JP2007180702A - Digital broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly switch between a strong hierarchical layer and a weak hierarchical layer by timing video output and audio output to each other when hierarchically transmitted signals are received and output by switching between the strong hierarchical layer and the weak hierarchical layer. <P>SOLUTION: A digital broadcast receiver includes a strong hierarchical layer buffer section which temporarily stores video and audio signals of the strong hierarchical layer, a weak hierarchical layer buffer section which temporarily stores video and audio signals of the weak hierarchical layer, a strong hierarchical layer decoding section which decodes the video and audio signals of the strong hierarchical layer, a weak hierarchical layer decoding section which decodes the video and audio signals of the weak hierarchical layer, and an output control section which controls buffering amount to time output from the strong hierarchical layer buffer section and output from the weak hierarchical layer buffer section to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a digital broadcast receiving apparatus, and more particularly to a digital broadcast receiving apparatus that receives a hierarchically transmitted broadcast.

  In digital broadcasting, hierarchical transmission in which one transport stream is transmitted using a plurality of transmission methods is used. In terrestrial digital broadcasting, it is possible to simultaneously transmit up to three layers composed of one or more segments, and in order of increasing required CN ratio due to differences in transmission channel coding schemes, It is called a weak hierarchy. The weaker the hierarchy, the higher the quality of data that can be transmitted, but the lower the reception stability. The stronger the hierarchy, the higher the quality of data that cannot be transmitted, but the higher the reception stability.

In digital broadcast receivers that receive broadcasts that have been transmitted hierarchically, when the reception level of the broadcast signal decreases, the video and audio are switched according to the reception status, such as switching from the weaker layer to the stronger layer and outputting video and audio. Can be output. An apparatus for switching the hierarchy and outputting video / audio is described in Patent Document 1 and the like.
JP 2003-274302 A

  Video and audio transmitted in the strong layer and weak layer are delayed by several seconds in the strong layer compared to the weak layer at the time of broadcast signal transmission. When audio is output, video / audio that is shifted by several seconds compared to before switching is output, which causes a problem in that the viewing user feels uncomfortable.

  In view of the above problems, an object of the present invention is to smoothly switch video / audio at the time of hierarchical switching by matching the output timing of video / audio of a weak hierarchy and a strong hierarchy.

  The digital broadcast receiving apparatus of the present invention includes a receiving unit that receives and demodulates a broadcast signal in which video / audio / data is encoded / multiplexed and modulated and transmitted hierarchically, and a desired signal from the signal demodulated by the receiving unit. A packet separation unit that extracts and separates signals of the above, a strong layer and a weak layer buffer unit that temporarily stores video signals and audio signals of the strong layer and weak layer from the packet separation unit, and the buffer unit Strong layer decoding unit and weak layer decoding unit for decoding temporarily stored video signal / audio signal, and output selection unit for selecting one of the strong layer decoding unit and the weak layer decoding unit Adjusting the buffer amount and controlling the selection of the output selection unit in order to match the output timings of the strong layer video signal / audio signal and the weak layer video signal / audio signal from the buffer unit. And an output control unit, characterized in that to adjust the output timing of the video signal and audio signal of strong hierarchy and weak hierarchy.

  The digital broadcast receiving apparatus of the present invention can synchronize the video and audio output timings of the weak hierarchy and the strong hierarchy, so that the video / audio output can be smoothly switched when the hierarchy is switched.

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

  FIG. 1 is a block diagram showing a first embodiment of a digital broadcast receiving apparatus according to the present invention. In FIG. 1, 100 is a digital broadcast receiving apparatus, 101 is an input terminal for a signal that is multiplexed and modulated with some video / audio / data, and is transmitted hierarchically, and 102 is a receiver that corrects errors generated during demodulation and transmission. , 103 is a packet separation unit for selectively extracting a desired video / audio / data signal from the multiplexed signal, 104 is a strong layer buffer unit for buffering a strong layer signal, and 105 is a coded strong layer. , 106 is a weak layer buffer unit for buffering weak layer signals, 107 is a weak layer decoder unit for decoding encoded weak layer signals, and 109 is a strong layer decoder unit 105. And an output selection unit 108 that selects one of the outputs of the weak layer decoding unit 107, and adjusts the buffer amounts of the strong layer buffer unit 104 and the weak layer buffer unit 106 Output control unit which together control the selection of the output selection unit 109, 110 is an output terminal for outputting a signal selected by the output selecting section 109.

The operation of the first embodiment will be described below. First, an operation example for matching the video / audio output timings of the strong layer signal and the weak layer signal will be described. A digital signal in which a plurality of information is multiplexed and transmitted hierarchically is input to the input terminal 101, and the receiving unit 102 demodulates the digital signal. The packet separation unit 103 extracts a strong layer video / audio signal and inputs it to the strong layer buffer unit 104, and extracts a weak layer video / audio signal and inputs it to the weak layer buffer unit 106. When the buffer of the strong layer buffer unit 104 becomes full, the video / audio signal is input to the strong layer decoding unit 105 and the video / audio is decoded. Similarly, when the buffer of the weak layer buffer unit 106 becomes full, the video / audio signal is input to the weak layer decoding unit 107 and the video / audio is decoded. The output control unit 108 sets the buffer amount of the weak layer buffer unit 106 to be a certain amount larger than the strong layer buffer unit 104 in order to adjust the delay of the strong layer video / audio with respect to the weak layer. . The video / audio signal selected by the output selection unit 109 is output to the output terminal 110. In this way, by adjusting the buffer amount of the video / audio signal, the output timing of the video / audio of the strong hierarchy and the weak hierarchy can be matched. As a result, even when the strong hierarchy and the weak hierarchy are switched and output, the video / audio can be smoothly switched.
In the above description, the strong layer buffer unit 104 and the weak layer buffer unit are provided and the output timing is adjusted. However, in some cases, the buffer amount is adjusted by one buffer unit and the signals of the strong layer and the weak layer are adjusted. It is also possible to adjust the output timing.

  FIG. 2 is a block diagram showing a second embodiment of the digital broadcast receiving apparatus according to the present invention. In FIG. 2, 100 is a digital broadcast receiving apparatus, 101 is an input terminal for signals that are multiplexed and modulated with several video / audio / data, and is transmitted hierarchically, and 102 is a receiver that corrects errors generated during demodulation and transmission. , 103 is a packet separation unit for selectively extracting a desired video / audio / data signal from the multiplexed signal, 104A and 104V are strong layer audio signals, and a strong layer buffer unit for buffering video signals, 105A, 105V is an encoded strong layer audio signal and a strong layer decoding unit that decodes a video signal, 106A and 106V are weak layer audio signals and a weak layer buffer unit that buffers the video signal, and 107A and 107V are encoded. The weak layer decoding unit 109 for decoding the weak layer audio signal and the video signal, and 109 is the audio signal of the strong layer decoding unit 105A and the weak layer decoding unit 107A. An output selection unit that selects one of the outputs and selects one of the video signals of the strong layer decoding unit 105V and the weak layer decoding unit 107V, and 108 is a strong layer buffer unit 104A, 104V and a weak layer buffer unit. The output control units 110 A and 110 V adjust the buffer amounts 106 A and 106 V and control the selection of the output selection unit 109. The output terminals 110 A and 110 V are output terminals for outputting the audio signal and video signal selected by the output selection unit 109.

  The operation of the second embodiment will be described below. First, an operation example for matching the output timings of the video signal and audio signal of the strong layer signal and the weak layer signal will be described. A digital signal in which a plurality of information is multiplexed and transmitted hierarchically is input to the input terminal 101, and the receiving unit 102 demodulates the digital signal. The packet separation unit 103 extracts strong layer audio signals and strong layer video signals and inputs them to the strong layer buffer units 104A and 104V, and extracts weak layer audio signals and weak layer video signals. Input to the weak hierarchy buffer units 106A and 106V. When the buffers of the strong layer buffers 104A and 104V are full, the strong layer video signal and the strong layer audio signal are input to the strong layer decoding units 105A and 105V, and the audio signal and the video signal are decoded. Similarly, when the buffers of the weak layer buffers 106A and 106V are full, the weak layer audio signals and the weak layer video signals are input to the weak layer decoders 107A and 107V, and the video and audio are decoded. . The output control unit 108 adjusts the buffer amount of the weak layer buffer units 106A and 106V to a fixed amount rather than the strong layer buffer units 104A and 104V in order to adjust the delay of the video signal and audio signal of the strong layer with respect to the weak layer. Set to increase. The video signal and audio signal selected by the output selection unit 109 are output to the output terminal 110. In this way, by adjusting the buffer amount of the video signal and the audio signal, it is possible to match the output timing of the video and audio of the strong hierarchy and the weak hierarchy. Thus, smooth switching is possible not only when switching between the strong hierarchy and the weak hierarchy and outputting, but also when switching to various combinations such as a strong hierarchy audio signal and a weak hierarchy video signal, for example.

  Next, as a third embodiment of the present invention, the operation of output selection switching after channel selection will be described. When the buffer amount of the video and audio of the weak layer is increased, it takes time until the buffer becomes full, so that there is a problem that it takes time until the video and audio of the weak layer starts to be output immediately after channel selection. For this reason, control is performed so that the video and audio of the strong hierarchy are output immediately after the channel selection, and the output is switched to the output of the weak hierarchy when the timing for outputting the video and audio of the weak hierarchy comes. First, immediately after channel selection, the output control unit 108 controls the output selection unit 109 so as to output a video / audio signal of a strong hierarchy. Thereafter, the output control unit 108 controls the output selection unit 109 to output a weak layer video / audio signal when detecting that the buffer of the weak layer buffer unit 106 becomes Full. In this way, it is possible to output the strong hierarchy video / audio immediately after channel selection, and switch to the weak hierarchy video / audio output when the output timing of the strong hierarchy matches the weak hierarchy.

In this way, by adjusting the video and audio buffer amounts of the strong and weak layers, the output timing of the strong and weak layers can be adjusted, and video and audio output can be performed when switching between the strong and weak layers. You can switch smoothly. Furthermore, by outputting the video and audio of a strong hierarchy immediately after the channel selection, the start of video / audio output can be presented without delay.
The above has described the operation of switching output selection after channel selection in the case of the first embodiment, but the switching operation after channel selection described above can be similarly applied to the case of the second embodiment.

  The operation of the fourth embodiment will be described below. This embodiment is different from the first embodiment in that the user can set the output timing adjustment of the strong hierarchy and the weak hierarchy. Others are the same as the first embodiment.

  FIG. 3 is a block diagram showing the fourth embodiment. The same means as those in the digital broadcast receiving apparatus shown in FIG. Reference numeral 201 denotes a user input terminal that receives an input from a user such as a remote control signal, and 202 denotes an output timing setting unit that displays an output timing adjustment screen and holds an output timing setting value selected by the user.

  The operation of the fourth embodiment will be described below. FIG. 4 is a display example of the output timing adjustment screen. On this adjustment screen 300, the user can select the video / audio output timing of the strong hierarchy and the weak hierarchy. The adjustment screen 300 is an example, and as another example, an adjustment screen in which an adjustment value can be set for each broadcasting station can be displayed.

  The operation when the video / audio output timing is controlled in accordance with the output timing set value selected by the user will be described. The output timing adjustment screen 300 is displayed, and a user operation is received from the user input terminal 201 by a remote control signal or the like. The setting value selected on the screen of the output timing adjustment screen 300 is held in the output timing setting unit 202. The output control unit 108 calculates from the transmission rate of the video / audio signal and the setting value held in the output timing setting unit 202, and the buffer amount of the weak layer buffer unit 106 is larger than the strong layer buffer unit 104. Set to increase. Other operations are the same as those in the first embodiment.

  In this way, by adjusting the video and audio buffer amounts of the strong and weak layers, the output timing of the strong and weak layers can be adjusted, and video and audio output can be performed when switching between the strong and weak layers. You can switch smoothly.

  The adjustment of the video and audio buffer amounts of the strong hierarchy and the weak hierarchy described above has been described with respect to the adjustment of the output timing of the strong hierarchy and the weak hierarchy in the first embodiment. The means for setting the output timing can also be applied when adjusting the output timings of the video signal and audio signal of the strong layer and the video signal and audio signal of the weak layer as in the second embodiment. .

1 is a block diagram showing a first embodiment of a digital broadcast receiving apparatus according to the present invention. It is a block diagram which shows 2nd Example of the digital broadcast receiver concerning this invention. It is a block diagram which shows 3rd Example of the digital broadcast receiver concerning this invention. It is a figure which shows the example of an output timing adjustment screen regarding 3rd Example of the digital broadcast receiver concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Digital broadcast receiver 101 Input part 102 Reception part 103 Packet separation part 104,104A, 104V Strong hierarchy buffer part 105,105A, 105V Strong hierarchy decoding part 106,106A, 106V Weak hierarchy buffer part 107,107A, 107V Weak hierarchy decoding Unit 108 output control unit 109 output selection unit 110, 110A, 110V output terminal 201 user input terminal 202 output timing setting unit 300 output timing adjustment screen

Claims (5)

A receiving unit for receiving and demodulating a broadcast signal in which video / audio / data is encoded / multiplexed and modulated and transmitted hierarchically;
A packet separator that extracts and separates a desired signal from the signal demodulated by the receiver;
Strong layer and weak layer buffer units for temporarily storing video signals and audio signals of strong layers and weak layers from the packet separation unit;
A strong layer decoding unit and a weak layer decoding unit for decoding the video signal / audio signal temporarily stored in the buffer unit;
An output selection unit for selecting one of the video signal / audio signal of the strong layer decoding unit and the weak layer decoding unit;
An output control unit that adjusts a buffer amount in order to match the output timing of the video signal / audio signal of the strong hierarchy and the video signal / audio signal of the weak hierarchy from the buffer unit, and controls the selection of the output selection unit; With
A digital broadcast receiver characterized by matching the output timing of video signals and audio signals of a strong hierarchy and a weak hierarchy. A receiving unit for receiving and demodulating a broadcast signal in which video / audio / data etc. are encoded / multiplexed and modulated and transmitted hierarchically;
A packet separation unit for extracting and separating a strong layer video signal and a strong layer audio signal, a weak layer video signal and a weak layer audio signal from the signal demodulated by the reception unit;
A strong layer video signal buffer unit and a strong layer audio signal buffer unit for temporarily storing the strong layer video signal and the strong layer audio signal from the packet separation unit;
A weak layer video signal buffer unit and a weak layer audio signal buffer unit for temporarily storing the weak layer video signal and the weak layer audio signal from the packet separation unit;
A strong layer video signal decoding unit and a strong layer audio signal decoding unit for decoding the video signal and the audio signal temporarily stored in the strong layer video signal buffer unit and the strong layer audio signal buffer unit;
A weak layer video signal decoding unit and a weak layer audio signal decoding unit for decoding the video signal and the audio signal temporarily stored in the weak layer video signal buffer unit and the weak layer audio signal buffer unit;
One video signal of the strong layer video signal decoding unit and the weak layer video signal decoding unit,
An output selection unit that selects one audio signal of the strong layer audio signal decoding unit and the weak layer audio signal decoding unit;
In order to match the output timings of the video signals from the strong layer video signal buffer unit and the weak layer video signal buffer unit and the audio signals from the strong layer audio signal buffer unit and the weak layer audio signal buffer unit, An output control unit for adjusting the buffer amount and controlling the selection of the output selection unit;
With
A digital broadcast receiver characterized in that the output timings of a video signal of a strong hierarchy and a weak hierarchy and an audio signal of a strong hierarchy and a weak hierarchy are matched. The digital broadcast receiver according to claim 1 or 2,
Immediately after the channel selection, the output selection unit is set to output a strong layer signal, and when the weak layer signal is buffered and the video signal / audio signal of the strong layer matches the output timing, A digital broadcast receiver characterized in that the output of an audio signal is switched to a video signal / audio signal of a weak hierarchy. The digital broadcast receiver according to any one of claims 1 to 3,
A digital broadcast receiver characterized in that a user can set output timing adjustment of video and audio of a strong hierarchy and a weak hierarchy. The digital broadcast receiver according to claim 4, wherein
For the output timing adjustment of the video and audio of the strong hierarchy and the weak hierarchy, the setting value selected by the user operation on the output timing adjustment screen is held in the output timing setting section,
The digital broadcast receiving apparatus, wherein the output control unit sets a buffer amount by calculating from a transmission rate of a video / audio signal and a setting value held in the output timing setting unit.

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