JP4689231B2 - Transport stream switching device - Google Patents

Description

  The present invention relates to a transport stream switching device for switching and outputting a plurality of MPEG transport streams.

  In the digital transmission system, ITU-T recommendation H.264, which encodes video, audio, and other data constituting a program into an elementary stream (ES) and multiplexes them. 222.0 | There is a system for transmitting a transport stream (TS) according to ISO / IEC13818-1 (Systems). The receiving side performs demultiplexing processing, takes out the elementary stream from the transport stream, and reproduces the program in the decoder. FIG. 6 is a block diagram showing an example of an encoder and a decoder of this digital transmission system.

  The elementary stream is composed of a packet called a PES (Packetized Elementary Stream) packet, and a PES header is added. In the PES header, codes for identifying individual streams, packet sizes, time information for synchronous reproduction called PTS (Presentation Time Stamp) and DTS (Decoding Time Stamp), and other control information are described. (Hereinafter, time information of both PTS and DTS is referred to as a time stamp.) A PES packet is a payload of a TS packet composed of a plurality of 188 bytes having the same PID (Packet Identifier) number included in the header. Divided and transmitted. The transport stream is composed of a plurality of TS packets.

  The type of TS packet is composed of a 4-byte fixed length packet header, a variable length adaptation field, and a payload. A PID (packet identifier) and various flags are defined in the header of the packet. The type of TS packet is identified by this PID. The adaptation field has a stuffing function in the TS packet for transmitting information such as PCR (Progam Clock Reference) and making the TS packet a fixed length of 188 packets.

  In a digital transmission system, an encoder and a decoder have an STC (System Time Clock) that is a common reference time. The STC, which is the system clock (27 MHz) of the encoder, is encoded into PCR and transmitted by TS. The two are synchronized by reproducing them with a decoder. In a stream multiplexing apparatus, when a plurality of streams are multiplexed, a transport stream that is simultaneously input is corrected and multiplexed so as to be synchronized with a common reference clock (see, for example, Patent Document 1).

JP 2001-53703 A (paragraphs [0011] to [0017], drawing FIG. 1)

  Unlike a stream multiplexing device, there is a case where a transport stream is switched to another transport. FIG. 7 is a block diagram of a transport stream switching device, and a program provider (such as a broadcast station) may switch some programs in the transport stream using this switching device. For example, when switching from a certain program to a stream with different contents or commercial contents and supplying the stream to the receiving side, there is a problem that the continuity of the stream cannot be maintained if switching in the middle of the stream. The reason why such continuity of streams cannot be maintained is that each stream is not synchronized with the video frame of the baseband signal, and time information such as STC is also independent.

  The fact that the time information of each stream is independent will be described with reference to FIGS. 8 (a) and 8 (b). In FIGS. 8A and 8B, the horizontal axis is the time axis, the elapsed time from the start of encoding (for example, when the encoder is started), and the vertical axis is PCR that increases with the passage of time. Alternatively, it is a time stamp value. FIG. 8A shows a case where the encoding start times of the first stream and the second stream do not match or there is no synchronization means (asynchronous), and the PCR values at the switching position are different. That is, the time information of each stream is independent. Therefore, when such stream switching is performed, time information of PCR and time stamp becomes discontinuous as shown in FIG. The stream is transmitted with a PCR or time stamp value obtained by encoding a discrete value on a straight line, and a decoder that controls processing with reference to a value as shown in FIG. become unable.

  In order to deal with such a problem, the stream is once decoded, then switched with the video of the baseband signal, and encoded again into the MPEG stream. When switching by such a method, the circuit scale becomes large because the decoding process and the encoding process that require a lot of processing and memory are performed, the delay increases, and further, the video quality deteriorates due to the re-encoding. However, this is not preferable.

  In addition, when the conventional switching method is viewed from a different point of view, it is necessary to provide a separate device to synchronize the reference time and synchronize with the reference time at the time of switching, which complicates the system. In particular, when switching a transport stream transmitted from a remote location, the reference time may be different, and it is necessary to adjust the time difference and synchronize. There are difficult aspects.

  The present invention has been made in view of the above problems, and transport that can synchronize independent asynchronous time information in each transport stream and ensure continuity of time information when switching transport streams. An object of the present invention is to provide a stream switching device.

The present invention achieves the above-mentioned problems, and the invention of claim 1 is a transport stream switching device for switching at least two transport streams,
PCR acquisition means for acquiring the PCR of the reference first transport stream;
Time stamp information obtaining means for obtaining time stamp information of the first transport stream;
A reference time generation unit configured by an independent self-running system clock oscillator and a reference time counter, and generating a reference time from the PCR of the first transport stream;
Time stamp correction information calculating means for calculating time stamp correction information from the time stamp information of the first transport stream, the reference time, and the PCR of the second transport stream before the change;
PCR changing means for obtaining a PCR from the second transport stream and changing the PCR based on the reference time;
Time stamp changing means for obtaining time stamp information of the second transport stream and changing the time stamp correction information;
Switching means for switching the first transport stream and the second transport stream in which the PCR and the time stamp information are changed ,
The reference time counter is a reference time correction unit that obtains a correction value from a difference between the PCR of the first transport stream and the reference time counter, and corrects the reference time counter at predetermined intervals. A transport stream switching device. The reference time counter has the same configuration as the PCR field defined in the MPEG-2 system.

The invention according to claim 2 is the transport stream switching device according to claim 1,
The transport stream switching device, wherein the time stamp correction information is generated from difference information between a PCR of the second transport stream and the reference time .

The invention according to claim 3 is the transport stream switching device according to claim 1 ,
The transport stream switching device is characterized in that the time stamp information of the first and second transport streams is detected from the GOP head pictures of the first and second transport streams .

The invention according to claim 4 is the transport stream switching device according to claim 1,
The difference information is corrected so that a difference between the reference time and the time stamp information obtained by the time stamp information acquisition unit is equal to a difference between the PCR of the second transport stream before the change and the time stamp information. It is a transport stream switching device.

The invention of claim 1 is a transport stream switching device for switching at least two transport streams,
PCR acquisition means for acquiring the PCR of the reference first transport stream;
Time stamp information obtaining means for obtaining time stamp information of the first transport stream;
A reference time generation unit configured by an independent self-running system clock oscillator and a reference time counter, and generating a reference time from the PCR of the first transport stream;
Time stamp correction information calculating means for calculating time stamp correction information from the time stamp information of the first transport stream, the reference time, and the PCR of the second transport stream before the change;
PCR changing means for obtaining a PCR from the second transport stream and changing the PCR based on the reference time;
Time stamp changing means for obtaining time stamp information of the second transport stream and changing the time stamp correction information;
Switching means for switching the first transport stream and the second transport stream in which the PCR and the time stamp information are changed ,
The reference time counter includes a reference time correction unit that obtains a correction value from a difference between the PCR of the first transport stream and the reference time counter, and corrects the reference time counter at predetermined intervals. Therefore, the continuity of time information is secured by changing the PCR and time stamp information of the second transport stream on the basis of the PCR and time stamp information of the first transport stream. It is possible to provide a transport stream switching device that can maintain the continuity of the port stream, and that the decoded video on the receiving side does not freeze when the transport stream is switched, and the appropriate video can be demodulated.

  Further, the invention of claim 1 has an advantage that the time information of the transport stream to be switched can be shared by the free-running clock. In addition, the reference time counter has the same configuration as the PCR field defined in the MPEG-2 system, matching with the transport stream is good for switching, and the processing becomes simple.

  According to the first aspect of the present invention, the reference time can be generated with high accuracy by a simple method using information of the reference time counter. Therefore, there is an advantage that the error between the PCR of the first transport stream and the reference time can be reduced, and the continuity is good.

According to a second aspect of the present invention, in the transport stream switching device according to the first aspect, the time stamp correction information is generated from the PCR of the second transport stream, the reference time, and difference information. Therefore, the time stamp of the second transport stream can be changed with high accuracy by using the reference time counter value and the PCR of the transport stream.

According to a third aspect of the present invention, in the transport stream switching device according to the first aspect, the time stamp information of the first and second transport streams is the GOP of the first and second transport streams. Since the detection is performed from the first picture, fluctuations in the difference between the PCR and the time stamp can be suppressed. It should be noted that the code amount per GOP is substantially constant, and an accurate value is obtained in which the GOP head positions are equally spaced.

According to a fourth aspect of the present invention, in the transport stream switching device according to the first aspect, the difference between the reference time and the time stamp information obtained by the time stamp information obtaining means is the second transport stream before the change. Since the difference information is corrected so as to be equal to the difference between the PCR and the time stamp information, the difference between the first transport stream and the time stamp and the difference between the PCR and the time stamp before the change in the second transport stream are By correcting the correction information so as to be the same, it is possible to prevent the time stamp from becoming discontinuous.

  Embodiments of a transport stream switching device according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of the present invention, which is a transport stream switching device for switching two transport streams in synchronization. First, the configuration of the present embodiment will be described with reference to FIG. 1. 1 is an input terminal of a first transport stream (hereinafter referred to as a first stream), and 2 is a second transport stream (hereinafter referred to as a second stream). 3 is a first stream PCR acquisition unit input from the input terminal 1, and 4 is a first stream time stamp acquisition unit input from the input terminal 1. 5 is an oscillator (self-running system clock oscillator), 6 is a reference time generation unit that generates a reference time from the system clock frequency from the oscillator 5 and the output of the PCR acquisition unit 3, and 7 is input from the input terminal 2. The second stream PCR acquisition and change unit 8 is a time stamp calculation unit that calculates a time stamp correction value based on outputs from the reference time generation unit 6, the time stamp acquisition unit 4, and the second stream PCR acquisition and change unit 7. , 9 is a time stamp acquisition / change unit for the second stream that changes the time stamp value according to outputs from the PCR acquisition / change unit 7 and the time stamp calculation unit 8, and 10 is a switching output that synchronizes the first and second streams. A switching unit 11 is an output stream output terminal.

  Next, the operation of this embodiment will be described for each configuration. The PCR acquisition unit 3 of the first stream acquires the PCR (Program clock reference: time reference value) of the first stream. PCR is obtained as follows. A PAT (Program Association Table) table having a PID (Packet Identifier) of 0x0000 (hexadecimal 13 bits) is acquired. There is a program map PID (Program Map PID) indicating a PID of a PMT (Program Map Table) in the Program Association Section of the PAT. When a PMT packet having a PID value of Program Map PID is acquired, there is a PCR PID indicating the PID of the packet including the PCR in the TS program map section of the PMT. A packet having a PID value of PCR PID is acquired, and an adaptation field control (Adaptation field control) indicating the presence or absence of an adaptation field (Adaptation field) is examined. As seen, if there is a PCR, a program clock reference base and a program clock reference extension, that is, a PCR, are obtained. The PCR acquisition unit 3 is such a PCR acquisition unit.

  The time stamp acquisition unit 4 of the first stream acquires the time stamp of the first stream. The time stamp is acquired as follows. First, a PAT (Program Association Table) packet having a PID of 0x0000 (13 bits in hexadecimal) is acquired. There is a program map PID (Program Map PID) indicating the PID of the PMT (Program Map Table) in the program association section of the PAT. When a PMT packet having a PID value of Program Map PID is acquired, the payload of the TS header of the packet indicating the type of elements (video or audio, etc.) constituting the program in the TS program map section (Program association section) of the PMT -It is possible to determine whether or not the payload starts from the beginning of the PES packet by using a unit start indicator (payload unit start indicator). There is a PTS / DTS flag in the header portion of the PES packet, and the presence of PTS and DTS (time information for synchronous reproduction) can be understood from the value. By these procedures, the time stamp of PTS or DTS is acquired for each program component (PID). The time stamp acquisition unit 4 is such a time stamp acquisition means. Incidentally, when the PTS / DTS flag is “10” (2 bits in binary), only PTS exists, and when it is “11”, PTS and DTS exist. In the case of “00”, PTS and DTS do not exist. “01” is prohibited.

  The reference time generation unit 6 is a reference time generation unit that generates a reference time for realizing synchronization from the PCR of a transport stream serving as a reference, based on a system clock by the oscillator 5. In order to facilitate processing, the reference time has the same configuration as a PCR field defined in the MPEG-2 system, and a reference time counter (not shown) has such a PCR field. That is, the reference time counter has a portion representing a 9-bit program clock reference extension (hereinafter referred to as pcr_ex) having a system clock frequency of 27 MHz as a unit, and a program clock reference base (hereinafter referred to as pcr_bs) having a unit of 90 KHz. ) Is represented by 33 bits. A system clock frequency of 27 MHz is supplied from the oscillator 5. The reference PCR is supplied from the PCR acquisition unit 3 of the first stream. The reference time generation unit 6 sets the PCR of the first stream in the reference time counter composed of pcr_ex and pcr_bs having the same configuration as the PCR field of the MPEG-2 system standard. The reference time counter is driven by the system clock of the oscillator 5. pcr_ex operates in synchronization with the system clock and increases by 1 from 0 to 299. After 299, it returns to 0 and goes around. pcr_bs increases by 1 every time pcr_ex reaches 299. That is, pcr_bs is a counter that operates at 90 KHz (27000/300 = 90 KHz).

  Next, the PCR acquisition and change unit 7 of the second stream will be described. First, for the second stream PCR acquisition, the second stream PCR is acquired by the same operation as the first stream PCR acquisition. The PCR acquisition and change unit 7 has the same PCR acquisition means as described above, and also has a PCR change means described below.

  Hereinafter, a method for changing the PCR of the second stream by the PCR acquisition and change unit 7 will be described. The PCR changing method is changed by the PCR changing means. This PCR changing means detects the PCR of the second stream, and reads the value of the reference time counter of the reference time generating unit 6 at that moment. Then, the PCR of the second stream is changed to the value of the read reference time counter. In this way, the time information of the second stream can be synchronized with the PCR of the first stream by referring to the same time information as the first stream. Thus, even if the first stream and the second stream are switched at an arbitrary switching timing, the PCR value does not become discontinuous as shown in FIG. 2, so that the switching process can be easily performed. The problem at the time of stream switching described with reference to 8 (a) and (b) can be improved.

  Although the first stream and the second stream have been described as being synchronized, there are cases in which this is not strictly the case. The PCR of the first stream is generated from the system clock of an encoding device different from the oscillator 5, whereas the reference time counter is generated from the system clock of the oscillator 5. Therefore, since the two are different system clocks, the frequencies do not always coincide completely. For this reason, an error occurs little by little between the PCR of the first stream and the value of the reference time counter generated by the reference time generation unit 6. For example, even if a system clock frequency conforming to the standard is used, if the time from the acquisition of the reference first stream PCR to the arrival of the next PCR is 50 milliseconds, the reference time counter is about 40 An error of the order of a clock may occur. This is more than 1000 nanoseconds in terms of PCR jitter, which is significantly higher than the allowable value of the standard of ± 500 nanoseconds, which adversely affects the decoding process on the receiving side and may disturb video and audio.

  As a method of eliminating such a bad influence on the receiving side, in order to improve the accuracy of the reference time counter, the system clock is regenerated by a PLL (Phase Locked Loop) based on the PCR, A technique for creating a synchronized system clock can be used. Although it is possible to reproduce the system clock with high accuracy by such a creation method, there are problems that complicated processing is required and the circuit scale increases. Of course, such a PCR changing means may be used, but the PCR changing means described below is most preferable.

  A reference time correction method using a simple circuit that does not increase the circuit scale will be described below. This reference time correction method is a method for obtaining a difference between the PCR and the reference time counter value when the reference time generating unit 6 acquires the PCR of the first stream, and correcting the reference time counter value by the difference. At the start of correction, the PCR of the first stream is set in the reference time counter as it is. When the next PCR of the first stream is acquired, an initial correction value D0 is obtained based on the following [Equation 1].

  Thereafter, the correction value Dn is obtained every time the PCR of the first stream is acquired based on the following [Equation 2].

  As shown in FIG. 3, the reference time correction may cause a large error (jitter) in the reference time correction diagram on the upper side of FIG. 3 if the value of the reference time counter is corrected once. In the lower reference time correction diagram, the correction is gradually performed one by one with a time interval (time interval for one round of pcr_ex), and Dn (the first correction is made until the next PCR of the first stream is acquired. In this case, only D0) is corrected. That is, when the PCR of the second stream is detected, the value of the reference time counter is read, but it is not possible to specify when this PCR will come, and it may come at a fixed interval or may arrive at an indefinite interval. Also, it may come immediately before correcting the reference time counter, or may come immediately after correction. For example, if it arrives immediately before the correction, if it is necessary to perform the correction of about 40 clocks as described above, the PCR of the second stream is changed with the reference time counter value including an error corresponding thereto. A very large PCR jitter will occur. Therefore, as shown in the reference time correction diagram on the lower side of FIG. 3, if correction is performed one clock at a time, the error is only one clock, immediately before or after correction, and the jitter is minimized. Can be suppressed. Here, the correction is performed one clock at a time, but the present invention is not limited to this embodiment, and the correction can be performed by increasing to about 5 clocks. The PCR jitter at this time is 200 nanoseconds or less, which is not a big problem.

  Subsequently, the reference time correction will be described more specifically. There is pcr_ex in the reference time counter. This pcr_ex is circulated at 300 clocks, that is, about 11 microseconds, and each time pcr_ex becomes 0, the reference time counter is corrected by one. If the correction value Dn is 40, the correction is completed in about 40 microseconds. The correction may be performed when pcr_ex is other than zero. In this way, it is possible to easily perform correction without the need for providing a complicated circuit such as a PLL or a timer for obtaining correction timing. In this description, correction is made every time pcr_ex makes a round. However, the correction may be made every two or more rounds, or conversely, two or more rounds may be corrected during one round. It is also possible. Further, as described above, one or more correction values can be set per correction time. Such processing can reduce the error of the PCR value.

  Next, the time stamp calculation unit 8 will be described. The time stamp calculation unit 8 has time stamp correction information calculation means. The time stamp has a unit of 90 KHz as in the program clock reference base. In accordance with the change in the PCR of the second stream, the time stamp is also changed by the time stamp correction information calculating means in order to accurately indicate the decoding time and the display time. The time stamp is changed for both DTS and PTS (time information for synchronous reproduction). As in the case of PCR, only the time stamp of the second stream is changed because only the time stamp becomes discontinuous as shown in FIG. First, the PCR of the second stream before the PCR change (synchronization) is acquired from the PCR acquisition and change unit 7 of the second stream, and the difference DT from the reference time counter value is obtained based on the following [Equation 3]. Since the time stamp has an accuracy of 90 KHz, only the difference of pcr_bs needs to be obtained. Similarly, it is only necessary to obtain pcr_bs for PCR.

  In the above [Equation 3], the difference DT is obtained by calculating pcr_bs of the PCR of the second stream with the reference time counter because the reference time counter is already synchronized with the first stream. In addition, it is convenient that the calculation can be performed immediately when the second stream is acquired. Furthermore, since the PCR of the first stream and the PCR of the second stream are not acquired (arrived) at the same time, if they do not arrive at the same time, it is necessary to wait for one to arrive and the other to arrive. This is because jitter will occur after a lapse of time. Next, a time stamp of the second stream is acquired, and a difference DT is added to this time stamp to calculate a time stamp change value.

  The time stamp acquisition / change unit 9 includes a time stamp acquisition unit and a time stamp change unit, and acquires the time stamp of the second stream by the same time stamp acquisition unit as the time stamp acquisition unit 4 of the first stream. Thereafter, the time stamp of the second stream is changed by the time stamp changing means on the basis of the result of the time stamp calculating unit 8 to obtain a new time stamp.

  By such means, the time stamp can be corrected and synchronized from the reference time (PCR). FIG. 4 shows such switching, FIG. 4 (a) shows the PCR and time stamp of the first stream and the second stream, and FIG. 4 (b) shows the first stream and the second stream. Indicates the PCR and time stamp when switching from the first stream to the second stream at the switching position, and represents time information at the time of synchronized stream switching. However, the precondition for applying this method is that the difference between the PCR and the time stamp is equal between the first stream and the second stream.

  At the time of stream switching, if the difference between the PCR and the time stamp is not equal between the first stream and the second stream, the time stamp becomes discontinuous even if the PCR is synchronized and can maintain continuity. Decoding becomes difficult. That is, when correcting the time stamp, it is necessary to consider the difference between the PCR and time stamp of the first stream and the difference between the PCR and time stamp of the second stream. Here, the problem is the time stamp when the data amount differs for each picture (frame) such as an MPEG-2 video stream. Since the interval between video frames of the baseband signal is equal, the time stamp of the stream increases by 3003. When encoded with MPEG-2, the intra-frame encoded I (intra) picture has a large amount of code, and the B picture for bidirectional interframe predictive encoding has a small amount of code. A time stamp is attached when a picture is made into a PES packet, but the positions are not equally spaced. FIG. 5 shows the relationship between the picture code amount and the time stamp position. When such a picture is transmitted at a constant bit rate, it is clear that the transmission takes time if the code amount is large, and the time is short if the code amount is small. Therefore, if the time stamp of an arbitrary picture is acquired and the difference from the PCR is obtained, it varies greatly from time to time and cannot be changed accurately.

  Therefore, a method for suppressing the variation in the difference between the PCR and the time stamp as much as possible will be described. When encoding and transmitting with MPEG-2 video, encoding is usually performed with GOP (Group Of Picture) as a large unit. When transmitting at a fixed bit rate such as digital broadcasting, the code amount of each picture in the GOP may vary greatly, but the code amount in GOP units is controlled to be substantially constant. If this feature is used, it can be said that the start positions of the GOP are equally spaced. Therefore, if the time stamp of the start picture of the GOP is obtained and the difference from the PCR is obtained, it is possible to suppress a large fluctuation every time the difference is obtained. Accurate value can be obtained. The GOP start position can easily detect a group start code (specific 32-bit pattern, 000001 B8 in hexadecimal notation) indicating the start of the GOP header.

  The time stamp calculation unit (time stamp correction information calculation means) 8 uses such a time stamp of the first picture of the GOP, the difference between the PCR (reference time) of the first stream and the time stamp, and the pre-change time. Based on the difference information obtained by comparing the PCR of the second stream and the difference between the time stamps, the difference DT obtained above is corrected so that they are equal, and the time stamp change value is calculated from the corrected difference DT. calculate. In this way, synchronization can be realized by changing the time stamp of the second stream. Therefore, even if the first stream and the second stream are switched at an arbitrary switching timing, the time stamp does not become discontinuous, so that the switching process can be easily performed.

  The switching unit (switching unit) 10 is a switching unit that switches from the first stream to the second stream with the changed PCR and time stamp, and outputs a new second stream from the output terminal 11. The transport stream switching device of the present embodiment operates as described above.

  As an application example of the present invention, it can be used for video equipment such as an editing apparatus or broadcasting equipment.

It is a block diagram which shows one Embodiment of the transport stream switching apparatus of this invention. It is explanatory drawing about the synchronization of PCR in this embodiment. It is a figure explaining the reference time correction in this embodiment, and an upper reference time correction figure is a reference time correction figure which shows that an error becomes large, and a lower reference time correction figure shows that an error becomes small. It is explanatory drawing made into time information synchronizing with the time information of the stream on the basis of the stream after switching in this embodiment. It is explanatory drawing about a picture code amount and a time stamp position. It is a block diagram which shows the transmission example of the transport stream by an encoder and a decoder. It is a block diagram which shows the conventional transport stream switching apparatus. It is explanatory drawing about the time information at the time of the stream switching by the conventional apparatus, (a) shows the time information of the transport stream of switching object, (b) has shown the time information at the time of switching.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Input terminal 3 PCR acquisition part 4 Time stamp acquisition part 5 Oscillator 6 Reference time generation part 7 PCR acquisition and change part 8 Time stamp calculation part 9 Time stamp acquisition and change part 10 Switching part 11 Output terminal

Claims (4)

A transport stream switching device for switching at least two transport streams,
PCR acquisition means for acquiring the PCR of the reference first transport stream;
Time stamp information obtaining means for obtaining time stamp information of the first transport stream;
A reference time generation unit configured by an independent self-running system clock oscillator and a reference time counter, and generating a reference time from the PCR of the first transport stream;
Time stamp correction information calculating means for calculating time stamp correction information from the time stamp information of the first transport stream, the reference time, and the PCR of the second transport stream before the change;
PCR changing means for obtaining a PCR from the second transport stream and changing the PCR based on the reference time;
Time stamp changing means for obtaining time stamp information of the second transport stream and changing the time stamp correction information;
Switching means for switching the first transport stream and the second transport stream in which the PCR and the time stamp information are changed ,
The reference time counter is a reference time correction unit that obtains a correction value from a difference between the PCR of the first transport stream and the reference time counter, and corrects the reference time counter at predetermined intervals. Transport stream switching device. In the transport stream switching device according to claim 1,
The transport stream switching device , wherein the time stamp correction information is generated from difference information between a PCR of the second transport stream and the reference time . In the transport stream switching device according to claim 1 ,
The transport stream switching device , wherein time stamp information of the first and second transport streams is detected from a GOP head picture of the first and second transport streams . In the transport stream switching device according to claim 1,
The difference information is corrected so that a difference between the reference time and the time stamp information obtained by the time stamp information acquisition unit is equal to a difference between the PCR of the second transport stream before the change and the time stamp information. Transport stream switching device.

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