JP2001258003A - Transmission device with active standby switching for scrambled digital broadcast signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission device that can smoothly switch an active and standby state for a scrambled digital broadcast signal. SOLUTION: Buffers 11, 14 sequentially store a prescribed number of TS packets of a transport stream, and packet identification sections 12, 15 detect a TS header of each stored TS packet, to discriminate whether a PES header and an ES header are included in each TS packet, on the basis of the TS header and inform a timing control section 18 about the result of discrimination. The timing control section 18 applies switching control to an active and standby changeover device 17, when receiving an active and standby switching trigger signal after controlling scramblers 13, 16 to apply no scrambling to the TS packets including the PES header and the ES header and to scramble the other TS packets by using one scramble key, on the basis of the received discrimination result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast transmission equipment having a dual working / standby structure, and more particularly to a technique for controlling switching between working and protection scrambling.

[0002]

2. Description of the Related Art Conventionally, broadcast transmission equipment has generally been provided with a dual working / standby configuration for troubleshooting and maintenance of equipment.

Here, in the conventional analog broadcasting transmission equipment, since the signal is not compressed, in order to make the shock inconspicuous at the time of switching between the active and the standby, switching is performed at the frame position after performing frame synchronization. Shall be
It was sufficient to take measures such as noise generated when switching the contacts. However, in digital broadcasting,
At the time of preliminary switching, the broadcast signal to be transmitted is compression-encoded in the transport stream, making it difficult to see the frame breaks. Can not.

On the other hand, a method has been considered in which the switching device side performs switching by identifying the frame position by analyzing the contents of the input working and protection transport streams. Then
In some cases, the transport stream may be scrambled for broadcasting. In this case, the frame position of the transport stream cannot be identified.

[0005]

As described above, in the digital broadcasting transmission equipment, when the transport stream to be switched at the time of switching between the active and the standby is scrambled, the switching device side is required. However, since the contents of the transport stream cannot be grasped, the frame position cannot be identified, and smooth switching cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital broadcast signal active / backup scramble switching and transmitting apparatus which can smoothly switch between a working and a standby of a scrambled digital broadcast signal without causing a disturbance in a transmitted signal. It is in.

[0007]

SUMMARY OF THE INVENTION A digital broadcast signal active / backup scramble switching and transmitting apparatus according to the present invention is compression-encoded independently of each other in an active system and a standby system, and is used to identify the frame in units of compressed frames. Digital broadcast signal currently / preliminarily scrambled and transmitted by selectively scrambling digital broadcast signals assigned to a plurality of transmission blocks including information blocks carrying necessary information in accordance with a current / preliminary switching signal. In the apparatus, an active buffer and a standby buffer for storing a predetermined number of blocks of each of the active and standby digital broadcast signals, an active scramble processing unit for selectively scrambling the output of the active buffer, and a standby buffer Scrambling processor that selectively scrambles the output of the system buffer A working / standby switching unit that selectively derives one of the outputs of the working scrambling processing unit and the protection scrambling processing unit as a transmission signal; and a digital broadcast signal stored in the working buffer and the protection buffer. A block identification unit for detecting header information from the block and identifying the content of the block from the header information; and a transmission block excluding the information block based on the identification result of the block identification unit when a working / standby switching signal is input. And a timing control unit that switches the working / standby switching unit after controlling the working scrambling unit and the standby scrambling unit so that scrambling is performed using the same scrambling key information between systems or blocks. It is prepared for.

In particular, when the digital broadcast signal is a transport stream generated in a format defined by the MPEG2 encoding method, the working buffer and the backup buffer store the transport stream for a predetermined number of packets, and The identification unit detects header information of each packet of the transport stream stored in the working buffer and the backup buffer, and identifies the content from the header information. At this time, the timing control unit determines, from the identification result of the block identification unit, a packet including information necessary for identifying a frame among the packets of the transport stream, and does not scramble the packet. In this way, for the other plurality of packets, the active system scramble processing unit and the standby system scramble processing unit are controlled so that scrambling is performed using the same scramble key information between systems or between packets. The present invention is characterized in that the active / standby switching unit is controlled to switch at a switchable point based on a packet including information necessary for identification.

That is, according to the present invention, the transport stream to be processed by the active scramble processing unit and the standby scramble processing unit is first held in the active buffer and the standby buffer for a predetermined number of packets, respectively, and the block identification unit , Header information is detected from each of the packets held respectively, and it is determined from the detected header information whether or not the packet includes information for frame identification, which is a unit of decoding of the transport stream. Is notified to the timing control unit. When the working / standby switching signal is input, the timing control unit does not scramble the packet including the information for frame identification based on the notified determination result, and does not perform scrambling for other packets. Alternatively, it is possible to control the scrambling timing for each of the active scrambling processing unit and the standby scrambling processing unit so that scrambling is performed using the same scrambling key between packets, and thereafter, the transport stream frame is transmitted to the active / standby switching unit. The switching timing can be controlled so that switching is performed at a switchable frame position based on the packet including the identification information.

Therefore, according to the present invention, the working / standby switching unit detects a packet that has not been scrambled for the working system and the protection system at the switching timing by the timing control unit, and based on the detection result. By performing the switching, it is possible to smoothly switch between the active and the standby of the scrambled transport stream without causing disturbance of the transmission signal, and furthermore, the active system scrambling processing unit and the standby system scrambling processing unit. At the time of system switching, each packet of the transport stream is scrambled using the same scrambling key information between systems or between packets, so that the working / standby switching unit performs switching-derived transmission signals and scramble key information. Since there is no need to consider synchronization with It is possible reduce, it is possible to use an inexpensive switching device with a simple structure.

In the above configuration, the timing control unit controls the read start position of the standby buffer so that a packet synchronized with the output of the active buffer is read from the standby buffer based on the identification result of the block identification unit. After that, since the control of the active scrambling processing unit and the standby scrambling processing unit is performed,
Even when the phases of the transport streams input to the working buffer and the protection buffer are different, the transport stream can be switched in a synchronized state at the time of system switching in the working / standby switching unit. .

Further, in the above configuration, a standby system which functions as a redundant system of the active / standby switching unit and selectively derives any one of the outputs of the active and standby scrambling units as a transmission signal. It is also characterized by including a working / standby switching unit, so that even if an abnormality occurs on the switching unit side, it is possible to take effective measures.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a digital broadcast signal working / spare scramble switching and transmitting apparatus according to the present invention.

The apparatus shown in FIG. 1 operates independently for the active system and the standby system. For the active system, a buffer 11, a packet identification unit 12, and a scrambler 13
And the buffer 14
, A packet identification unit 15 and a scrambler 16.

The buffers 11 and 14 are MPEs.
A predetermined number of TS (transport stream) packet sequences of a transport stream that has been subjected to variable-length compression encoding based on the G2 encoding method are temporarily held. The packet identification units 12 and 15 detect a TS header added to each TS packet held in each of the buffers 11 and 14,
The contents of each TS packet are identified from the detected TS header. Each of the scramblers 13 and 16 has a buffer 1
Outputs 1 and 14 are scrambled for each TS packet and output to working / standby switching device 17, and scramble key information used for scrambling is also output to working / standby switching device 17. Note that the scramble key information is appropriately changed for each TS packet.

The working / standby switching device 17 selectively derives one of the outputs of the scrambling devices 13 and 16 as a transmission signal.

In this embodiment, the identification result of each of the packet identification units 12 and 15 is transmitted to the timing control unit 1.
8, respectively. When a separately provided active / standby switching trigger signal is input, the timing control unit 18 determines a PE required to identify a frame which is a transport stream decoding unit from the notified identification result.
S (Packetized Elementary Stream) header, ES (Eleme
Each scrambler 13 and 16 is controlled to scramble a TS packet excluding a TS packet including information such as an ntary stream (header) between systems or between packets using the same scramble key. Is switched from the active system to the standby system.

The processing operation of the above configuration will be described below. First, in order to facilitate switching between the active system and the standby system, it is conceivable to scramble the two streams so that their phases are matched and the active / standby switching device 17 can identify the switching point. FIG. 2 shows the scramble process of the scramblers 13 and 16 in this case.
(A) to (c) are shown. 2A shows a transport stream before being input to the scramblers 13 and 16, FIG. 2B shows an output of the conventional scrambler, and FIG. 16
Shows the output.

The working / standby switching device 17 can determine the switching point from the time stamp of the PES header on the transport stream and the frame type of the ES header at the time of system switching. The frame type includes an I picture type, a P picture type, and a B picture type. However, in the scrambling standard, as shown in FIG. 2 (b), since the TS payload is scrambled, it is impossible to extract information for identifying a frame position such as a PES header and an ES header as it is. It is. Therefore, in the present invention, the scrambler 1
3 and 16 so that only the TS packet including the PES header and the ES header is not scrambled and the same so that the synchronization between the transmission signal and the scramble key information need not be considered at the time of switching. Is scrambled using the scramble key.

That is, in the above-described configuration, the transport streams generated in the format specified by the MPEG2 encoding system independently of the working system and the standby system at the transmission destination are input to the buffers 11 and 14, and are respectively specified. The number of TS packets is sequentially held. Each buffer 11, 1
4 are identified by the packet identification units 12 and 15, respectively, and the identification result is notified to the timing control unit 18.

In the timing control section 18, when a working / standby switching trigger signal is given, the packet identifying section 1
As shown in FIG. 2 (c), the PE packet of the TS packet of the transport stream
Each scrambler 1 does not scramble a TS packet including an S header and an ES header.
A non-scramble execution trigger is given to 3, 3 and a scramble execution trigger is applied to other TS packets so as to scramble using fixed scramble key information. Then, at the timing of detecting a TS packet including the PES header and the ES header, the active / standby switching device 17 is controlled to switch from the active system to the standby system. Therefore, the working / standby switching device 17 uses the PES header and ES at the detection timing from the timing control unit 18.
The TS packet including the header is determined, and the determined T
Switching can be performed by finding a switchable point from the S packet.

When the TS packets of the transport streams input to the buffers 11 and 14 have the same phase, the working / standby switching device 17
It is only necessary to switch the input signal at the timing of the TS packet including the S header and the ES header. However, if the TS packet phase does not match, it is necessary to match the phase before inputting to the buffer. On the other hand, in the present invention, the transport streams of the working system and the protection system are input to the buffers 11 and 14 without matching the phases in packet units, and are held in the buffers 11 and 14 by the timing control unit 18. The contents of the TS packet are compared. And
At the time of system switching, the read start position of the buffer 14 is appropriately shifted so that packets synchronized with the output of the buffer 11 are read from the buffer 14 based on the result of the content comparison, and the outputs of the buffers 11 and 14 are respectively scrambled by the scrambler 11, At 14, scramble processing is performed. As a result, switching can be performed at a synchronization point with respect to a synchronized working / standby transport stream, which can only be switched with a shock to the stream in the past, so that the receiver side can perform seamless switching. Can play video.

As described above, in the above-described embodiment, the transport streams to be processed by the scramblers 13 and 16 are first held in the buffers 11 and 14 for a predetermined number of TS packets, respectively.
The TS header is detected from each TS packet held by each of the TS packets 2 and 15, and from the detected TS header, information for frame identification as a unit of decoding of the transport stream, that is, the PES header and the ES header
It is determined whether or not the packet is included in the packet, and the result of the determination is notified to the timing control unit 18. When the active / standby switching trigger signal is input, the timing control unit 18 does not scramble the TS packet including the PES header and the ES header based on the notified determination result, and The scrambling device 1 is configured to scramble using the same scramble key between systems or between packets.
The scramble timing can be controlled for each of 3, 3 and 16, and the working / standby switching device 17 can then switch at a switchable point based on the TS packet including the PES header and the ES header of the transport stream. , The switching timing can be controlled.

Therefore, in the working / standby switching device 17, the TS which is not scrambled for the working system and the protection system at the switching timing by the timing control unit 18.
By detecting a packet and determining a switchable point from the detection result and performing the switching, the switching between the current and the spare of the scrambled transport stream can be performed smoothly without causing a disturbance in the transmission signal. Can be performed. Also, the scrambler 13,
At the time of system switching, each packet of the transport stream is scrambled using the same scrambling key information between systems or between packets at the time of system switching, so that the working / standby switching device 17 uses a scrambled transmission signal derived from the switching. Since there is no need to consider the synchronization with the key information, the processing load can be reduced, so that it is possible to use a simple configuration and use an inexpensive switching device.

Note that a frame serving as a transport stream decoding unit is composed of a plurality of packets, and even if several TS packets are not scrambled, complete reproduction cannot be performed on the receiver side. Function is not impaired. In addition, there is no problem in making the scramble key the same because the switching is performed for about several seconds.

The present invention is not limited to the configuration of the above embodiment. For example, the working / standby switching device may have a duplex configuration as shown in FIG. In FIG. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

That is, in the device shown in FIG. 3, the output of the working scrambler 13 and the output of the protection scrambler 16 are input to the working / standby switching device 21 functioning as a protection system. , The respective inputs can be selectively derived. Thereafter, the signal derived from the working / standby switching device 21 is sent out as a sending signal via the relay contact part 22 shared with the working / standby switching device 17.

According to the above configuration, when an abnormality occurs in the working / standby switching device 17 functioning as the working system, the scrambling device 1 is switched by the working / standby switching device 21 of the protection system.
By selectively deriving one of the outputs 3 and 16, it is possible to cope with an abnormality of the switching device.

Further, in addition to the above, in the case of handling a digital broadcast signal specified by a method other than the MPEG2 encoding method, and in a method of scrambling by a scrambler, various modifications are made without departing from the scope of the present invention. it can.

[0031]

As described in detail above, according to the present invention,
It is possible to provide a digital broadcast signal active / backup scramble switching / sending device that can smoothly switch between a working and a standby of a scrambled digital broadcast signal without causing disturbance in a transmission signal.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a digital broadcast signal working / spare scramble switching and transmitting apparatus according to an embodiment of the present invention.

FIG. 2 is an exemplary timing chart for explaining the processing operation in the system configuration of the embodiment;

FIG. 3 is a block diagram showing the configuration of a digital broadcast signal working / spare scramble switching and transmitting apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 Reference numerals 11, 14: buffer, 12, 15: packet identification unit, 13, 16: scramble device, 17, 21: working / standby switching device, 18: timing control unit, 22: relay contact unit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme Court ゛ (Reference) H04N 7/24 H04N 7/13 Z (72) Inventor Susumu Yamaguchi 3-3-9 Shimbashi, Minato-ku, Tokyo F-term (reference) in Toshiba AV E. Co., Ltd.

Claims (6)

[Claims] 1. A digital system which is compression-encoded independently of each other in a working system and a protection system and is assigned to a plurality of transmission blocks including an information block in which information necessary for identifying the frame is placed in units of a compressed frame. A digital broadcast signal working / standby scramble switching and transmitting device for selectively scrambling a broadcast signal according to a working / standby switching signal, wherein each of the working and protection digital broadcast signals is divided by a predetermined number of blocks. A working buffer and a protection buffer to be stored; a working scrambling unit for selectively scrambling the output of the working buffer; and a protection scrambling unit for selectively scrambling the output of the protection buffer. And outputs of the active scrambling unit and the standby scrambling unit. A working / standby switching unit that selectively derives either of them as a transmission signal, and detects header information from each block of the digital broadcast signal stored in the working buffer and the protection buffer, and detects the header information from the header information. A block identification unit for identifying the contents of the block, and when the working / standby switching signal is input, the same scrambling between transmission lines or transmission blocks excluding the information block based on the identification result of the block identification unit. A timing control unit that switches the working / standby switching unit after controlling the working scrambling unit and the standby scrambling unit to perform scrambling using key information. Digital broadcast signal active / backup scramble switching and transmitting device. 2. The digital broadcast signal is a transport stream generated in a format defined by the MPEG2 encoding system, and the working buffer and the backup buffer store the transport stream for a predetermined number of packets. 2. The apparatus according to claim 1, wherein the block identification unit detects header information of each packet of the transport stream stored in the working buffer and the backup buffer, and identifies the contents from the header information. Digital broadcast signal active / backup scramble switching and transmitting device. 3. The timing control unit determines, from the identification result of the block identification unit, a packet including information necessary for identifying a frame among packets of the transport stream. Does not scramble, for the other plurality of packets between the system or between the packets using the same scramble key information to scramble the active scramble processing unit and the standby scramble processing unit 3. The digital broadcast signal active / backup scramble switching and transmitting apparatus according to claim 1 or 2, wherein the apparatus is controlled. 4. The timing control unit determines, from the identification result of the block identification unit, a packet including information necessary for identifying a frame among the packets of the transport stream, and Controls the working scrambling processing unit and the protection scrambling processing unit so that scrambling is not performed, and controls the working / standby switching unit so as to determine a switchable point based on the determined packet and perform switching. 3. The digital broadcast signal active / backup scramble switching and transmitting apparatus according to claim 1 or 2, wherein: 5. The read start position of the backup buffer so that a packet synchronized with the output of the active buffer is read from the backup buffer based on the identification result of the block identification unit. 3. The digital broadcast signal active / backup scramble switching and transmitting apparatus according to claim 1, wherein after the control, the active system scramble processing section and the standby system scramble processing section are controlled. 6. A backup system which functions as a redundant system of the working / standby switching unit and selectively derives one of the outputs of the working system scrambling unit and the protection system scrambling unit as a transmission signal. 2. The digital broadcast signal active / backup scramble switching / transmission apparatus according to claim 1, further comprising: a current / backup switching section.