JP2008288791A - Data receiving and reproducing apparatus, and data receiving and reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decode and reproduce data without using decoding start time information by providing only one STC control mechanism and generating an STC for each of two or more pieces of broadcasting data. <P>SOLUTION: The data receiving and reproducing apparatus includes: an oscillator 132 whose oscillation frequency is adjusted on the basis of control signals CS; a counter 14 for outputting a counter value by the oscillation frequency; packet reception parts 11a-11c for receiving the broadcasting data and the counter value and outputting the broadcasting data, a PCR value and the counter value when receiving a PCR packet; a PCR information management part 12 for calculating and storing a difference value between the PCR value and the counter value when receiving the PCR packet which are outputted from the packet reception parts, generating and outputting the control signals CS based on the variation of the difference value, adding the counter value and the difference value and generating and outputting a corrected counter value; and a data reproducing part 2 for reproducing the broadcasting data outputted from the packet reception parts on the basis of the corrected counter value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a data reception / playback apparatus and a data reception / playback method.

  In digital broadcasting that transmits and receives digitally, broadcast data is transmitted as a packet sequence in the MPEG-2 TS (transport stream) format defined by ISO / IEC13818-2.

  In order to synchronize the time between the transmitter (encoder) and the receiver (decoder), the transmitter transmits information for setting a time reference called PCR (Program Clock Reference) as one of packet data. To do. The receiver uses this PCR value to set an STC (System Time Clock) serving as a reference for the decoding process and the reproduction process.

In order to set this STC, the receiver is equipped with a PLL circuit (phase synchronization circuit) including an STC counter as described in ISO / IEC13818-2 Annex D, and each time a PCR is received, the value of the STC counter is PCR by controlling to match the values it is performed STC control for synchronizing the time reference of the transmitter time reference of the receiver.

  When simultaneously receiving and reproducing a plurality of broadcast data, it is necessary to mount the same number of PLL circuits (STC control mechanisms) as the number of broadcast data received simultaneously. There has been a problem that etc. increase.

  In order to solve such a problem, a difference value between a reference time (PCR) included in each stream of a plurality of received image encoded data and a counter value of an STC counter counted up by a system time clock is held. The system time clock is adjusted based on the difference between the stored difference value and the added value of the counter value and the PCR, and the added value and decoding start time information (DTS: Decoding Time Stamp) in each bit stream A multi-channel decoding method for decoding encoded image data based on the comparison result is proposed (see, for example, Patent Document 1). Thereby, a plurality of encoded image data can be decoded by one STC counter.

However, since the conventional method as described above requires decoding start time information at the time of data decoding, decoding of encoded data that does not include or hardly includes decoding start time information. It is difficult to do.
Japanese Patent No. 3538033

  The present invention provides a data receiving / reproducing apparatus that has only one STC control mechanism, generates an STC for each of a plurality of broadcast data, and can decode and reproduce data without using decoding start time information, and An object of the present invention is to provide a data reception / playback method.

  A data receiving / reproducing apparatus according to an aspect of the present invention performs a count based on a reference STC control unit including an oscillator whose oscillation frequency is adjusted based on a control signal, and the oscillation frequency output from the reference STC control unit. A reference STC counter that outputs a counter value, and the encoded data and the counter value output from the reference STC counter, respectively, and the encoded data, the reference time included in the encoded data, and the reference time A plurality of packet receivers that output the counter value when received, and a difference value between the reference time output from the plurality of packet receivers and the counter value when the reference time is received, respectively. And storing the control signal based on a variation in the difference value for at least one of the plurality of packet receiving units. A PCR information management unit that generates and outputs a correction counter value by adding one of the difference values and the counter value output from the reference STC counter, and outputs from the plurality of packet reception units And a data reproduction unit that reproduces the corresponding encoded data based on the correction counter value output from the PCR information management unit.

  A data reception / reproduction method according to an aspect of the present invention includes a data reception / reproduction device including a reference STC control unit including an oscillator, a reference STC counter, a plurality of packet reception units, a PCR information management unit, and a data reproduction unit. The reference STC control unit adjusts the oscillation frequency of the oscillator based on a control signal, the reference STC counter counts based on the oscillation frequency, outputs a counter value, and the plurality of packets The reception unit receives the encoded data and the counter value, respectively, outputs the encoded data, the reference time included in the encoded data, and the counter value when the reference time is received, and the PCR information management unit Is the difference between the reference time output from the plurality of packet receivers and the counter value when the reference time is received Is calculated and stored, and the control signal is generated and output based on the variation of the difference value for at least one of the plurality of packet receivers, and is corrected by adding the counter value and the difference value A counter value is generated and output, and the data reproduction unit receives the encoded data output from the plurality of packet receivers and the correction counter value output from the PCR information management unit, and the correction counter value The corresponding encoded data is reproduced based on the above.

  According to the present invention, it is possible to have only one STC control mechanism, generate an STC for each of a plurality of broadcast data, and perform data decoding and reproduction without using decoding start time information.

  Hereinafter, a data reception / playback apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a data reception / playback apparatus according to an embodiment of the present invention. The data reception / playback apparatus includes a broadcast data processing unit 1 and a broadcast data playback unit 2. The data receiving / reproducing apparatus can receive and reproduce a plurality of broadcast data, and here, as an example, it is assumed that three types of broadcast data D1 to D3 are received. The data reception / playback apparatus according to the present embodiment performs STC control using reference time information (PCR) included in one of a plurality of broadcast data, and a time (STC) serving as a reference for playback processing corresponding to each broadcast data. ).

  Usually, the time accuracy on the broadcast data transmission side (broadcast station side) is extremely high, and drift and jitter when comparing PCRs generated from different transmission sources can be ignored. Therefore, even if STC control is performed using only the PCR included in one broadcast data among the plurality of received broadcast data, the plurality of broadcast data can be reproduced at the correct timing.

  An example of transmitted broadcast data is shown in FIG. Encoded moving image data, audio data, and the like are stored in a packet and transmitted. This packet is sometimes called a TS packet, and the continuation of the packet becomes a transport stream. For example, the packet P1 includes moving image data, the packet P2 includes audio data, the packet P3 includes data unnecessary for reproduction, and the packet P4 includes reference time information (PCR). Each packet includes information called a packet identifier (PID) for indicating what is being transmitted. A PMT (Program Map Table) storing PID information for each data such as image data and audio data is called a PMT (Program Map Table), and a packet having a PMT like a packet P5 is also transmitted.

  The broadcast data processing unit 1 includes packet receiving units 11a to 11c, a PCR information management unit 12, a reference STC control unit 13, and a reference STC counter 14.

  The packet receiving units 11a to 11c receive and store broadcast data D1 to D3, which are packet strings, respectively. Further, the counter value of the reference STC counter 14 (reference STC counter value) when each packet is received is stored. Then, it is determined whether or not the received packet is a packet including PCR.

  Whether or not the packet includes a PCR is determined based on the PID included in each packet. The packet receivers 11 a to 11 c transmit the received packet PIDs to the PCR information manager 12. The PCR information management unit 12 has the PID information of the PCR packet that each of the broadcast data D1 to D3 has, and whether or not the PID received from the packet receiving units 11a to 11c matches the PID indicating the PCR packet. The packet receivers 11a to 11c are notified. When the packet receivers 11a to 11c receive the notification that they match, the PCR is included in the received packet, so the PCR value included in the packet and the reference STC counter value when the packet is received, Is transmitted to the PCR information management unit 12.

  Broadcast data D1 to D3 received by the packet receivers 11a to 11c are output to the broadcast data reproducing unit 2, and data reproduction is performed. Note that the broadcast data includes NULL data unnecessary for reproduction such as the packet P3 shown in FIG. 2, but this NULL data may be discarded by the packet receivers 11a to 11c.

  The PCR information management unit 12 holds PID information of PCR packets included in the broadcast data D1 to D3, respectively. The PID information is given from the broadcast data reproduction unit 2. Also, the PCR value received by each of the packet receiving units 11a to 11c and the reference STC counter value when the packet including the PCR value is received are given, and the difference value (PCR difference value = PCR value−reference STC counter value). ) Is calculated and stored.

  Further, the control signal CS based on the variation value between any one of the PCR receiving values of the packet receiving units 11 a to 11 c and the previously held PCR differential value is generated and output to the reference STC control unit 13. Further, in response to a request from the broadcast data reproducing unit 2, a correction counter value that is an addition value of the reference STC counter value and the held PCR difference value is output. The broadcast data reproduction unit 2 uses this correction counter value as the STC, and reproduces the corresponding broadcast data based on the correction counter value (STC).

  An example of information held in the PCR information management unit 12 is shown in FIG. This indicates that STC control is performed using the PCR value included in the broadcast data D2. Further, the PID of the PCR packet included in the broadcast data D1 is 100, and the difference value (PCR difference value) between the PCR value and the reference STC counter value is 35800. Similarly, the PIDs of the PCR packets included in the broadcast data D2 and D3 are 190 and 150, respectively, and the PCR difference values are 3 and −1535, respectively.

  For example, when the STC (correction counter value) for the broadcast data D1 is requested from the broadcast data reproduction unit 2, the PCR information management unit 12 corrects the reference STC counter value and the PCR difference value (35800). The counter value is output to the broadcast data reproducing unit 2.

  The reference STC control unit 13 has a low-pass filter 131 and a voltage controlled oscillator (VCO) 132, and is supplied with an internal clock of the data receiving / reproducing apparatus. A control signal CS output from the PCR information management unit 12 is provided to the voltage controlled oscillator 132 via the low pass filter 131. The control signal CS is based on the fluctuation value of the PCR difference value, and includes the past fluctuation value component by passing through the low-pass filter 131. The voltage controlled oscillator 132 adjusts the oscillation frequency based on the control signal CS that has passed through the low pass filter 131. For example, when the fluctuation value of the PCR difference value is a negative value and the control signal CS indicates that the clock frequency of the reference STC counter 14 is faster than the broadcast data transmission side, the oscillation frequency of the voltage controlled oscillator 132 is lowered. . On the contrary, when the fluctuation value of the PCR difference value is a positive value and the control signal CS indicates that the clock frequency of the reference STC counter 14 is slower than the broadcast data transmission side, the oscillation frequency of the voltage controlled oscillator 132 is increased. .

  The reference STC counter 14 counts based on the oscillation frequency of the voltage controlled oscillator 132 and outputs a counter value (reference STC counter value) to the packet receiving units 11 a to 11 c and the PCR information management unit 12.

  As described above, the PCR information management unit 12, the low-pass filter 131 and the voltage control oscillator 132 included in the reference STC control unit 13, and the reference STC counter 14 constitute a PLL circuit that performs STC control.

  The broadcast data reproduction unit 2 extracts the PID of the PCR packet from the PMT included in each of the broadcast data D1 to D3 and gives it to the PCR information management unit 12. In addition, an STC value corresponding to broadcast data to be reproduced is requested from the PCR information management unit 12 and received from the PCR information management unit 12. This STC value is output from the PCR information management unit 12 as a correction counter value. The broadcast data playback unit 2 performs broadcast data playback processing (decoding, etc.) based on this correction counter value, and outputs it to a display, a speaker, or the like.

  An example of the STC control method will be described with reference to FIGS. In this example, it is assumed that the broadcast data processing unit 1 receives three pieces of broadcast data D1 to D3 at the same time. Further, it is assumed that the reference STC counter 14 is initialized and is in a free-run state synchronized with the internal clock. For convenience of explanation, it is assumed that the count-up frequency in the free-run state is 1 kHz, the transmitter side clock of the broadcast data D1 to D3 is 1 kHz, and the packet reception interval of the broadcast data D1 to D3 is constant and 10 ms. The PCR information storage unit 12 has three broadcast data to be received, performs STC control using the PCR included in the broadcast data D2, and the PID of the PCR packet included in each broadcast data. It is assumed that it is set in advance.

  An example of broadcast data reception at a certain timing is shown in FIG. The counter value of the reference STC counter 14 is 800. As for the difference value (PCR difference value) between the PCR value included in each of the broadcast data D1 to D3 and the counter value of the reference STC counter 14, 200 is stored in the PCR information management unit 12 for the data D2, and the data D1, D3 is not set.

  For the broadcast data D1, the packet receiver 11a has received a NULL packet. The PCR packet P11 having a PCR value of 500 is received four packets ahead, that is, 40 ms later.

  For broadcast data D2, the packet receiver 11b has just received the PCR packet P12, and its PCR value is 1000. The packet receiving unit 11b transmits the PID included in the packet P12 to the PCR information management unit 12, and receives a notification that it is a PCR packet. Based on this notification, the packet receiving unit 11b outputs the PCR value (1000) and the counter value (800) of the reference STC counter 14 to the PCR information managing unit 12, and the PCR information managing unit 12 outputs the difference value (1000-800). = 200) is calculated and stored. Also, a fluctuation value (200−200 = 0) with the previously stored PCR difference value (200) is calculated, and a control signal CS based on this fluctuation value is output to the STC control unit 13. Further, the PCR packet P14 having a PCR value of 1060 is received six packets ahead, that is, 60 ms later.

  As for the broadcast data D3, the packet receiving unit 11c has received a packet including moving image data. The PCR packet P13 with a PCR value of 200 is received one packet ahead, that is, 10 ms later.

  FIG. 5 shows broadcast data reception 10 ms after the timing shown in FIG. Since the count-up frequency of the reference STC counter 14 is 1 kHz, the reference STC counter value is 810.

  The packet receiving unit 11c receives the PCR packet P13 having the PCR value 200. The packet receiving unit 11c transmits the PID included in the packet P13 to the PCR information management unit 12, and receives a notification that it is a PCR packet. Based on this notification, the packet receiver 11c outputs the PCR value and the reference STC counter value (810) to the PCR information manager 12. The PCR information management unit 12 calculates and stores the PCR difference value (200−810 = −610).

  FIG. 6 shows broadcast data reception 30 ms after the timing shown in FIG. Since the count-up frequency of the reference STC counter 14 is 1 kHz, the reference STC counter value is 840.

  The packet receiving unit 11a receives the PCR packet P11 having the PCR value 500. The packet receiving unit 11a transmits the PID included in the packet P11 to the PCR information management unit 12, and receives a notification that it is a PCR packet. Based on this notification, the packet reception unit 11a outputs the PCR value and the reference STC counter value (840) to the PCR information management unit 12. The PCR information management unit 12 calculates and stores the PCR difference value (500−840 = −340).

  FIG. 7 shows broadcast data reception 20 ms after the timing shown in FIG. Since the count-up frequency of the reference STC counter 14 is 1 kHz, the reference STC counter value is 860.

  The packet receiving unit 11b receives the PCR packet P14 having the PCR value 1060. The packet receiving unit 11b transmits the PID included in the packet P14 to the PCR information management unit 12, and receives a notification that it is a PCR packet. Based on this notification, the packet reception unit 11b outputs the PCR value and the reference STC counter value (860) to the PCR information management unit 12. The PCR information management unit 12 calculates and stores the PCR difference value (1060−860 = 200). Also, a fluctuation value (200−200 = 0) with the PCR difference value (200) that has already been stored is calculated, and a control signal based on this fluctuation value is output to the STC control unit 13.

  The above example is a case where the transmission side and the reception side of broadcast data operate at the same clock frequency, and there is no deviation in the clock. However, a shift may occur due to drift or jitter. In the case of jitter, if STC control by a PLL is performed as in the present embodiment, the PLL is locked (synchronized), so that the reception side clock is synchronized with the transmission side clock, so that there is no problem. On the other hand, in the case of drift, there is a difference between the reference STC counter value and the received PCR value until the PLL is locked.

  As an example, a case where the frequency of the receiving clock is slow at the timing shown in FIG. 7 will be described with reference to FIG. At this time, the counter value of the reference STC counter 14 is assumed to be 859.

  The packet receiving unit 11b receives the PCR packet P14 having the PCR value 1060. The packet receiving unit 11b transmits the PID included in the packet P14 to the PCR information management unit 12, and receives a notification that it is a PCR packet. Based on this notification, the packet receiving unit 11b outputs the PCR value and the reference STC counter value (859) to the PCR information management unit 12. The PCR information management unit 12 calculates and stores the PCR difference value (1060-859 = 201). Further, a fluctuation value (201−200 = 1) with respect to the difference value (200) already stored is calculated, and a control signal CS based on the fluctuation value is output to the STC control unit 13.

  Further, the fluctuation value (1) is added to the PCR difference value (−340) of the broadcast data D1 and the PCR difference value (−610) of the broadcast data D3 to replace the respective PCR difference values. That is, the PCR difference value of the broadcast data D1 is −339, and the PCR difference value of the broadcast data D3 is −609.

  The STC control unit 13 performs STC control based on the control signal CS. In this case, since the fluctuation value is a positive value, that is, the frequency of the reception side clock is slow, control is performed so as to increase the oscillation frequency of the voltage controlled oscillator 132 included in the STC control unit 13.

  When the STC value is requested from the broadcast data reproducing unit 2, the PCR information management unit 12 adds the reference STC counter value and the PCR difference value for the broadcast data for which the STC value is requested, and the added value (correction counter). Value) is output to the broadcast data reproduction unit 2.

  For example, when the broadcast data reproduction unit 2 performs reproduction processing of the broadcast data D1, the STC value (correction counter value) output from the PCR information management unit 12 at the timing shown in FIG. 8 is 859 + (− 339) = 520. . The broadcast data reproduction unit 2 outputs from the PCR information management unit 12 a display time stamp (PTS: Presentation Time Stamp) defined for each piece of moving image data and audio data received from the packet reception unit 11a. When it becomes equal to the STC value (correction counter value), it is reproduced and output.

  In this way, using the PCR value included in one of a plurality of broadcast data received at the same time, STC control is performed for each broadcast data, and the transmission clock and the reception clock of the broadcast data are synchronized. Can do. Also, the decoding start time information is not required for performing STC control and data reproduction processing.

  The data reception / playback apparatus according to the present embodiment can have only one STC control mechanism, generate an STC for each of a plurality of broadcast data, and decode and play back the data without using the decoding start time information.

  Each of the above-described embodiments is an example and should be considered not restrictive. For example, the reference STC counter 14 in the above embodiment may write the PCR value when the packet receiving unit 11 receives the PCR value included in the broadcast data used for the reference STC control for the first time. In this case, the PCR difference value for the broadcast data used for STC control stored in the PCR information management unit 12 is always 0 unless a clock frequency shift due to drift or the like occurs.

  Alternatively, the broadcast data reproduction unit 2 may store the user's viewing frequency for each broadcast data, and STC control may be performed using the PCR value included in the broadcast data with the highest frequency of viewing by the user. .

  In the above embodiment, STC control is performed using a PCR value included in one of a plurality of broadcast data. However, STC control may be performed using a PCR value included in a plurality of broadcast data. As shown in FIG. 9, it is assumed that the data reception / playback apparatus receives three types of broadcast data D1 to D3, and each PCR packet is transmitted in the order of broadcast data D2, D1, and D3.

  First, the packet receiving unit 11b receives the PCR packet P91 included in the broadcast data D2, and the PCR information difference between the reference STC counter value and the PCR value of the PCR packet P91 (PCR difference value Dif2) is stored in the PCR information management unit 12. A control signal CS based on the variation value of the PCR difference value Dif2 and the PCR difference value Dif2 stored so far is output from the PCR information management unit 12 to the reference STC control unit 13. Based on the control signal CS, the oscillation frequency of the voltage controlled oscillator 132 in the reference STC control unit 13 is controlled.

  Next, the packet reception unit 11a receives the PCR packet P92 included in the broadcast data D1, and the PCR information difference between the reference STC counter value and the PCR value of the PCR packet P92 (PCR difference value Dif1) is stored in the PCR information management unit 12. . A control signal CS based on the variation value of the PCR difference value Dif1 and the PCR difference value Dif1 stored so far is output from the PCR information management unit 12 to the reference STC control unit 13. Based on the control signal CS, the oscillation frequency of the voltage controlled oscillator 132 in the reference STC control unit 13 is controlled.

  Next, the packet receiving unit 11c receives the PCR packet P93 included in the broadcast data D3, and the PCR information difference between the reference STC counter value and the PCR value of the PCR packet P93 (PCR difference value Dif3) is stored in the PCR information management unit 12. . A control signal CS based on the variation value of the PCR difference value Dif3 and the PCR difference value Dif3 stored so far is output from the PCR information management unit 12 to the reference STC control unit 13. Based on the control signal CS, the oscillation frequency of the voltage controlled oscillator 132 in the reference STC control unit 13 is controlled.

  By using PCR values included in a plurality of broadcast data in this way, the appearance frequency of PCR packets increases, and the time required until the reference STC counter 14 converges can be shortened.

  In the above embodiment, the PCR information management unit 12 calculates and stores the PCR difference value for each broadcast data. However, each packet reception unit 11 may calculate and store the difference value. In this case, the PID information of the PCR packet output from the data reproducing unit 2 is directly given to the packet receiving unit 11 or is given via the PCR information management unit 12. As a result, the packet receiving unit 11 can determine whether or not PCR information is included in the packet. The packet receiving unit 11 calculates and stores a difference value between the reference STC counter value and the PCR value when the PCR packet is received. The PCR information management unit 12 extracts the PCR difference value for the broadcast data for which the STC value is requested from the broadcast data reproduction unit 2 from the packet reception unit, adds it to the reference STC counter value, and outputs it to the broadcast data reproduction unit 2 . Further, when the packet receiving unit 11 receives a PCR packet and calculates a new PCR difference value, the packet receiving unit 11 calculates a variation value from the previously stored PCR difference value and outputs the variation value to the PCR information management unit 12. To do. The PCR information management unit 12 generates a control signal CS based on the fluctuation value and outputs the control signal CS to the STC control unit 13.

  In the above embodiment, the number of broadcast data to be received is three, but the number may be other than three, and it is only necessary to have the same number of packet receiving units as the number of broadcast data to be received.

  The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic configuration diagram of a data reception / playback apparatus according to an embodiment of the present invention. It is a figure which shows an example of broadcast data. It is a figure which shows an example of the information hold | maintained at a PCR information management part. It is a figure which shows an example of broadcast data reception. It is a figure which shows an example of broadcast data reception. It is a figure which shows an example of broadcast data reception. It is a figure which shows an example of broadcast data reception. It is a figure which shows an example of broadcast data reception. It is a figure which shows an example of broadcast data reception.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Broadcast data processing part 2 Broadcast data reproduction | regeneration parts 11a-11c Packet receiving part 12 PCR information management part 13 Reference | standard STC control part 14 Reference | standard STC counter

Claims (5)

A reference STC control unit including an oscillator whose oscillation frequency is adjusted based on a control signal;
A reference STC counter that counts based on the oscillation frequency output from the reference STC control unit and outputs a counter value;
A plurality of receiving units for receiving the encoded data and the counter value output from the reference STC counter, and outputting the encoded data, a reference time included in the encoded data, and the counter value when the reference time is received; The packet receiver of
A difference value between the reference time output from the plurality of packet reception units and the counter value when the reference time is received is calculated and stored, and at least one of the plurality of packet reception units PCR information that generates and outputs the control signal based on the variation of the difference value, and generates and outputs a correction counter value by adding any of the difference values and the counter value output from the reference STC counter The management department,
The encoded data output from the plurality of packet receiving units is input, and a data reproducing unit that reproduces the corresponding encoded data based on the correction counter value output from the PCR information management unit;
A data receiving / reproducing apparatus comprising:   The data reproduction unit detects the encoded data with the highest reproduction frequency, and the PCR information management unit is output from the packet reception unit that outputs the encoded data with the highest reproduction frequency based on the detection result. The data receiving / reproducing apparatus according to claim 1, wherein the control signal is generated and output based on a change in a difference value between the reference time and the counter value when the reference time is received.   The encoded data includes a plurality of packets each having an identifier attached thereto, the packet receiving unit outputs the identifier to the PCR information management unit, and the PCR information management unit applies the reference to the packet based on the identifier. It is determined whether the time is included, and the determination result is notified to the packet reception unit, and the packet reception unit outputs the reference time and the counter value when the reference time is received based on the notification The data receiving / reproducing apparatus according to claim 1 or 2.   4. The data receiving / reproducing apparatus according to claim 1, wherein when the predetermined packet receiving unit first receives the reference time, the reference time is written in the reference STC counter. A data reception / reproduction method using a data reception / reproduction device having a reference STC control unit including an oscillator, a reference STC counter, a plurality of packet reception units, a PCR information management unit, and a data reproduction unit,
The reference STC control unit adjusts the oscillation frequency of the oscillator based on a control signal,
The reference STC counter performs counting based on the oscillation frequency, and outputs a counter value;
The plurality of packet receivers respectively receive the encoded data and the counter value, and output the encoded data, the reference time included in the encoded data and the counter value when the reference time is received,
The PCR information management unit calculates and stores a difference value between the reference time output from the plurality of packet reception units and the counter value when the reference time is received, and among the plurality of packet reception units Generating and outputting the control signal based on a change in the difference value for at least one, generating and outputting a correction counter value by adding the counter value and the difference value, and
The data reproduction unit receives the encoded data output from the plurality of packet receivers and the correction counter value output from the PCR information management unit, and the corresponding encoded data based on the correction counter value Receiving and playing back data.

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