JP2008236667A - Digital broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To record video/audio content data so as to stably play back the video/audio content data recorded on a DSM. <P>SOLUTION: A digital broadcast receiver comprises: receiving means 8, 3, 10 for outputting an MPEG-TS; data extracting means 5, 10 for extracting a program map table (PMT) corresponding to a receiving channel and extracting content data contained in a predetermined channel on the basis of the PMT; a layer transmission determining means 9a for determining whether the channel is layer transmission broadcast or not; a generation means 9b for separating a PID within the PMT to a higher-layer side and a lower-layer side in a case where it is determined that the channel is layer transmission broadcast, newly generating a higher-layer PMT describing the separated higher-layer side PID and a lower-layer PMT describing the lower-layer side PID and generating a new-layer program association table (PAT) for specifying these PMTs; and a digital data output means 11 in which the layer PAT, the higher-layer PMT, the lower-layer PMT and the respective content data are multiplexed and outputted to the outside. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a digital broadcast receiving apparatus that receives a broadcast signal from a broadcast station.

  In digital broadcasting, a plurality of video / audio content data compressed by the MPEG2 system is multiplexed and transmitted as a transport stream (hereinafter referred to as TS) together with additional information such as program information.

  In a general digital broadcast receiver, the video / audio content data of a specific channel desired by the user is selected from the multiplexed TS and MPEG-decoded to give the user an analog video / audio. Present.

  On the other hand, digital storage media (hereinafter referred to as DSM) that can directly record digital video / audio content data compressed by the MPEG2 system on a digital VCR, a hard disk, or the like are in widespread use. Therefore, if the audio / video content data transmitted using the DSM is recorded in the state of digital data, it can be recorded more efficiently and without deterioration in image quality than in the case of recording with an analog VCR. Further, additional information such as program information, which is a feature of digital broadcasting, can be recorded at the same time, so that the information can be used even during reproduction.

  Here, the data rate of the digital stream that can be recorded in the DSM is often smaller than the TS rate of digital broadcasting. In addition, the information included in the TS of the broadcast wave includes information depending on the broadcasting method such as conditional access information and network information, and these information becomes unnecessary at the time of reproduction after being stored in the DSM. There are many cases.

  Therefore, in a digital broadcast receiver having a digital interface that outputs a digital stream to the DSM, or a digital broadcast receiver having a built-in DSM, the transmission rate of the recorded digital stream is reduced, and information that is not required at the time of playback is obtained. In order to delete, it is necessary to reconfigure the TS by selecting only information related to a specific channel and performing necessary packet editing. This reconstructed TS is referred to as a partial TS.

  In BS digital broadcasting, hierarchical transmission is performed for the purpose of reducing the interruption time of broadcasting due to rain attenuation. The BS digital broadcasting transmission line coding method can be used in combination with switching of the transmission method, transmits high-resolution content data with a modulation method that is weak in signal degradation but fast in transmission speed, and the transmission speed is slow but the signal is low. Content data can be transmitted by combining transmission methods such as transmitting low-resolution content data with a modulation method that is strong against deterioration.

  Therefore, on the broadcast station side, high-resolution video content data is transmitted by TC8PSK (trellis-encoded 8-phase phase modulation) capable of transmitting a large volume, and BPSK (two-phase phase shift) that can be received even at low C / N. Hierarchical transmission is often performed in such a manner that low-resolution video content data is transmitted by the method.

  FIG. 5 is a conceptual explanatory diagram for explaining a configuration of a hierarchically transmitted TS. In the example of TS shown in FIG. 5, channel 1 and channel 2 are included, and channel 1 transmits high-level video content data for transmitting high-resolution video content data and low-resolution video content data. Hierarchical transmission is performed with low-layer transmission.

  A TS is composed of a transport packet having a fixed length of 188 bytes. This transport packet includes, in addition to video content data and audio content data, which channel audio / video content data is transmitted to which transport packet in the TS. PSI (Program Specific Information) data indicating whether it is stored is also stored.

  Although not shown, a packet identifier (PID) in the header portion of each transport packet indicates the type of data included in the payload portion of the transport packet.

  In the PSI, PMT (Program Map Table) in which data related to content included in a specific channel is described as a PID list of a transport packet transmitting the content data, and information on all channels included in the TS Is a PAT (Program Association Table) described in the form of a PMT PID list.

  As shown in FIG. 5, the PAT packet 21 stores the PID “100” of the PMT of channel 1 and the PID “200” of the PMT of channel 2. The PMT 1 for channel 1 shown in the PMT packet 22 includes the PID “101” of the video content data “V1-1” for the high hierarchy and the PID “103” of the audio content data “A1-1” for the high hierarchy. The PID of the four content data, that is, the PID “102” of the video content data “V1-2” for the low hierarchy and the PID “104” of the audio content data “A1-2” for the low hierarchy is stored.

  Then, as shown in the data packet 24 of FIG. 5, the video content data for the higher hierarchy is stored in the transport packet “V1-1”, and the transport packet for the higher hierarchy is stored in the transport packet “A1-1”. Audio content data is stored, low-level video content data is stored in the “V1-2” transport packet, and low-level audio content data is stored in the “A1-2” transport packet. The

  FIG. 6 is an explanatory diagram showing an example of a TS in which a transport packet is configured by the configuration shown in FIG.

  In FIG. 6, a transport packet including an n-channel PAT is indicated by “PATn”. For example, a transport packet including a PMT of channel 1 is indicated by “PMT1”. Similarly, “V1-1” is a transport packet including video content data for high hierarchy of channel 1 and “A1-1” is a transport packet including audio content data for high hierarchy of channel 1. A transport packet including video content data for one lower layer is indicated by “V1-2”, and a transport packet including audio content data for lower layer of channel 1 is indicated by “A1-2”.

  For example, when content data transmitted in a hierarchical manner is received by a digital broadcast receiver described in Patent Document 1, in the case of high C / N, high-resolution content data modulated by TC8PSK is selected. To decode and output the decoded video. When the content data of TC8PSK modulation cannot be decoded due to strong rain attenuation, it is automatically switched to output low-resolution content data modulated by BPSK.

  FIG. 7 is an explanatory diagram showing a configuration of a partial TS generated by a digital broadcast receiver described in Patent Document 1 from a hierarchically transmitted TS.

  As shown in FIG. 7, when a high C / N ratio can be secured, a PSI for high-layer transmission is generated. When a high C / N ratio cannot be secured, a PSI for low-layer transmission is generated. Generated and configured a partial TS.

  Specifically, as shown in FIG. 7, at high C / N, the PID “100” of the PMT of channel 1 is stored in the PAT packet 31. The PMT 1 for channel 1 shown in the PMT packet 32 includes the PID “101” of the video content data “V1-1” for the high hierarchy and the PID “103” of the audio content data “A1-1” for the high hierarchy. Remembered. Then, as shown in the data packet 33, the video content data for the high hierarchy is stored in the transport packet “V1-1”, and the audio content data for the high hierarchy is stored in the transport packet “A1-1”. Is memorized.

  On the other hand, at low C / N, the PID “100” of the PMT of channel 1 is stored in the PAT packet 34. The PMT 1 for channel 1 shown in the PMT packet 35 includes the PID “102” of the video content data “V1-2” for the lower layer and the PID “104” of the audio content data “A1-2” for the lower layer. Remembered. As shown in the data packet 36, the video content data for the lower hierarchy is stored in the transport packet “V1-2”, and the audio content data for the lower hierarchy is stored in the transport packet “A1-2”. Is memorized.

  FIG. 8A is an explanatory diagram showing an example of a partial TS generated at the time of high C / N, and FIG. 8B shows an example of the partial TS generated at the time of low C / N. FIG.

In the digital broadcast receiver described in Patent Document 1, when a high C / N ratio can be secured, a PSI for high-layer transmission as shown in FIG. When it cannot be secured, switching is performed so as to generate a PSI for low-layer transmission as shown in FIG.
JP 2006-41976 A

  However, in the digital broadcast receiver described in Patent Document 1, if the C / N ratio fluctuates during hierarchical transmission, a service interruption that is not short when switching between high-resolution content data and low-resolution content data occurs. . Further, when the C / N ratio is unstable, switching between high resolution content data and low resolution content data may occur frequently.

  Since the timing of this switching depends on the C / N ratio, the user cannot freely select it and is recorded in the DSM under the situation where the C / N ratio fluctuates as described above. The video / audio content data may be switched at a timing not intended by the user, which makes it difficult for the user to view.

  The present invention has been made in view of the above problems, and even if it is video / audio content data recorded in a DSM under a situation where the C / N ratio is fluctuating, the content is a content that has been broadcast in a hierarchical transmission manner. In such a case, it is an object of the present invention to provide a digital broadcast receiving apparatus capable of recording video / audio content data so that at least content on the lower layer side can be stably reproduced.

  In order to achieve the above object, a first feature of a digital broadcast receiving apparatus according to the present invention is a receiving means for receiving a digital broadcast wave including a predetermined channel to be set and outputting MPEG-TS, and MPEG-TS. Data for extracting and identifying the PMT corresponding to this channel based on the PAT included in the channel and the channel information of the predetermined channel, and extracting the content data included in the predetermined channel based on the extracted PMT A hierarchical transmission determination unit that determines whether or not a predetermined channel is a channel of a hierarchical transmission broadcast having two layers, a high layer and a low layer, based on the PMT extracted by the extraction unit and the data extraction unit; If the hierarchical transmission determination means determines that the channel is a hierarchical transmission broadcast channel, each content data described in the extracted PMT is displayed. The PID for identifying the content data on the higher hierarchy side and the PID for identifying the content data on the lower hierarchy side are separated, and the PID for identifying the separated content data on the higher hierarchy side is described. A high-level PMT and a low-level PMT that describes a PID for specifying content data on the lower level are newly generated, and a new PID for specifying the two newly generated PMTs is described There is provided a generation unit that newly generates a layer PAT, a layer PAT, a high layer PMT, a low layer PMT, and a digital data output unit that multiplexes and outputs each content data to the outside.

  According to the digital broadcast receiving apparatus according to the present invention, even if the audio / video content data is recorded in the DSM under the situation where the C / N ratio is fluctuating, the content is the content that has been broadcast by hierarchical transmission. In this case, the video / audio content data can be recorded so that at least the content on the lower hierarchy side is stably reproduced.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of an embodiment of a digital broadcast receiving apparatus for carrying out the present invention.

  As shown in FIG. 1, a digital broadcast receiving apparatus 1 according to the present embodiment includes an antenna 2, a network interface module 3, a descrambler 4, an MPEG_TS demultiplexer 5 that is data extraction means, an MPEG decoder 6, The OSD superimposing circuit unit 7, the channel selection unit 8, the hierarchical transmission determination unit 9 a, the generation unit 9 b, and the digital signal output unit 11 are provided.

  The network interface module 3 has transmission system signal processing functions such as tuner, digital demodulation, error correction, etc., receives digital broadcast waves from the antenna 2, and conforms to the MPEG standard in which PSI is added to video / audio content data. As a transport stream (hereinafter referred to as TS).

  The descrambler 4 descrambles the TS supplied from the network interface module 3 according to an instruction from the control unit 10.

  The MPEG_TS demultiplexer 5 specifies and extracts the PMT corresponding to this channel based on the PAT included in the TS compliant with the MPEG standard and the channel information of the predetermined channel, based on the instruction of the control unit 10, and this extraction Based on the PMT, video / audio content data included in a predetermined channel is extracted.

  The MPEG decoder 6 decodes the video / audio content data supplied from the MPEG_TS demultiplexer 5 and outputs each of the video content data and the audio content data.

  The OSD superimposing circuit unit 7 superimposes and displays a menu screen for initial setting, a program name of a currently viewed channel, an electronic program guide, and the like on the video content data.

  The channel selection unit 8 selects one of the channels included in the TS as a channel selection channel according to an instruction from the control unit 10.

  Based on the PMT extracted by the MPEG_TS demultiplexer 5, the hierarchical transmission determination means 9a determines whether or not the predetermined channel is a hierarchical transmission broadcast channel having two layers, a high layer and a low layer.

  When the generation means 9b determines that the channel is a layer transmission broadcast channel by the layer transmission determination means 9a, the generation means 9b uses the PID for specifying each content data described in the extracted PMT as the content data on the higher layer side. Is separated into PID for identifying the content data on the lower layer side and PID for identifying the content data on the lower layer side, and the PMT for high layer describing the PID for identifying the separated content data on the higher layer side and the content data on the lower layer side are identified. A new lower layer PMT describing the PID to be generated is generated, and a new layer PAT describing the PID for specifying the two newly generated PMTs is generated.

  The digital signal output unit 11 re-multiplexes the video / audio content data extracted by the MPEG_TS demultiplexer 5 and the high-layer PMT, the low-layer PMT, and the layer PAT generated as described above and outputs them to the outside.

  The control unit 10 plays a central role in the digital broadcast receiving apparatus 1 and controls the entire digital broadcast receiving apparatus 1.

<Action>
Below, the process sequence of the digital broadcast receiver 1 which is this embodiment is demonstrated.

  FIG. 2 is a flowchart showing a processing procedure of the digital broadcast receiving apparatus 1 according to the present embodiment.

  First, when receiving a recording request signal for recording a partial TS in a DSM such as a recording reservation signal, the control unit 10 of the digital broadcast receiving apparatus 1 according to the present embodiment transmits a channel selection signal of the corresponding channel to the channel selection unit 8. To do.

  Thereafter, the MPEG_TS demultiplexer 5 extracts the PMT of the channel selected by the channel selection unit 8 from the TS supplied by the instruction of the control unit 10 (step S101). Then, the hierarchical transmission determination means 9a receives the PMT extracted by the MPEG_TS demultiplexer 5, and determines whether the broadcast of the selected channel is hierarchically transmitted based on the received PMT (step S102).

  Specifically, the hierarchical transmission identifier is searched from the extracted PMT, and if the hierarchical transmission identifier exists, it is determined that the broadcast of the selected channel is hierarchically transmitted.

  Next, when it is determined that the broadcast of the selected channel is not hierarchically transmitted, the hierarchical transmission determination unit 9a generates a partial TS as a channel that is not hierarchically transmitted (step S103).

  If the hierarchical transmission determination means 9a determines that the broadcast of the selected channel is being hierarchically transmitted, the generation means 9b generates a PMT for high-layer transmission that transmits high-resolution video content data (step S104). . Specifically, referring to the contents of the hierarchical transmission descriptor described in the PMT, the transport packet including the content data for high-layer transmission is specified, and the high-layer transmission is performed from the description of the PMT extracted from the TS. The information about the content data for use is extracted, and a PMT for high-layer transmission is newly generated.

  Next, the generation unit 9b generates a PMT for low-layer transmission that transmits low-resolution video content data (step S105). Specifically, referring to the contents of the hierarchical transmission descriptor described in the PMT, the transport packet including the content data for the lower hierarchical transmission is specified, and the lower hierarchical transmission is performed from the PMT description extracted from the TS. The information regarding the content data for use is extracted, and a PMT for low-layer transmission is newly generated.

  Then, the generation unit 9b generates PAT and SIT based on both information of the PMT for higher layer transmission generated in step S104 and the PMT for lower layer transmission generated in step S105 (step S104). S106).

  Next, the digital signal output unit 11 includes the PAT and SIT generated in step S106, the PMT for high layer transmission generated in step S104, the PMT for low layer transmission generated in step S105, It is multiplexed from the video / audio content data supplied by the MPEG_TS demultiplexer 5 to generate a new partial TS and output it to the DSM recording apparatus.

  FIG. 3 is an explanatory diagram showing the configuration of the partial TS generated by the digital broadcast receiving apparatus 1 according to the present embodiment from the hierarchically transmitted TS.

  As shown in FIG. 3, it is reconfigured as a partial TS so as to include both high-layer content data and low-layer content data.

  Specifically, the PAT packet 41 describes the PID “110” of the PMT for channel 1 high-layer transmission and the PID “120” of the PMT for channel 1 low-layer transmission.

  The PMT 1-1 for high-layer transmission for channel 1 shown in the PMT packet 42 includes the PID “101” of the video content data “V1-1” for high layer and the audio content data “A1-1” for high layer. "PID" 103 "is stored. As shown in the data packet 43, high-level video content data is stored in the transport packet “V1-1”, and high-level audio content data is stored in the transport packet “A1-1”. Is memorized.

  The PMT 1-2 for low-layer transmission for channel 1 shown in the PMT packet 44 includes the PID “102” of the video content data “V1-2” for low-layer and the audio content data “A1” for high-layer. -2 "is stored. As shown in the data packet 45, the video content data for the lower hierarchy is stored in the transport packet “V1-2”, and the audio content data for the lower hierarchy is stored in the transport packet “A1-2”. Is memorized.

  FIG. 4 is an explanatory diagram showing an example of a partial TS generated by the digital broadcast receiving apparatus 1 according to the present embodiment from a hierarchically transmitted TS.

  Based on the configuration of the partial TS shown in FIG. 3, a partial TS as shown in FIG. 4 is generated.

  Thus, according to the digital broadcast receiving apparatus 1 according to the present embodiment, the partial TS is reconfigured so as to include both the high-level content and the low-level content data. Therefore, when the DSM in which the partial TS is recorded is reproduced, it can be set so that either the high-level content data or the low-level content data can be selected by the user.

  Thus, when playing back a DSM recorded under a situation where the C / N ratio is unstable, if the user selects low-level video / audio content data that is resistant to signal degradation during transmission, the user can It is possible to view low-level content stably.

It is a block diagram which shows the structure of one Embodiment of the digital broadcast receiver for implementing this invention. It is the flowchart which showed the process sequence of the digital broadcast receiver which is this embodiment. It is explanatory drawing which showed the structure of the partial TS produced | generated by the digital broadcast receiver which concerns on this embodiment from TS transmitted hierarchically. It is explanatory drawing which showed an example of the partial TS produced | generated by the digital broadcast receiver which concerns on this embodiment from TS transmitted hierarchically. It is a conceptual explanatory drawing explaining the structure of TS transmitted hierarchically. It is explanatory drawing which showed an example of TS transmitted hierarchically. It is explanatory drawing which showed the structure of the partial TS produced | generated by the digital broadcasting receiver which is a prior art from TS transmitted hierarchically. (A) is explanatory drawing which showed an example of the partial TS produced | generated at the time of high C / N by the digital broadcasting receiver which is a prior art, (b) is the partial TS produced | generated at the time of low C / N. It is explanatory drawing which showed an example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Digital broadcast receiver 2 ... Antenna 3 ... Network interface module 4 ... Descrambler 5 ... MPEG_TS demultiplexer (data extraction means)
DESCRIPTION OF SYMBOLS 6 ... MPEG decoder 7 ... OSD superimposition circuit part 8 ... Channel selection part 9a ... Hierarchical transmission judgment means 9b ... Generation means 10 ... Control part 11 ... Digital signal output part (digital data output means)

Claims (1)

Program information data including PAT and PMT and content data, which is at least one of video data and audio data, in conformity with the MPEG standard included in the received channel are transmitted via a digital interface. In a digital broadcast receiving device having a function of outputting to the outside,
Receiving means for receiving a digital broadcast wave including a predetermined channel to be set and outputting MPEG-TS;
Based on the PAT included in the MPEG-TS and the channel information of the predetermined channel, the PMT corresponding to the channel is specified and extracted, and the PMT included in the predetermined channel is extracted based on the extracted PMT. Data extraction means for extracting content data;
Hierarchical transmission determination means for determining whether or not the predetermined channel is a channel for hierarchical transmission broadcasting having two hierarchies, a high hierarchy and a low hierarchy, based on the PMT extracted by the data extraction means;
When it is determined by the hierarchical transmission determining means that the channel is a hierarchical transmission broadcast channel, the PID for specifying each content data described in the extracted PMT is specified, and the content data on the higher hierarchy side is specified. The PID is separated into a PID that specifies content data on the lower layer side, and a PMT for high layer that describes the PID that specifies the separated content data on the higher layer side, and a PID that specifies the content data on the lower layer side A generation unit for newly generating the described lower layer PMT, and for newly generating a layer PAT describing a new PID for specifying the two newly generated PMTs;
Digital data output means for multiplexing the PAT for the hierarchy, the PMT for the high hierarchy, the PMT for the low hierarchy, and the content data and outputting the multiplexed data to the outside;
A digital broadcast receiver characterized by comprising:

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