WO2005043783A1

WO2005043783A1 - Mobile-terminal-oriented transmission method and apparatus

Info

Publication number: WO2005043783A1
Application number: PCT/JP2004/015810
Authority: WO
Inventors: Izumi Usuki; Sadashi Kageyama; Akira Kisoda; Hidekuni Yomo
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2003-10-30
Filing date: 2004-10-26
Publication date: 2005-05-12
Also published as: EP2051510A3; JP4423263B2; JPWO2005043783A1; EP2051510B1; EP1657835A1; EP1657835A4; EP2051510A2

Abstract

The time slice system has a problem that, since data is burst transmitted, a wait time occurs, during tuning, until a reproduction of a service starts, with the result that zapping cannot be smoothly performed. In order to solve this problem, a first stream for burst transmitting a packet set and a second stream for continuously transmitting a packet at a rate suitable for a transmission rate required for a service are multiplexed with each other and then transmitted. During zapping, the second stream, which is constantly transmitted, is used to reproduce the contents, and after a completion of the zapping, the first stream, in which the packet is burst transmitted, is reproduced.

Description

Specification

Transmission method and device for mobile terminal

Technical field

The present invention relates to digital broadcasting for mobile terminals, and more particularly, to a transmission method and apparatus for digital data broadcasting for mobile terminals.

Background art

[0002] European terrestrial digital broadcasting transmission systems are standardized by ETSI. (DVB-T

See EN 300 477). However, it supports segment-specific partial reception such as the Japanese domestic standard (ARIB STD-B31 etc.). Therefore, when receiving a DVB-T broadcast on a mobile terminal, a fixed terminal such as an STB must be used. As in the above, all terminals need to receive all signals, and mobile terminals with limited power supply capacity consume a lot of power and have a problem in practicality such as a reduction in continuous playback time.

[0003] Therefore, in the document EP1337071A2, as shown in Fig. 11, packets of the same service are grouped into a packet set, and each packet set is transmitted as a data burst 10 at high speed in a short time to transmit one packet service. In the meantime, the packet sets of each service are transmitted in order so that the packet sets of other services are not mixed.

[0004] The receiver realizes low power consumption by supplying power to the receiving unit only during a packet set transmission period during which a desired service is transmitted. (Hereinafter referred to as the time slice method)

[0005] However, in this time slice method, when the receiver selects a channel after turning on the power or when selecting a channel to another service, the receiver waits until a packet set of the corresponding service is transmitted. For a few seconds, there is a problem that the reproduction of the content does not start.

Patent document 1: EP1337071A2

Disclosure of the invention

Problems to be solved by the invention

[0006] As described above, in the time slice method, since data is transmitted in bursts, a waiting time occurs until the reproduction of the service is started at the time of channel selection, and zubbing viewing is smooth. There is a problem!

The present invention solves the above-mentioned conventional problems, and reduces the waiting time until playback is started by selectively receiving a time slice including content and data for zubbing at the time of zubbing. The purpose is to:

Means for solving the problem

[0007] The present invention relates to a transmission method in a broadcasting system, comprising the steps of: generating a first stream (intermittent data section) for burst transmission of a single content packet set for each service; Generating a second stream (continuous data portion) for transmitting packets at a rate according to the rate, wherein the second stream relates to the content being transmitted in the first stream. Provided is a transmission method characterized by transmitting information. Here, burst transmission refers to transmission in which content is transmitted collectively in a short period of time and transmission is stopped for a while.

[0008] In one embodiment of the present invention, in the first stream, intermittent data for a plurality of services is sequentially transmitted, and in the second stream, the first stream is transmitted by the first stream intermittent data unit. Content that is the same as the content sent by all or some of the services that are being sent.

In one embodiment of the present invention, the first stream has high-quality data, and the second stream has high compression rate data having the same contents as the first stream but having a small amount of information. Is transmitted.

[0010] The second stream of the present invention is related data based on the contents of the first stream, and it can be said that the data amount of the second stream is smaller than the data amount of the first stream. For example, the second stream is a stream that is generated at a compression rate higher than the compression rate used when generating the first stream.

[0011] In one embodiment of the present invention, the first stream includes data including high-quality audio and moving images, and the second stream includes a still image or a still image related to the first stream. Includes at least one of audio.

[0012] In one embodiment of the present invention, at least one of the first stream and the second stream includes the second stream and a content transmitted in the first stream. Contains an information field indicating the association of the connection.

[0013] In one embodiment of the present invention, an information field indicating the association between the second stream and the content transmitted in the first stream is included in a third stream.

[0014] In one embodiment of the present invention, an information field indicating a relation between the second stream and the content transmitted in the first stream is included in a PMT of a PSI.

[0015] In one embodiment of the present invention, a time information field between the transmission time of the packet set and the transmission time of the next packet set is included in the second stream.

[0016] The present invention is also a transmission method for performing burst transmission of a packet set consisting of a single content for each service, and generating a first format packet set consisting of a single content for each service. Generating a second format packet set that contains all or some services and equivalent or related content transmitted in the first format packet set; and a first format packet set. And transmitting the packet set of the second format in the first stream in order.

In one embodiment of the present invention, the packet set of the first format has high-quality data, and the packet set of the second format has the same contents as the packet set of the first format. Transmits high compression rate data with a small amount of information.

In one embodiment of the present invention, the packet set of the first format includes data including high-quality audio and video, and the packet set of the second format includes a packet set of the first format. At least one of the related still image and sound is included.

[0019] In one embodiment of the present invention, at least one of the first format packet set and the second format packet set includes the second format packet set and the first format packet set. Contains an information field indicating the relevance of the content being transmitted in the packet set

[0020] In one embodiment of the present invention, the information field indicating the association between the contents of the packet set of the second format and the packet set of the first format and indicating the content of the content is an independent second stream. Included.

In one embodiment of the present invention, the packet set of the second format and the packet set of the first format The information field indicating the relation of the content transmitted in the packet set of PSI is included in PMT of PSI.

[0022] In one embodiment of the present invention, the content transmitted in the packet set of the second format and the content transmitted in the packet set of the first format have time stamps synchronized with each other.

[0023] In one embodiment of the present invention, the content transmitted in the packet set of the second format and the packet set of the first format transmits information indicating a time stamp shift.

The present invention provides a first stream for transmitting a packet set in bursts at a sufficiently high transmission rate in a short time and a second stream for transmitting packets at a transmission rate required for a service. The stream is transmitted by time-division multiplexing, and the second stream transmits, for example, low-quality data of the same content as the first stream, and receives the second stream that is always transmitted during subbing. After the subbing is completed, the first stream transmitted in a burst is received and reproduced.

[0025] Further, the present invention relates to a transmission apparatus in a broadcasting system, comprising: a first stream (intermittent data section) generating means for performing burst transmission of a packet set consisting of a single contentor for each service; Second stream (continuous data portion) generating means for transmitting packets at a speed according to the speed, wherein the second stream transmits information related to the content transmitted by the first stream. Provided is a transmission device characterized by transmitting.

[0026] Further, the present invention is a transmission method for performing burst transmission of a packet set consisting of a single content for each service, and means for generating a first format packet set consisting of a single content for each service. Means for generating a second format packet set containing all or some of the services transmitted in the first format packet set and equivalent or related content; and A content transmitting apparatus comprising: a packet set; and means for sequentially transmitting a packet set of a second format in a first stream.

As described above, according to the present invention, by using burst transmission and continuous transmission together, During listening, power consumption can be suppressed by intermittently receiving the first stream, and during channel selection operations such as zubbing, other content can be instantaneously reproduced by playing the second stream. You can watch.

[0028] The present invention also provides a transmitter for transmitting to a receiver using the above-described transmission method or content transmission method, a transmission method relating to the above-described transmission method or content transmission method, and a program for executing the same, and Provide a recorded recording medium.

[0029] The present invention will be described with reference to the following "embodiments of the invention" and the drawings, but this is for the purpose of illustration, and the present invention is not intended to be limited to these.

The invention's effect

[0030] According to the present invention, high-quality burst data and low-quality continuous data are multiplexed and transmitted, and continuous data that can be received at all times during zubbing viewing is reproduced, thereby reducing the waiting time when selecting a channel. You can do it. In addition, by synchronizing or correcting the time stamp, the influence of switching the mode of the receiver during reproduction can be reduced.

Brief Description of Drawings

FIG. 1 is a diagram illustrating a transmission method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a data arrangement image on a transmission channel 14 according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a power control operation according to the first embodiment of the present invention.

FIG. 4 is a diagram explaining a receiving method at the time of subbing reception of a stream in the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a transmission method according to a first modification of the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a transmission method according to a second modification of the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a transmission method according to a third modification of the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a transmission method according to the second embodiment of the present invention.

FIG. 9 is a diagram showing a data arrangement image on a transmission channel 14 according to the second embodiment of the present invention.

FIG. 10 shows a reception method at the time of zubbing reception of a stream according to the second embodiment of the present invention. FIG.

FIG. 11 is a diagram illustrating a conventional example of the present invention.

FIG. 12 is a diagram illustrating a transmission method according to the third embodiment of the present invention.

FIG. 13 is a diagram showing another arrangement of subbing data in the third embodiment of the present invention.

FIG. 14 is a diagram showing conversion from an IP packet to a TS packet.

FIG. 15 is a diagram showing a state in which multipletus is performed by a multiplexer.

Explanation of symbols

[0032]

2—6 Services S1—Content Source of S5

7, 7b IP packet

8 processor 1

9 Processor 2

10 burst data

11 Transport stream with low quality data multiplexed

l lsl—l ls5 low quality data package

12 Multiplexer

13 Transmitter

14 transmission channels

15 Burst for subbing

16 Timestamp offset detector

17 Time stamp correction processing section

BEST MODE FOR CARRYING OUT THE INVENTION

In the embodiment of the present invention, a content transmission method of intermittent and continuous mixed transmission will be described. Intermittent transmission refers to high-quality compression of a signal including a video signal and a Z or audio signal at every predetermined presentation period Tin (for example, 5 seconds), and 1ZN of Tin (N is a positive integer, for example, N = 36 ). In this case, the presentation period Tin can have up to 36 different services (for example, 36 TV channels). Screws) can be sent in a time-division manner, and a new video signal is sent for each Tin. Here, a program to which a certain channel or provider power is sent is called a service. Focusing on a specific service (eg, channel 1 program), the video signal is sent every period Tin, so it is called intermittent transmission. On the other hand, continuous transmission is a method of transmitting low-quality compressed signals every Tcon (about 23 ms) shorter than one frame period (for example, (1Z30) seconds). The present invention relates to a method of transmitting a stream in which intermittently transmitted packets and continuously transmitted packets are mixed. If only intermittent transmission is used, high-quality images can be viewed, but each service switch requires a waiting time of about 5 seconds. Intermittent transmission is not suitable for performing an operation of switching services one after another and searching for a desired service, that is, performing zapping. On the other hand, if only continuous transmission is used, even if the service is switched, it is possible to immediately watch the video of the service at the switching destination without waiting time. In the present invention, intermittent transmission and continuous transmission are mixed, so that services such as video can be received without waiting time even if zubbing is performed. Can be seen in quality images.

[0034] The following processes of the present invention can all be realized by software.

(Embodiment 1)

An embodiment of the transmission system of the present invention will be described with reference to the drawings, taking the case of zubbing viewing as an example.

FIG. 1 is a diagram illustrating generation of a transmission signal according to the present invention.

It is a digital panorama broadcasting head end, and is a content source for services SI, S2, S3, S4, and S5. Each piece of content is encoded in two qualities, high quality and low quality, resulting in a high quality IP (Internet Protocol) packet 7 and a low quality IP packet 7b. Each content source includes a high-quality encoder that generates the IP packet 7 and a low-quality encoder that generates the IP packet 7b, and is composed of independent real-time encoders. The high quality encoder has an internal clock CLa indicating real time, while the low quality encoder has an internal clock CLb indicating real time. Needless to say, the time of the internal clock CLa and the time of the internal clock CLb match. [0036] The same IP address is assigned to each of the IP packets 7 from the same content source, for example, the content source 2. Different content sources, ie different services, have different IP addresses. The high-quality IP packet 7 and the low-quality IP packet 7b from the same content source may use the same IP address or different IP addresses.

[0037] The high-quality encoder is capable of MPEG4 compression of video signals and content including Z or video signals at an average transmission rate of 350 kbps. The low-quality encoder can compress the same content using MPEG4 at an average transmission rate of 64 kbps.

When the transmission band of the broadcast wave is about 15 Mbps, one service (350 + 64

=) If 414 kbps is required, (15000 ÷ 414 =) 36 services can be transmitted. The above transmission rates and MPEG4 compression are examples, and other transmission rates and compression methods may be used.

[0039] Parameters such as the transmission rate are not limited to those described above. Further, the compression method may be a method such as the WindowsMedia method, the QuickTime method, or the JPEG2000 method.

First, high quality data will be described with reference to FIG. Video and audio data MPEG4 compressed at an average transmission rate of 350 kbps is generated as RTP (Real-time Transport Protocol) data, and an RTP header is added. A time stamp Ta for synchronizing between transmission and reception is added to the RTP header. RTP data and RTP header are contained in RTP packets. RTP packets are generated as User Datagram Protocol (UDP) data and have a UDP header. DUP data and UDP header are stored in UDP packet. The UDP packet is generated as IP data and has an IP header. The IP data and IP header are contained in IP packet 7.

[0041] The IP packet 7 thus encoded with high quality is input to the processing device 8 shown in FIG. The processing device 8 has a number of buffers corresponding to the number of content sources. In the example of FIG. 1, there are five buffers Bl, B2, B3, B4, and B5, and each buffer has an IP bucket 7 (for example, 1163 I) corresponding to a predetermined presentation period Tin (for example, 5 seconds). P packets). Since the IP packet is MPEG-compressed, the actual storage time is about (5Z36) seconds instead of 5 seconds.

First, if the IP packets 7 of the service S1 corresponding to the period Tin are stored from the buffer B1, the stored IP packets are sequentially sent to the processing unit PP1. The processing unit PP1 converts the IP packet 7 into a DSM-CC (Digital Storage Media Command and Control) section, and further converts it into a TS (Transport Stream) packet, as shown in FIG. A TS packet has a fixed length (for example, 188 bytes). Each TS packet includes a TS header at the beginning. A packet HD for specifying the type of the TS packet, that is, a PID is added to the TS header. For example, PID1 is assigned to the PID of the TS packet including the service S1.

Note that the same PID is given to TS packets including data of the same service, such as PID2 for the PID of the TS packet including the service S2 and PID3 for the TS bucket including the service S3. You. Conversion from IP packets to TS packets is performed according to standard documents such as ISO / IEC 13818-1, ISO / IEC 13818-6, ETSI / DVB EN301192

[0044] The plurality of TS packets to which PID1 has been added are sequentially output. The group of TS packets for about 5 seconds transmitted in this way is called burst 10. In FIG. 1, a block S1 output from the processing device 8 indicates a burst, and TS packets of the service S1 corresponding to a presentation for about 5 seconds are continuously included.

[0045] Subsequently, if the IP packet 7 of the service S2 corresponding to the period Tin is accumulated from the buffer B2, the accumulated IP packet is sent to the processing unit PP1, where the IP packet is converted into a TS packet. At the same time, PID2 is assigned to each converted TS packet as a packet ID. The plurality of TS packets to which PID2 is assigned are sequentially output. The block S2 output from the processing device 8 indicates a burst, and TS packets of the service S2 corresponding to a presentation of about 5 seconds are included continuously.

Thereafter, similarly, TS packets of different services are output to the multiplexer 12 to be output for each burst.

Next, the low quality data will be described. MPEG4 compression to average transmission rate 64kbps The moving image and audio data thus generated are used to generate an IP bucket 7b in the same manner as the high-quality data in the procedure shown in FIG. Therefore, the RTP packet is also included in the IP packet 7b, and includes the time stamp Tb for synchronizing between transmission and reception.

[0047] The low-quality encoded IP packet 7b is input to the processing device 9 shown in FIG. The processing device 9 has one buffer Bz, and accumulates IP packets 7b from all content sources in the order in which they are sent. If all or some of the IP packets 7b from different content sources overlap, a plurality of buffers may be provided similarly to the processing device 8. However, the capacity of the buffer may be a capacity that can store one IP packet 7b. The sent IP packet 7b is sent to the processing unit PP2, and is converted from an IP packet to a TS packet in the same manner as the processing unit PP1. All converted TS packets have the same PID, for example PIDX, regardless of service. PIDX is a unique PID and indicates that it is a TS packet for subbing. The TS packet from the processing device 9 is sent to the multiplexer 12. The multiplexer 12 is further connected to a PSI generator 18.

[0048] Here, it is assumed that the same PID, for example, PIDX, is assigned to all TS packets transmitting low-quality data regardless of the service. However, similarly to the transmission of high-quality data, a different PID is provided for each service. The effect of the present invention is not impaired even if the transmission is performed with the addition of.

[0049] The format of the low quality data is not limited to a format including both a moving image and a sound, and may be any one of a moving image, a still image, a sound, character information, or a combination thereof. .

Further, the format of low quality data may be dynamically determined according to conditions such as the number of bursts to be simultaneously serviced and the average transmission rate.

[0050] The PSI generator 18 generates a PSI (Program Specific Information). PSI includes PAT (Program Association Table), PMT (Program Map Table), CAT (Conditional Access Table), and NIT (Network Information Table). Each table is divided into one or more TS packets. In the present embodiment, the conditional access function is irrelevant to the present invention, so that the description of CAT is omitted. The data structure of these tables This will be described later. First, the multiplexer 12 will be described.

As shown in FIG. 15, the multiplexer 12 includes three types of high-quality TS packets from the processing device 8, low-quality TS packets from the processing device 9, and PSI TS packets from the PSI generator 18. And incorporates them into one stream. For each of PAT and NIT, one table is set for all services. For PMT, different tables are set for each service. The positions where PAT, PMT, and NIT are inserted are specified in the above-mentioned standard. The low-quality TS packets are dispersedly inserted. The time difference Tzl between one low-quality TS packet S1 and the next low-quality TS packet S2 is about 0.65 msec. The time difference Tz2 between one low-quality TS packet S1 and the next low-quality TS packet S1 of the same service is about 23.5 msec. The time differences Tzl and Tz2 change when the transmission rates are different. The multiplexed stream is passed to a transmitter 13 as a transmission channel 14, and the transmitter 13 is sent out to a transmission path.

Next, a data structure will be described.

First, the packet ID (PID) included in the header of the TS packet is determined as follows. High quality TS packet: PID including code that differs for each service (a code indicating high quality may be included)

Low quality TS packet: same PID related to service (may include code for low quality)

PAT TS packet: OXOOOO

PMT TS packet: PID that contains a different code for each service (a code that indicates PMT may be included)

NIT TS packet: 0X0010

In the PAT, a program number value set for each service and a PMT PID set for each service are shown as a pair. This data is

It is over the "programjiumber" area and the "program_map_PID" area. For example, if there are five services SI, S2, S3, S4, S5 force S, there are five PMT forces S. The PIDs of the five PMTs are PMT-PIDl, PMT— PID2, PMT— PID3, PMT— PID4, PMT— PI When D5 is set, the PAT contains the data in the following correspondence table shown in Table 1.

[0054] Table 1

Service Corresponding PMT PID

51 PMT PID1

52 PMT PID2

53 PMT PID3

54 PMT PID4

55 PMT PID5

[0055] The PMT indicates the PID of the high quality TS packet of the service corresponding to the PMT. This data is written in the "elementary_PID" area of the PMT.

Therefore, if a service is specified, the PID of the PMT corresponding to the service is specified from Table 1, the PMT is specified by the PID of the PMT, and if the PMT is specified, a high-quality TS packet is specified. You.

[0056] The PMT includes a descriptor. In the descriptor, the value of the program number set for each service and the IP address of the IP packet to which the service is sent are shown as a pair. For example, PMT—The IP address of service S1 is associated with the PMT specified by PID1. The PMT specified by PMT—PID2 is associated with the IP address of service S2. In this way, a service-IP address mapping table can be obtained from the five PMTs.

Note that the descriptor may be included in the NIT.

Also, instead of PSI, SI (Service Information) may be used to store the above information.

Also, the PSI generator 18 may be provided in the processing device 8 and included in a high-quality TS packet stream, or may be provided in the processing device 9 and included in a low-quality TS packet stream. .

FIG. 2 shows an image of data arrangement on the transmission channel 14. Actually, SI or PSI is also transmitted. However, since it is similar to general digital broadcasting, illustration is omitted. When a signal having such a configuration is transmitted, a receiving method will be described with reference to the drawings. FIG. 3 is a diagram showing power supply control in the transmission method of the present invention, particularly when high quality data of the service S1 is received.

[0058] The high quality data of the service S1 is sent in bursts as shown in FIG. Since the receiver takes about 250 ms from the start of burst reception to the output of a power packet, it starts power supply to the demodulation unit about 250 ms before the start of burst reception and receives the service S 1 transmitted in burst. Store data in internal buffer. After the end of the burst transmission, the power supply to the demodulation unit is stopped, but the playback unit plays back the content while reading data from the buffer at the rate required for playback while power is being supplied. As a result, power consumption can be reduced. (Hereinafter, such a state of intermittent reception will be referred to as an intermittent reception mode.)

Next, a receiving method at the time of zubbing will be described. FIG. 4 is a diagram illustrating a receiving method at the time of subbing reception according to the present invention.

Now, at time tO, the service S1 is received in the intermittent reception mode. At time tl, when the user operates the user interface such as the service selection button to change the service to S2, the power of the receiving unit is turned on, and the Enter Bing mode. Using the service-to-PID correspondence table and the service-to-IP address correspondence table obtained from the PSI, the receiver can convert the low-quality TS packet stream (also called subbing stream) to the S2 low-quality data. Remove the data and start playback. At the same time, it waits for the reception of the S2 high-quality data burst.

[0060] In this state, when S3 is selected by a user operation at time t2, the receiver extracts low-quality data of S3 from the stream for subbing and starts reproduction. At the same time, it waits for reception of S3 high-quality data burst. Further, when S1 is selected by a user operation at time t3, the receiver extracts the low-quality data of S1 from the subbing stream, starts reproduction, and waits for reception of the high-quality data burst of S1.

[0061] In the operation up to this point, the beginning of the burst of the service currently selected in the burst data is not detected! Therefore, in any case, the subbing mode is maintained.

Next, when S4 is selected by a user operation at time t4, the receiver extracts the low-quality data of the streaming force for subbing S4, starts reproduction, and starts the reproduction of the high-quality data burst of S4. Wait for reception. As soon as the burst of service 4 is transmitted at time t5, the reception of the burst of service S4 is started immediately, the reproduction of high-quality data is started, and the mode shifts to the burst reception mode. The power supply to the receiving unit is stopped until time t7 when is transmitted.

[0062] In the present embodiment, the correspondence table between the service and the PID for transmitting the service and the high-quality data is assumed to be transmitted by SI or PSI. However, the transmission format of the correspondence table is as follows. The transmission is not limited to burst 10 and may be transmitted in transport stream 11, or a receiver having a communication line may be transmitted via a communication line. The same applies to the correspondence table between services and IP addresses that transmit low-quality data. Alternatively, another Internet route may be used.

(Modification 1)

Next, a first variation of the seamless switching from low-quality data reproduction to high-quality data reproduction (or vice versa) will be described.

As shown in FIG. 1, the frequency at which the IP packet 7b is generated is lower than the frequency at which the IP packet 7 is generated. Since the high-quality encoder and the low-quality encoder are real-time encoders, the timing at which the IP packet 7 and the IP packet 7b are generated is substantially the same as the timing at which the actual video is sent. Here, if one of the internal clock CLa of the encoder for high quality and the internal clock CLb of the encoder for low quality is advanced by ΔΤ or delayed by ΔΤ from the other, the time stamp for the same video is used. An error of ΔΤ occurs between Ta and time stamp Tb. Therefore, when switching from high-quality data reproduction to low-quality data reproduction or vice versa, images become discontinuous. Modification 1 in which this discontinuous image is corrected to a continuous image, that is, a seamless image will be described.

FIG. 5 is different from FIG. 1 in that a time stamp offset detector 16 is further provided. The time stamp offset detector 16 includes a time stamp Ta added to the RTP header for high-quality data indicating the presentation of a certain screen, and a time stamp Tb added to the RTP header for low quality indicating the presentation of the same screen. Is detected as a time stamp offset. This time difference ΔΤ is input to the PSI generator 18. In the descriptor of the PMT, the value of the program number set for each service and the time difference ΔT are shown as a pair.

[0065] The time difference ΔΤ is sent to the receiving apparatus, and the receiving apparatus adds or subtracts ΔΤ to the time stamp Tb of the low-quality data so that the video of the high-quality data and the video of the low-quality data are synchronized. I do. Alternatively, ΔΤ may be added or subtracted from the time stamp Ta of the high quality data to synchronize the video of the high quality data with the video of the low quality data.

[0066] Such synchronization is described with reference to FIG. When S4 is selected by a user operation at time t4, the receiver extracts low-quality data of S4 from the stream for subbing, starts reproduction, and waits for reception of a high-quality data burst of S4. As soon as the burst of the service S4 is transmitted at time t5, the reception of the burst of the service S4 is started immediately. After that, the time stamp Ta of the high quality data is corrected by the time difference Δ 、 so as to be equal to the time stamp Tb of the low quality data. In this way, reproduction of high-quality data is started at the corrected timing. Make corrections for the data you are about to play

When the reception of the burst is completed, the mode shifts to the burst reception mode, and the power supply to the reception unit is stopped from time t6 to time t7 when the next burst of S4 is transmitted.

In this way, the time stamps of the two streams can be synchronized, and it is possible to switch from low-quality data playback in zapping mode to high-quality data in intermittent reception mode.

Although the time stamp uses the time stamp in the RTP header included in the IP packet, an MPEG packet can also be used. In this case, use the time stamp PCR in the MPEG packet!

(Modification 2)

Next, another modified example 2 of seamless switching from low-quality data reproduction to high-quality data reproduction (or vice versa) will be described.

FIG. 6 is different from FIG. 1 in that a time stamp correction processing unit 17 is further provided. The time stamp correction processing unit 17 calculates the time difference ΔΤ between the time stamp Ta of the screen having high quality data and the time stamp Tb of the screen of low quality data corresponding to the screen. Detected as a pump offset. Further, all the time stamps of one of the streams are corrected using the time difference ΔΤ so that the reference clocks are equal in both streams. As a result, the same time stamp is given to the same screen between the IP packet 7 and the IP packet 7b. This enables seamless image switching.

(Modification 3)

[0070] A third modification of the first embodiment for transmitting the data for subbing will be described with reference to FIG. In the third modification, a still image and audio are transmitted as data for subbing.

FIG. 7 shows a data arrangement image on the transmission channel 14. In the figure, reference numeral 10 denotes a time slice in which the high-quality data of the service 115 is transmitted. The average transmission rate of video and audio is 350 kbps and MPEG4 compression is performed. In the figure, l lsl, l ls2, l ls3, lis 4, l ls5 are low-quality data for zubbing. Approximately 2 kbytes of still images representing moving images transmitted in each time slice of each service and approximately 5 seconds of audio data compressed to approximately 8 kbps of audio transmitted in one time slice of high quality data It is transmitted in the package. The still image may be character information such as a program title.

[0071] When the number of services transmitted in the time slice is mixed with the DVB-T standard signal and transmitted, as in this example, the number is about several, and the time and the average transmission rate are 64kbps. Within one time slice duration (approximately 130 msec) in the subbing stream 11, it is possible to transmit a low quality data package of all services of 1 lsl-lls5. Since the receiver can receive all the low-quality data packages for subbing of other services at the same time as receiving the time slice, it should display still images and audio without waiting for the power of the demodulation unit to be always on. Can be.

(Embodiment 2)

[0072] Another embodiment of the transmission system of the present invention will be described using FIG.

FIG. 8 is a diagram illustrating generation of a transmission signal according to the present invention. 8 differs from FIG. 1 in that the output of the processing device 9 is input to the processing device 8 instead of the multiplexer 12, and the processing device 8 is further provided with a buffer B6. The low-quality TS packet stream 11 output from the processing device 9 is added to the buffer 6 for about 5 seconds, and is output from the processing device 8 as one burst 15. Needless to say, the burst 15 includes a TS packet group SO for subbing to which the same PID address is assigned, which corresponds to the low-quality TS packet stream 11.

[0073] The section of the bursting 15 for subbing is provided with time information indicating the timing at which the corresponding high-quality burst is transmitted. A plurality of bursts 10 and bursts 15 for subbing are sequentially transmitted in bursts and sent to the multiplexer 12. In the multiplexer 12, the four types of tables PAT, PMT, CAT, and NIT generated by the PSI generator 18 are multiplied.

In other words, the transmission channel is composed of high quality data that constitutes a burst for each service, and one burst of low quality data for subbing.

[0074] A reception method in a receiver when a signal having such a configuration is transmitted will be described with reference to the drawings.

FIG. 9 shows an image of data arrangement on the transmission channel 14. Actually, SI or PSI is also transmitted, but it is not shown because it is similar to general digital broadcasting.

FIG. 10 is a diagram illustrating a receiving method at the time of subbing reception according to the present embodiment.

Now, at time tO, the service S1 is received in the intermittent reception mode. At time tl, when the user operates the user interface such as the service selection button to change the service to S2, the power of the receiving unit is turned on, and the Enter Bing mode.

At this time, the zubbing burst 15 is transmitted! Therefore, S1 is reproduced until the zubbing burst 15 can be received at time t2. After receiving the subbing burst 15, the receiver uses the service-to-PID correspondence table and the service-to-IP address correspondence table obtained from the SI or PSI while the S2 is selected. Extract the low-quality data of S2 from and start playback. At the same time, it waits for the reception of the S2 high-quality data burst.

In this state, when S3 is selected by a user operation at time t3, the receiver extracts the low-quality data of S3 from the stream for subbing, and starts reproduction. At the same time, it waits for reception of S3 high-quality data burst. With the operations so far, the beginning of the burst of the service currently selected in the burst data is not detected! Therefore, in any case, the subbing mode is maintained.

Next, when S4 is selected by a user operation at time t4, the receiver extracts the low-quality data of S4 from the bursting for subbing 15, starts reproduction, and waits for reception of the high-quality data burst of S4. At time t5, when it is detected that the burst of service 4 is being transmitted, it immediately starts receiving the burst of service 4, starts reproducing high-quality data, and shifts to the burst reception mode. At time t6, the power supply to the receiver is stopped until time t7 when the next burst of S4 is transmitted.

[0077] Also in this example, the low-quality data may be data obtained by highly compressing high-quality data, or the same effect may be obtained even if only a still image and audio related to the content or only audio is used. Needless to say.

In the present embodiment, the correspondence table between the service and the PID for transmitting the service and the high-quality data is assumed to be transmitted by SI or PSI, but the transmission format of the correspondence table is not limited to this. The transmission may be performed within the burst 10 and the transport stream 11, or may be performed via a communication line such as an Internet communication line if the receiver has a communication line. Service and transmission of low quality data The correspondence table of IP addresses is the same.

According to this transmission method, the intermittent reception is performed even during the zubbing period, so that the low power consumption effect is higher than in the first embodiment.

However, immediately after the start of the zubbing, it is necessary to wait until the reception of the burst for the zubbing, but it is possible to switch the channel again during the zubbing immediately.

(Embodiment 3) Transmission of subbing data in burst (transmission of still image and audio)

The third embodiment is an improvement of the transmission of the data for subbing of the first embodiment, and will be described with reference to FIGS.

FIG. 12 of the present embodiment shows an image of data arrangement on the transmission channel 14. In the figure, reference numeral 10 denotes a time slice in which high-quality data of the service 115 is transmitted, which is obtained by applying MPEG4 compression to an average video and audio transmission rate of 350 kbps. l lsl, 11 s2, l ls3, l ls4, l ls5 are low quality data for subbing, A still image lOkbyte representing a moving image transmitted by rice, and audio data for about 25 seconds, in which the audio transmitted in one time slice of high-quality data is compressed to approximately 8 kbps, transmitted in a package. It is.

[0080] Only one data for subbing is multiplexed and transmitted in each service time slice.

In Fig. 12, assuming that service 1 is selected and received, service 1 subbing data for the first 5 seconds, service 2 subbing data for the next 5 seconds, and service 3 for the next 5 seconds. In the next 5 seconds, it is possible to receive the service 4 subbing data, and in the next 5 seconds, the service 5 subbing data. In this way, if the same time slice is received continuously for 25 seconds or more, all of the service zubbing data can be received over 25 seconds!

FIG. 13 is a diagram showing another arrangement of the zubbing data, where the zubbing data in a service time slice is shifted by one every 5 seconds. Similarly, in Fig. 13, if the same time slice is received continuously for 25 seconds or more, all service subbing data can be received over 25 seconds!

Each time the receiver receives the time slice, it keeps updating the data in the internal data storage area for subbing (subbing buffer). When zubbing is started by user operation, etc., the data in the zubbing buffer can be played back, and still images and audio can be displayed without waiting for the power of the demodulation unit to be constantly turned on.

[0082] It is desirable that a different address be assigned to each service for the IP address of the IP packet so that the receiving side can process low quality data and high quality data without distinction. For example, it is desirable to assign the same IP address to IP packets of the same content, for example, S1-a and SI-b. However, different IP addresses can be used for IP packets carrying high-quality data and low-quality data with the same content.

When there are a plurality of subbing streams (a text-type subbing stream, a still-image-type subbing stream, and the like), a plurality of pieces of information on the subbing stream in the PMT may be described.

(Zubbing data transmission of multiple channels)

[0083] In the examples so far, the subbing stream is composed of a plurality of services in one channel. The same effect can be obtained also in a case where a plurality of channels are transmitted as described for the subbing stream corresponding to the service and the subbing stream is included in each channel.

Further, when a service is received using a plurality of transmission channels, if the zubbing data of the service transmitted on the first channel is multiplexed with the zubbing stream in the second channel and transmitted. By using the zappin stream included in the second channel, it is possible to see the zubbing data included in the first channel even when receiving the second channel.

Industrial applicability

INDUSTRIAL APPLICATION This invention can be utilized for the transmission system of digital data broadcasting.

Claims

The scope of the claims

[1] A transmission method in a broadcasting system,

Generating a first stream for burst transmission of a packet set having a single content capability for each service, and generating a second stream for transmitting packets at a rate according to a transmission rate required for the service And a transmission method, wherein the second stream transmits information related to the content transmitted in the first stream.

[2] In the first stream, intermittent data for a plurality of services is transmitted in order, and in the second stream, all or some of the services transmitted in the first stream intermittent data section are transmitted. 2. The transmission method according to claim 1, wherein a content equivalent to the content transmitted in step (1) is transmitted!

[3] The first stream transmits high-quality data, and the second stream transmits high compression rate data having the same content as the first stream but a small amount of information. The transmission method according to claim 2.

[4] The first stream includes data including high-quality audio and video, and the second stream includes at least one of a still image and audio related to the first stream. 3. The transmission method according to claim 2, wherein

[5] At least one of the first stream and the second stream includes:

5. The transmission method according to claim 2, further comprising an information field indicating an association between the second stream and the content transmitted in the first stream.

[6] The information processing apparatus according to claim 2, wherein an information field indicating an association between the second stream and the content transmitted in the first stream is included in a third stream. Or the transmission method described in

[7] The information processing apparatus according to claim 2, wherein an information field indicating a relation between the second stream and the content transmitted in the first stream is included in PMT of PSI. Or the transmission method described in

[8] A time information file between the transmission time of the packet set and the transmission time of the next packet set. The method of claim 1, 2, 3, 4, 5, 6, or 7, wherein a field is included in the second stream. , The transmission method described in any of the above.

[9] A transmission device in a broadcasting system,

A first stream (intermittent data section) generation means for burst transmission of a packet set having a single content capability for each service, and a second stream (packet transmission) for transmitting a bucket at a rate corresponding to a transmission rate required for the service A continuous data section) generating means, wherein the second stream transmits information related to the content transmitted in the first stream.