JPH0832622A - Packet separation device - Google Patents

Abstract

PURPOSE:To generate a sure packet start timing signal for precisely separating a transport packet from a transport stream. CONSTITUTION:A start code detection part 410 detects the pattern of a start code showing the break of the packets in a bit stream. An internal synchronizing signal generation part 411 obtains an internal synchronizing signal synchronized with the length of the packet in response to the detection signal. When the detection signal is synchronized with the internal synchronizing signal and it is repeated for plural times, a packet synchronizing signal generation part 412 obtains a packet synchronizing signal. A timing signal generation part 415 and a PID separation part 416 extract a packet identification signal which is transmitted from the start code after prescribed time without fail, a comparison part 417 recognizes it and a coincidence signal is supplied to a packet synchronism judgement part 413. Thus, the packet synchronism jdugement part 413 outputs the packet start timing signal 455 synchronized with the packet synchronizing signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet separation device effective in a digital data transmission system for multimedia.

[0002]

2. Description of the Related Art As is well known, in recent years, the technology of digitizing various information signals such as video and audio and processing the signals has made remarkable progress, and along with this, digital broadcasting systems and digital broadcasting and digital communication Development of digital broadcast transmission / reception systems has been actively carried out in various countries around the world in order to realize integrated systems and the like. By the way, one of the most important factors in developing such a digital broadcast transmission / reception system is a technique of compressing a digitized video signal / audio signal and other information data.

As a standard of this data compression processing technology,
MPEG (Moving Picture Image Coding Experts Grou
p), JPEG (Joint Photographic Coding Experts
Group) and H.H. 261 was the mainstream, but now I
SO (International Organization for Standardization) / IEC (International Electrotechnical Commission)
13818 [ISO / IEC JTC (Joint Technical Committee)
1 / SC (Subcommittee) 29 / WG (Working Group) 11] is a method proposed for global standardization across a wide range of technical fields such as broadcasting, communication, and storage media. is there.

According to ISO / IEC13818, not only the above-mentioned data compression method is specified, but also the broadcasting station performs a compression process on each digital video / audio data and other information data which form a program. The system is also established for a control part for a digital broadcast transmission / reception system in which the above-mentioned bit streams are multiplexed and broadcast, and a receiver receives a desired program.

Here, FIG. 11 shows ISO / IEC138.
18 schematically shows a means for multiplexing a bitstream for broadcasting and a bitstream for communication, which are obtained by respectively compressing digital video / audio data based on the regulations of 18. First,
The digital video data is compressed by a video encoding circuit 11 to be a video ES (Elementary Stream), and then supplied to a packetization circuit 12 to be video PES (Packetiziz) divided into packet units of 188 bytes.
ed Elementary Stream) and is supplied to the multiplexing circuit 13.

Further, the digital audio data is compressed by the audio encoding circuit 14 to be an audio ES, and then supplied to the packetization circuit 15 to be an audio PES divided into packet units of 188 bytes. It is supplied to the multiplexing circuit 13. And this multiplexing circuit 1
In 3, the video PES and the audio PES are time-division-multiplexed to generate a multiplexed signal of a TS (Transport Stream) system.

As shown in FIG. 12, the multiplex signal is divided into units of one frame for both video and audio, and a header is added to the frame to form a PES. This PES has a variable length. The PES generated in this manner is basically divided into 184-byte packets for time-division multiplexing of video and audio, and a 4-byte header is attached to each PES to provide a 188-byte TP. (Transport
Packet) is formed. Note that although FIG. 11 has described multiplexing of video and audio, in practice, various information data such as additional information data of programs and program information may also be converted into TP and time-division multiplexed with video and audio. become.

Next, FIG. 13 shows a means for constructing a bit stream for broadcasting. That is, FIG.
In 3, the program 1 shows one program,
By the multiplexing circuit 161, two systems of video data, two systems of audio data, one system of other information data and PMT (Prog
ram Map Table) 1 line is multiplexed. In this PMT, PID (Packet Identify) for identifying video data, audio data, and information data, a description about a program, and the like are put.

As shown in FIG. 13, n multiplexing circuits 1 are provided.
By preparing 61, 162, ..., 16n, n
Individual programs 1, 2, ..., N can be set. The program for which n pieces are set in this way is multiplexed by the multiplexing circuit 17
Thus, each data is time-division multiplexed. In this case, the multiplexing circuit 17 uses a PAT (Program Association) as comprehensive program information for extracting the PMT of each program.
application table), CAT (Conditional Access Table) for controlling scrambling, and NIT (Network Info) indicating information on the network used.
rmation Table) etc. are also time division multiplexed.

As described above, according to the standard of ISO / IEC13818, PMT, PAT, CA regarding program information are provided.
Four types of tables, T and NIT, are set.
The PID of these tables is PAT "00", CA
When T is "01", PMT and NIT can be freely specified. Therefore, on the receiving side, in order to specify the program, first, the PAT is decoded and the PI of each PMT is decoded.
D is detected, and the PID of the detected PMT is designated. After that, the PIDs of the video data, audio data, and information data of the designated program are detected and the PIs to be decoded
By specifying D, various data can be decoded.

By the way, at present, the above ISO / I
By further expanding the standard of EC13818,
It is also considered to separately send program information for each broadcasting station by setting the self / cross instruction flag by using the reserved areas of PAT and PMT shown in 4 (a) and 4 (b), respectively. In addition to this, it is considered that various types of flags are set in the PAT and PMT as shown in FIGS. 15 and 16, respectively, so as to make the digital broadcasting system multifunctional.

On the receiving side, it is necessary to separate the packet from the multi-channel bit stream that is packetized and transmitted as described above, and take in the packet of the desired channel.

FIG. 17 shows a conventional device for separating packets from a bitstream. ISO / IEC13818 Transpor as a packetized bitstream
The configuration and operation of the device shown in FIG. 17 will be described by taking t Stream as an example. The Transport Stream has a structure as shown in FIG. This Transport Stream is configured in packet units, and Transport Packets, which are packets, have the same length, and the length is 188 bytes. Of these, 4 bytes are the header, and the structure of the header is shown in FIG. Of the 4 bytes of the header, the first 1 byte is the start code,
This value is a fixed value of Ox47 (47 in hexadecimal notation and 01000111 in binary notation). The next 3 bits are a flag and the next 13 bits are a PID. PID is one program one
It is a unique value attached to one. The next 4 bits of the PID is a flag, and the next 4 bits are a counter. The value of this counter is incremented one by one in the packet of the same PID, or is a constant value.

The conventional device shown in FIG. 17 has terminals 101,
The terminal 102, the start code detector 110, the internal synchronization signal generator 111, the packet synchronization signal generator 112, and the terminal 103 are included.

From the terminal 101, the Tr shown in FIG.
Ansport Stream is input. Transport Stream 151
Are supplied to the start code detector 110 and the terminal 102. The start code detection unit 110 uses the Transport Stre
A pattern of Ox47 which is a start code is detected from am, a start code detection signal 152 is obtained, and this detection signal is supplied to the internal synchronization signal generation section 111 and the packet synchronization signal generation section 112. Start code detection signal 15
2 is shown in FIG. Start code detection signal 1
52 drops to Low if the pattern Ox47 exists in the Transport Stream.

The internal sync signal generator 111 includes a start code detection signal 152 and a packet sync signal generator 112.
In response to the reset signal 155 supplied from, the internal synchronization signal 153 is generated and supplied to the packet synchronization signal generator 112. The internal synchronization signal generator 111 uses the reset signal 1
A low level (Low) portion of the start code detection signal 152 that is input immediately after resetting is detected by 55 is detected, and an internal synchronization signal 153 that outputs a Low pulse at 188 byte intervals is output therefrom. .
This internal synchronization signal 153 is shown in FIG.

The packet sync signal generator 112 receives the start code detection signal 152 and the internal sync signal 153,
The packet synchronization signal 154 and the reset signal 155 are output. The packet synchronization signal generator 112 compares the start code detection signal 152 and the internal synchronization signal 153, and resets the reset signal 155 until the phases of the Low portion of the start code detection signal 152 and the Low portion of the internal synchronization signal 153 match. Is output and the internal synchronization signal generator 111 is reset to adjust the phase of the internal synchronization signal 153. Further, if the period in which the start code detection signal 152 falls to Low coincides with the period in which the internal synchronization signal 153 falls to Low, the number of times that the Low period coincides is counted.

As shown after the period B shown in FIG.
When the number of times of coincidence becomes a certain value or more, the packet synchronization signal generation unit 112 outputs a Low pulse having a cycle of 188 bytes to the terminal 103 as a packet synchronization signal 154. The packet synchronization signal 154 is shown in FIG. 19C, and this signal is a signal indicating that the Ox47 pattern is detected at 188 byte intervals. The Ox47 pattern that appears at 188-byte intervals is determined to be the start code that exists in the Transport Packet header, and this packet synchronization signal 154 is transferred from the Transport Stream to the Transport Pack.
will be used as the signal to separate et.

On the other hand, in the periods C and D shown in FIG. 19, if the Low period of the start code detection signal 152 and the Low period of the internal synchronization signal 153 do not match, only once in the period C. , And outputs Low as a packet synchronization signal. This is because the Ox47 pattern should have actually existed, but it is considered that the Ox47 pattern disappeared due to an error during transmission. However, if the low period of the start code detection signal 152 and the low period of the internal synchronization signal 153 do not match twice in succession in the periods C and D, the period E is used in the sense that the packets are synchronized again. The reset signal 155 is set to Low to reset the internal synchronization signal generator 111.

While repeating the above operation, the terminal 103
To output a packet synchronization signal 154 having a cycle of 188 bytes. According to the packet synchronization signal 154 output to the terminal 103, from the Transport Stream output to the terminal 102
Transport Packets are separated.

As described above, in the conventional device, the value of Ox47 detected at 188 byte intervals is set as Transport Packet.
It was determined to be the start code existing in the header of. However, in the header of Transport Packet, a pattern of Ox47 appears in addition to the start code, and this is 188
It may be detected in byte cycles. In particular, when a packet having a PID including the Ox47 pattern at the same position is multiplexed, an Ox47 pattern having a 188-byte cycle appears in a portion other than the start code. Ox47 patterns other than this start code are detected, and Transport Stream to Tr
If the packet start timing is used to separate the ansport Packet, the Transport Packet is separated from the Transport Stream by mistake, and the decoding process cannot be performed normally.

Except for the start code, there is a possibility that a pattern of Ox47 may appear in a cycle of 188 bytes, where flags and PID in the header of Transport Packet are used.
Part of. In order to prevent the pattern Ox47 from appearing in the flag and PID portions, there is a method of prohibiting the use of PIDs in which the pattern Ox47 may appear. However, this method can be used for PID
When the range of is narrowed and multi-channel transmission is carried out,
The number of channels and the combination of channels can be limited.

[0023]

In the conventional device, Ox47 is used.
If a pattern similar to the start code appears in a portion other than the start code at a period of 188 bytes, it may be erroneously detected as the start code. If Ox47 that appears in a part other than this start code is mistakenly detected as a start code and the packets are separated,
There is a drawback that the decoding process is incorrect.

In view of this, the present invention provides a packet demultiplexing device that reliably captures a start code pattern and generates a packet start timing for accurately demultiplexing a Transport Packet from a Transport Stream. The purpose is to do.

[0025]

According to the present invention, as a first means, a start code is generated from Transport Stream.
When the PID value of a specific packet that is always sent within a certain period of time is detected after detecting the Ox47 pattern at a 188-byte cycle, the Transport Stream to Transport Pack
A device for determining a packet start timing of a 188-byte cycle for separating et is provided.

As a second means, after detecting a pattern of Ox47, which is a start code, from the Transport Stream at a cycle of 188 bytes, the PID value of a specific packet that is always sent within a fixed time is recorded in the Transport Stream. Transport Stream to Transport when a specified number of times is detected
A device for determining a packet start timing of a 188-byte cycle for separating packets is provided.

As a third means, a pattern of Ox47, which is a start code, is detected from the Transport Stream at a cycle of 188 bytes, and then the value of the PID of a specific packet which is always sent within a fixed time is detected. For a packet having a PID value of a specific packet that is always sent within a certain period of time, a counter value indicating continuity of packets having the same PID is extracted, and it is determined that the counter value is constantly or sequentially increasing. From the Transport Stream
A device for determining a packet start timing of a 188-byte cycle for separating a Transport Packet is provided.

As a fourth means, a pattern of Ox47, which is a start code, is detected from the Transport Stream at a cycle of 188 bytes, and then an unspecified one PID value is held.
When the value of the held PID is detected a specified number of times in the Transport Stream, the Tran is transferred from the Transport Stream.
A device for determining a packet start timing of a 188-byte cycle for separating sport packets is provided.

As a fifth means, a pattern of Ox47 which is a start code is detected from the Transport Stream at a cycle of 188 bytes, and then an unspecified one PID value is held,
Next, regarding the packet with the value of the held PID,
A counter value indicating the continuity of packets having the same PID is extracted, and when it is determined that the counter value is constant or sequentially increasing, Transport
A device for determining a packet start timing of a 188-byte cycle for separating ort packets is provided.

[0030]

By the above means, the start code existing in the Transport Stream can be captured and the packet can be accurately separated from the Transport Stream. As a result, the receiver can perform the decoding process without error.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a first embodiment of the present invention.

One embodiment of a circuit for separating packets from a packetized bitstream is shown in FIG. In this embodiment, as an example, the case of receiving a Transport Stream of ISO / IEC13818 as a bit stream will be described.

A packetized bit stream is input from the terminal 401. This bitstream is
In this embodiment, the Tr of ISO / IEC13818 is used.
It is ansport Stream. The Transport Stream 451 input from the terminal 401 is led out to the terminal 402 and also input to the start code detection unit 410 and the PID separation unit 416.

The start code detector 410 is a Transpor
A pattern of Ox47 which is a start code pattern is detected from the t Stream 451 to obtain a start code detection signal 452, and this signal is supplied to the internal synchronization signal generation unit 411 and the packet synchronization signal generation unit 412. Figure 2 (a)
A start code detection signal 452 is shown in FIG. The start code detection unit 410 is a start code pattern.
When it detects Ox47, it outputs a low level (Low).
In addition to the start code, a large number of Ox47 patterns may exist randomly in the bitstream, so the start code detection signal 452 becomes Low at irregular timings as shown in FIG. 2A. It is a signal.

In the internal synchronizing signal generator 411, the Low value of the start code detection signal 452 which is input immediately after reset by the reset signal 458 is applied as a reference,
The packet synchronizing signal generator 4 outputs the internal synchronizing signal 453 that generates a periodic pulse once per packet.
12 and the timing signal generator 415. The internal synchronization signal 453 is 188 as shown in FIG.
It is a signal that emits a Low pulse at a byte cycle.

The packet sync signal generator 412 outputs the start code detection signal 452 and the internal sync signal 453 to 1
Only the Ox47 pattern that appears in the packet once is detected and supplied as a packet synchronization signal 454 to the packet synchronization determination unit 413. The signal 456 output from the packet synchronization signal generator 412 is a reset signal. The packet synchronization signal 454 is shown in FIG. The packet synchronization signal generation unit 412 compares the start code detection signal 452 and the internal synchronization signal 453, and outputs the reset signal 456 until the Low period of the start code detection signal 452 coincides with the Low period of the internal synchronization signal 453. The internal sync signal generator 411 outputs the signal and resets the internal sync signal generator 411 via the logical product circuit 414.
Adjust the phase of 3. While the internal synchronizing signal 453 is Low, the start code detection signal 452 is Low.
If the periods that are equal to each other match, the number of times that the Low period matches is counted. As shown after time T1 in FIG.
When the number of times of coincidence becomes a certain value or more, the packet synchronization signal generator 412 outputs a pulse that goes low once every 188 bytes.

On the other hand, in the timing signal generator 415,
Upon receiving the internal synchronization signal 453, the timing signal 459 for separating the PID from the Transport Stream 451 is generated. The timing signal 459 is shown in FIG.
The timing signal 459 is supplied to the PID separation unit 416.

The PID separating unit 416 separates the PID value from the Transport Stream 451 according to the timing signal 459 and supplies it to the comparing unit 417. Comparison unit 4
At 17, it is determined whether the PID value input from the PID separation unit 416 matches the PID value of a specific packet input from the terminal 404 and always sent within a fixed time, and the result is determined. The PID match signal 461 is output to the packet synchronization determination unit 413. The output signal 460 of the PID separation unit 416 is shown in FIG. 2E, and the PID coincidence signal 461 is shown in FIG. In FIG. 2, the separated PID values are S, T, U, R, A, Z, A, and B. In this embodiment, assuming that the PID value of a specific packet that is always sent within a fixed time is Z, the output signal 4 of the PID separation unit 416 in FIG.
When 60 is Z, the PID match signal 461 will be Low. Therefore, after time T3 in FIG. 2, the PID coincidence signal 461 is Low.

Here, the PID of a specific packet that is always sent within a fixed time refers to OxOOOO to OxOOOF, Ox1FFF, and among these, OxOOOO is used for a packet for sending program information. This PID exists in any Transport Stream. Therefore, it is optimal to input OxOOOO to the terminal 404 as the PID value of a specific packet that is always sent within a fixed time.

The packet synchronization judgment unit 413 judges according to the PID coincidence signal 461 whether or not the pattern of the start code detected once per packet is really the start code. If the result of determination is that it is a start code, packet start timing signal 455 is output to terminal 403. On the other hand, if it is not determined to be the start code, the reset signal 457 is output, and this reset signal is supplied to the internal synchronization signal generation unit 411 via the AND circuit 414 and resets.
The packet sync signal 454 is shown in FIG.
The PID match signal 461 is shown in FIG. 2 (f), and the packet start timing signal 455 is shown in FIG. 2 (h). The reset signal 457 is shown in FIG. When the PID match signal 461 shown in FIG. 2 becomes Low, it means that the PID value of the specific packet that is surely sent within the fixed time is detected in the Transport Stream 451. , The packet start timing signal 455 is Lo with a cycle of 188 bytes.
It becomes a pulse of w. However, if the PID value of the specific packet that is always sent within a certain time is not detected and the High (high level) period of the PID coincidence signal 461 continues for a designated period or more, the time T2 shown in FIG. As described above, the reset signal 457 becomes Low, and the internal synchronization signal generator 411 is reset.

The packet synchronization determination unit 413 outputs the packet start timing signal using the packet synchronization signal, and this determination is permitted when the PID coincidence signal 461 is Low. Further, the packet synchronization determination unit 413 may have a function of determining the packet start code of the bit stream at this time, and may be able to confirm whether or not the start code exists in the timing period of the packet synchronization signal.

By the above operation, a pulse having a cycle of once every 188 bytes made based on the start code is output to the terminal 403, which is Transport Stream 4
It is a packet start timing signal for separating Transport Packet from 51. Therefore, by using this packet start timing signal, Transport
Packets can be reliably separated from Stream. (Effects of Embodiment 1) Transp
Even if a pattern similar to the ort Stream start code exists in the packet cycle, it is possible to reliably detect only the start code and create the packet start timing that separates the packet from the Transport Stream. (Second Embodiment) FIG. 3 shows a second embodiment of the present invention.

Basically, the same parts as those in the previous embodiment are designated by the same reference numerals. As in the first embodiment, a Tr of ISO / IEC13818 is used as a packetized bit stream.
Let's take ansport Stream as an example.

From the terminal 401, the ISO / IEC138
18 Transport Streams are input. The Transport Stream 451 input from the terminal 401 is input to the terminal 402, the start code detection unit 410, and the PID separation unit 616.

The start code detector 410 is a Transpor
The Ox47 pattern that is the start code pattern is detected from the t Stream 451 to obtain the start code detection signal 452, and this detection signal is used as the internal synchronization signal generation unit 41.
1 and the packet synchronization signal generator 412. FIG.
As shown in (a), the start code detector 410 is
When Ox47, which is the start code pattern, is detected, L
Output ow. In addition to the start code, a large number of Ox47 patterns may exist randomly in the bitstream. Therefore, the start code detection signal 452
Is an irregularly low signal as shown in FIG.

The internal synchronizing signal generator 411 uses the Low value of the start code detection signal 452, which is input immediately after the reset signal 458 is applied, as a reference.
The packet synchronizing signal generator 4 outputs the internal synchronizing signal 453 that generates a periodic pulse once per packet.
12 and the timing signal generator 415. The internal synchronization signal 453 is 188 as shown in FIG.
It is a signal that emits a Low pulse at a byte cycle.

The packet sync signal generator 412 outputs the start code detection signal 452 and the internal sync signal 453 to 1
Only the Ox47 pattern that appears in the packet once is detected and supplied as a packet synchronization signal 454 to the packet synchronization determination unit 413. The signal 456 output from the packet synchronization signal generator 412 is a reset signal. The packet synchronization signal 454 is shown in FIG. The packet synchronization signal generation unit 412 compares the start code detection signal 452 with the internal synchronization signal 453, and resets the period when the start code detection signal 452 is Low with respect to the period when the internal synchronization signal 453 is Low. The signal 456 is output, and the logical product circuit 41
After 4, the internal synchronization signal generator 411 is reset and the phase of the internal synchronization signal 453 is adjusted. When the period in which the start code detection signal 452 is Low matches the period in which the internal synchronization signal 453 is Low, Low
The number of times that the periods are matched is counted. When the number of coincidences exceeds a certain value, the packet synchronization signal generator 412 outputs a Low pulse once for 188 bytes (after time T1 in FIG. 4).

On the other hand, in the timing signal generator 615,
Upon receiving the internal synchronization signal 453, the timing signal 659 for separating the PID from the Transport Stream 451 is generated. The timing signal 659 is shown in FIG.
The timing signal 659 is supplied to the PID separation unit 616.

The PID separation unit 616 separates the PID portion from the Transport Stream 451 according to the timing signal 659 and outputs it to the comparison unit 617. In the comparison unit 617, the PID input from the PID separation unit 616
And the PID value of a specific packet that is always sent within a fixed time input from the terminal 604 are determined, and the determination result is a PID match signal 661.
It is output to the PID coincidence signal counting unit 618. FIG.
The output signal 460 of the PID separation unit 416 is shown in FIG.
The PID coincidence signal 661 is shown in (f). In this example, the separated PID values are A, C, Z, B,
A, Z, A, Z, C, A. In this embodiment, assuming that the PID value of a specific packet that is always sent within a fixed time is Z, in FIG.
When the output signal 660 of the separation unit 616 is Z, the PID match signal 661 becomes Low.

In the PID coincidence signal counting section 618, P
Upon receiving the ID match signal 661, the number of times the PID separated from the Transport Stream 451 and the PID value of a specific packet that is always sent within a certain time input from the terminal 604 are counted is counted. When the count value becomes a certain value or more, as in the time T2 and thereafter shown in FIG.
The output signal 662 of the PID coincidence signal counting unit 618 is
It becomes Low. Also, the PID match signal counting unit 618
Are reset within a specified time by a reset signal 458. Output signal 6 of PID coincidence signal counting section 618
62 is input to the packet synchronization determination unit 413.

The packet synchronization judgment unit 413 judges whether the pattern of the start code detected at a cycle of once per packet is really a start code by the output signal 662 of the PID coincidence signal counting unit 618. There is. As a result, if the start code is determined, the packet start timing 455 is supplied to the terminal 403. On the other hand, if it is not determined to be the start code, a reset signal 457 is output, and this reset signal is supplied to the internal synchronization signal generation section 411 and the PID coincidence signal counting section 418 via the AND circuit 414 and resets.
As shown in FIG. 4, when the output signal 662 of the PID coincidence signal counting unit 618 falls to Low, the PID value of a specific packet that is always sent within a fixed time is Tran.
Since it indicates that the sport stream 451 has been detected more than the specified number of times, the packet start timing signal 455 is the first time at this time that the 188-byte cycle Lo
It becomes a pulse of w.

By the above operation, a pulse having a cycle of once every 188 bytes created based on the start code is output to the terminal 403, which is Transport Stream 4
It is the packet start timing for separating the Transport Packet from 51. Therefore, by using this packet start timing, the packet can be reliably separated from the Transport Stream. (Effects of Second Embodiment) According to this embodiment, Transp
Even if a pattern similar to the ort Stream start code exists in the packet cycle, it is possible to reliably detect only the start code and create the packet start timing that separates the packet from the Transport Stream. (Embodiment 3) FIG. 5 shows a third embodiment of the present invention.

Basically the same parts as those of the previous embodiment are designated by the same reference numerals. As in the first embodiment, a Tr of ISO / IEC13818 is used as a packetized bit stream.
Let's take ansport Stream as an example.

From the terminal 401, the ISO / IEC138
18 Transport Streams are input. The Transport Stream 451 input from the terminal 401 is input to the terminal 402, the start code detection unit 410, the PID separation unit 816, and the count value separation unit 818.

The start code detecting section 410 is a Transpor
A pattern of Ox47 which is a start code pattern is detected from the t Stream 451 to obtain a start code detection signal 452, and this signal is supplied to the internal synchronization signal generation unit 411 and the packet synchronization signal generation unit 412. Figure 6 (a)
As shown in, the start code detection unit 410 outputs Low when detecting Ox47 which is the pattern of the start code. In addition to the start code, a large number of Ox47 patterns may exist in the bit stream at random, so the start code detection signal 452 is a signal that randomly changes to Low as shown in FIG. 6A. Has become.

In the internal synchronizing signal generator 411, 1 is set based on the Low value of the start code detection signal 452 which is input immediately after reset by the reset signal 458.
The packet synchronizing signal generator 41 outputs the internal synchronizing signal 453 that generates a periodic pulse once per packet.
2 and the timing signal generator 815. As shown in FIG. 6B, the internal synchronization signal 453 is a signal that becomes a Low pulse at a cycle of 188 bytes.

The packet sync signal generator 412 outputs the start code detection signal 452 and the internal sync signal 453 from 1 to 1.
Only the Ox47 pattern that appears in the packet once is detected and supplied as a packet synchronization signal 454 to the packet synchronization determination unit 413. The signal 456 output from the packet synchronization signal generator 412 is a reset signal. The packet synchronization signal 454 is a pulse as shown in FIG. The packet synchronization signal generation unit 412 compares the start code detection signal 452 with the internal synchronization signal 453, and resets the period when the start code detection signal 452 is Low with respect to the period when the internal synchronization signal 453 is Low. Output signal 456,
The internal sync signal generator 411 is reset via the AND circuit 414 to adjust the phase of the internal sync signal 453. When the period in which the start code detection signal 452 is Low matches the period in which the internal synchronization signal 453 is Low, the number of times the Low period is matched is counted.
When the number of times of coincidence becomes a certain value or more, the packet synchronization signal generation unit 412 outputs a pulse that becomes Low once in 188 bytes (after time T1 in FIG. 6).

On the other hand, in the timing signal generator 815,
The timing signal 859 for separating the PID from the Transport Stream 451 by receiving the internal synchronization signal 453, and Tr
A timing signal 862 for separating a continuity counter indicating continuity of packets having the same PID from the ansport Stream 451 is generated. The timing signal 859 is shown in FIG. 6 (d), and the timing signal 862 is shown in FIG. 6 (g).

In the PID separation unit 816, according to the timing signal 859, the Transport Stream 4
The PID portion is separated from 51 and supplied to the comparison unit 817. The comparison unit 817 determines whether or not the PID value input from the PID separation unit 816 and the PID value of a specific packet input from the terminal 804 that are necessarily sent within a fixed time match. The result is output as a PID coincidence signal 861 to the counter value determination unit 819. The output signal 860 of the PID separation unit 816 is shown in FIG.
6 (f) shows a PID coincidence signal 861.

In this embodiment, the separated PID values are A, C, Z, B, A, Z, A, Z and C. In this embodiment, assuming that the PID value of a specific packet that is always sent within a fixed time is Z, the output signal 860 of the PID separation unit 816 is Z in FIG.
At this time, the PID coincidence signal 861 becomes Low.

On the other hand, in the counter value separation unit 818, according to the timing signal 862, the Transport St
The value part of the continuity counter is separated from the ream 451 and supplied to the counter value determination unit 819. In FIG. 6, the values of the separated continuity counters are 3, 2, 2, 10, 4, 3, 5, 4, 3.

The counter value judgment unit 819 extracts only the value of the continuity counter of the packet having the PID value of the specific packet which is always sent within a fixed time, and within the designated time, this continuity counter is extracted.・ It is judged whether the value of the counter is constant or increases by one. In this example, if the value of the continuity counter is constant or has increased by one by one, the counter value determination unit 819 changes the determination signal 864 to Low and outputs it to the packet synchronization determination unit 413. In FIG. 6, immediately after the times T2, T3, and T4, the PID match signal 861
Are Low respectively. Counter value at this time 86
Looking at 3, it is 2 after time T2, 3 after time T3, and time T
After 4, the value has increased by 1 and 4. Therefore, the determination signal 864 becomes Low after the time T4.

The packet synchronization judgment unit 413 judges from the judgment signal 864 whether or not the pattern of the start code detected once per packet is really the start code. As a result, if the start code is determined, the packet start timing 455 is supplied to the terminal 403. On the other hand, if the start code is not determined within the designated time, the reset signal 457 is output, and the reset signal is supplied to the internal synchronization signal generation unit 411 via the AND circuit 414 and resets.
As shown in FIG. 6, when the determination signal 864 becomes Low, the Low pulse of the packet synchronization signal 454 becomes
It is determined that the start code of the Transport Stream 451 is matched, and at this time, the packet start timing signal 455 is the first Lo level of 188 bytes.
It becomes a pulse of w.

By the above operation, a pulse having a cycle of once every 188 bytes made based on the start code is output to the terminal 403.
It is a packet start timing signal for separating Transport Packet from 51. Therefore, by using this packet start timing signal, Transport
Packets can be reliably separated from Stream. (Effect of Embodiment 3) According to the above-mentioned embodiment, the Transport
Even if a pattern similar to the start code is present in the Stream in the packet cycle, only the start code is reliably detected,
It is possible to create a packet start timing that separates the packet from the Transport Stream. (Fourth Embodiment) FIG. 7 shows a fourth embodiment of the present invention.

Basically the same parts as those in the previous embodiment are designated by the same reference numerals. As in the first embodiment, a Tr of ISO / IEC13818 is used as a packetized bit stream.
Let's take ansport Stream as an example.

From the terminal 401, the ISO / IEC138
18 Transport Streams are input. The Transport Stream 451 input from the terminal 401 includes a terminal 402, a start code detection unit 410, a PID separation unit 1216, and a PID separation unit 1216.
It is input to the ID holding unit 1219.

The start code detecting section 410 uses the Transpor
A pattern of Ox47 which is a start code pattern is detected from the t Stream 451 to obtain a start code detection signal 452, and this signal is supplied to the internal synchronization signal generation unit 411 and the packet synchronization signal generation unit 412. Figure 8 (a)
As shown in, when the start code detection unit 410 detects the start code pattern Ox47, the start code detection unit 410 outputs a detection signal that becomes Low. In addition to the start code, a large number of Ox47 patterns may exist randomly in the bitstream, so the start code detection signal 452 is irregularly low as shown in FIG. 8A. Has become.

In the internal synchronizing signal generation section 411, the Low value of the start code detection signal 452 which is input immediately after the reset signal 458 is applied is used as a reference.
The packet synchronizing signal generator 4 outputs the internal synchronizing signal 453 that generates a periodic pulse once per packet.
12 and the timing signal generator 1215.
The internal synchronization signal 453 is 18 as shown in FIG.
It is a signal that emits a Low pulse at a cycle of 8 bytes.

The packet sync signal generator 412 outputs the start code detection signal 452 and the internal sync signal 453 to 1
Only the Ox47 pattern that appears in the packet once is detected and supplied as a packet synchronization signal 454 to the packet synchronization determination unit 413. The signal 456 output from the packet synchronization signal generator 412 is a reset signal. The packet synchronization signal 454 is shown in FIG. The packet sync signal generator 412 compares the start code detection signal 452 with the internal sync signal 453,
Until the period in which the start code detection signal 452 is Low matches the period in which the internal synchronization signal 453 is Low,
The reset signal 456 is output, the internal sync signal generator 411 is reset via the AND circuit 414, and the phase of the internal sync signal 453 is adjusted. Internal synchronization signal 453
Start code detection signal 4 for the period when is Low
When the period in which 52 becomes Low coincides, the number of times that the period in Low coincides is counted. When the number of times of coincidence becomes a certain value or more, the packet synchronization signal generator 412
A low pulse is output once every 188 bytes (see FIG. 8).
After time T1).

On the other hand, the timing signal generator 1215 receives the internal synchronization signal 453 and receives the Transport Stream 45.
Control signal 1263 for holding one unspecified PID from 1 and PID held in PID holding unit 1219
, And a timing signal 1259 for separating the PID from the Transport Stream 451.

The PID holding unit 1219 holds the PID of one unspecified packet from the Transport Stream 451 according to the signal 1263 shown in FIG. 8D while the signal 1263 is Low. The retained PID is shown in FIG.
According to the timing signal 1259 shown in (f), the timing signal 1259 is read at the timing of Low. The read PID is input to the comparison unit 1217. In this embodiment, the PID value held in the PID holding unit 1219 is D.

In the PID separation unit 1216, according to the timing signal 1259, the transport stream 451 to PI
The portion D is separated and supplied to the comparison unit 1217.
The comparison unit 1217 determines whether or not the PID value input from the PID separation unit 1216 and the PID value read from the PID holding unit 1219 match, and if they match, the result is PID. The match signal 1261 is output to the PID match signal counting unit 1218. The output signal 12 of the PID separation unit 1216 is shown in FIG.
60, and the PID coincidence signal 1261 is shown in FIG. In this example, the separated PID values are D,
D, B, A, D, A, D, C, A. PID
Since the value of the PID held in the holding unit 1219 is D, the output signal 1 of the PID separation unit 1216 in FIG.
When 260 is D, the PID match signal 1261 is Lo
It is w.

In the PID coincidence signal counting section 1218,
By the PID match signal 1261, the PID holding unit 1219
The number of times the PID held by the PID and the PID separated by the PID separation unit 1216 match are counted. Counting is performed for a designated time, and after the designated time has passed, the reset signal 1258 resets the PID coincidence signal counting unit 1218. When the counted value exceeds a certain value, the PID coincidence signal counting unit 1218 outputs the determination signal 1262 that becomes Low. The determination signal 1262 is
This is shown in FIG. 8 (i). In FIG. 8, when the time T4 is reached, the counted value becomes equal to or larger than a certain value, and therefore the determination signal 1262 changes to the instant Low of the time T4. The determination signal 1262 output from the PID coincidence signal counting unit 1218 is the packet synchronization determination unit 413.
Is input to

The packet synchronization judgment unit 413 judges according to the judgment signal 1262 whether the pattern of the start code detected once per packet is really the start code. As a result, if the start code is determined, the packet start timing 45
5 is supplied to the terminal 403. On the other hand, if it is not determined to be the start code, a reset signal 457 is output, and the reset signal is supplied to the internal synchronization signal generation unit 411 and the PID coincidence signal counting unit 1218 via the AND circuit 414 to reset. As shown in FIG. 8, when the determination signal 1262 becomes Low, it is determined that the Low pulse of the packet synchronization signal 454 matches the start code of the TransportStream 451. 455 (FIG. 8 (j))
Is output as a pulse train that becomes Low in a cycle of 188 bytes.

By the above operation, a pulse having a cycle of once every 188 bytes created based on the start code is output to the terminal 403.
It is the packet start timing for separating the Transport Packet from 51. Therefore, by using this packet start timing, the packet can be reliably separated from the Transport Stream. (Effect of Fourth Embodiment) As described above, according to this embodiment, even if a pattern similar to the start code is present in the Transport Stream in the packet cycle, only the start code is reliably detected and the Transport Stream is detected. A packet start timing that separates packets can be created. (Embodiment 5) FIG. 9 shows a fifth embodiment of the present invention.

Basically the same parts as those of the previous embodiment are designated by the same reference numerals. As in the first embodiment, a Tr of ISO / IEC13818 is used as a packetized bit stream.
Let's take ansport Stream as an example.

From the terminal 401, the ISO / IEC138
18 Transport Streams are input. The Transport Stream 451 input from the terminal 401 is input to the terminal 402, the start code detection unit 410, the PID separation unit 1016, the counter value separation unit 1018, and the PID holding unit 1020.

The start code detecting section 410 uses the Transpor
The Ox47 pattern that is the start code pattern is detected from the t Stream 451 to obtain the start code detection signal 1052, and this signal is used as the internal synchronization signal generation unit 411.
And packet synchronization signal generator 412. Figure 10
As shown in (a), the start code detector 41
When 0 detects Ox47 which is the pattern of the start code, 0 outputs a detection signal which becomes Low. In addition to the start code, a large number of Ox47 patterns may exist randomly in the bitstream, so the start code detection signal 452 is an irregular Low signal as shown in FIG. 10A. Has become.

In the internal synchronizing signal generation section 411, the Low value of the start code detection signal 452 which is input immediately after being reset by the reset signal 458 is used as a reference.
The internal synchronization signal 453 that generates a periodic pulse once per packet is output, and this signal is supplied to the packet synchronization signal generation unit 412 and the timing signal generation unit 1015. The internal synchronization signal 453 is a pulse signal that becomes Low in a cycle of 188 bytes, as shown in FIG.

The packet sync signal generator 412 outputs the start code detection signal 452 and the internal sync signal 453 from 1 to 1.
Only the Ox47 pattern that appears in the packet once is detected and supplied as a packet synchronization signal 454 to the packet synchronization determination unit 413. The signal 456 output from the packet synchronization signal generator 412 is a reset signal. The packet synchronization signal 454 is a signal as shown in FIG. The packet synchronization signal generation unit 412 compares the start code detection signal 452 and the internal synchronization signal 453, and resets them until the period when the start code detection signal 452 is Low matches the period when the internal synchronization signal 453 is Low. Output signal 456,
The internal sync signal generator 411 is reset via the AND circuit 414 to adjust the phase of the internal sync signal 453. When the period in which the start code detection signal 452 is Low coincides with the period in which the internal synchronization signal 453 is Low, the number of times the Low period is coincident is counted. When the number of coincidences exceeds a certain value, the packet synchronization signal generator 1012 generates a Low pulse once in 188 bytes (after time T1 in FIG. 10).

Here, the timing signal generator 1015 receives the internal synchronization signal 453 and receives the Transport Stream 45.
The control signal 1065 for holding one unspecified PID from 1 and the PID held in the PID holding unit 1020
To read the PID from TransportStream1051
Signal 1059 for separating the
A timing signal 1062 for separating the value of the continuity counter indicating the continuity of packets having the same PID from the t Stream 1051 is generated.

In the PID holding unit 1020, FIG.
In accordance with the signal 1065 shown in FIG.
Holds the ID. The held PID is read at the timing when the timing signal 1059 becomes Low according to the timing signal 1059 shown in FIG. The read PID is input to the comparison unit 1017. In this embodiment, the PID value held in the PID holding unit 1020 is D.

In the PID separation unit 1016, according to the timing signal 1059, the transport stream 451 to PI
The portion D is separated and output to the comparison unit 1017.
The comparison unit 1017 determines whether the PID value input from the PID separation unit 1016 and the PID value read from the PID holding unit 1020 match, and the result is set as the PID match signal 1061 and the counter is set. It is output to the value determination unit 1019. An output signal 1060 of the PID separation unit 1016 is shown in FIG.
The D match signal 1061 is shown. In this example, the separated PID values are D, D, B, A, D, A, D,
It is C and A. Since the value of the PID held in the PID holding unit 1020 is D, in FIG.
When the output signal 1060 of the separation unit 1016 is D, PI
The D match signal 1061 changes to Low.

On the other hand, in the counter value separation unit 1018, according to the timing signal 1062, the Transport Stream 45
The value of the continuity counter is separated from 1 and supplied to the counter value determination unit 1019. In FIG. 10, the values of the separated continuity counters are 1, 2, 10, 4, 3, 5, 4, 3, and 6.

The counter value determining unit 1019 extracts only the value of the continuity counter of the packet having the PID value held in the PID holding unit 1020, and the value of the continuity counter is constant or sequentially one. It is determined within a specified time whether it is rising. If the value of the continuity counter is constant or increases by one, the counter value determination unit 1019 determines that the determination signal 1
064 to Low, and the packet synchronization determination unit 413
Supply to. In FIG. 10, immediately before the times T2, T3, and T4, the PID match signal 1061 is Low.
Is. Looking at the counter value 1063 at this time, the value increases by 2 after the time T2, 3 after the time T3, and 4 after the time T4. Therefore, the determination signal 1064 changes to Low after the time T4.

The packet synchronization judgment unit 413 judges according to the judgment signal 1064 whether the pattern of the start code detected at the rate of once per packet is really the start code. As a result, if the start code is determined, the packet start timing 45
5 is supplied to the terminal 403. On the other hand, if the designated time has passed and the start code is not determined, the reset signal 457
This reset signal is supplied to the internal synchronizing signal generator 411 via the AND circuit 414 and resets. As shown in FIG. 10, the determination signal 1064 is Lo
When it changes to w, the packet synchronization signal 454 is Low.
Since it was determined that the pulse of was matched with the start code of Transport Stream 451, for the first time at this time,
The PID separation signal 455 is a pulse train signal that becomes Low at a cycle of 188 bytes.

By the above operation, a pulse having a cycle of once every 188 bytes created based on the start code is output to the terminal 403.
It is the packet start timing for separating the Transport Packet from 51. Therefore, by using this packet start timing, the packet can be reliably separated from the Transport Stream. (Effects of Fifth Embodiment) As described above, according to this embodiment, even if a pattern similar to the start code exists in the Transport Stream in the packet cycle, only the start code is reliably detected and the Transport Stream is detected. A packet start timing that separates packets can be created.

In each of the above-mentioned embodiments, the packetized bit stream is ISO / IEC131.
It is a bit stream in digital broadcasting using the standard of 8, and the start code pattern of the packet is
The packet synchronization signal is Ox47 (47 in hexadecimal notation and 01000111 in binary notation), and the packet synchronization signal is a pulse having a cycle of 188 bytes. However, it goes without saying that the present invention can be applied not only to signals of such a format, but also to signals of other formats as a device for separating packets from a bit stream that is packetized and transmitted.

[0089]

As described above, according to the present invention,
Be sure to capture the start code pattern and use Transport
Stream (Transport Stream) to Transport Pa
It is possible to generate a packet start timing for accurately separating a cket (transport packet).

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a timing diagram shown to explain the operation of the apparatus of FIG.

FIG. 3 is a diagram showing a second embodiment of the present invention.

4 is a timing diagram shown for explaining the operation of the apparatus of FIG.

FIG. 5 is a diagram showing a third embodiment of the present invention.

FIG. 6 is a timing diagram shown for explaining the operation of the apparatus of FIG.

FIG. 7 is a diagram showing a fourth embodiment of the present invention.

8 is a timing diagram shown for explaining the operation of the apparatus shown in FIG.

FIG. 9 is a diagram showing a fifth embodiment of the present invention.

10 is a timing diagram shown for explaining the operation of the apparatus of FIG.

FIG. 11 is an explanatory diagram of a multiplexing system.

FIG. 12 is an explanatory diagram of a multiplexed signal.

FIG. 13 is an explanatory diagram of a multiplexing system for broadcasting.

FIG. 14 is a diagram showing a configuration example of a program association table (PAT) and a program map table (PMT) used in a multiplexing system.

FIG. 15: Program Association Table (PA
The figure which shows the further another structural example of T).

FIG. 16 is a diagram showing still another configuration example of a program map table (PMT).

FIG. 17 is a diagram showing a conventional packet separation device.

FIG. 18 is an explanatory diagram of the structure of a transport stream.

FIG. 19 is a timing diagram shown for explaining the operation of the apparatus of FIG.

[Explanation of symbols]

451 ... Transport stream, 410 ... Start code detecting section, 411 ... Internal synchronization signal generating section, 412 ...
Packet synchronization signal generation unit, 413 ... Packet synchronization determination unit, 414 ... AND circuit, 415, 615, 815, 1
215 ... Timing signal generators 416, 616, 81
6, 1216, 1016 ... PID separation unit, 417, 61
7, 817, 1217, 1017 ... Comparison section, 618, 1
218 ... PID coincidence signal counting unit, 818, 1018
... Counter value separation unit, 819, 1019 ... Counter value determination unit, 1219, 1020 ... PID holding unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04N 7/24 7/14

Claims (7)

[Claims] 1. A device for separating a packet from a packetized bit stream, and a synchronization signal generating means for detecting a start code pattern indicating a packet break and generating a packet synchronization signal of a predetermined cycle; and the packet synchronization. Separation means for extracting a packet index (hereinafter referred to as ID) from the packetized bit stream using a timing signal synchronized with the signal, and the extracted packet ID is always sent within a fixed time. A comparison packet that determines whether or not it matches the comparison ID of a specific packet that has been received for a specified time, and outputs a match signal when the packets match, using the packet synchronization signal according to the match signal of the comparison means. When the output of the start timing signal is determined and the ID of the extracted packet is constant A packet separating device comprising: a judging means for resetting the synchronizing signal generating means when the comparison ID of a specific packet which is surely sent within the space does not match. 2. The determining means, when determining the output of a packet start timing signal using the packet synchronization signal, counts the number of consecutive times of the coincidence signal supplied from the comparing means within a designated time, and counts this count. A means for determining the output of the packet start timing signal when the value reaches a certain value or more, and for resetting the synchronization signal generating means when the count number is less than the certain value within the designated time. The packet separation device according to claim 1, wherein 3. A counter for extracting a counter value indicating the continuity of packets having the same ID from the packetized bit stream when the output of the packet start timing signal is determined using the packet synchronization signal. It is determined whether the counter value extracted at the same timing as the coincidence signal supplied from the value separating means and the comparing means is constant or sequentially increasing, and if the counter value is constant or sequentially increasing. 2. A means for determining the output of the packet start timing signal, and resetting the synchronization signal generating means if the counter value is not constant or is not sequentially increased.
The packet separation device described. 4. The comparing means selects an unspecified 1 from the packetized bit stream.
A holding unit that extracts and holds the IDs of one packet, and the IDs of the packets that are sequentially separated by the separating unit.
And a comparing unit that compares the ID of the unspecified one packet and obtains a match signal each time they match, the determining unit determines the output of the packet start timing signal using the packet synchronization signal. In that case, the number of times of the coincidence signal from the comparison unit is counted for a designated time, and when the counted value reaches a certain value or more, the output of the packet start timing is determined, and the value counted within the designated time is less than a certain value. 2. Then, the packet separating apparatus according to claim 1, further comprising means for resetting the means for generating the packet synchronization signal. 5. The comparing means selects an unspecified 1 from the packetized bit stream.
A holding unit that extracts and holds the IDs of one packet, and the IDs of the packets that are sequentially separated by the separating unit.
And a comparing unit that compares the ID of the unspecified one packet and obtains a match signal each time they match, the determining unit determines the output of the packet start timing signal using the packet synchronization signal. In this case, the counter value separating means for extracting the counter value indicating the continuity of the packets having the same ID from the packetized bit stream, and the counter value extracting means for extracting the counter value at the same timing as the coincidence signal supplied from the comparing unit. It is determined whether or not the counter value is constant or sequentially increasing, and if the counter value is constant or sequentially increasing, the output of the packet start timing signal is determined. The packet according to claim 1, further comprising means for resetting the synchronizing signal generating means. Separation device. 6. The comparison ID in the comparison means is a code set in advance.
The packet separation device described. 7. The packetized bitstream is a bitstream in digital broadcasting using the ISO / IEC13818 standard, and the start code pattern of the packet is Ox47.
7. The hexadecimal number is 47 and the binary number is 01000111, and the packet synchronization signal is a pulse having a 188-byte cycle, and the packet synchronization signal is any one of claims 2, 3, 4, 5, and 6. Packet separator.