JP4792157B2 - Digital broadcast receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital broadcast receiving apparatus that receives a digital broadcast in which two or more hierarchical services exist in the same channel.
[0002]
[Prior art]
In recent years, in addition to television broadcasting using terrestrial waves, digital broadcasting services have been started and are becoming popular in satellite broadcasting using geostationary satellites and CATV (cable television).
[0003]
In this digital broadcasting, a moving picture compression coding technology such as MPEG2 (Moving Picture Image coding Experts Group phase 2) is adopted as a video coding method, and a plurality of MPEG image and audio data streams are multiplexed. Yes. The MPEG2 standard is well known and will not be described in detail, but this MPEG2 has a maximum transfer rate of 60 Mbit / s and is suitable for high-definition image quality of HDTV (High Definition TeleVision). It is a possible standard.
[0004]
For example, a digital broadcasting system using a geostationary satellite provides a plurality of television broadcast program signals compressed by a compression technique such as MPEG2 on one carrier (carrier wave) and provides a conventional terrestrial wave. The TV program broadcast can be performed in a mode different from the TV broadcast broadcast using.
[0005]
By the way, in digital broadcasting, weather and atmospheric conditions have a great influence on the reception situation. For example, when the thunderstorm or snowfall, the received radio wave intensity is weak, there is a risk that the image quality will deteriorate due to noise mixed in the video. A slight deterioration in image quality can be dealt with by error correction of the received signal, but if the reception quality is greatly deteriorated, error correction cannot be performed.
[0006]
As a coping means when such a reception state deteriorates, for example, “broadcast apparatus” disclosed in JP-A-9-107303 and “demodulation apparatus and demodulation method disclosed in JP-A-11-239192” Are proposed.
[0007]
The above-mentioned “broadcasting device” monitors the reception status of satellite broadcasting for digital music broadcasting in communication satellite broadcasting (CS (Communications Satellite) broadcasting), and if the reception status deteriorates, the broadcasting sound source is automatically selected. The sound source is switched to another system, the reception state is automatically monitored, and the satellite broadcast is switched again when the reception state is recovered.
[0008]
Also, the above-mentioned “demodulation device and demodulation method” relates to satellite broadcasting and CATV broadcasting, and automatically selects a demodulation method corresponding to a signal of a plurality of modulation methods, and a demodulation means capable of demodulating with a plurality of demodulation methods; Demodulation error detecting means for detecting a demodulation error based on the error of the received data, demodulation method determining means for determining the demodulation method according to the output of the demodulation error detecting means, and the demodulation means being determined by the demodulation method determining means And a demodulating means control means for performing a control for performing a demodulating operation by the demodulation method.
[0009]
[Problems to be solved by the invention]
The above-described conventional technology can be applied to a digital television broadcast receiving apparatus having two layers of a high layer video display and a low layer video display. That is, for example, as shown in the flowchart of FIG. 4, a channel is selected and received in step S200, and the presence or absence of a low-layer video is determined in step S201. If it is determined in step S201 that there is no low hierarchy video, the process proceeds to step S202, and high hierarchy video is output. On the other hand, if it is determined in step S201 that there is a low-level video, the process proceeds to step S203, where it is determined whether or not the reception sensitivity is equal to or higher than a specified value (for example, C / N 11 dB). In Yes), the high-level video is output in step S204, and if it is less than the specified value, the low-level video is output in step S205. Thereby, it is possible to automatically switch between high-level video display and low-level video display according to reception sensitivity (reception state).
[0010]
However, the feeling of deterioration in the quality of the displayed video due to the deterioration of the reception state often differs depending on the subjective and preference of the viewer of the television broadcast. It is considerably difficult to automatically switch the display at an appropriate timing.
[0011]
That is, in a state where the reception state has deteriorated to some extent, a certain viewer desires to “continue high-resolution and high-level display even if there is some noise or the like”. There is a case where it is desired to switch the display to a low resolution that does not contain noise, and it is very difficult to appropriately respond to these conflicting demands by the control method as described above.
[0012]
The present invention has been devised to solve the above-described problems, and provides a digital broadcast receiving apparatus that allows a viewer to arbitrarily select a video hierarchy when a reception state deteriorates in digital broadcasting. The purpose is to do.
[0013]
[Means for Solving the Problems]
To achieve the above object, a digital broadcast receiving apparatus according to the present invention is a digital broadcast receiving apparatus that receives a digital broadcast in which two or more hierarchical services exist in the same channel. Frequency tuning means (tuner pack 1) that extracts and outputs a selected channel, and hierarchical demodulation means (demodulation / demodulation / demodulation / demodulation / demodulation A decoding unit 2), and error correction rate determination means (Reed-Solomon decoding unit 5 and control device 30) for determining for each layer whether or not the error correction rate of the video signals of the two or more layers exceeds a predetermined value; When the error correction rate determination means determines that the error correction rate has exceeded a predetermined value, the parallel display for displaying the images of the respective layers in parallel on one screen Selection and stage (video synthesizing display processor 13), an error correction rate is determined to exceed the predetermined value, one of the images of each hierarchy which are displayed in parallel by the parallel display means by said error correction rate determination means And a hierarchy switching display means (control device 30) that can be output, and an input operation means capable of inputting a command for selection , wherein the hierarchy switching display means displays in response to a signal from the input operation means the screen to select one in which was switched so that.
[0014]
According to this, when the error correction rate of the video signal of one or more layers exceeds a predetermined value due to deterioration of the reception state or the like, the images of each layer are displayed in parallel on one screen, and the layer switching display means By operating, it is possible to select and output one of the videos of each layer, and it is possible to arbitrarily select and display image quality and resolution that meet the viewer's request.
[0015]
The two or more hierarchical services can be of two types, a high hierarchical display and a low hierarchical display. As a result, when the reception state is deteriorated, either the high hierarchy display or the low hierarchy display can be arbitrarily selected and displayed.
[0016]
The parallel display means can display the video of each layer as a still image or a frame advance image that updates the video every predetermined time. According to this, it is possible to perform parallel display of videos of each layer with relatively light processing, and to reduce the manufacturing cost.
[0017]
The parallel display means may display the video of each layer as a moving image. According to this, it is possible to more reliably grasp the degree of video degradation of each layer.
[0018]
Further, the predetermined value in the error correction rate determination means may be an error correction rate of 50%. Thereby, video selection can be performed when the reception state deteriorates to some extent.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings of FIGS.
[0020]
FIG. 1 is a block diagram showing an outline of the configuration and signal flow of the digital broadcast receiving apparatus according to this embodiment.
[0021]
In FIG. 1, first, for example, a satellite broadcast radio wave of 12 GHz band received by a BS antenna 20 constituted by a parabolic antenna or the like is transmitted to a 1 GHz band by an LNB (Low Noise Block downconverter) provided in the BS antenna 20. After the transport stream output signal TS is converted to an intermediate frequency signal, it is input to the tuner pack 1 of the digital broadcast receiver.
[0022]
The tuner pack 1 selects a frequency received from the transport stream output signal TS, performs quadrature detection, and outputs it to the demodulation / decoding unit 2. The demodulation / decoding unit 2 performs 8PSK (8 Phase Shift Keying) demodulation processing, QPSK (Quadrature Phase Shift Keying) demodulation processing, and BPSK (Binary Phase Shift Keying: binary PSK) processing on the signal. To the deinterleave unit 4.
[0023]
Here, 8PSK is a digital modulation method used for BS digital broadcasting, and higher transmission efficiency can be obtained than QPSK method used for CS digital broadcasting. QPSK is a digital modulation method used for CS digital broadcasting currently being broadcast. Note that PSK is a phase modulation method for transmitting information using the phase of a carrier wave (a high-frequency signal for transmitting information), and the 8PSK indicates that the number of phases used is eight. Yes. Also, transmission of 3 bits in 8PSK, 2 bits in 4PSK (QPSK), and 1 bit in 2PSK (BPSK) is possible. Incidentally, in the current BS digital broadcasting, a time division multiplexing system that multiplexes and transmits 8/4 / 2PSK modulated waves at a constant time interval is adopted.
[0024]
Further, a part of the signal selected and orthogonally detected by the tuner pack 1 is input to a TMCC (Transmission & Multiplexing Configuration Control) decoding unit 3. The TMCC is inserted in order to specify a carrier modulation scheme and error correction for each layer.
[0025]
Here, the deinterleaving process is a process of restoring the interleaved symbols to the original time series. Note that interleaving is a technique for improving the resistance to burst errors used in transmission line coding technology, and by rearranging symbols sent in time series, burst errors are converted into pseudo-random errors. Some improve error correction capability. The descrambling process is a process of decrypting the scrambled (encrypted) transport stream output signal TS.
[0026]
Next, the transport stream output signal TS is input to the Reed-Solomon decoding unit 5. Here, the Reed-Solomon code is a kind of error correction code, and is one block code system that corrects errors in byte units. In satellite broadcasting, a powerful error correction function is added using this Reed-Solomon code or the like in order to maintain stable reception quality even when the reception state deteriorates due to rainfall or the like. The Reed-Solomon decoding unit 5 performs error correction processing using Reed-Solomon codes. In this error correction process, an error correction rate can be calculated. In the digital broadcast receiving apparatus according to the present embodiment, whether to display a high-level video or a low-level video based on whether the error correction rate exceeds a specified value (for example, 50%) is viewed. The person can choose arbitrarily.
[0027]
Subsequently, the transport stream output signal TS is input to the CA descrambling unit 6 and the CA module 7. The CA module 7 is a module having a high-speed digital interface for receiving data that enables limited reception (CA: conditional access) such as pay broadcasting, and is connected to a telephone line, a dedicated line, etc. via a modem 14. And configured to be able to communicate with a host computer or the like of a broadcasting company billing center. Then, the CA descramble unit 6 performs a process of releasing the limited reception scrambling based on the received data.
[0028]
Next, the descrambled transport stream output signal TS is input to the MPEG2 demultiplexing unit 8 and the multiplexing of the broadcast content compressed by MPEG2 is released. Then, the demultiplexed signal is input to the EPC & basic data decoder 9, the high layer video decoding unit 10, the low layer video decoding unit 11 and the audio decoding unit 12.
[0029]
The EPC & basic data decoder 9 separates and extracts electronic program guide (EPC: Electronic Program Guide) data and basic data related to program selection and conditional access from a signal compressed by MPEG2.
[0030]
The high layer video decoding unit 10 separates and extracts high layer high resolution video data from the MPEG2 compressed signal, and the low layer video decoding unit 11 extracts low layer low resolution video from the MPEG2 compressed signal. Data separation / extraction is performed. The audio decoder 12 separates and extracts audio data from the MPEG2 compressed signal and outputs the audio.
[0031]
The electronic program guide data, high-resolution video data, and low-resolution video data separated and extracted as described above are input to the video synthesis display processor 13, and the synthesized video signal such as a CRT or a liquid crystal display device is displayed. Output to the display. A parallel display of a high-level video and a low-level video, which will be described later, can be displayed by synthesizing each video by the video synthesis display processor 13.
[0032]
Reference numeral 30 denotes a control device including a microcomputer that controls the above-described units in an integrated manner.
[0033]
Here, a processing procedure in the control apparatus of the digital broadcast receiving apparatus according to the present embodiment will be described with reference to the flowchart shown in FIG. 2 and the explanatory diagram of FIG.
[0034]
First, in step S100, selection / reception of a desired channel is performed by the tuner pack 1 or the like. Next, the process proceeds to step S101, where it is determined whether or not there is a low hierarchy video. If it is determined that the low hierarchy video is not included, the process proceeds to step S102 and only the high hierarchy video (HD) is output to the display. (This corresponds to the state of FIG. 3A).
[0035]
On the other hand, if it is determined in step S101 that the lower hierarchy video is included, the process proceeds to step S103, and it is determined whether or not the error correction rate is equal to or higher than a specified value (for example, 50%).
[0036]
If it is determined that the error correction rate is less than the specified value, the process proceeds to step S104, where it is determined whether or not the low-layer video is being displayed on the display. Returning to step S103, if it is determined that the image is not being displayed, the process proceeds to step S105.
[0037]
If it is determined in step S103 that the error correction rate is equal to or higher than the specified value, the process proceeds to step S106 to determine whether or not a high-level video is being displayed on the display. Returns to step S103 again, and if it is determined that it is being displayed, the process proceeds to step S105.
[0038]
In step S105, the low hierarchical video (SD) and the high hierarchical video (HD) are displayed in parallel on one screen (see FIG. 3B). Thus, the viewer can compare the low-level video (SD) and the high-level video (HD) in a state where the error correction rate is equal to or higher than the predetermined value and the reception sensitivity is deteriorated. The display mode of the low-level video (SD) and the high-level video (HD) may be a still image, a frame-by-frame still image that is updated every predetermined time, or a moving image that is displayed in real time.
[0039]
Then, the process proceeds to step S107, and a predetermined button switch disposed on the remote control device or the digital broadcast receiving device is operated to display the high-level video in step S1071 according to the viewer's preference (FIG. 3C). ) Or the display of the low-level image in step S1072 (FIG. 3D) can be arbitrarily selected.
[0040]
In other words, when the error correction rate is higher than the specified value and the reception sensitivity is degraded, image degradation such as video distortion and dropped frames may occur in high-level images. Viewers who wish to continue displaying high-level images can select “Display high-level images”, and conversely, even at low resolutions, image degradation such as distorted images and dropped frames may occur. A viewer who desires a small display can select “display of a low-level image”.
[0041]
In addition, when it becomes possible to display two or more types of layered images including a high layer image and a low layer image in the future due to a change in the standard of satellite broadcasting or the like, in step S105, the images of all the layers are displayed. By displaying in parallel, the viewer can arbitrarily select and display video in any hierarchy.
[0042]
Further, in the present embodiment, a case has been described in which a low-layer video and a high-layer video are displayed in parallel on one screen based on the error correction rate. However, when the reception sensitivity can be measured, the reception sensitivity is equal to or less than a specified value. The parallel display and the selection of the hierarchical image may be executed based on whether or not.
[0043]
Although the invention made by the present inventor has been specifically described based on the examples, the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the scope of the invention. .
[0044]
【The invention's effect】
According to the present invention, in a digital broadcast receiving apparatus that receives a digital broadcast in which two or more hierarchical services exist in the same channel, a frequency tuning unit that extracts and outputs a desired tuning channel from the received signal of the digital broadcast. A demodulator for demodulating two or more hierarchies in the channel selected by the frequency tuning means for each hierarchies, and whether an error correction rate of the video signals of the one or more hierarchies exceeds a predetermined value If the error correction rate is determined to have exceeded a predetermined value by the error correction rate determination unit and the error correction rate determination unit, the video of each layer is displayed in parallel on one screen. Since parallel display means and hierarchy switching display means for selecting and outputting one of the videos of each hierarchy displayed in parallel are provided, it is possible to reduce the reception state, etc. When the error correction rate of the video signal of one or more layers exceeds a predetermined value, the images of each layer are displayed in parallel on one screen and the layer switching display means is operated to display the images in each layer. 1 can be selected and output, and the image quality and resolution meeting the viewer's request can be arbitrarily selected and displayed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an outline of a configuration and a signal flow of a digital broadcast receiving apparatus according to the present embodiment.
FIG. 2 is a flowchart showing a processing procedure in the control apparatus of the digital broadcast receiving apparatus according to the present embodiment.
FIG. 3 is an explanatory diagram showing a state of hierarchical video display in the digital broadcast receiving apparatus according to the present embodiment.
FIG. 4 is a flowchart showing a processing procedure in a control device of a conventional digital broadcast receiving device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tuner pack 2 Demodulation and decoding part 3 TMCC decoding part 4 Deinterleaving part 5 Reed-Solomon decoding part 6 CA descrambling part 7 CA module 8 MPEG2 demultiplex part 9 EPC, basic data decoder 10 High hierarchy video decoding part 11 Low hierarchy Video decoding unit 12 Audio decoding unit 13 Video composition display processor 14 Modem 20 BS antenna 30 Control device (microcomputer)
TS transport stream output signal

Claims (6)

In a digital broadcast receiving apparatus that receives a digital broadcast in which video information of two layers of a high layer video and a low layer video exists in the same channel,
Frequency tuning means for extracting and outputting a desired channel from the received signal of the digital broadcast;
Hierarchical demodulation means for demodulating the hierarchy of video information in the channel selected by the frequency tuning means for each hierarchy;
Error correction rate determination means for determining whether or not the error correction rate of any of the video signals in the two layers exceeds a predetermined value;
When the error correction rate is determined by the error correction rate determination means to exceed a predetermined value, parallel display means for displaying the still images or frame advance images of each layer in parallel on one screen;
Hierarchy switching display capable of selecting and outputting one of the two hierarchies displayed in parallel by the parallel display unit when the error correction rate is determined to have exceeded a predetermined value by the error correction rate determination unit Means,
An input operation means capable of inputting a command for selection;
Wherein the hierarchical switching display means digital broadcast receiving apparatus according to claim switching isosamples select the screen to be displayed according to a signal from said input operation means. In a digital broadcast receiving apparatus that receives a digital broadcast in which two or more hierarchical services exist in the same channel,
Frequency tuning means for extracting and outputting a desired channel from the received signal of the digital broadcast;
Hierarchical demodulating means for demodulating two or more hierarchies in the channel selected by the frequency tuning means for each hierarchy;
Error correction rate determination means for determining, for each layer, whether or not an error correction rate of the video signal of the one or more layers exceeds a predetermined value;
When the error correction rate is determined by the error correction rate determination means to exceed a predetermined value, parallel display means for displaying the images of the respective layers in parallel on one screen;
Hierarchy switching display means capable of selecting and outputting one of the videos of the respective hierarchies displayed in parallel by the parallel display means when the error correction rate determination means determines that the error correction rate has exceeded a predetermined value. ,
An input operation means capable of inputting a command for selection;
Wherein the hierarchical switching display means digital broadcast receiving apparatus according to claim switching isosamples select the screen to be displayed according to a signal from said input operation means.   3. The digital broadcast receiving apparatus according to claim 2, wherein the two or more hierarchical services are two types of high hierarchical video display and low hierarchical video display.   4. The digital broadcast receiving apparatus according to claim 2, wherein the parallel display unit displays the video of each layer as a still image or a frame advance image that updates the video every predetermined time.   4. The digital broadcast receiving apparatus according to claim 2, wherein the parallel display unit displays the video of each layer as a moving image.   6. The digital broadcast receiving apparatus according to claim 2, wherein the predetermined value of the error correction rate in the error correction rate determination means is 50%.

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