JP2005102053A - Video display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a broadband broadcast correspondent receiver capable of outputting received TS data to a DEMUX AV decoder unit so as to satisfy the limitation of an audio buffer amount and a video buffer amount in the DEMUX AV decoder unit. <P>SOLUTION: The broadband broadcast correspondent receiver is provided with an output controller which outputs the TS data received from a contents server to the DEMUX AV decoder unit by a method which holds the TS data, continuously transmits data of the number of required packets in the held TS data to the DEMUX AV decoder unit and subsequently sleeps for a fixed period of time. The output controller is provided with the number of packets correcting means for correcting the number of packets to be continuously outputted to the DEMUX AV decoder unit whenever the DEMUX AV decoder unit receives a PCR (program clock reference). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a receiver compatible with broadband broadcasting.

  In conventional digital broadcast receivers that receive digital BS broadcasts, there is no particular need for adjustment to input TS transmitted from the satellite to the DEMUX / AV decoder unit, so the transmitted data is used as it is in the DEMUX / AV decoder unit. To enter. When using a digital BS broadcast dedicated DEMUX / AV decoder unit to input a TS via the network to the DEMUX / AV decoder unit, the interval at which TS is sent due to network line delays, etc. is not constant. TS cannot be input to the DEMUX / AV decoder unit in the same way as digital BS broadcasting.

Japanese Patent Application Laid-Open No. 08-297602

  The present invention outputs received TS data to a DEMUX / AV decoder unit so as to satisfy the limitations on the audio buffer amount and video buffer amount in the DEMUX / AV decoder unit even when the TS reception interval is not constant. An object is to provide a receiver compatible with broadband broadcasting that can be used.

  The invention according to claim 1 comprises a content server and a broadband broadcast compatible receiver connected to the content server via a network, and the content server is requested when content is requested from the broadband broadcast compatible receiver. DEMUX / AV decoder for extracting and decoding content from TS data in a broadband broadcast compatible receiver in a broadband broadcast transmission / reception system having a function of supplying a TS corresponding to the received content to the broadband broadcast compatible receiver Holds TS data received from the unit and the content server, and continuously sends the required number of packets of the held TS data to the DEMUX / AV decoder unit, and then sleeps for a certain period of time. An output control device that outputs TS data to the DEMUX / AV decoder unit, and the output control device is connected to the DEMUX / AV decoder unit every time PCR is received by the DEMUX / AV decoder unit. A packet number correcting means for correcting the number of packets to be output is provided.

  According to a second aspect of the present invention, in the broadband broadcast-compatible receiver according to the first aspect, a basic counter whose count value is updated by a clock having a predetermined frequency is provided in the DEMUX / AV decoder unit. Each time the PCR is received by the DEMUX / AV decoder unit, the packet number correcting means performs a difference between the count value of the basic counter at the previous reception of the PCR and the count value of the basic counter at the current reception of the PCR. From this, the value obtained by subtracting the difference between the STC value in the PCR at the previous reception of the PCR and the STC value in the PCR at the current reception of the PCR is calculated, and based on the obtained value, the DEMUX / AV decoder unit It is intended to correct the number of packets output continuously.

  According to the present invention, even when the TS reception interval is not constant, the received TS data is output to the DEMUX / AV decoder unit so as to satisfy the limitations of the audio buffer amount and the video buffer amount in the DEMUX / AV decoder unit. It becomes possible to do.

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

  FIG. 1 shows the configuration of a broadband broadcast system.

  A content server 1 and a client (a broadband broadcast receiver) 3 are connected via the Internet 2. The server 1 is prepared with TS (transport stream) content. The client 3 displays a client substrate 11 provided with a DEMUX / AV decoder unit 23 (see FIG. 2) for extracting and decoding AV data from the TS sent from the content server 1 and the received content. The display TV 12 is provided. When the client 3 requests content from the content server 1, the content server 1 supplies the client 3 with a TS corresponding to the requested content.

  FIG. 2 shows the flow of TS data on the client board 11.

  The TS data distributed from the content server 1 is received via the Ethernet (registered trademark) port 21 and stored in the buffer 22 a in the output control device 22. The output control device 22 outputs the TS stored in the buffer 22 a to the DEMUX / AV decoder unit 23 by performing TS output control as will be described later. The DEMUX / AV decoder unit 23 extracts AV data from the input TS, decodes it, and sends it to the display TV 12.

  FIG. 3 shows a TS output control processing procedure by the output control device 22.

  It is assumed that TS data input to the output control device 22 is accumulated in a buffer 22a in the output control device 22. It is assumed that the bit rate B [bps] is stored in advance in the main memory in the output control device 22.

  When reception of TS data is started, the bit rate B [bps] stored in the main memory is acquired (step 1). Then, based on the following equation (1), from the acquired bit rate B [bps], the number of packets N [pkt] for the preset sleep time X [s], that is, DEMUX within X [s] Calculate the number of packets N [pkt] to be output to the AV decoder unit 23 (step 2).

  N = (X × B) / (188 × 8) (1)

  Here, it is assumed that TS data is transmitted in packet units of 188 bytes (188 × 8 bits). N shall be rounded off to the nearest decimal place.

  Next, from the TS data stored in the buffer 22a, the number of packets corresponding to the number N of packets calculated in step 2 is output to the DEMUX / AV decoder unit 23 (step 3). Then, sleep for X [s] (step 4). Next, based on the packet sent to the DEMUX / AV decoder unit 23 in step 3, it is determined whether or not a PCR (program clock reference) has been received by the DEMUX / AV decoder unit 23 (step 5). In this embodiment, when the DEMUX / AV decoder unit 23 receives the PCR, the DEMUX / AV decoder unit 23 sends the received PCR to the output control device 22. Therefore, the output control device 22 It can be determined whether or not a PCR is received by the AV decoder unit 23.

  PCR refers to information for setting an STC value as a time reference (reference synchronization information) to a value intended on the encoder side in a decoder of the MPEG system, at a rate of once per a plurality of packets. It is written in the adaptation field in the TS header.

  If no PCR is received by the DEMUX / AV decoder unit 23, the process returns to Step 3. That is, from the start of TS reception until the DEMUX / AV decoder unit 23 receives the first PCR, the processes in steps 3 to 5 are repeated.

  When the first PCR is received by the DEMUX / AV decoder unit 23 (YES in step 5), the STC value in the received PCR is loaded into the basic counter BC in the DEMUX / AV decoder unit 23, and the basic counter BC is loaded. Is started (step 6). At this time, the STC value in the PCR and the count value of the basic counter BC (hereinafter referred to as the STC value in the BC) are acquired. Thereafter, the basic counter BC performs a count operation with a 90 kH clock. That is, when the basic counter BC is activated, the count value is updated every 1/90 k [s].

  Next, the DEMUX / AV decoder unit 23 determines whether or not the next PCR has been received (step 7). When the next PCR is not received by the DEMUX / AV decoder unit 23, the number of packets corresponding to the number N of packets is output to the DEMUX / AV decoder unit 23 (step 12). Then, it sleeps for X [s] (step 13). Then, it is determined whether or not transmission of all packets to be received this time to the DEMUX / AV decoder unit 23 has been completed (packet end) (step 14). If transmission of all packets to be received this time to the DEMUX / AV decoder unit 23 has not been completed, the process returns to step 7. If it is determined in step 14 that transmission of all packets to be received this time to the DEMUX / AV decoder unit 23 has been completed, the current processing is terminated.

  If it is determined in step 7 that the next PCR has been received by the DEMUX / AV decoder unit 23, the processing (steps 8 to 11) is performed to correct the number N of packets to be output to the DEMUX / AV decoder unit 23. Transition.

  That is, first, the STC value in the current BC (the STC value in the BC when the PCR is currently received) and the STC value in the PCR received this time are acquired (step 8). The difference ΔBC between the STC value in the BC at the previous reception of the PCR and the STC value in the BC at the current reception of the PCR, the STC value in the PCR at the previous reception of the PCR, and the PCR at the current reception of the PCR A difference ΔPCR from the STC value is obtained (step 9).

  Then, the correction packet number K is obtained from the difference Dk (Dk = ΔBC−ΔPCR) between ΔBC and ΔPCR (step 10).

  The correction packet number K [pkt] is calculated based on the following equation (2).

  K = (Dk × B) / (188 × 8 × 90k) (2)

  K shall be rounded off to the nearest decimal place.

  Next, N is updated to a value of N + K (step 11). Then, the process proceeds to step 12.

  The reason why the number N of packets is corrected in steps 8 to 11 will be described. If such correction is not performed, an error occurs compared to packet transmission adapted to the bit rate B. There are various factors that cause this error. One of them is an error caused by rounding the number N of transmission packets. For example, if N = 6.33 before rounding, N = 6 after rounding. In such a case, if a packet is output to the DEMUX / AV decoder unit 23 with N = 6, the audio buffer and video buffer in the DEMUX / AV decoder unit will underflow.

  For example, if N = 6.55 before rounding, N = 7 after rounding. In such a case, if the packet is output to the DEMUX / AV decoder unit 23 with N = 7, the audio buffer and video buffer in the DEMUX / AV decoder unit overflow. Another possible cause of the error is a delay in reading the BC register when a high priority task operates.

  Due to the cause of such an error, a difference occurs between ΔBC and ΔPCR. For example, if N = 6.33 before rounding and N = 6 by rounding, if N = 6 and the packet is output to the DEMUX / AV decoder unit 23, ΔBC> ΔPCR. Since Dk> 0, N is increased.

It is a block diagram which shows the structure of a broadband broadcast system. 3 is a block diagram showing a flow of TS data on the client substrate 11. FIG. 4 is a flowchart showing a TS output control processing procedure by the output control device 22.

Explanation of symbols

1 Content Server 2 Internet 3 Client 11 Client Board 12 Display TV
21 Ethernet (registered trademark) port 22 Output control device 22a Buffer 23 DEMUX / AV decoder unit

Claims (2)

A content server and a broadband broadcast-compatible receiver connected to the content server via a network. When the content server requests content from the broadband broadcast-compatible receiver, the content server sends a TS corresponding to the requested content to the TS A DEMUX / AV decoder unit for extracting and decoding content from TS data and a TS received from a content server in a broadband broadcast compatible receiver in a broadband broadcast transmission / reception system having a function of supplying to a broadband broadcast compatible receiver The TS data is stored in a manner such that the data is held and the required number of packets of the held TS data is continuously sent to the DEMUX / AV decoder unit and then sleeps for a predetermined time. An output control device that outputs to the UX / AV decoder unit is provided. The output control device corrects the number of packets that are continuously output to the DEMUX / AV decoder unit each time a PCR is received by the DEMUX / AV decoder unit. A broadband broadcast-compatible receiver, characterized in that it comprises a packet number correcting means. In the DEMUX / AV decoder unit, a basic counter whose count value is updated by a clock having a predetermined frequency is provided. Further, from the difference between the count value of the basic counter at the previous reception of the PCR and the count value of the basic counter at the current reception of the PCR, the STC value in the PCR at the previous reception of the PCR and the PCR at the current reception of the PCR 2. A value obtained by subtracting a difference from the STC value of the first step is calculated, and based on the obtained value, the number of packets continuously output to the DEMUX / AV decoder unit is corrected. The listed broadband broadcast receiver.

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