switching accumulated in the reception buffer is decoded until the maximum amount of data is accumulated.