JP2004129121A - Transmitting apparatus and receiving apparatus of digital broadcast content, broadcast system and broadcast method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compensate a break caused by an interruption of the broadcast audio content in real time accurately, enabling reception of the audio content having good quality. <P>SOLUTION: Depending on kinds of audio broadcasts and services, bit rates are set by AAC encoders 21, 22. The program materials of these audio broadcasts are read out from a DB2, and both a main stream having the bit rate specified by the AAC encoder 21 and a sub-stream having the bit rate specified by the AAC encoder 22 are generated, respectively. In buffers 23, 24, the sub-stream is delayed more than the main stream for a predetermined delay time. Processing means 25 performs PES packetizing of the main stream and the sub-stream, respectively, and further TS packetizing thereof. These streams are multiplexed by a multiplexing means 26 on a TS packet basis, and then broadcast. In a receiving terminal, on the occurrence of the interruption, the interrupted portion in the main stream is compensated using the sub-stream. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to broadcasting of content such as audio information, and in particular, a broadcasting device for distributing such content to viewers by broadcasting, a receiving device for receiving such broadcasted content, and a broadcasting system for distributing such content And a broadcasting method.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, during reception of a digital broadcast, when radio waves are interrupted (short interruption) and data cannot be received, a phenomenon called “cliff effect” in which the broadcast is suddenly interrupted may occur.
[0003]
Conventionally, as one method of correcting this, it is detected whether or not discontinuous information is included in additional information in a TS (transport stream) received from another device, and the discontinuous information is detected. In such a case, there is a technique of taking in additional information in the TS to quickly decode data when a program (program) input from the outside is changed, so that the decoded output is not interrupted. (For example, see Patent Document 1).
[0004]
As another method, when a transmission data file due to data broadcasting is interrupted, a data file is transmitted using radio waves from a broadcasting station, and transmission with auxiliary information including a file attribute of the data file is performed. There is a data broadcasting system that transmits a file list as a file different from a data file. As a result, the existence of the unarrived data file can be confirmed, and its file name can be specified. In addition, there is no need to separately display an error message, and there is no interruption. Furthermore, it avoids the problem that the retry is repeated to retrieve unarrived data, and it takes time to display already received data and an error message (for example, see Patent Document 2).
[0005]
[Patent Document 1]
JP 2000-216848 A
[0006]
[Patent Document 2]
JP-A-10-243366
[0007]
[Problems to be solved by the invention]
However, in the above-described conventional technology, the last normally output digital data is continuously output until the digital data is detected again normally after the discontinuity information is detected. In such a method, the sound becomes unnatural for the viewer.
[0008]
In addition, in the above-described conventional techniques, since it is detected that no broadcast data is coming, the generation of substitute data and the output of the last normally output data are likely to cause a time lag in processing, so that real-time processing is difficult. Is difficult to satisfy. This time delay is not comfortable for a viewer of digital broadcasting, and a method of complementing and outputting digital data in real time so that the viewer is not conscious of it is desirable.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, to compensate for a break caused by instantaneous interruption of broadcast audio content with high accuracy in real time, and to be able to receive audio content of good quality. , A broadcasting system and a broadcasting method.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a digital broadcast content transmitting apparatus according to the present invention compresses and encodes digital audio material with an encoder and transmits a bit stream obtained by this process as digital broadcast content. Then, the encoder generates two streams of the compressed and encoded digital audio material, a main stream and a substream, and converts the main stream and the substream to a time length of an instantaneous interruption that occurs during broadcasting between them. An instantaneous interruption handling means for providing the digital broadcast content with an appropriate time difference is provided.
[0011]
The digital broadcast content receiving apparatus according to the present invention includes a multiplexed signal of a packetized main stream of digital audio material and a packetized substream of the digital audio material delayed from the main stream. Receiving means for receiving a program signal; packet extracting means for extracting packets of a main stream and a sub-stream of a desired program signal from the program signal received by the receiving means; A packet separating unit that separates a stream packet and a substream packet; a main stream buffer that holds a main stream packet separated by the packet separating unit; and a main stream buffer that holds the substream packet separated by the packet separating unit. Substream buffer and The main stream packets are sequentially fetched from the main stream buffer, depacketized and converted into compression-encoded digital audio material, and when the main stream packets cannot be fetched from the in-stream buffer due to a momentary interruption, they cannot be fetched. A depacketization processing means for taking in a substream packet corresponding to the main stream from a substream buffer, complementing the instantaneous interruption of the main stream and performing depacketization processing to produce compression-encoded digital audio material, And an AAC decoder for decompressing and decoding the data data compressed and coded from the encoding means.
[0012]
Further, in the broadcasting system for digital broadcasting content according to the present invention, the digital audio material is compressed and coded, and a main stream composed of a bit stream and a delay time corresponding to a time length of an instantaneous interruption occurring during broadcasting compared to the main stream are delayed. A sub-stream is generated, a main stream and a sub-stream are packetized and multiplexed, and a program material distribution device that transmits a broadcast signal, a broadcast device that transmits a broadcast signal and broadcasts a program, and a broadcast device that receives a broadcast signal. A receiving terminal for restoring the original digital audio material after decompression decoding, while supplementing the main stream with a sub-stream in a packet unit during the interruption due to a momentary interruption, It consists of
[0013]
Further, the broadcasting method of the digital broadcasting content according to the present invention comprises the steps of: compressing and encoding the digital audio material; a main stream comprising a bit string; Stream, packetize each, multiplex and broadcast, receive this broadcast, separate it from the received signal into a main stream and sub-stream, and divide the main stream into packet breaks due to momentary interruptions. And restores the original digital audio material after decompression decoding while complementing with a substream.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing one embodiment of a transmitting apparatus, a receiving apparatus, a broadcasting system and a broadcasting method of digital broadcast content according to the present invention.
[0015]
In the figure, it is a transmission side device. The program material distribution station 1 is provided with a material DB (database) 2 managed by a material management / editing unit 3 and stores audio program materials (contents) as digital information to be broadcast. The audio program material includes monaural audio and stereo audio of an audio program, audio of a television program, audio of a mobile terminal and a mobile terminal, and the like. Such program material may be recorded on a recording medium such as a magnetic tape, or may be input from the TV camera 8 or the microphone 9. The program material is edited and digitized for the program by the material management / editing unit 3, and is stored in the material DB2. The material switching unit 4 switches between the stored content from the material DB 2 and live containers such as the TV camera 8 and the microphone 9.
[0016]
When a predetermined program material stored in the material DB 2 is broadcast, the program material is read out by the material management / editing unit 3, supplied to the encoder 5, compression-encoded, and then responded to the station side instantaneous interruption. The processing unit 6 performs a process for preventing an instantaneous interruption that occurs during broadcasting of the program material. The program material output from the station-side instantaneous interruption handling unit 6 is supplied to a sending unit 7, where it is digitally modulated and sent.
[0017]
When such a program material is broadcast by satellite digital communication, the program material transmitted from the program material distribution station 1 is sent to the uplink station 10 as program information, and the frequency band assigned to the uplink station 10 is The signal is converted into a program broadcast signal and transmitted to the satellite 11 (broadcast satellite, communication satellite, or the like), where predetermined processing is performed and the signal is transmitted to the ground. When the program material transmitted from the program material distribution station 1 is broadcast by terrestrial digital communication, the program material is transmitted to the terrestrial digital broadcast station 12 as program information. It is converted into a program broadcast signal of the allocated frequency band and transmitted.
[0018]
On the other hand, in the receiving terminal 13 which is the receiving side device, the program broadcast signal from the satellite 11 or the terrestrial digital broadcasting station 12 is received by the RF receiving unit 15 from the receiving antenna 14 by the user's tuning operation, and the frequency conversion and amplification are performed. Are performed. The program broadcast signal that has been subjected to such processing in the RF receiving unit 15 is digitally demodulated in the digital demodulating unit 16 and then supplied to the terminal-side instantaneous interruption handling unit 17. The terminal-side instantaneous interruption processing unit 17 converts a program broadcast signal broadcast from the satellite 11 or the terrestrial digital broadcasting station 12 to the receiving terminal 13, particularly an audio broadcast signal (of course, also includes an audio signal of a television program). When an instantaneous interruption occurs, based on the instantaneous interruption prevention processing performed by the station-side instantaneous interruption correspondence processing unit 6 of the program material distribution station 1, processing for eliminating interruption of audio due to the instantaneous interruption (instantaneous interruption correction processing) is performed. It is. The program broadcast signal processed by the station side instantaneous interruption correspondence processing unit 6 is decoded and expanded by the decoder 18 and then converted into an analog signal. The video signal is supplied to the video / graphic display unit 19 and The video is displayed, and the audio signal is supplied to the audio reproduction unit 20 to reproduce the audio.
[0019]
Here, the instantaneous interruption is particularly problematic for audio information, so the station-side instantaneous interruption handling processing unit 6 performs an instantaneous interruption prevention process for audio information in the program material. In this way, even if an instantaneous interruption occurs in the broadcast note, the receiving terminal 13 corrects the instantaneous interruption of the received audio signal based on the instantaneous prevention processing on the transmission side, and eliminates interruption of audio. be able to.
[0020]
Further, the encoder 5 in the program material distribution station 1 performs a compression encoding process (encoding) based on the MPEG (Moving Picture Experts Group) 2 standard. Therefore, the decoder 18 in the receiving terminal 13 uses the MPEG 2 standard. To perform a decoding / decompression process (encoding) based on the. For audio information, as the encoder 5, an AAC (Advanced Audio Coding) encoder that uses sub-band coding and performs highly efficient compression using psychoacoustic characteristics is used. Therefore, on the receiving terminal 13 side, an AAC decoder that expands and decodes the audio information compressed and coded thereby is used as the decoder 18.
[0021]
As shown in FIG. 2, each broadcasting station 12 is assigned a frequency band of 5.6 MHz for broadcasting, and this frequency band is divided into 13 segments 1 to 13 for use. The segments 1 to 5 and 9 to 13 are used for broadcasting a high bit (high quality) image for a home channel (fixed service). In addition, the segment A as the layer A is used for broadcasting contents for mobile terminals, and the segments 6 and 8 as the layer B are used for broadcasting contents for mobile objects. Thus, each broadcast station 12 is assigned the frequency band of the program broadcast of three channels, and one broadcast station 12 can perform three broadcasts for home, portable terminal, and mobile. it can. The same applies to audio program materials. Therefore, the receiving terminal in FIG. 1 may be a home TV receiver or a radio receiver, a mobile terminal such as a mobile phone or a PDA (Personal Digital Assistant), or a car navigation system. It may be a mobile terminal.
[0022]
FIG. 3 is an explanatory diagram showing the basic principle of the instantaneous interruption correction process by the station-side instantaneous interruption handling unit 6 and the terminal-side instantaneous interruption handling unit 17 of this embodiment.
[0023]
In the figure, on the broadcast station side, the station side instantaneous interruption handling processing unit 6 in the program material distribution station 6 converts the stream itself consisting of a bit string which is compression-encoded data of the audio program material supplied from the encoder 5 into a main stream. From the same audio program material for a predetermined time T _D In this case, a sub-stream delayed by only the main stream is created, and the main stream and the sub-stream are multiplexed and broadcast.
On the receiving terminal side, the terminal-side instantaneous interruption processing unit 17 separates the received audio program signal into a main stream and a sub-stream and accumulates them in a buffer. , Is complemented by the corresponding part of the substream.
[0024]
In this embodiment, based on such a principle, the main service is divided into a fixed service for the reception terminal in the home, a mobile service for the mobile terminal, and a mobile service for the mobile terminal for each terminal to be broadcast service. The relationship between the stream and the sub-stream is made different so that the relationship is adapted to each service.
[0025]
Next, the main parts of the program material distribution station 1 and the receiving terminal 13 in FIG. 1 will be described in more detail.
[0026]
FIG. 4 is a block diagram showing a specific example of the main part of the program material distribution station 1 in FIG. 1 relating to the audio program material, and the portions corresponding to FIG.
[0027]
In the drawing, the instantaneous interruption corresponding profile table 28 defines a relationship between a main stream and a substream for coping with an instantaneous interruption for each type of broadcast service (that is, fixed service, mobile service, portable service). The profile is stored.
[0028]
One specific example of such a profile will be described with reference to FIG. 5. Here, as shown in FIG. 5, one example is shown in which the audio program is directed to music and news, and is shown for each fixed service, mobile service, and mobile service. The bit rates of the main stream and the sub-stream between the program for music and the program for news, and the delay time T of the sub-stream with respect to the main stream for instantaneous interruption complementation _D (FIG. 3).
[0029]
Here, in the case of a fixed service to a home or the like, as shown in FIG. 5A, the main stream is set to a high bit rate of 144 kbps in order to provide high-quality music and news sound, and Similarly, the substream for complementing the disconnection has a bit rate of 144 kbps. In addition, the instantaneous interruption is very short due to lightning strike or the like. _D Is also 2 seconds, so that momentary interruptions up to 2 seconds can be complemented.
[0030]
As shown in FIG. 5 (b), in the case of a mobile service to an in-vehicle receiving terminal or the like, as shown in FIG. Both the stream and the substream have a high bit rate of 144 kbps. In the case of a program for news, the bit rate of the main stream is set to 128 kbps, which is lower than that of a program for music, and the bit rate of the sub stream is further reduced to 64 kbps. I do. Even if the quality is reduced in this way, there is no problem in listening to the news program, and even if the instantaneous interruption is complemented by a lower-quality substream, it will not be particularly noticeable. In the case of this service for mobiles, a relatively long instantaneous interruption may occur due to a tunnel or the like. Therefore, the delay time T _D In the case of a program for music, it is set to 10 seconds so as to be able to provide such a high quality music by compensating for such a long momentary break, and in the case of a program for news, it is as high as music. Since the quality is not required, the instantaneous interruption of 5 seconds is shortened.
[0031]
In the case of a mobile service such as a mobile phone, as shown in FIG. 5 (c), since high-quality audio is not required, the main stream bit rate is set to 96 kbps for both music and news programs, and The stream is 96 kbps for music programs and 64 kbps for news programs. Then, the delay time T of the substream with respect to the main stream for instantaneous interruption complementation _D For both music and news, the time between the fixed service and the mobile service is set to 5 seconds.
[0032]
Returning to FIG. 4, the rules for each service as described above are stored in the instantaneous interruption corresponding profile table 28, and when the instantaneous interruption setting man-machine 29 is operated by the user, the regulations corresponding to the audio program to be broadcasted The contents can be read. That is, the setting screen 32 shown in FIG. 6 is displayed on the display screen of the instantaneous interruption corresponding setting man-machine 29 by a predetermined operation of the user. In the setting screen 32, “fixed service”, “moving” One of "body service" and "mobile service" can be selected, and one of "for news" and "for music" can be selected as a type of audio program.
[0033]
Now, assuming that the audio program to be broadcast is, for example, a news program of a mobile service, the user can switch between “mobile service” and “for news” by touching the setting screen 32 or by a predetermined key operation. select. As a result, the instantaneous interruption corresponding setting man-machine 29 operates on the instantaneous interruption corresponding profile table 28, and reads a bit rate of 128 kbps for the main stream and a bit rate of 64 kbps for the sub stream from the specified contents shown in FIG. The data is supplied to the bit rate setting means 30 and the delay time 5 seconds is read and supplied to the delay time setting means 31.
[0034]
Therefore, the bit rate setting means 30 sets the bit rate of 128 kbps in the AAC encoder 21 on the main stream side and sets 64 kbps in the AAC encoder 22 on the sub stream side. The delay time setting means 31 sets a delay time of 5 seconds in the protocol processing means 25.
[0035]
Thereafter, when the broadcast start time comes, the material management / editing unit 3 (FIG. 1) operates, and the news audio program material is read from the material DB 2 and supplied to the AAC encoders 21 and 22. The AAC encoder 21 compresses and encodes this audio program material to generate a main stream having a bit rate of 128 kbps and stores it in the main stream buffer 23. The AAC encoder 22 compresses and encodes the same audio program material. Thus, a substream having a bit rate of 64 kbps is generated and stored in the substream buffer 24.
[0036]
The protocol processing means 25 includes a main stream from the main stream buffer 23, a substream from the substream buffer 24, and a PSI / SI setting means 27 from the PSI (Program Specific Information) / SI (Service Information: Program). Array data) is fetched and packetized based on the MPEG2 standard. The fetching of the sub-stream from the sub-stream buffer 24 takes the delay time T set by the delay time setting means 31. _D (= 5 seconds). As a result, the sub stream is delayed by 5 seconds with respect to the main stream. The packetized main and substreams and PSI / SI data are multiplexed by the packet multiplexing unit 26 and supplied to the transmission unit 7 as one multiplexed stream.
[0037]
Here, a specific example of the operation of the protocol processing unit 25 and the packet multiplexing unit 26 will be described with reference to FIG.
[0038]
In the figure, at the start of audio program broadcasting, the protocol processing means 25 first secures the buffer size of the main stream buffer 23 (step 100), and then sets the delay time T set by the delay time setting means 31. _D (= 5 seconds), the size of the sub-stream buffer 24 is set to be longer than the buffer size of the main stream buffer 23 by this delay time T. _D Is set to a size larger by the data size of the substream corresponding to (step 101). Therefore, the size of the substream buffer 24 is determined by the delay time T for each type of service or material shown in FIG. _D According to the difference. The writing of the main stream to the main stream buffer 23 and the writing of the sub stream to the sub stream buffer 24 are started at the same time, but the reading of the sub stream from the sub stream buffer 24 is performed by reading the main stream from the main stream buffer 23. Delay time T rather than reading _D Will be started only late. Therefore, the protocol processing means 25 indicates that the sub stream has a delay time T _D Will be supplied only late.
[0039]
The protocol processing unit 25 packetizes the main stream from the main stream buffer 23, the substream from the substream buffer 24, and the PSI / SI data from the PSI / SI setting unit 27 by parallel processing. , The main stream and the substream are packetized into PES (Packetized Elementary Stream) (steps 103 and 104), and the PSI / SI data is sectioned (step 108).
[0040]
In FIG. 7, the PSI / SI data sectioning process is shown as a parallel process with respect to the program content stream (main stream and sub-stream). However, the program content stream is shown in FIG. It is shown in the same processing flow. Step 102 is inserted for convenience to indicate that the processing is parallel processing.
[0041]
FIG. 8 schematically shows the format of a PES packet. As shown in the drawing, the PES packet divides a main stream or a sub-stream into access units, which are coding / decoding units. The unit is a payload, to which a PES header is added. A 128-bit "PES_private_data (PES private data)" can be added to the PES header. In this embodiment, the "PES_private_data" is a number indicating the order of the PES packet (hereinafter referred to as a packet number). It is. Therefore, a 128-bit counter that counts up each time a PES packet is created is used, and the count value of this counter is added to the PES header as a packet number in the process of creating the PES packet. As a result, a series of PES packets is given a sequential packet number in the order of creation, and the order of the PES packets can be determined. In addition, the same packet number is added to PES packets of the same order in the main stream and the substream.
[0042]
Further, as shown in FIGS. 5B and 5C, when the data amount of the payload of the PES packet differs between the main stream and the sub-stream, the bit rate of the main stream and the sub-stream are different. Is proportional to the bit rate. Therefore, for example, in the case of a news program in the mobile service shown in FIG. 5B, the ratio of the payload data amount between the main stream and the substream is 128: 64 = 2: 1. In this way, by setting the data amount of the payload of the main stream and the substream, the payload of the PES packet having the same packet number of the main stream and the substream compresses the same part of the original audio program material. It becomes a thing. In addition, as described later, by using the packet number, the instantaneous interruption of the main stream can be complemented by using the PES packet of the substream, as described with reference to FIG.
[0043]
FIG. 9 is a diagram showing the notation of the PES header in FIG.
[0044]
In the figure, “stream_id” represents a stream ID (Identification: identification code) of a payload of a PES packet, and it can be determined whether the PES packet is of a main stream or a substream.
[0045]
As described above, when a serial number is added to a PES packet, “stream_id” is specified (at this time, if (streamid = 110xxxxxx) as shown), and “PES_extension_flag” as shown in the figure. Is set to 1 (set a flag) and “PES_extension_flag = 1”, a flag in parentheses {} starting with “PES_private_data_flag” can be set as “if (PES_extension_flag == {1 ′)” ”. When the flag “PES_extension_frag_2” in the parentheses {} is set to 1, “if (PES_private_data_flag == {1 ′)” ”, and“ PES_private_data ”can be used in the parentheses {} immediately after the parentheses.
[0046]
In this way, by setting each flag of the PES header to be created, PES_private_data can be added as a serial number, and the protocol processing unit 25 performs a process of setting such a flag in the header of the PES packet every time a PES packet is created. At the same time, the count value from the counter is added to the PES header as a packet number. Therefore, the type of each PES packet can be determined by “stream_id”, and the order of PES packets in the same stream can be determined by “PES_private_data”.
[0047]
FIG. 10 is a flowchart showing a specific example of a process for adding a packet number to “PES_private_data” in the PES header.
[0048]
In the figure, when the broadcasting of the program material is started (step 200), the counter is reset and the count value is set to 0 (decimal number for convenience) (step 201). Then, when the first PES packet is generated, this count value 0 is added to the header of this PES packet as a packet number (step 202), and this counter is incremented by 1 so that the counter value becomes 1 (step 203). . When the count value does not reach the maximum value MAX (step 204), the count value 2 is added as a packet number to the header of the PES packet to be created next (step 202).
[0049]
In this way, every time a PES packet is created, the count value of the counter is incremented by one, and this is used as the packet number of the next PES packet to be created. A number will be added. Thereafter, when the count value of the counter reaches the maximum value (step 204), the process returns to step 200, where the counter is initialized (step 201), the count value becomes 0, and the same processing is performed.
[0050]
Returning to FIG. 7, in this way, the main and sub-streams are PES-packetized (steps 103 and 104), and the PSI / SI information is sectioned (step 108). The PES packet is packetized into a fixed-length TS (Transport stream) packet (steps 105 and 106), and the PSI / SI information constituted by the section is converted into a TS packet (step 109).
[0051]
As shown in FIG. 11, this TS packet is obtained by dividing one PES packet into 184 bytes as a TS payload and adding a 4-byte TS header to the TS payload, for a total of 188 bits. To the TS header of this TS packet, a PID (Packet IDentification: identification of packet) indicating the type of data of the TS payload (data of the main stream or substream, PSI / SI data) is added, whereby the TS stream Can be determined as to what data is.
[0052]
Returning to FIG. 7, each stream thus formed into TS packets is supplied to the packet multiplexing means 26 (FIG. 4), and each stream is time-division multiplexed in units of TS packets (step 107). As a result, the main and sub-stream and PSI / SI data are multiplexed into one multiplexed signal, which is supplied to the transmitting unit 7 (FIG. 4) and broadcast.
[0053]
Here, PSI / SI will be briefly described with reference to FIG.
[0054]
The PSI / SI is composed of program identification information (PSI) and program arrangement information (SI). By transmitting the PSI / SI to the receiving terminal together with the program material, the receiving terminal identifies the program material, and the receiving terminal selects the program material. It is intended to correctly receive the broadcast program material.
[0055]
As shown in FIG. 12, the PSI / SI includes a PMT (Program Map Table) for identifying the program material to be received by the PID of the TS packet, manages the PMT, and receives the PMT by selecting the program. A PAT (Program Association Table) for sending to the terminal. The PAT is assigned on a broadcast station basis. When the PAT and the PMT are transmitted as a pair and the receiving terminal selects a channel of a predetermined broadcasting station, the PAT assigned to the broadcasting station is received, and the PMT managed by the PAT is managed based on the PAT. Is received. Then, based on the PMT, only the TS packet of the PID specified by the PMT is received, and only the selected program material is received.
[0056]
Here, in the PMT, a plurality of PIDs can be specified. Therefore, as described above, even if the main stream and the substream are transmitted in units of TS packets, they can be received together. For example, as shown in the figure, the main stream obtained by the AAC encoder 21 (FIG. 4) on the transmission side is set to PID = 300 (hexadecimal), and similarly, obtained by the AAC encoder 22 (FIG. 4). It is assumed that PID = 301 (hexadecimal number) for the substream obtained. According to such PSI / SI, the receiving terminal can receive TS packets of PID = 300, 301.
[0057]
Further, the receiving terminal cannot receive a broadcast program of a selected channel (broadcasting station) unless the PSI / SI is used. For this reason, such PSI / SI is transmitted at a rate of, for example, 10 to 20 times / second during transmission of a program. Even when the power is turned on, the PSI / SI can be received, so that the program can be received.
[0058]
FIG. 13 is a block diagram showing a specific example of a main part of the receiving terminal 13 in FIG.
[0059]
In the figure, the packet multiplexed signal from the digital demodulation section 16 (FIG. 1) is supplied to the packet extracting means 33, and the PSI / SI in the PSI / SI management means 39 causes the PSI / SI Only TS packets having the designated PID are selected and supplied to the inverse TS packetization processing means 34. The inverse TS packetization processing means 34 extracts a TS payload from the TS packet having the configuration shown in FIG. 11 and reconstructs the PES packet shown in FIG. 8 by connecting the TS payload. Based on “stream_id” in the PES header (FIG. 9), the PES packet is distributed for each of the main and sub-streams. The TS packet of the PSI / SI data is supplied to the PSI / SI management unit 39, subjected to depacketization processing to obtain PSI / SI data, and manages the packet extraction unit 33. As a result, only the TS packet of the designated PID is extracted. Each time the PSI / SI is received, it is supplied to the PSI / SI management means 39 as described above.
[0060]
The PES packet of the substream from the inverse TS packetizing means 34 is stored in the substream buffer 35, and the PES packet of the main stream is stored in the main stream buffer 36. The inverse TS packetization processing means 34 reads the packet number in the PES header every time a main stream PES packet is formed, and stores the packet number in the register 40. Therefore, if the PES packet of the main stream is interrupted due to an instantaneous interruption, a new packet number is not supplied to the register 40, and the packet number of the PES packet immediately before the instantaneous interruption is maintained until a new PES packet is reconstructed. Will be retained.
[0061]
When there is no instantaneous interruption in the main stream and no loss of the PES packet, the reverse PES packetization processing means 37 reads the PES packet of the main stream from the main stream buffer 36. It is checked whether or not the main stream PES packet has been correctly fetched from the PES header “stream_id” and the packet number “PES_private_data”. Reconstruct the compressed encoded stream. The AAC decoder 38 decompresses and decodes this compression-encoded stream to reproduce the original audio program material.
[0062]
Also, when the next PES packet cannot be obtained from the main stream buffer 36 due to the momentary interruption, the reverse PES packetizing processing means 37 cannot obtain the next “stream_id” and the packet number “PES_private_data” because the next PES packet cannot be obtained. Is determined, and the packet number stored in the register 40 at this time is read. Then, 1 is added to the packet number read from the register 40 to create the next packet number, the PES packet of the substream having this packet number is fetched from the substream 35, and this is added to the corresponding PES packet of the main stream. Instead, the payload is extracted. Thereafter, the inverse PES packetization processing means 37 takes in the PES packets of the sub-stream in order from the sub-stream buffer 35 and supplies the payload to the AAC decoder 38, while monitoring the main stream buffer 36 during that time. When the main stream PES packet from which the stream_id and the packet number can be detected can be read from the stream buffer 36, it is determined that the interruption of the PES packet due to the instantaneous interruption has ended, and the main stream PES packet is read again from the main stream buffer 36. I do.
[0063]
As described above, the receiving terminal 13 can supplement the discontinuity caused by the instantaneous interruption of the received audio program material with the substream, and can listen to the audio program without interruption.
[0064]
In order to compensate for such an instantaneous interruption, the timing of reading the main stream from the main stream buffer 36 and the timing of reading the substream from the substream buffer 35 are determined by the delay time T. _D , The timing of reading the main stream from the main stream buffer 36 is determined by the delay time T _D Just to be late. Therefore, the delay time T from reception to reproduction by the audio reproduction unit 20 (FIG. 1) _D But the delay time T _D As described with reference to FIG. 5, the delay time T _D To minimize the useless delay time until playback as much as possible. _D And the delay time T depends on the length of the instantaneous interruption that occurs. _D Can be set.
[0065]
Further, since the occurrence of the instantaneous interruption is determined using the information of the header of the PES packet from the main stream buffer 36, the instantaneous interruption can be reliably and instantaneously determined, and the sub-interruption is performed only during the instantaneous interruption. Since it is complemented by the stream, the sub-stream does not perform the complementing process even in the part other than the momentary interruption period, and the deterioration of the quality of the program material can be prevented.
[0066]
In addition. When the receiving terminal 13 shown in FIG. 1 receives an audio program capable of complementing the instantaneous interruption as described above, at the start of listening to the program, a message as shown in FIG. Is displayed to notify the user that a program that has undergone the process of complementing the instantaneous interruption is being received, and a message as shown in FIG. The maximum momentary interruption may be notified. In FIG. 14A, the notification method to the user is the timing at which the character or bitmap information stored in the memory space of the video / graphics display unit 19 (FIG. 1) of the receiving terminal 13 is instantaneously interrupted. And may be displayed by performing a rendering process. In FIG. 14B, the number of access units of data stored in the substream is measured from the start of the program, and the number is calculated based on the reproduction time of the access units and the number of access units. It is possible to display how many seconds are not interrupted.
[0067]
FIG. 15 is a block diagram showing a main part of another specific example of the program material distribution station 1 shown in FIG. 1. Parts corresponding to those in FIG. 4 are denoted by the same reference numerals, and redundant description is omitted.
[0068]
In this figure, this specific example is provided with a sub-stream generating means 41 for generating a sub-stream from a compression-encoded main stream generated by the AAC encoder 21, and as the encoder 5 (FIG. 1), Only the AAC encoders 21 are used.
[0069]
The sub-stream generating means 41 generates a sub-stream from the main stream from the AAC encoder 21 according to the contents specified in the instantaneous interruption corresponding profile table 28 supported by the instantaneous interruption corresponding man-machine 29. In the case of a fixed service (FIG. 5 (a)) and a mobile service (FIG. 5 (b)) or a mobile service (FIG. 5 (c)) music programs having the same bit rate between the Is simply rewritten for the sub-stream for the sub-stream. On the other hand, when the sub stream is for a mobile program or a mobile service news program with a lower bit rate than the main stream, the bit rate is reduced by filtering the main stream and sub-band processing to reduce the bit. Then, the header is rewritten for the sub-stream to make the sub-stream.
[0070]
Except for the above, the configuration is the same as that of the specific example shown in FIG. 4, and the same effect is obtained. In addition, the AAC encoder 21 and the sub-stream generation unit 41 can be configured by the same IC, and the circuit occupies. Space can be reduced.
[0071]
【The invention's effect】
As described above, according to the present invention, the information for complementing the instantaneous interruption of the stream of the audio program material is transmitted as a sub-stream multiplexed with the stream of the audio program material. When an instantaneous interruption of the stream of audio program material is detected, this substream can be used for complementation immediately. Therefore, the interruption due to the instantaneous interruption of the broadcast audio content can be accurately complemented in real time, and the audio content of good quality can be complemented. Can be obtained.
[0072]
In addition, since the instantaneous interruption is detected based on the packet number added to the packet of the packetized stream, the instantaneous interruption can be detected in packet units, and can be complemented in packet units. Can be complemented in real time only, and unnecessary supplementary processing during periods other than the momentary interruption period can be prevented, and the quality degradation of the received audio content due to the complementary processing can be minimized.
[0073]
Further, when realizing a broadcast service corresponding to the instantaneous interruption on the broadcast station side, the broadcast operator can easily change the service method corresponding to the instantaneous interruption while effectively utilizing the broadcast band.
[0074]
Further, the service corresponding to the instantaneous interruption can be realized without procuring a plurality of expensive encoder devices on the broadcast station side.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a transmitting device, a receiving device, a broadcasting system, and a broadcasting method of digital broadcast content according to the present invention.
FIG. 2 is an explanatory diagram of a broadcast frequency band assigned to a broadcast station.
FIG. 3 is an explanatory diagram showing a basic principle of a correction process of an instantaneous interruption of the embodiment shown in FIG. 1;
FIG. 4 is a block diagram showing a specific example of a main part of a program material distribution station in FIG. 1;
FIG. 5 is a diagram showing a specific example of an instantaneous interruption corresponding profile table in FIG. 4;
FIG. 6 is a diagram showing a specific example of a setting screen of the instantaneous interruption correspondence setting man-machine in FIG. 4;
FIG. 7 is a flowchart showing a specific example of a processing operation of a protocol processing unit and a packet multiplexing unit in FIG. 4;
8 is a diagram showing a configuration of a PES packet generated by a protocol processing unit in FIG.
9 is a diagram illustrating a notation example of a PES header in the PES packet illustrated in FIG. 8;
FIG. 10 is a flowchart showing an operation of embedding a counter value in steps 103, 104, and 108 in FIG. 7;
FIG. 11 is a diagram illustrating a configuration of a TS packet generated by a protocol processing unit in FIG. 4;
FIG. 12 is a diagram showing a configuration of PSI / SI in FIG.
FIG. 13 is a block diagram showing a specific example of a main part of the receiving terminal in FIG. 1;
FIG. 14 is a diagram showing an example of a display for an instantaneous interruption process in the video / graphic display unit of the receiving terminal shown in FIG.
FIG. 15 is a block diagram showing another specific example of a main part of the program material distribution station in FIG. 1;
[Explanation of symbols]
1 Program material distribution station
5 Encoder
6 Station side instantaneous interruption response processing unit
13 receiving terminal
17 Terminal-side instantaneous interruption handling processor
18 Decoder
21,22 AAC encoder
23 Main stream buffer
24 Substream buffer
25 Protocol processing means
26 Packet multiplexing means
28 Profile table for instantaneous interruption
29 Instantaneous interruption man-machine
30 Bit rate setting means
31 Delay time setting means
33 Packet extraction means
34 Reverse TS packetization processing means
35 Substream buffer
36 Main stream buffer
37 Reverse PES packetization processing means
38 AAC decoder
39 PSI / SI management means
40 registers
41 Substream generator

Claims (19)

A digital broadcast content transmission side that performs compression encoding processing on a program composed of digital video and audio material using an encoder that compresses the video and audio by a compression encoding method, and transmits a bit stream obtained by the processing as digital broadcast content. In the device,
The encoder generates two streams of a compressed and coded digital video / audio material, a main stream and a substream,
The main stream and the sub-stream are provided with a time difference corresponding to the time length of an instantaneous interruption occurring during broadcasting between them, and an instantaneous interruption correspondence processing means is provided as the digital broadcast content. A device for transmitting digital broadcast content. In claim 1,
The encoder includes a first encoder that compresses and encodes the digital video / audio material to generate the main stream, and a second encoder that compresses and encodes the digital audio material to generate the substream,
A digital broadcast content transmitting apparatus comprising means for setting a bit rate of a stream generated for each of the first and second encoders. In claim 1,
The encoder comprises: an encoder that compresses and encodes the digital audio material to generate the main stream; and a sub-stream generating unit that processes the main stream generated by the encoder to generate the sub-stream. An apparatus for transmitting digital broadcast content, comprising: means for setting a bit rate of the main stream in a first encoder; and means for setting a bit rate of the sub stream in the sub stream generating means. In claim 2 or 3,
A digital broadcast content transmitting apparatus, wherein a plurality of broadcast services can be selected, and the bit rates of the main stream and the substream are set according to the selected broadcast services. In claim 4,
The instantaneous interruption correspondence processing means packetizes and multiplexes the main stream and the substream having the time difference, respectively, generates a broadcast stream, and varies the time difference according to the broadcast service. Device for transmitting digital broadcast content. In claim 4,
The instantaneous interruption handling processing means packetizes the main stream and the sub-stream having the time difference, and PSI (Program Specific Information) / SI (Service Information) information relating to the main stream and the sub-stream, and multiplexes the packets. A digital broadcast content transmitting apparatus characterized in that the digital broadcast content is converted into a broadcast stream, and the time difference is varied according to the broadcast service. In claim 6,
A digital broadcast content transmitting apparatus characterized in that, when selecting the plurality of broadcast services, reference is made to corresponding data relating to the bit rate of the main stream, the bit rate of the sub-stream, and the time difference, which are stored in advance. . Receiving means for receiving a program signal comprising a multiplexed signal of a packetized main stream of digital video / audio material and a packetized sub-stream of the digital video / audio material delayed from the main stream; Packet extracting means for extracting packets of a main stream and a sub-stream of a desired program signal from the program signal received by the receiving means;
Packet separating means for separating the packet extracted by the packet extracting means into a packet of the main stream and a packet of the substream;
A main stream buffer for holding the main stream packets separated by the packet separating means;
A sub-stream buffer that holds packets of the sub-stream separated by the packet separating unit;
The main stream packets are sequentially fetched from the main stream buffer, depacketized and converted into the compressed and coded digital video / audio material, and the main stream packets are converted from the main stream buffer by an instantaneous interruption. When the digital video is not captured, the packet of the sub-stream corresponding to the main stream that cannot be captured is captured from the sub-stream buffer, the instantaneous interruption of the main stream is complemented, and depacketization processing is performed. Depacketization processing means for making audio material;
A decoder for expanding and decoding the compression-encoded data video / audio material from the depacketization processing means. In claim 8,
Each of the main stream and the substream is formed into a PES (Packetized Elementary Stream) packet in which a packet number which is a serial number is added to a header.
When the packet number of the PES packet of the main stream cannot be detected from the main stream buffer, the reverse packet processing means determines that the interruption period due to the instantaneous interruption has started, and returns the PES of the main stream from the main stream buffer again. When the packet number of the packet can be detected, it is determined that the interruption period due to the instantaneous interruption has ended, and during the period from the determination of the start of the interruption period to the determination of the end of the interruption period, the sub-stream is transmitted to the main stream. A receiving device for digital broadcast content, which performs a complementing process. In claim 9,
The packet separating unit extracts the packet number from the separated PES packet every time the PES packet of the main stream is separated from the multiplexed signal, and stores the packet number in a holding unit.
The reverse packet processing means, when the packet number of the PES packet of the main stream cannot be detected, adds the PES packet of the sub-stream of the packet number next to the packet number held in the holding means to the main stream. A receiving device for digital broadcast content, which is supplemented. In claim 8, 9 or 10,
In the multiplexed signal, PSI (Program Specific Information) / SI (Service Information) information relating to the main stream and the substream is packetized and multiplexed.
The packet extracting means extracts a packet of the PSI / SI information of the desired program from the multiplex signal, and extracts a packet of the main stream and the substream of the program specified by the extracted PSI / SI. An apparatus for receiving digital broadcast content, characterized by extracting the content. A digital video / audio material is compression-encoded to generate a main stream composed of a bit stream and a sub-stream delayed by a delay time corresponding to the time length of an instantaneous interruption that occurs during broadcasting from the main stream. A program material distribution device that packetizes and multiplexes the sub-stream and transmits the multiplexed sub-stream as a broadcast signal;
A broadcasting device for transmitting the broadcast signal to broadcast a program,
The broadcast signal is received and separated into the main stream and the sub-stream, and the main stream is expanded and decoded while supplementing the discontinuous period due to a momentary interruption with the sub-stream in packet units. And a receiving terminal for restoring the digital video / audio material. In claim 12,
The broadcasting device is capable of providing a plurality of broadcast services for different program broadcast targets,
The broadcast system of digital broadcast content, wherein the program material distribution apparatus changes the delay time of the sub stream with respect to the main stream according to a type of broadcast of the digital program material and the broadcast service. In claim 13,
The broadcast system of digital broadcast contents, wherein the program material distribution apparatus sets a bit rate of the sub-stream with respect to a bit rate of the main stream according to a type of broadcast of the digital program material and the broadcast service. In claim 12, 13, or 14,
The receiving terminal detects the period of the instantaneous interruption depending on whether or not a packet number added to each packet of the main stream is detected, and the sub stream having the same packet number as a packet number of the main stream not detected. The digital broadcast content broadcasting system, wherein the instantaneous interruption period of the main stream is complemented by the packet. A digital video / audio material is compression-encoded to generate a main stream consisting of a bit stream and a sub-stream delayed by a delay time corresponding to the time length of an instantaneous interruption occurring during broadcasting from the main stream, and packetized them, respectively. Multiplex and broadcast
Receiving the broadcast, separating the received signal into the main stream and the sub-stream, and expanding and decoding the main stream while supplementing the interruption period due to the instantaneous interruption with the sub-stream in packet units. A method for broadcasting digital broadcast content, comprising restoring the original digital audio material. In claim 16,
A plurality of broadcast services for different program broadcast targets are possible, and the delay time of the sub-stream with respect to the main stream is made different according to the type of broadcast of the digital program material and the broadcast service. The method of broadcasting digital broadcast content. In claim 17,
A method for broadcasting digital broadcast content, comprising setting a bit rate of the sub-stream with respect to a bit rate of the main stream according to a type of broadcast of the digital program material and the broadcast service. In claim 16, 17 or 18,
The instantaneous interruption period is detected in accordance with the presence or absence of the detection of the packet number added to each of the received packets of the main stream, and the packet of the sub stream having the same packet number as the undetected packet number of the main stream is detected. A method of broadcasting digital broadcast content, wherein a period of the momentary interruption of the main stream is complemented.

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