KR20100081430A - Digital broadcating reciever and broadcating recieving method - Google Patents

Abstract

PURPOSE: A digital broadcasting receiver and a broadcasting receiving method are provided to enhance a user convenience about a channel search. CONSTITUTION: A low resolution decoder(160) obtains an image which pixel of an image which is recorded in a second baseband signal is reduced. A JPEG(Joint Photographic Expert Group) encoder compresses an reduced image. An image buffer(175) stores the compressed image. A combiner mixes image data stored in the image buffer to a first baseband signal. An image output processor(190) decodes the mixed first baseband signal and displays the signal.

Description

Digital broadcasting receiver and broadcast receiving method {DIGITAL BROADCATING RECIEVER AND BROADCATING RECIEVING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast receiver capable of receiving digital television broadcasts, and more particularly, to a digital broadcast receiver supporting a channel browsing function for previewing images on a viewable channel in thumbnail format.

The television broadcasting system is classified into an analog television broadcasting system and a digital television broadcasting system according to a transmission form of a television signal. The analog television broadcasting system transmits an analog television signal as it is, and thus is greatly affected by noise and difficult to reproduce the original image. On the other hand, digital television broadcasting systems transmit analog television signals in digital form, thereby minimizing the effects of noise and facilitating the reproduction of the original image.

In addition, recent advances in the compression technology of image information allow digital television broadcast signals to be transmitted over narrow bandwidths. Accordingly, the digital television broadcasting system can provide a large number of television broadcasting programs to viewers as compared to analog television broadcasting systems. In other words, digital television broadcasting systems increase the number of television broadcast channels through which television signals can be transmitted.

With the rapid development of digital broadcasting technology and the diversification of services, digital TVs and set-top boxes are more effective and differentiated to accommodate the changing environment and the increasing demands of users in addition to the basic functions of receiving digital broadcasting. This is necessary.

One such function is to provide a function of effectively viewing information of another channel while fixing a channel currently being viewed.

To this end, a study on a channel browser that can provide image information of a plurality of channels that can be broadcast in a digital broadcasting receiver (television) in the form of a thumbnail or a movie clip to a user on one screen Is going on.

Representative methods for expressing other channel information in the conventional method include a PIP (Picture In Picture) function and an EPG (Electronic Program Guide) display function.

The PIP function may be used to provide, as broadcast information, for image selectable channels, image information including a picture on which the broadcast is broadcast.

To implement such a function, two receivers are built in, and one receiver is used to receive information broadcast on a channel currently being viewed. After receiving the information broadcasted on the other channel by using the other receiver, the video information of the other channel is shown in the PIP form or the EPG information of the program broadcasted on the other channel is sequentially displayed by using the OSD function. have.

The present invention is to provide a digital broadcast receiver that can increase user convenience for channel search.

In addition, the present invention is to provide a digital broadcast receiver that can reduce the cost required to implement a channel search function.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In accordance with an aspect of the present invention, a digital broadcast receiver includes: a first tuner for receiving a broadcast signal of a tuned channel; A first demodulator for demodulating the output signal of the first tuner to generate a first baseband signal; A second tuner for receiving a broadcast signal of a channel selectable; A second demodulator for demodulating the output signal of the second tuner to generate a second baseband signal; A low resolution decoder for decoding the second baseband signal to obtain an image of which the number of pixels of the image carried in the second baseband signal is reduced; A compression unit to compress the reduced image; An image buffer for storing the compressed image; A mixing unit mixing the image data stored in the image buffer with the first baseband signal; And an image output processor for decoding and displaying the mixed first baseband signal.

The reduced image decoder may acquire an image in which each channel is sequentially reduced by one for a plurality of selectable channels. In addition, it is possible to obtain N consecutive still images for one channel (an integer of 1 <N <100).

If the second baseband signal is field data, the reduced image decoder may replace vertical reduction by using only one of a top field or a bottom field.

In accordance with an aspect of the present invention, a broadcast receiving method includes decoding a baseband signal for each channel for a plurality of tunable channels, thereby reducing the number of pixels in the image included in the baseband signal. Obtaining a thumbnail screen image, comprising: acquiring a compressed image, compressing the obtained image, and storing the compressed image; And displaying a thumbnail list consisting of thumbnail screens displaying the stored images.

In the reduced image acquisition process, an image having a reduced number of pixels may be acquired from an image of an I picture carried in the baseband signals.

In addition, the reduced image acquisition process may acquire an image of which the number of pixels is reduced in N consecutive I pictures for one channel.

The obtaining of the thumbnail screen image may include decoding the baseband signal received from the tuned channel to obtain image data for broadcast output, and simultaneously displaying the acquired channel data. Can be performed.

According to an embodiment of the present invention, there is an advantage in that a user of the digital broadcast receiver increases convenience for searching a channel.

In addition, the present invention has the advantage that the configuration for convenient channel search can be realized at a low cost.

In addition, according to a more specific embodiment of the present invention, there is an advantage of supporting a channel browsing function for not only digital broadcasting but also analog broadcasting channels.

In the description of the present invention, a PIP function implemented in the form of a thumbnail list consisting of a plurality of thumbnail screens displaying image information of each channel will be referred to as a channel browsing function.

1 is a block diagram illustrating an embodiment of a digital broadcast receiver capable of performing a channel browsing function. First and second tuners 11 and 14 and first and second channel demodulators 12 and 17 for demodulating the broadcast signals tuned by the tuners 11 and 14, respectively, are provided. The outputs of the first and second channel demodulators 12 and 17 are output to the demultiplexer 13.

The first and second tuners 11 and 14 tune a broadcast signal of a specific channel, and the first and second channel demodulators 12 and 17 demodulate the tuned broadcast signal to the inverse of the modulation scheme and then transport it. Output to the demultiplexer 13 in the form of a (TP) stream. For example, if the modulation method on the transmitting side is the VSB method, VSB demodulation. If the QPSK method, QPSK demodulation. In the present invention, the first tuner 11 tunes the main screen broadcast signal, and the second tuner 14 tunes the thumbnail screen broadcast signal. This is one embodiment, and according to the designer, the first tuner 11 may tune the broadcast signal for the thumbnail screen, and the second tuner 14 may tune the broadcast signal for the main screen.

The demultiplexer 13 separates elementary streams such as video / audio / EPG from baseband signal streams (eg, transport streams) output from the first and second channel demodulators 12 and 17. . The video decoder 16 decodes the video ES separated by the demultiplexer 13 into the reverse of the video compression process, and outputs the main screen image data to the display processor 18, and the thumbnail screen image data is the thumbnail generator 19 )

When the input video stream is for the main picture, the video decoder 16 performs a complete video decoding and outputs it to the display processor 18. When the input video stream is for the thumbnail picture, the video decoder 16 decodes a predetermined portion (eg, decodes only the DC coefficient of the I picture). And outputs to the thumbnail generator 19.

The thumbnail generator 19 generates a thumbnail image from the partial decoded data of the plurality of channels and outputs the thumbnail image to the display processor 18. The display processor 18 outputs a main screen on which a video / EPG of a program broadcast on a channel currently being watched is output, and at least two or more thumbnail screens on which a video / EPG of a program broadcasting on another channel is output. It may consist of. According to a user's manipulation, the output of the display unit 18 may consist of only a plurality of thumbnail screens, or may consist of a full screen of tuned channel broadcasts.

The decoding process of the broadcast stream and the driving process of the display apparatus for the full screen output for the channel broadcast tuned in FIG. 1 follow a general digital TV reception and output method and thus are not described separately. In the description of FIG. 1, it is assumed that the first tuner and the channel demodulators 11 and 12 tune and demodulate the broadcast signal of the main picture. In addition, it is assumed that the second tuner and the channel demodulators 14 and 17 tune and demodulate broadcast signals of other channels.

That is, image data of another channel other than the viewing channel is output through the thumbnail screen, and for this purpose, the second tuner 14, the second channel demodulator 17, the demultiplexer 13, the video decoder 16, and the thumbnail are generated. Part 19 is required.

In addition, in FIG. 1, the demultiplexer 13 and the multi video decoder 16 may process two streams at the same time. For example, the demultiplexer 13 may be implemented to enable video / audio / EPG separation for two baseband signal streams simultaneously through algorithms such as combining two independent demultiplexers or proper time division.

Similarly, video decoder 16 is also implemented to allow decoding of two image streams at the same time. For example, the multi-video decoder 16 of FIG. 1 may be composed of one video decoder that performs a full form of decoding and another DC coefficient decoder that performs decoding only DC coefficients of an I picture of the video stream.

The display processor 18 in charge of the final video output is responsible for controlling the full screen / thumbnail screen image input from the video decoder 16 and the thumbnail generator 19 to be divided into the full screen and the thumbnail screen for output In charge.

However, the demultiplexer 13 and the multi-video decoder 16 of FIG. 1 are each independently an image stream processing line for broadcasting a tuned channel and an image stream processing line for outputting an image for channel browsing. If configured, the production cost can be increased.

Accordingly, in order to actually implement the configuration of FIG. 1, a broadcast reception structure capable of providing a general broadcast screen and a PIP type channel browsing screen using a relatively large portion of overlapped stream processing lines should be presented. In addition, the broadcast reception structure proposed above should be able to easily apply the protocol structure or the integrated IC structure of the digital television broadcasting currently widely used.

FIG. 2 is a block diagram illustrating a digital broadcast receiver according to an embodiment of the present invention capable of providing a broadcast broadcast screen and a channel browsing screen in a PIP format for a channel selected by using a redundant image stream processing line.

The illustrated digital broadcast receiver comprises: a first tuner 110 for receiving a broadcast signal of a tuned channel; A first demodulator (120) for demodulating the output signal of the first tuner to generate a first baseband signal; A second tuner 140 for receiving a broadcast signal of an untuned channel; A second demodulator (150) for demodulating the output signal of the second tuner to generate a second baseband signal; A low resolution decoder (160) for decoding the second baseband signal to obtain an image in which the number of pixels of the image carried in the second baseband signal is reduced; A compression unit 170 for compressing the reduced image; An image buffer 175 for storing the compressed image; A mixing unit 180 mixing the image data stored in the image buffer with the first baseband signal; And an image output processor 190 for decoding and displaying the mixed first baseband signal.

The first tuner 110 and the second tuner 140 may be implemented as general tuners including an antenna resonance circuit and an adjustment circuit for channel selection.

The first demodulator 120 demodulates the broadcast signal in the inverse of the modulation scheme (for example, if the modulation scheme is a VSB scheme at the transmitting side, VSB demodulates, and QPSK demodulates if the QPSK scheme) is packaged according to the digital broadcasting protocol. For outputting an AV packet stream (eg transport stream).

The low resolution decoder 160 may further include an I picture decoder 162 for decoding only data for an I picture in a second baseband signal, and a number of pixels of the image data decoded by the I picture decoder 162. It may include a scaler 164.

The functions of the I picture decoder 162 and the scaler 164 will be described later.

As shown, the image output processor 190 may include a high resolution decoder 192 that decodes the first baseband signal. In another implementation, as the image output processor 190, an 'integrated processor for general use in decoding and displaying broadcast data' may be applied.

The image output processor 190 may apply a decoding processor, currently implemented in various digital television products. For example, a video / audio integrated decoding processor may be applied, or a video integrated decoding processor may be applied. When implemented as a decoding processor applied to an ATSC digital television, image data in the form of a packetized elementary stream (PES) stream, a transport stream (TS) stream, or a program stream (PS) stream may be input.

The image buffer 175 may be implemented as a memory (register, etc.) built in the low resolution decoder 160, may be implemented as a separate memory, or may be formed on the system memory of the digital broadcast receiver. The last case is preferable for cost reduction.

In FIG. 2, each image data processing line is described as follows according to a state of a screen displayed on a display panel.

First, when only the broadcast of the channel tuned to the full screen is broadcast, the broadcast data of the tuned channel is the first tuner 110, the first demodulator 120 of FIG. Mixing unit 180; And an image output processor 190, to the display panel.

Second, when only thumbnail screens for channel browsing are output, the image data displayed on each thumbnail screen is stored in the image buffer 175 and then displayed through the mixing unit 180 and the image output processor 190. Output to the panel.

Third, when the thumbnail screen image for channel browsing is output while the broadcast of the channel tuned to the full screen is superimposed, the broadcast data of the tuned channel is the first tuner 110 and the first demodulator of FIG. 2. 120; Mixing unit 180; And image data of the thumbnail screen stored in the image buffer through the image output processor 190 and through the mixing unit 180 and the image output processor 190, and output to the display panel. In this case, the image data of the thumbnail screen is mixed with the first baseband signal by the mixing unit 180 in a form conforming to the protocol for the first baseband signal.

Accordingly, the image output processor 190 is in charge of a load similar to processing image data for one image data processing line even in the third case.

The mixer 180 transmits only the signal received from the first demodulator 120 to the image output processor 190 in a time-divisionally specific time period (ie, a time slot) according to a user's operation. In the time section, only thumbnail screens combining the signals received from the second demodulator 150 may be transmitted to the image output processor 190.

In another time interval, the channel browser 160 mixes the thumbnail screen image data stored in the image buffer 175 with the first baseband signal in the form of a stream received from the first demodulator 120 to mix the image. May be sent to an output processor 190.

An embodiment of the image mixing method performed by the mixing unit 180 and the operation of the image output processor 190 in this case will be described below.

3 is a flowchart illustrating a process of performing channel browsing for a digital television broadcast in which movie data is transmitted through a transport stream and displaying the same along with a main screen according to an embodiment of the present invention.

When the channel browsing function is used in FIG. 3, one of route # 1 and route # 3 is selectively performed depending on whether the selected channel is a digital broadcast channel or an analog broadcast channel. At this time, route # 2 for channel browsing may be performed along with the selected route.

The illustrated channel browsing and display method may be performed by the mixer 180 of FIG. 2.

The illustrated method applies the idea of the present invention when the first baseband signal has a transport stream form.

The illustrated channel browsing method comprises the steps of: (A) obtaining a transport stream for a tuned channel; (B) concurrently performing step (A), performing browsing on other untuned channels to create transport stream packets for a thumbnail screen; (C) mixing the transport stream obtained in step (A) and the TS packet created in step (B); And (D) outputting the mixed transport stream to an external integrated display processor.

Step (A), more specifically, the step of tuning the tuned digital channel (S110); The method may include identifying PIDs used for a transport stream obtained from the tuned channel with reference to PSI / SI information and filtering the transport stream (S120).

In order to secure a PID that can be used to TS packetize sub-screen images for channel browsing, the loops of steps S122 to S126 are repeated to bypass the first packet to the last packet of each transport stream. PID can be read.

In the illustrated step S128, using the PID to filter TS packets that do not have image data. As a result, only the TS packets carrying the image data in step S180 are mixed with the TS packets carrying the sub-screen image (generated in step S600).

Step S128 may be omitted depending on the implementation. In this case, all TS packets of the channel selected in step S180 are mixed with TS packets carrying a sub-screen image (generated in step S600).

In the case of a digital television capable of watching both a digital broadcast channel and an analog broadcast channel, the step (A) includes: checking whether the tuned channel is an analog channel or a digital channel (S105); If the tuned channel is an analog channel, performing analog channel broadcasting (route 3); If the tuned channel is a digital channel, step (a) to (d) may be performed (route 1).

The broadcasting of the analog channel (route 3) may include tuning a tuned analog channel (S210); The analog broadcast signal received through the analog channel may be output to an external integrated display processor (S290).

The step S600 is performed when a user's instruction to express the main screen for the channel selected on the display screen and the thumbnail screens for channel browsing together is input. In this case, the operation of route 2 is completed.

While waiting for the user's instruction, step S200 is repeatedly performed.

That is, when the image storing operation of the thumbnail screen for one channel is completed, the digital broadcasting receiver of the present embodiment continues to store the image of the thumbnail screen for the next channel in the background while changing channels.

Meanwhile, preferably, the second tuner 140, the second demodulator 150, the I picture decoder 162, and the scaler 164 of FIG. 2 are configured to display thumbnail screens for channel browsing in the image buffer 175. Periodically save the data. That is, even when the broadcast broadcast screen and / or the channel browsing screen of the tuned channel are output, the operation of storing image data for the thumbnail screens for channel browsing may be performed as a background operation.

The digital broadcast receiver according to an embodiment of the present invention may perform channel browsing in the following shape.

If a user instructs the user to perform a channel browsing function while broadcasting a channel tuned to the full screen of the display panel, thumbnail screens for channel browsing are superimposed and displayed. That is, thumbnail screens are arranged in series at the bottom of the entire screen on which the channel of the tuned channel is broadcast or at the left / right side of the screen.

To this end, the broadcast reception method of the digital broadcast receiver, for the plurality of tunable channels, by decoding the baseband signal for each channel, to obtain an image of a reduced number of pixels in the image on the baseband signal Obtaining a thumbnail screen image including a process of compressing the obtained image, and storing the compressed image; And displaying a thumbnail list consisting of thumbnail screens displaying the stored images.

4 illustrates a detailed process of acquiring the thumbnail screen image. In addition, FIG. 4 may be a detailed process of step S200 of FIG. 3.

The illustrated image data obtaining method may include tuning to a channel to which a thumbnail screen image is to be acquired (S220); Decoding the I picture image data among the signals received in the tuned channel and reducing the number of pixels (S240); Compressing the decoded image data (S260); Buffering the compressed image data (S270); Incrementing the repetition counter and returning to step S240 if the incremented counter is less than N (S280); And changing the current channel to the next channel to perform channel browsing, and returning to step S220 (S290).

The step S280 is for repeating the steps S240 to S270 N times. As a result, in step S240, an image having a reduced number of pixels may be obtained from N consecutive I pictures for one channel. Here, it is preferable that N is an integer of 1 <N <100. This is because storing too many thumbnail images increases the memory capacity burden.

The step S220 is performed by the second tuner 140 of FIG.

The step S240 is performed by the second demodulator 150 and the low resolution decoder 160.

The step S260 is performed by the compression unit 170, and preferably compressed into a JPEG file. This is because JPEG files are easy to perform various processing in the image processing field.

Controlling the branching of the steps S280 and S290 may be performed by an apparatus for a control function such as a controller (not shown) of the digital broadcast receiver or a controller (not shown) for image processing.

The image obtained by the illustrated process may be a YUV 4: 2: 0 Row Image, and may be processed as a buffer in a slice unit.

The obtained image may be stored in a predetermined number of output image buffers, and may be read by a CPU for image processing or may be input to an existing DTVSoc unit through a TP encoder.

In the case of a digital television capable of watching both a digital broadcast channel and an analog broadcast channel, before the step S220, a step of checking whether the channel to be browsed is an analog channel or a digital channel may be performed. If the channel to be browsed is an analog channel, an AD converted signal decoded in an analog manner may be extracted, and only data of necessary pixels may be extracted to obtain a thumbnail screen image.

FIG. 5 illustrates one embodiment of a S240 portion of FIG. 4.

The illustrated method for obtaining a low resolution image for a thumbnail screen includes parsing header information of an AV packet stream forming a baseband signal of a channel to which channel browsing is to be performed (S242); As a result of parsing the header information, checking whether the channel uses an interlaced scanning scheme (S242); If the channel does not use the interlaced scanning method, loading image data to perform horizontal scaling down (S244), and performing vertical scaling down (S245); Loading the image data of only one of the top and bottom fields (S246) and performing horizontal scaling down (S247) if the channel uses the interlaced scanning method; Compressing the down-scaled image data (S248); And storing the compressed image data in an image buffer (S249).

The illustrated image acquisition method can be easily applied when performing image down scaling by dividing the number of pixels of the original image by a multiple of two. This is because the illustrated image acquisition method acquires an image by taking only one of the top or bottom field with respect to the interlaced scanning channel, because the downscaling effect of reducing the number of pixels by half is shown by this operation.

The illustrated decoding may be performed in an automatic control mode in which N still images of a corresponding channel are automatically extracted after tuning a channel to be browsed.

After extracting N still images for one channel, the current channel of the second tuner is changed to the channel to be browsed next. When N still images are extracted for each channel to be browsed, all image data for channel browsing are obtained.

When extracting N still images for each channel and / or extracting N still images for all channels to be bridged, an interrupt is generated, and the interrupt service routine checks whether the operation after the decoder is completed or not. Subsequent image processing or control can be performed. With the above process, it is possible to provide a means for continuously generating a plurality of images for the channel, and at the same time to prevent the image buffer from overflowing.

It should be noted that the above embodiment is for the purpose of illustration and not for the purpose of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

1 is a block diagram illustrating a digital broadcast receiver having a channel browsing function.

2 is a block diagram illustrating a digital broadcast receiver for performing a channel browsing function using a duplicated image stream processing line.

3 is a flowchart illustrating a process of performing channel browsing for a digital television broadcast in which movie data is transmitted through a transport stream and displaying the same along with a main screen;

4 is a flowchart illustrating a detailed process of acquiring image data for a thumbnail screen according to the spirit of the present invention.

FIG. 5 is a flow diagram illustrating one embodiment of a S240 portion of FIG. 4. FIG.

Claims (11)

A first tuner for receiving a broadcast signal of a tuned channel; A first demodulator for demodulating the output signal of the first tuner to generate a first baseband signal; A second tuner for receiving a broadcast signal of a channel selectable; A second demodulator for demodulating the output signal of the second tuner to generate a second baseband signal; A low resolution decoder for decoding the second baseband signal to obtain an image of which the number of pixels of the image carried in the second baseband signal is reduced; A compression unit to compress the reduced image; An image buffer for storing the compressed image; A mixing unit mixing the image data stored in the image buffer with the first baseband signal; And An image output processor to decode and display the mixed first baseband signal Digital broadcast receiver comprising a. The method of claim 1, The low resolution decoder, An I picture decoder for decoding only data for an I picture in the second baseband signal; And Scaler for reducing the number of pixels of the image data decoded by the I picture decoder Digital broadcast receiver comprising a. The method of claim 1, The reduced image decoder, A digital broadcast receiver for acquiring a reduced image of each channel sequentially one by one for a plurality of tunable channels. The method of claim 3, wherein The reduced image decoder, A digital broadcast receiver for acquiring N (an integer of 1 &lt; N &lt; 100) successive still images for one channel. The method of claim 1, The reduced image decoder, And if the second baseband signal is field data, use only one of a top field or a bottom field to replace vertical reduction. The method of claim 1, And the first baseband signal and the second baseband signal have a transport stream form. The method of claim 1, And the compression unit compresses the JPEG file format. For a number of tuneable channels, Decoding a baseband signal for each channel to obtain an image having a reduced number of pixels in an image carried in the baseband signal; Compressing the obtained image; Obtaining a thumbnail screen image including the step of storing the compressed image; And Displaying a thumbnail list comprising thumbnail screens displaying the stored images Broadcast receiving method comprising a. The method of claim 8, The reduced image acquisition process, And receiving an image of a reduced pixel count from an image of an I picture carried in the baseband signals. The method of claim 9, The reduced image acquisition process, A broadcast receiving method for acquiring an image of reduced pixel count in N consecutive I pictures for one channel. The method of claim 8, Decoding the baseband signal received from the tuned channel to obtain image data for broadcast output; Displaying the obtained image data Channel broadcasting stage comprising And simultaneously performing the step of acquiring the thumbnail screen image.

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