JP4495558B2 - Transport stream switching method and apparatus - Google Patents

Description

  The present invention relates to a transport stream switching method and apparatus, and more particularly, to a transport stream switching method and apparatus for reducing the influence of fading when receiving digital broadcasting.

  For example, when receiving digital broadcasting such as terrestrial digital television broadcasting, terrestrial digital audio broadcasting, and long- and short-wave digital broadcasting with a portable receiver, due to the effects of buildings such as buildings or terrain such as mountains, or the effects of heavy rainfall, Fading occurs in which the reception level at the portable receiver decreases and the communication quality deteriorates.

  It is known that the situation in which radio waves are interrupted due to fading during reception is caused by rainfall in BS digital broadcasting, and in order to avoid this, different transmission path coding methods by reducing the amount of information for the same program content A system that broadcasts simultaneously is being developed.

In Patent Document 1, the delay and phase of the input OFDM signal of the active system and the standby system are adjusted to the same timing, the signal quality of the input OFDM signal of each system is monitored, and the quality of the active system is It describes switching from the active system to the standby system when the quality is lower.
JP 2004-96468 A

  For portable services that are broadcast using only one segment of the terrestrial digital television broadcast OFDM signal, the transmission channel coding method cannot be changed by TS (Transport Stream), so information on the same program content There has been a problem that the conventional method of broadcasting simultaneously with different transmission path coding methods with a reduced amount cannot be adopted.

  In addition, the frequency diversity method described in Patent Document 1 has a problem that it cannot respond when the quality of both the active system and the standby system deteriorates due to fading.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a transport stream switching method and apparatus for reducing service interruption due to fading.

The invention according to claim 1 and 2, a first transport stream, and a second transport stream of said first transport stream delayed by a predetermined time, a third of performing interleaving of the second transport stream The transport stream is multiplexed and transmitted,
A first transport stream separated from a received signal and delayed by the predetermined time, a second transport stream separated from the received signal, and a third transport stream separated from the received signal and deinterleaved By switching and outputting based on the normal / abnormal determination result of the first and third transport streams,
When the first transport stream is abnormal, the first transport stream is switched to the second transport stream, and when the second transport stream is abnormal, the second transport stream is switched to the third transport stream. By switching, service interruption due to fading can be further reduced.

According to a third aspect of the present invention, a first transport stream that has been interleaved and a second transport stream that is the same as or part of the first transport stream and that is not interleaved are multiplexed and transmitted. A receiving device for receiving a received signal,
Deinterleaving means for deinterleaving the first transport stream that has been interleaved separated from the received signal;
Determination means for performing normality / abnormality determination of the first transport stream or the second transport stream separated from the received signal;
Switching means for switching and outputting the first transport stream from the deinterleave means and the second transport stream separated from the received signal based on the determination result of the determination means;
The second transport stream is a part of the content of the first transport stream;
The switching means, when the first transport stream is not normal, switches from the first transport stream to the second transport stream to output, thereby easily reducing the influence of fading and interrupting service. Can be reduced.

The invention described in claim 4 is a means for delaying the first transport stream by a predetermined time and outputting the second transport stream;
Means for interleaving the second transport stream to output a third transport stream;
By means for multiplexing and transmitting the first transport stream, the second transport stream, and the third transport stream,
A signal obtained by multiplexing the first transport stream, the second transport stream obtained by delaying the first transport stream by a predetermined time, and the third transport stream obtained by interleaving the second transport stream can be transmitted.

The invention according to claim 5 multiplexes the first transport stream delayed after interleaving and the second transport stream not interleaved with the same or a part of the contents of the first transport stream. Send
The first transport stream separated from the received signal and deinterleaved and the second transport stream separated from the received signal and delayed are based on the normal / abnormal judgment result of the first or second transport stream. By switching and sending,
It is possible to remove the influence of time fading obtained by adding a delay time to the deinterleave processing time.

According to the present invention, it is possible to reduce service interruption due to a propagation path failure such as fading.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a block diagram of a reference example of the transport stream switching method of the present invention. Here, an explanation will be given by taking an example of broadcasting for a portable receiver using one segment of an OFDM signal of terrestrial digital television broadcasting.

  In the figure, in the transmission system 100, each of video, audio, and data is encoded by the information source encoding unit 101, then multiplexed by the multiplexing unit 102 to be a TS signal, and supplied to the branching device 103. .

  The branching unit 103 bifurcates the TS signal, one of them is supplied as a TS packet TS_A to the transmission path encoding unit 105, and the other is delayed by the delay unit 104 from the TS packet TS_A to a delay time τ1 (τ1 is several milliseconds to ) And is supplied to the transmission path encoding unit 105 as a TS packet TS_B. The transmission path encoding unit 105 performs transmission path encoding on the TS packets TS_A and TS_B as the same segment of the OFDM signal of digital terrestrial television broadcasting, and modulates it to obtain a transmission signal.

  In the receiving system 200, the transmission path decoding unit 201 receives a signal from the transmission path, and decodes the TS packet TS_A and the TS packet TS_B from the received signal. After the TS packet TS_A is determined to be normal / abnormal in the TS packet by the determination unit 202, the delay unit 203 delays the delay time τ2 (τ2 = τ1−the determination time of the determination unit 202) and synchronizes with the TS packet TS_B. The TS packet TS_A ′ is supplied to the switching unit 204. The TS packet TS_B is directly supplied from the transmission path decoding unit 201 to the switching unit 204.

  The switching unit 204 selects one of the TS packets TS_B and TS_A ′ in units of TS packets based on the determination result of the determination unit 202, and supplies the selected TS packet TS_C to the information source decoding unit 205. The information source decoding unit 205 decodes video, audio, and data from the TS packet TS_C and supplies them to the subsequent viewing unit (not shown).

  2 shows a flowchart of the switching process performed by the switching unit 205, and FIG. 3 shows a signal timing chart in each unit of FIG. In FIG. 2, it is determined whether or not the delay time τ1 or more has elapsed since the start of viewing in step S1, and if it is less than the delay time τ1, the TS packet TS_B is selected as the TS packet TS_C in step S2, and the process proceeds to step S1.

  On the other hand, if the delay time τ1 or more has elapsed in step S1, it is determined whether or not the determination result of the TS packet TS_A acquired after the start of viewing is normal in step S3. If normal, the TS is determined in step S4. The packet TS_A ′ is selected as the TS packet TS_C, and the process proceeds to step S1. If the TS packet TS_A is not normal, the abnormal TS packet TS_A ′ delayed in step S5 is switched to the TS packet TS_B and selected as the TS packet TS_C, and the process proceeds to step S1.

  In FIG. 3, TS packet TS_B (B1, B2, B3) is selected as TS packet TS_C when viewing time is less than delay time τ1, and then TS packet TS_A ′ (A4, A5, A6) is selected as TS packet TS_C. Selected.

  If there is an abnormality in the TS packet TS_A (A7, A8) between the times t2 and t3, the switching unit 204 switches the delayed abnormality TS packet TS_A ′ (A7, A8) to the TS packet TS_B (B7, B8), and the TS. The packet TS_C is selected.

  FIG. 4 shows a block diagram of the first embodiment of the transport stream switching method of the present invention. Here, an explanation will be given by taking an example of broadcasting for a portable receiver using one segment of an OFDM signal of terrestrial digital television broadcasting.

  In the figure, in the transmission system 300, each of video, audio, and data is encoded by the information source encoding unit 301, then multiplexed by the multiplexing unit 302 to be a TS signal, and supplied to the branching device 303. .

  The branching unit 303 bifurcates the TS signal, interleaves one of them in the interleaving unit 304 and supplies it as a TS packet TS_A to the transmission line encoding unit 305, and supplies the other as a TS packet TS_B directly to the transmission line encoding unit 305. To do. Interleaving section 304 changes the order of TS packets in units of blocks. For example, when one block is composed of three TS packets and arranged in the order of TS packets X1, X2, and X3, the blocks are rearranged in the order of TS packets X3, X1, and X2. Note that the number of TS packets constituting one block may be two or more, but is, for example, the number of packets corresponding to several milliseconds to several minutes.

  The transmission path encoding unit 305 performs transmission path encoding on the TS packets TS_A and TS_B as the same segment of the OFDM signal of terrestrial digital television broadcasting, and modulates it to obtain a transmission signal.

  In the reception system 400, the transmission path decoding unit 401 receives a signal from the transmission path, and decodes the TS packet TS_A and the TS packet TS_B from the received signal. The TS packet TS_A is deinterleaved by the deinterleave unit 403 after the determination unit 402 determines whether the TS packet is normal or abnormal. Note that deinterleaving is processing for rearranging TS packets A1, A2, and A3 in the order of TS packets A3, A1, and A2, and the deinterleaving processing time τ3 required for rearrangement is, for example, several Milliseconds to minutes.

  The TS packet TS_A ′ output from the deinterleaving unit 403 is supplied to the switching unit 405 via the synchronization unit 404. On the other hand, the TS packet TS_B output from the transmission path decoding unit 401 is directly supplied to the switching unit 405 via the synchronization unit 406.

  Synchronizers 404 and 406 are provided to absorb deinterleave processing time τ3 and perform switching accurately in packet units, and operate with the same clock to accurately synchronize TS packets TS_A ′ and TS_B. .

  The switching unit 405 switches and selects one of the TS packets TS_B and TS_A ′ in units of TS packets based on the determination result of the determination unit 402, and supplies the selected TS packet TS_C to the information source decoding unit 407. The information source decoding unit 407 decodes video, audio, and data from the TS packet TS_C and supplies them to a subsequent viewing unit (not shown).

  FIG. 5 shows a flowchart of the switching process performed by the switching unit 405, and FIG. 6 shows a signal timing chart in each unit of FIG. In FIG. 5, it is determined whether or not the deinterleave processing time τ3 or more has elapsed since the start of viewing in step S11. If it is less than the deinterleave processing time τ3, the TS packet TS_B is selected as the TS packet TS_C in step S12, Proceed to S11.

  On the other hand, if the interleave processing time τ3 or more has elapsed in step S11, it is determined in step S13 whether or not the determination result of the TS packet TS_A acquired after the start of viewing is normal. The deinterleaved TS packet TS_A ′ is selected as the TS packet TS_C, and the process proceeds to step S11. If the TS packet TS_A is not normal, the abnormal TS packet TS_A ′ deinterleaved in step S12 is selected as the TS packet TS_C for switching to the TS packet TS_B, and the process proceeds to step S11.

  In FIG. 6, the TS packet TS_B (B0 to B3) is selected as the TS packet TS_C when the delay time τ3 is less than the viewing start time t11, and then the TS packet TS_A ′ (A4, A5, A6) is selected as the TS packet TS_C. The

  If there is an abnormality in the TS packet TS_A (A8, A12) between times t12 and t13, the switching unit 204 converts the deinterleaved abnormal TS packets TS_A ′ (A8) and TS_A ′ (A12) into TS packets TS_B (B8). , TS_B (B12) are switched in packet units and selected as TS packets TS_C.

  In this way, TS packets B5 and B6 that could not be normally received are interleaved, so that they are switched to A5 and A6 of TS packet TS_A that can be normally received, and further, A8 and A12 that are not normally received in TS_A. By switching to B_8 and B12 of TS_B, TS_C can be created with all normal packets. For this reason, even if fading occurs during reception of digital broadcast by a portable receiver, for example, it is possible to reduce the interruption of service due to the influence.

  FIG. 7 shows a block diagram of a modification of the first embodiment of the transport stream switching method of the present invention. In FIG. 7, in transmission system 300, TS packet TS_A output from interleaving section 304 is delayed by delay time τ4 by delay section 310 and supplied to transmission path coding section 305. At the same time, in the reception system 400, the TS packet TS_B output from the transmission path decoding unit 401 is delayed by the delay unit 410 by the delay time τ4 and supplied to the synchronization unit 406.

  As a result, even when the influence of fading cannot be removed at the deinterleave processing time τ3, the influence of fading in the time obtained by adding the delay time τ4 to the deinterleave processing time τ3 can be removed.

  4 and 7, the TS packet TS_A output from the transmission path decoding unit 401 is supplied to the deinterleaving unit 403 through the determination unit 402, and the TS packet TS_A is parallel to the determination unit 402 and the deinterleaving unit 403. The TS packet TS_A after deinterleaving by the deinterleaving unit 403 may be determined by the determining unit 402, or the normality / abnormality determination of the TS packet TS_B may be performed.

  Further, TS packets TS_A and TS_B may be broadcast using a plurality of segments of an OFDM signal of terrestrial digital television broadcasting. In that case, each TS packet may be transmitted in a separate segment group, or may be transmitted in the same segment group.

  Also, the description has been made on the assumption that the TS packets TS_A and TS_B are exactly the same data. However, one TS packet TS_A transmits video and audio, and the other TS packet TS_B transmits only audio. For example, a method of complementing only the data, or a method of reducing the amount of information by reducing the image size of the other TS packet TS_B relative to the TS packet TS_A or increasing the compression rate can be considered.

  The method of reducing the amount of information may be effective when, for example, the radio wave condition is stabilized and the frequency at which the radio wave is interrupted is drastically reduced with the spread of digital terrestrial broadcasting. If the situation where the radio wave condition is stable continues, the transmission of the other TS packet TS_B may be canceled and the transmission may be shifted to the transmission of only one TS packet TS_A.

  FIG. 8 shows a block diagram of a second embodiment of the transport stream switching method of the present invention. Here, an explanation will be given by taking an example of broadcasting for a portable receiver using one segment of an OFDM signal of terrestrial digital television broadcasting.

  In the figure, in the transmission system 600, each of video, audio, and data is encoded by the information source encoding unit 601 and then multiplexed by the multiplexing unit 602 to be a TS signal and supplied to the branching device 603. .

  The branching unit 603 branches the TS signal into three branches, one of which is supplied as a TS packet TS_A to the transmission path encoding unit 604, and the other two are supplied to the delay unit 605. The delay unit 605 delays each of the two TS signals by a delay time τ1, supplies one of them as a TS packet TS_B to the transmission line encoding unit 604, and supplies the other to the interleaving unit 606. The interleaving unit 606 interleaves the TS signal delayed by the delay time τ1, and supplies the TS signal to the transmission line coding unit 604 as a TS packet TS_C. Interleaving section 606 changes the order of TS packets in units of blocks. For example, when one block is composed of three TS packets and arranged in the order of TS packets X1, X2, and X3, the blocks are rearranged in the order of TS packets X3, X1, and X2. Note that the number of TS packets constituting one block may be two or more, but is, for example, the number of packets corresponding to several milliseconds to several minutes.

  The transmission path encoding unit 604 performs transmission path encoding on the TS packets TS_A, TS_B, and TS_C as the same segment of the OFDM signal of the terrestrial digital television broadcast, and modulates it into a transmission signal.

  In the receiving system 700, the transmission path decoding unit 701 receives a signal from the transmission path, and decodes the TS packet TS_A, TS packet TS_B, and TS packet TS_C from the received signal. The TS packet TS_A is determined by the determination unit 702 for normality / abnormality of the TS packet, and then delayed by the delay unit 703 by the delay time τ2 (τ2 = τ1−determination time of the determination unit 702). The TS packet TS_A ′ is supplied to the switching unit 705.

  The TS packet TS_B is supplied to the switching unit 705 as a TS packet TS_B through the synchronization unit 706. The TS packet TS_C is subjected to normality / abnormality determination of the TS packet by the determination unit 707, deinterleaved by the deinterleaving unit 708, and supplied to the switching unit 705 through the synchronization unit 709 as the TS packet TS_C ′. Note that deinterleaving is processing for rearranging TS packets C1, C2, and C3 in the order of TS packets C3, C1, and C2, and the deinterleaving processing time τ3 is greater than the delay time τ1. And

  The synchronizers 704, 706, and 709 are provided to absorb the delay time τ1 and the deinterleave processing time τ3 and perform switching accurately in units of packets, and operate with the same clock to perform TS packets TS_A ′, TS_B, TS_C ′. The synchronization between them is exactly the same. The switching unit 705 switches and selects any one of the TS packets TS_A ′, TS_B, TS_C ′ in units of TS packets based on the determination results of the determination units 702 and 707, and supplies the TS packet TS_D to the information source decoding unit 710. . The information source decoding unit 710 decodes video, audio, and data from the TS packet TS_D and supplies them to the subsequent viewing unit (not shown).

  9 shows a flowchart of the switching process performed by the switching unit 705, and FIG. 10 shows a signal timing chart in each unit of FIG. In FIG. 9, it is determined whether or not the delay time τ1 or more has elapsed since the start of viewing in step S21. If it is less than the delay time τ1, it is determined whether or not the deinterleaving processing time τ3 or more has elapsed since the start of viewing in step S22. If it is less than the deinterleaving processing time τ3, the TS packet TS_B is selected as the TS packet TS_D in step S23, and the process proceeds to step S21.

  On the other hand, if the interleave processing time τ3 or more has elapsed in step S22, it is determined in step S24 whether or not the determination result of the TS packet TS_C acquired after the start of viewing is normal. The deinterleaved TS packet TS_C ′ is selected as the TS packet TS_D, and the process proceeds to step S21. If the TS packet TS_C is not normal, the abnormal TS packet TS_C ′ deinterleaved in step S23 is switched to the TS packet TS_B and selected as the TS packet TS_D, and the process proceeds to step S21.

  Further, when the delay time τ1 or more has elapsed from the start of viewing in step S21, it is determined in step S27 whether or not the determination result of the TS packet TS_A acquired after the start of viewing is normal. The delayed TS packet TS_A ′ is selected as the TS packet TS_D, and the process proceeds to step S21. If the TS packet TS_A is not normal, the process proceeds to step S24.

  In FIG. 10, the TS packet TS_B is selected as the TS packet TS_D when the delay time τ1 is less than the viewing start time t21, and then the TS packet TS_C ′ is selected as the TS packet TS_D until the delay time τ3 elapses from the viewing start time t21. Thereafter, the TS packet TS_A ′ is selected as the TS packet TS_D.

  If there is an abnormality in the TS packet TS_A (A8, A12) between time t22 and t23, the switching unit 705 deinterleaves the TS packet at the timing (time t24, t25) at which the delayed abnormality TS packet TS_A ′ is obtained. It is determined whether or not TS_C ′ has an abnormality. When there is no abnormality, TS packet TS_C ′ is selected, and when there is an abnormality, TS packet TS_B is selected in units of TS packets. In the example of FIG. 10, since there is an abnormality in the deinterleaved TS packet TS_C ′, the TS packet TS_B is selected.

In this way, the TS packet TS_C ′ that could be normally received because the TS packet TS_A ′ that could not be normally received was interleaved.
Further, if this TS packet TS_C ′ cannot be normally received, the TS packet TS_B that can be normally received due to delay is switched, so that TS_D can be created with all normal packets.

  In this embodiment, the service interruption due to the influence of fading can be further reduced as compared with the embodiment of FIG.

  FIG. 11 shows a block diagram of a third embodiment of the transport stream switching method of the present invention. Here, an explanation will be given by taking an example of broadcasting for a portable receiver using one segment of an OFDM signal of terrestrial digital television broadcasting.

  In the figure, in the transmission system 800, each of video, audio, and data is encoded by the information source encoding unit 801, then multiplexed by the multiplexing unit 802 to be a TS signal, and supplied to the branching device 803. .

  The branching unit 803 bifurcates the TS signal, one is supplied as a TS packet TS_A to the transmission line coding unit 805, and the other is delayed by a delay time τ1 from the TS packet TS_A by the delay unit 804 as a TS packet TS_B. The data is supplied to the transmission path encoding unit 805. The transmission path encoding unit 805 performs transmission path encoding on the TS packets TS_A and TS_B as the same segment of the OFDM signal of the terrestrial digital television broadcast, and modulates it into a transmission signal.

  In the receiving system 900, the transmission path decoding unit 901 receives a signal from the transmission path, and decodes the TS packet TS_A and the delayed TS packet TS_B from the received signal. Each of the TS packets TS_A and TS_B is supplied to the switching unit 904.

  The switching unit 904 selects the TS packet TS_A at the start of viewing, and then manually switches to select the TS packet TS_B according to the operation of the receiving user, and the information source decoding unit 205 sets the selected TS packet as the TS packet TS_C. To supply. The information source decoding unit 205 decodes video, audio, and data from the TS packet TS_C and supplies them to the subsequent viewing unit (not shown).

  FIG. 12 shows a signal timing chart in each part of FIG. After the start of viewing, the TS packet TS_A without delay is selected as the TS packet TS_C. When the TS packet TS_A cannot be normally received in this state, when the switching unit 902 is manually switched, the delayed TS packet TS_B is selected as the TS packet TS_C. As a result, the receiving user can playback and view a scene that he / she missed without receiving. Note that the receiving user may manually switch the switching unit 902 when there is a scene that the user wants to view again.

  Thereafter, when it is determined that the receiving user has received unnecessary information, the switching operation of the switching unit 902 is performed, and the transition from the delayed TS packet TS_B to the selection of the TS packet TS_A is performed again. Back viewing is possible.

  When the delay time τ1 of the delay unit 804 is short, a delay unit 904 that further delays the TS packet TS_B output from the transmission path decoding unit 901 and supplies it to the switching unit 904 is provided as shown in FIG. Also good.

  The deinterleaving units 403 and 708 correspond to the deinterleaving unit described in the claims, the determination units 402, 702, and 707 correspond to the determination unit, and the switching units 405, 705, and 902 correspond to the switching unit.

It is a block diagram of the reference example of the transport stream switching method of this invention. It is a flowchart of the switching process which the switch part 205 performs. It is a signal timing chart in each part of FIG. It is a block diagram of 1st Embodiment of the transport stream switching method of this invention. It is a flowchart of the switching process which the switch part 405 performs. 5 is a signal timing chart in each part of FIG. 4. It is a block diagram of the modification of 1st Embodiment of the transport stream switching method of this invention. It is a block diagram of 2nd Embodiment of the transport stream switching method of this invention. It is a flowchart of the switching process which the switch part 705 performs. It is a signal timing chart in each part of FIG. It is a block diagram of 3rd Embodiment of the transport stream switching method of this invention. It is a signal timing chart in each part of FIG. It is a block diagram of the modification of 3rd Embodiment of the transport stream switching method of this invention.

Explanation of symbols

300, 600, 800 Transmission system 301, 601, 801 Information source coding unit 302, 602, 802 Multiplexing unit 303, 603, 803 Branch device 304, 606 Interleaving unit 305, 604, 805 Transmission path coding unit 400, 700 , 900 Receiving system 401, 701, 901 Transmission path decoding unit 402, 702, 707 Judgment unit 403, 708 Deinterleaving unit 404, 406, 704, 706, 709 Synchronization unit 405, 705, 902 Switching unit 407, 710, 903 Information Source decoding section 310, 410, 605, 703, 804, 904 Delay section

Claims (5)

A first transport stream, a second transport stream obtained by delaying the first transport stream by a predetermined time, and a third transport stream obtained by interleaving the second transport stream are multiplexed and transmitted.
A first transport stream separated from a received signal and delayed by the predetermined time, a second transport stream separated from the received signal, and a third transport stream separated from the received signal and deinterleaved A transport stream switching method comprising switching and outputting based on normal / abnormal determination results of the first and third transport streams. A signal transmitted by multiplexing a first transport stream, a second transport stream obtained by delaying the first transport stream by a predetermined time, and a third transport stream obtained by interleaving the second transport stream. A receiving device for receiving
Delay means for delaying the first transport stream separated from the received signal by the predetermined time;
Deinterleaving means for deinterleaving the third transport stream that has been interleaved separated from the received signal;
Determining means for determining normality / abnormality of the first and third transport streams;
The first transport stream from the delay unit, the second transport stream separated from the received signal, and the third transport stream from the deinterleave unit are switched and output based on the determination result of the determination unit. A receiving apparatus comprising switching means. A receiving device that receives a signal transmitted by multiplexing an interleaved first transport stream and a second transport stream that is the same as or a part of the first transport stream and that is not interleaved. And
Deinterleaving means for deinterleaving the first transport stream that has been interleaved separated from the received signal;
Determination means for performing normality / abnormality determination of the first transport stream or the second transport stream separated from the received signal;
Switching means for switching and outputting the first transport stream from the deinterleave means and the second transport stream separated from the received signal based on the determination result of the determination means;
The second transport stream is a part of the content of the first transport stream;
The switching device switches the first transport stream from the first transport stream to the second transport stream when the first transport stream is not normal, and outputs the second transport stream. Means for delaying the first transport stream by a predetermined time and outputting the second transport stream;
Means for interleaving the second transport stream to output a third transport stream;
A transmission apparatus comprising: means for multiplexing and transmitting the first transport stream, the second transport stream, and the third transport stream. The first transport stream delayed after interleaving and the second transport stream not interleaved with the same or a part of the contents of the first transport stream are transmitted,
The first transport stream separated from the received signal and deinterleaved and the second transport stream separated from the received signal and delayed are based on the normal / abnormal judgment result of the first or second transport stream. A transport stream switching method characterized by switching and transmitting.

Images