KR100722972B1 - Device and method for processing image signal in digital broadcasting receiver - Google Patents

Abstract

The video decoder of the digital broadcasting receiver includes a resizing controller for generating a control signal for resizing the received video data, a header analyzer for analyzing the header information from the demodulated video stream, and separately outputting the video data; Resizing control signal for variable-length decoding unit for decoding the video data outputted by the variable-length table into original pixel data size, inverse quantization unit for inverse quantization of decoded video data, and video data in dequantized frequency domain And an inverse transform unit for resizing and transforming the video data in the two-dimensional space region, and a motion compensator for motion compensating and adding motion compensation data among video data separated from the inverse transformed video data.

Digital broadcasting receiver, video decoder, resize,

Description

Image signal processing device and method of digital broadcasting receiver {DEVICE AND METHOD FOR PROCESSING IMAGE SIGNAL IN DIGITAL BROADCASTING RECEIVER}

1 is a diagram illustrating a configuration of a digital broadcast receiver according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the configuration of the decoder of FIG. 1. FIG.

3 is a diagram illustrating a configuration of the demultiplexer of FIG. 2.

4 is a diagram illustrating a configuration of the audio decoder of FIG. 2.

FIG. 5 is a diagram showing the configuration of the video decoder of FIG.

FIG. 6A is a diagram illustrating an RF band of a digital broadcast reception signal, FIG. 6B is a diagram illustrating an RF signal band of one channel in FIG. 6A, and FIG. 6C is a diagram illustrating filter characteristics of an IF filter of a digital broadcast receiver.

FIG. 7A illustrates a stream of a digital broadcast signal, and FIG. 7B illustrates a structure of a video packet in a digital broadcast signal.

8 illustrates a video hierarchy of a digital broadcast signal.

9A to 9C are diagrams for explaining an image scanning method of a digital broadcast signal, showing characteristics of a progressive scan and a perforated scan.

10A to 10B are diagrams for explaining a block scan method of a digital broadcast signal, illustrating characteristics of a zigzag scan and an alternative scan.

11A-11D illustrate characteristics of resizing a received video signal according to an embodiment of the present invention, illustrating 4 * 4, 8 * 2, 4 * 2 and a modified 4 * 2 resizing structure.

FIG. 12 is a diagram illustrating an IDCT characteristic according to an embodiment of the present invention, and illustrates a configuration of an IDCT unit using a zone filter.

13A to 13C are diagrams showing an example of setting a resize field in the IDCT unit as shown in FIG.

14A to 14D are diagrams for explaining characteristics of compensating for motion in a motion compensator, and illustrating half-pel, quarter-pel, and octapel motion compensation characteristics.

15A and 15B are diagrams showing the configuration of a video decoder according to an embodiment of the present invention, showing an example of using an inverse discrete cosine transform unit with an inverse transform unit.

16 is a flowchart illustrating a procedure for determining a control signal for resizing a video signal received at a video decoder according to an embodiment of the present invention.

FIG. 17 is a diagram showing the configuration of a variable length decoder having a resizer in FIGS. 15A and 15B.

FIG. 18 is a diagram showing a configuration of an IDCT unit including a resizer in FIGS. 15A and 15B.

FIG. 19 is a diagram showing a configuration of a motion compensation unit including a resizer in FIGS. 15A and 15B.

20 is a flowchart illustrating a procedure of decoding a video signal received by a video decoder having the configuration as shown in FIGS. 15A and 15B.

21A to 21D are diagrams for comparing variable length decoding and IDCT result characteristics of an original video signal and a resized video signal according to an embodiment of the present invention.

22A to 22B are diagrams comparing motion compensation result characteristics of an original video signal and a resized video signal according to an embodiment of the present invention.

FIG. 23 is a diagram showing a configuration for measuring a signal-to-noise ratio of a resized and decoded video signal according to an embodiment of the present invention; FIG.

24A to 24D are diagrams for comparing signal-to-noise ratio characteristics of resized video signals in a video decoder according to an embodiment of the present invention.

25A-25C illustrate an example of displaying a resizing result of video data according to an embodiment of the present invention.

26A and 26B are diagrams illustrating another configuration of a video decoder according to an embodiment of the present invention, showing an example of using an inverse transformer transform unit with an inverse transform unit.

27 is a diagram showing the configuration of a mobile terminal having a digital broadcast receiver according to an embodiment of the present invention.

The present invention relates to an additional service apparatus and method of a mobile terminal, and more particularly, to an apparatus and method capable of receiving and processing a broadcast signal.

In general, the current portable terminal is equipped with a multimedia processor or to enhance the multimedia capabilities. In addition, a technology for embedding a television function in a portable terminal has been announced, and a digital broadcasting receiver is being researched. Therefore, the current mobile terminal should be provided with a configuration that can service a variety of multimedia functions, which is complicated by the configuration and processing procedures of the mobile terminal.

In the case of a mobile terminal having a camera and a digital broadcast reception function as described above, the mobile terminal should be able to process images by processing data received from the devices. In this case, it is preferable to configure the mobile terminal to perform the multimedia function as small as possible. It is advantageous to have the smallest possible size since the portable terminal must be carried and moved by the user. Therefore, the portable terminal of the multimedia function is a trend that has been actively developed for the configuration to reduce the volume while processing the corresponding multimedia function faithfully.

Currently, standards for digital broadcasting are actively in progress worldwide. In the case of digital broadcasting, there is a DMB method in the US and a DVB method in Europe. The portable terminal including the digital broadcast receiver includes a tuner, a demodulator, a decoder, and the like, for receiving digital broadcast. The digital broadcast reception tuner, demodulator, and decoder are different from the RF unit, demodulator, and decoder of the mobile terminal. That is, the digital broadcast receiver uses a frequency different from the communication frequency of the mobile terminal, and a demodulation and decoding method uses a different method. Therefore, since the digital broadcast receiver must be additionally configured as described above, there is a problem in that the size of the mobile terminal increases.

Therefore, when implementing a mobile terminal having the digital broadcast receiver, processing the received digital broadcast in accordance with the characteristics of the mobile terminal can improve the size and processing speed of the digital broadcast receiver. For example, the display portion of a portable terminal is smaller than that of a general image processing apparatus, and thus displayable image data is also different. Therefore, when the broadcast signal is processed in accordance with the display unit of the portable terminal in the digital broadcast receiver, the configuration and processing speed of the portable terminal can be improved.

Accordingly, an object of the present invention is to provide a portable terminal device having a digital broadcast reception function and a method for processing a digital broadcast signal received by such a portable terminal device.

Another object of the present invention is to provide a decoding apparatus and method capable of processing a broadcast signal received by a portable terminal having a digital broadcast reception function according to a processing standard of the portable terminal.

It is still another object of the present invention to provide a device and a method for decoding and displaying a video signal of a broadcast signal received by a mobile terminal having a digital broadcast reception function according to a display standard.

Another object of the present invention is to provide an apparatus and method for selecting and decoding a region of a video signal according to a scanning method of the video signal when decoding a broadcast video signal in a mobile terminal having a digital broadcast reception function.

It is still another object of the present invention to provide an apparatus and method for selecting and decoding an area of a video signal according to a scanning method of a received video signal and a size of a display unit when decoding a broadcast signal in a mobile terminal having a digital broadcast reception function. In providing.

In order to achieve the above object, a video decoder of a digital broadcast receiver according to an embodiment of the present invention includes a resizing controller for generating a control signal for resizing the received video data, and analyzing the header information in the demodulated video stream. A header analyzer which separates and outputs data, a variable length decoder that decodes the video data output from the header analyzer to the original pixel data size by a variable length table, and an inverse quantization that dequantizes the decoded video data. And an inverse transform unit for resizing the video data of the inversely quantized frequency domain into video data of a two-dimensional space region by the resizing control signal, and motion compensation data of the inversely converted video data and the separated video data. Consists of a motion compensator that adds motion compensation And that is characterized.

The inverse transform unit is an inverse discrete cosine transform unit, the Y-axis resizer for selecting a point inverse discrete cosine transformer set by the Y-axis control signal of the resizing control signal, and a number corresponding to a plurality of points. The X-axis inverse discrete transformers for inverse discretely transforming the Y-axis video data of the resized region and the point inverse discrete cosine transformer set by the X-axis control signal of the resizing control signal. The X-axis inverse discrete cosine transformer is provided with a resizer and a number corresponding to a plurality of points, and the inverse discrete cosine transformer for inverse discrete cosine transforming the X-axis video data of the resized region stored in the Y buffer. Characterized in consisting of.

And a resizer for resizing the separated video data by the resizing control signal, wherein the variable length decoding unit decodes the received variable length encoded video data into video data having an original length, and the table. A buffer for storing the video data decoded by the converter, the table converter to decode up to the data of a block included in the resizing area set by the resizing control signal, and controlling to store the video data of the resizing area in the buffer. It is characterized in that consisting of the resizer.

The motion compensation unit may further include a buffer for storing the received motion compensation vector value, a previous image storage unit for storing a previous frame image for comparing the motion vector value, and a next frame image for comparing the motion vector value. Inputs the next image storage unit for storing the motion, the motion vector value, the output of the previous image storage unit, and the next image storage unit, and are driven by a motion compensation selection signal to perform half-pel, quarter-pel and octapel motion compensation, respectively. Compensators and a resizer for selecting one of the half pel, quarter fel or octafel compensator by the resizing control signal.

The resizing control unit may determine the resizing control value according to the size of the display unit of the digital broadcast receiver.

The resizing control unit may determine the resizing control value by the display unit screen size of the digital broadcast receiver and the image scanning method analyzed by the header analyzer.

The control unit may determine the resizing control value by the display unit screen size of the digital broadcast receiver, the image scan method analyzed by the header analysis unit, and the block scan method.

The resizing control unit may determine the resizing control value based on the display unit screen size of the digital broadcast receiver, an image scan method and a block scan method analyzed by the header analyzer, and a decoding speed selected by a user.

The resizing control unit may adjust the resizing control value according to the display unit screen size of the digital broadcast receiver, the image scan method and the block scan method analyzed by the header analyzer, the decoding speed selected by the user, and the decoding speed of the digital broadcast receiver. Characterized by determining.

The inverse transformer may be an inverse integer transformer, and the inverse transformer may be a Y-axis resizer for selecting a point inverse integer converter set by a Y-axis control signal of the resizing control signal, and a channel corresponding to a plurality of points. And a point de-integrator converter configured to de-integrate Y-axis video data of a resized region by an inverse-integrator converter of the selected point and an X-axis control signal of the resizing control signal. An X-axis resizer for selecting a number, and a number corresponding to a plurality of points, wherein the inverse-inverter converter of the selected point is the X-axis inverse for converting the X-axis video data of the resized region stored in the Y buffer. It is characterized by consisting of the teaser converter.

In addition, a video decoder of a digital broadcast receiver according to an embodiment of the present invention for achieving the above object, and a resizing control unit for generating a control signal for resizing the received video data, and by analyzing the header information in the demodulated video stream A header analyzer for separating and outputting video data and video data outputted from the header analyzer for decoding to the original pixel data size using a variable length table, and in the resizing area set by the resizing control signal during the variable length decoding. A variable length decoder controlling the table converter to decode data included in the block, and storing the video data of the resizing area in the buffer, an inverse quantizer for dequantizing the decoded video data; Video data of the dequantized frequency domain An inverse transform unit for resizing and converting the video data in a two-dimensional space region by the resizing control signal, and a motion compensator for at least one resizing, wherein the motion compensator is selected by the resizing control signal, and the selected motion compensator A motion compensator for motion compensating and summing motion compensation data among the inversely converted video data and the separated video data, and a color converter for converting outputs of the inverse transform part and the motion compensator into display data. do.

In addition, the digital broadcast receiver according to an embodiment of the present invention for achieving the above object is an RF communication unit for converting the transmission signal to the RF band, down-converting the received RF signal to a baseband signal, and the transmission signal It is embedded in a portable terminal having a data processing unit for encoding and modulating and demodulating and decoding the received baseband signal. The digital broadcasting receiver generates a channel selection signal by a user's selection, and the display unit of the portable terminal. A controller for generating a control signal for resizing the video data of the digital broadcast signal received according to the screen size, a tuner for selecting a channel of the digital broadcast signal received by channel selection of the controller, and the selected digital broadcast channel A demodulator for demodulating a signal of the audio signal; A demultiplexer for separating the video stream, a video decoder for decoding the data of the separated video stream, and an audio decoder for decoding the data of the separated audio stream, wherein the video decoder is output from the controller. A decoder for resizing the decoding region of the video data received by the signal and decoding the video data of the resized region, a display unit for displaying the decoded video data, and a digital broadcast signal output from the demodulator in the recording mode. And a memory comprising buffers for temporarily storing data processed by the decoder.

In addition, the method for decoding the encoded video data in the digital broadcast receiving apparatus according to an embodiment of the present invention for achieving the above object, the process of determining a control signal for resizing the received video data, and the demodulated video stream Splitting and outputting the video data by analyzing the header information, resizing the separated video data by the resizing control signal, and decoding the resized video data to the original pixel data size by a variable length table. Inversely quantizing the decoded video data, inversely transforming the dequantized frequency domain video data into video data in a two-dimensional space region by the resizing control signal, and inversely transforming the video data. And movement of the separated video data The process of summing the data to the motion compensation and, characterized by constituted by any process which converts the motion-compensated video data to the data for displaying on the display unit.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that the same components in the figures represent the same numerals wherever possible.

In the following description, specific details such as communication frequency, data structure, etc. of the digital broadcast receiver are shown to provide a more general understanding of the present invention. It will be apparent to one of ordinary skill in the art that the present invention may be readily practiced without these specific details and also by their modifications.

An embodiment of the present invention analyzes the size of a display screen of a digital broadcast receiver and performs a resizing of a decoding area of a received broadcast signal before performing a decoding operation in a digital broadcasting receiver, and decodes received data of the resized area. An apparatus and method are provided. Therefore, by adaptively resizing the decoding area according to the characteristics of the digital broadcasting receiver without decoding all the data received by the digital broadcasting receiver, the amount of computation during decoding can be greatly reduced according to the characteristics of the digital broadcasting receiver. It can save time. The factors resizing the decoding area of the received digital broadcast signal include the size of the screen displaying the digital broadcast signal, the image scanning method and the block scanning method of the digital broadcast signal, the decoding quality of the decoder, and the communication environment of the digital broadcast receiver. (Decoding processing speed), and the like. A control signal for resizing may be generated using one or two or more of the above resizing factors, and in the embodiment of the present invention, a configuration for controlling the resizing of the decoder in consideration of all five resizing factors and Suggest a method.

The resizing control of the decoder may be used when displaying a plurality of broadcast channel signals on a single screen by dividing the screen in a digital broadcast receiver (for example, a picture in picture (PIP) function or a multi screen display). . In addition, in the case of a mobile terminal having the digital broadcast receiver, since the display unit of the mobile terminal is small, it is not necessary to display the entire screen of the received digital broadcast signal. Therefore, it is preferable that the decoder decode the broadcast signal to be decoded so that it can be displayed on the screen of the display of the portable terminal. In addition, the resizing method may be implemented in consideration of all the resizing factors as described above.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a diagram illustrating a configuration of a digital broadcasting receiver of a mobile terminal according to an embodiment of the present invention. 1 illustrates a configuration in which the portable terminal includes an RF tuner 110, a demodulator 120, and a decoder 130 of the digital broadcast receiver. The decoder 130 may be built in the controller 100. In this case, the decoder performance of the digital broadcast receiver receiver may be implemented in software.

Referring to FIG. 1, the key input unit 170 includes keys for inputting numeric and text information and function keys for setting various functions. In addition, the function keys include keys for selecting a function such as channel selection for digital broadcast reception, control of a broadcast reception mode, and the like according to an embodiment of the present invention.

The controller 100 performs a function of performing overall control of the mobile terminal. In particular, the control unit 100 generates control data for determining channel selection control data of the digital broadcast receiver receiver, control of the demodulation and decoder, and decoding performance of the decoder by key input by the key input unit 170.

The memory 180 may be composed of a program memory and a data memory. The program memory stores programs for receiving a digital broadcast receiver broadcast, and stores programs according to an embodiment of the present invention. The data memory may be used as an image memory for storing digital broadcast receiver image data received under the control of the controller 100. Here, when the controller 100 is a controller of the portable terminal and includes another memory for executing a program, the memory 180 may be an image memory.

The display unit 150 displays the digital broadcast receiver video signal processed by the decoder 130 under the control of the controller 100. The speaker 160 performs a function of reproducing the audio signal processed by the decoder 130 under the control of the controller 100.

The RF tuner 110 selects the digital broadcast channel by the channel control data of the controller 100 and down-converts the frequency of the broadcast signal of the selected channel to generate an intermediate frequency signal. The demodulator 120 demodulates the modulated digital broadcast signal into an original signal.

The decoder 130 separates the broadcast signal demodulated by the demodulator 120 into a video and audio signal, and decodes and outputs the separated video and audio signal, respectively.

Referring to FIG. 1, the digital broadcasting reception signal of the mobile terminal is a signal in a VHF (174 MHz-230 MHz: C5-C12) region and / or a UHF (470 MHz-862 MHz: C21-C69) region and / or L-Band ( 1 GHz-2.6 GHz). At this time, when the user selects a broadcast channel, the controller 100 outputs control data corresponding to the channel selected by the RF tuner 110. The RF tuner 110 generates and mixes an RF frequency according to the channel data, thereby generating an intermediate frequency signal of the selected channel. In this case, the intermediate frequency (IF) may be 36.17 MHz.

The analog intermediate frequency signal is applied to the demodulator 120. Then, the demodulator 120 demodulates the received analog signal by analog to digital conversion, and demodulates the demodulated signal according to the set method. Here, the modulation scheme of the digital broadcast receiver may use coded orthogonal frequency division multiplexing (CODFM). In an embodiment of the present invention, the demodulator 120 uses an MT352 manufactured and sold by Zarlink. In this case, the signal demodulated by the demodulator 120 is output as 8-bit MPEG-2 TS data, that is, the demodulator 120 converts the signal of the selected channel output from the RF tuner 110 into digital data. The FFT signal is controlled according to the number of carriers, additional symbols, etc. The FFT signal is looped and the order and interval are reconstructed to reproduce the final signal through error correction. The final output is the MPEG-2 TS.

The MPEG-2 TS signal output from the demodulator 120 is applied to the decoder 130. The decoder 130 then separates the received MPEG-2 TS signal into video, audio and data, respectively, and decodes each of the received MPEG-2 TS signals and outputs the video and audio signals. In this case, the video signal may be a signal such as RGB or YUV, and the audio signal is generally output in the form of PCM stereo sound. The video signal output from the decoder 130 is output and displayed on the display unit 150, and the audio signal is applied to the speaker 160 and reproduced.

In this case, the controller 100 controls the overall operation of the digital broadcast receiver. To this end, the controller 110 outputs channel control data for determining a frequency domain of the channel selected by the user to the RF tuner 110, and outputs control data such as a carrier mode (for example, 2k, 8k, etc.). . In addition, the demodulator 120 specifies a code rate, a guard interval, and the like, which are information depending on broadcasting standards for each country, so that the demodulation operation can be normally performed. In addition, the decoder 130 designates a service to be actually watched within a predetermined physical channel, performs an initialization operation of specifying a frame rate, a display size, and the like, and simultaneously plays, stops, It performs commands such as recording and screen capture, and receives feedback information according to the decoding process.

In order to perform the decoding procedure, the decoder 130 requires a decoding memory that can be used as an input / output buffer of a digital broadcast signal, a storage space for other settings, and a temporary buffer for decoding. In this case, the decoding memory may be used in common by the controller 100 and the decoder 130. The decoding memory may be used as an input / output buffer of the video and audio signals and at the same time store the decoded information in a table. As data that can be stored in the table, various pieces of information including a picture sequence (GOP seqeuce: IBBPBBP ....) used as a criterion in the decoding process among the header information of each frame are stored. The decoding memory may be used as the memory 180, and when the memory 180 is used only as an image memory, a separate independent memory may be used.

The configuration of the decoder 130 in the digital broadcast receiver having the above structure will be described in detail.

2 is a diagram illustrating a configuration of the decoder 130.

Referring to FIG. 2, the demultiplexer 210 receives demodulated MPEG-2 TS data output from the demodulator 120 and separates each data into audio, video, and other data. In this case, the other data is data excluding video and audio included in the digital broadcast signal, and may be program data. In the following description, the description of the other data will be omitted. Therefore, in the following description, the broadcast signal will be limited to the video and audio signals. At this time, the control unit 100 selects and informs the broadcast information to be selected in the demultiplexer 210, that is, a service (PID: product ID), and accordingly, the demultiplexer 210 is selected from various data output from the demodulator 120 according to the selected PID. It selects target data and separates it into video and audio.

The input buffer 220 is a general cue (a similar structure to a FIFO, which can be a kind of circular buffer in which the input and output are reversed), and the video decoder 230 and the audio decoder 250 at the rear can process the demultiplexed data in real time. Save as much data as there is. The input buffer 220 may be configured as a single structure for storing video and audio data together, or may be configured as a structure for separately storing video and audio data.

The video decoder 230 is responsible for decoding the video data. In the digital broadcasting receiver broadcasting, MPEG-2 video elementary stream (ES) is generally received and converted into YUV 4: 2: 0 data. However, in the exemplary embodiment of the present invention, an output suitable for a display unit (LCD) of a mobile terminal is required. Therefore, it converts to the RGB data. Further, in the embodiment of the present invention, the video signal is selectively decoded according to the size of the display unit of the mobile terminal. The RGB data converted as described above is stored in the video output buffer 240 and output according to the output time point.

The audio decoder 250 is responsible for decoding the audio signal. Like the video decoding, the audio decoder 250 receives MPEG-2 audio ES and converts it to PCM audio. The converted PCM audio signal is stored in the audio output buffer 260 and output at the time of output.

FIG. 3 is a diagram illustrating a configuration of the demultiplexer 210 of FIG. 2.

Referring to FIG. 3, the MPEG-TS signal output from the demodulator 120 is stored in the buffer 211. The buffer 211 stores a data input using a high speed bus such as a camera interface. It is desirable to have the form of a general cue. The PID checker 213 searches for an audio PID or a video PID in the header of the MPEG-TS data stream, classifies the audio PID into video and video data, and checks the PID of other data. The bit parser 215 selects audio and video data from the TS stream stored in the buffer 211 according to the output of the PID inspector 213 and stores the audio and video data in the buffer 217. The buffer 217 may be the input buffer 220 of FIG. 2. As described above, the demultiplexer 210 distinguishes the audio and video signals by examining the PID in the header information from the TS stream output from the demodulator 120, and demultiplexes the audio and video signals in the TS stream according to the separated result. To store in the input buffer 220.

FIG. 4 is a diagram showing the configuration of the audio decoder 250 of FIG. The audio decoder of FIG. 4 shows a decoder structure of MPEG-1 Layer-1 / 2. However, the audio decoder may be composed of AAC +, BSAC, and WHA audio decoders for digital broadcasting (DVB, DMB).

Referring to FIG. 4, when a sufficient amount of packet data is buffered in the input buffer 220, a header analyzer and un-packer 253 un-packing the packing of data stored in the input buffer 220. The header is analyzed and the header analysis result is output to the matching unit 253. The table constructor 253 includes a decoding table and bit parses audio data stored in the input buffer 220 based on the analyzed header information. The sub-band analyzer 255 analyzes the subbands of the bit-parsed audio data, and the matrix matrix unit 257 generates a filter matrix by the subband analysis and then performs a filter calculation. Do this. Thereafter, the data packer 259 combines the decoded audio data output from the matrix calculator 257 by time alignment, and the audio data output from the data combiner 259 is stored in the audio output buffer 260.

FIG. 5 is a diagram illustrating a configuration of the video decoder 230 of FIG. 2. 5 shows the structure of an MPEG-2 video decoder. Here, the H.264, WMV, or MPEG-4 video decoder has a slightly different structure from that of FIG. 5, but has a variable length decoder (VLD) for decoding the variable length coded data to its original size. Important parts, such as an inverse transform unit for converting data into image data of a two-dimensional space region and a motion compensator MC for compensating the movement of the image data, have the same configuration. The inverse transform unit may use inverse discrete cosine transform (IDCT) when the video decoder decodes the MPEG coded data, and the inverse transform unit may use an inverse integer (IIT) when the video decoder decodes the data encoded by the H.264 method. transform).

Referring to FIG. 5, the demultiplexed video data stored in the input buffer 220 is input to the header analyzer 311. Then, the header analyzer 311 extracts header information for decoding the video data stream and delivers only the actual image compressed data to the buffer 313. In this case, the buffer 313 stores the information until information on one frame is delivered. In this case, the frame image stored in the buffer 313 may be an I frame, a P frame, or a B frame image. Here, the I frame is an intra frame and has a structure similar to that of JPEG image data and does not perform a motion compensation operation. However, P-frame and B-frame images are non-intra frames, which are frames that should be compensated for by referring to the previous frame image and the previous frame image, respectively. Therefore, if the video signal stored in the buffer 313 is an I frame, the I frame video signal is applied to a variable length decoder (VLD) to perform a decoding operation. However, if the video signal stored in the buffer 313 is a B frame or a P frame, the motion compensation should be performed.

Referring to the decoding operation, the variable length decoding unit 315 reads the input data sequentially, decodes the data through a matching table, and transfers the most advanced data of the decoded result to the dequantization unit 317. The dequantizer 317 dequantizes the output of the variable length decoder 315 to extract only the DC component of the frequency domain data and outputs the DC component to the IDCT unit 319. Thereafter, the IDCT (Inverse Discrete Cosine Transformer) unit 319 converts data of the frequency domain into spatial domain data for the remaining domains based on the DC component obtained in the inverse quantization operation. The converted value has a YUV 4: 2: 0 format in the case of MPEG-2.

In addition, the decoding operation of P and B frame images requiring motion compensation will be described. First, since the P frame requires a previous frame image, the motion compensator 335 detects a motion vector by comparing the previous image data stored in the previous image storage unit 331 with the input P frame image, and then moves the motion vector according to the motion vector value. To compensate. Second, since the B frame requires the previous frame image and the next frame image, the motion compensator 335 stores the previous frame image stored in the previous image storage unit 331 and the next frame image stored in the next image storage unit 333 and the inputted B frame. After the motion vectors are detected by comparing the images, the motion is compensated for by the detected motion vector values. In addition, the P and B frame images are applied to the variable length decoding unit 315 to perform the same procedure as the decoding of the I frame image. The motion compensation data output from the motion compensator 335 is added to the extracted data by performing IDCT in the previous I frame or P frame in the adder 337, and the summed data is also YUV 4: 2: 0. Has a form.

The video data having the YUV 4: 2: 0 format output as described above should be converted according to the display characteristics of the display unit 150 displaying the same. In general, the display unit 150 of the portable terminal uses an LCD. In this case, the display unit 150 should be converted into a 16-bit or 18-bit RGB format if the LCD (TFT LCD), and a 24-bit RGB format if the general monitor. Therefore, the converter 321 converts the YUV 4: 2: 0 format video data into video data that matches the format of the output unit (eg, RGB format), and outputs the video data. It is stored in the buffer 240.

The overall operation of the digital broadcast receiver having the above configuration will be described.

RF signals of digital broadcasting received from an antenna exist in the VHF band and the UHF band as in a general television. In addition, each channel has a constant bandwidth (for example, 8MHz bandwidth). 6A is a diagram illustrating characteristics of RF signals of a digital broadcast receiver system receiver. FIG. 6A illustrates that RF signals exist for each frequency band around 386MHz. FIG. 6B is a diagram illustrating in detail a specific physical channel (8 MHz) among the RF channels as shown in FIG. 6A. Therefore, when the user selects a specific channel, the control unit 100 transmits control data for selecting a channel to the RF tuner 110. Accordingly, the RF tuner 110 generates a channel frequency according to the control data, as shown in FIG. 6B. The signal of the selected specific channel is selected. The signal output from the RF tuner 110 is a signal obtained by performing a filtering operation on a set channel and performing a frequency down conversion of the filtered signal to an intermediate frequency. FIG. 6C illustrates a result of converting and filtering a center frequency (center frquency) of the RF signal of one channel as shown in FIG. 6B, and mixing the center frequency to 36.167 MHz to convert to an IF signal.

The demodulator 120 then converts the input signal into a digital signal, and converts the converted intermediate frequency digital signal into a baseband digital signal. Thereafter, the baseband signal is looped while controlling the baseband signal according to the number of carriers, additional symbols, and the like. In addition, the signal output through the FFT circuit is reconstructed in order and interval to be reproduced as a final signal through error correction, and output as MPEG2-TS (Transport Stream) data, which is the final output. The MPEG2-TS data may have a configuration as shown in FIG. 7A. Herein, the TS stream constitutes one packet in units of 188 bytes, and each packet includes a header and a data area. The audio / video data may be here, the order of which is determined in a multiplexed order, without regularity. Table 1 below is a table illustrating a configuration of the TS header of FIG. 7A.

Packet contents Explanation Bit allocation Sync Byte 0x47 sync code 8 Error Indicator Presence of errors in TS packets One Payload Start Indicator payload starting position One Transport priority Decoder Priority One PID Packet type separator 13 Scrambling Control Scrambled mode 2 Adaptation Field Control Adaptation field data / payload present 2 Continuity Counter 4bit counter 4

FIG. 7B is a diagram showing the configuration of the data area of FIG. 7A. As shown in FIG. 7B, the data area may be a payload area. In this case, the payload region includes an adaptation field, a PES header, and a payload region (payload-video / audio data). In the following description, the term payload is used as a term meaning video / audio / data (herein, the data may be data such as EPG). Among them, PCR (clock reference) information is basically included in the adaptation field, and additional information added at the time of manufacture is added. In addition, the PES header area includes information for decoding each packet, and in particular, time information for synchronization, such as PTS / DTS (Presentation Time Stamp, Decoding Time Stamp), is included. <Table 2> is a table showing the configuration of the PES header area of the data area. In addition, video or audio data basically exists in the payload region, and an additional header data region may be added in the PES header structure. The video and audio data of the payload region is a video ES (elementary stream) or audio ES, which is generally called MPEG2 video, and may also be binary data for data broadcasting.

Packet contents Explanation Bit allocation Start code 0x000001 24 Stream ID Stream delimiter 8 PES Packet Length "10" 2 PES Scrambling Control Scramble on / off 2 PES Priority Decoding priority One Data Alignment Indicator Decoding order One Copyright Copyright One Original or Copy Original / Copy One PTS / DTS Flag Presence of PTS / DTS 2 Etc. Flag Flag according to MEPT-2 standard such as ESCR, ES 6 PES Header Data Length Overall length of PES Packet Header 8 Additional Header Data 'data length-base allocation' amount of data -

The decoder 130 for inputting the MPEG2-TS data output from the demodulator 120 includes a demultiplexer 210 for demultiplexing the video into audio and video data, and an audio decoder 250 and a video decoder 230 for decoding the demultiplexed audio and video data. It is composed. The video decoder decodes the received video data in units of frames and outputs the same to the display unit 150. Data transmitted from the decoder 130 to the display unit 150 varies depending on the form in which the display unit 150 is input. Table 3 below shows various input examples of the display unit 150.

In addition, since the signal output from the decoder 130 to the speaker 160 is generally output through an audio codec chip, the signal is directly decoded by the PCM or output as a raw audio analog signal.

In this case, the RF tuner 110 and the demodulator 120 perform different functions and operate independently, but may also be referred to as a network interface module (NIM). The control unit 100 may be the communication method of the RF tuner 110 and the demodulator 120 is I2C. In addition, between the control unit 100 and the video decoder 230 of the decoder 130, control data for broadcast reception start, pause, recording, termination, frame rate adjustment, screen resizing, color balance adjustment, and the like, and the result of video decoding are exchanged. In addition, between the control unit 100 and the audio decoder 250 of the decoder 130, control data for start, recording, equalizer, volume, mute, frame rate control, and audio decoding results are exchanged. The input / output signals between the controller 100 and the decoder 130 are shown in Table 4 below.

In the following process, a procedure of resizing an image screen to be displayed by the video decoder 230 according to a screen display method in the video decoder 230 will be described in detail.

In an embodiment of the present invention, a resizing factor for resizing the size of the video screen displayed is composed of a plurality of elements. The resizing elements may include a display size, an image scan method, a block scan method, a decoding speed, a decoding quality of a decoded screen, and the like. have. When resizing the decoded screen image, it may be implemented by using some of the above resizing elements, or may perform a resizing function in consideration of all the resizing elements. An embodiment of the present invention looks at the case of resizing the video screen applied to the display unit 150 in consideration of all the above resizing elements.

Before describing the resizing operation, the operation of the video decoder 230 performing the resizing function will be described in detail. As the video encoding method used in the video encoder of the digital broadcast transmission side, various encoding methods such as MPEG2, H.264, MPEG4 and the like may be used. In this case, the video decoder 230 of the receiver of the digital broadcast receiver should use a decoding method corresponding to the video encoding method used in the video encoder. In this embodiment of the present invention, the digital broadcast receiver is a receiver for receiving an MPEG2 video signal. It is assumed that the video decoder 230 having the configuration as shown in FIG. 5 may be an MPEG2 video decoder. However, the video decoder 230 may be an H.264, MPEG-4 video decoder as necessary.

Referring to FIG. 5, a header analyzer 311 separates packets for each layer in the MPEG2 video ES structure as shown in FIG. 8 and analyzes headers of the separated layers. The MPEG2 video hierarchical structure consists of six layers as shown in FIGS. 8A to 8F.

Referring to FIG. 8, first, a video squence layer as shown in FIG. 8A is a screen group having a series of the same attributes. The main function of the sequence header is a function capable of enabling playback in the middle of a bit stream. That is, the sequence header is the most basic information in MPEG2, and after the sequence start code, the horizontal size, vertical size, pixel aspect ratio, picture rate, bit rate VBV (video buffering verifier) buffer size, Information such as plate making parameter flags and flags loading two quantization matrices is followed. Secondly, the GOP layer (group of picture layer) as shown in FIG. 8B is a minimum unit of a screen group that is a random access unit and has information for editing and a time from the start of a sequence. After the start code, a plurality of flags (time_code flag, closed_GOP flag, broken_link flag) are followed. Thirdly, a picture coding mode, a picture type, and the like are set in the picture layer as shown in FIG. 8C as characteristics common to one picture. A D picture used in MPEG1 has a picture having only a DC component used for fast forwarding, fast forwarding, and the like. The picture type is composed of I, P, and B pictures. After the start code, a temporary reference indicating the screen order in the GOP, a picture type, a flag indicating whether an encoder or a motion vector is an integer unit, a frame interval (F_code) of the motion vector, and so on are followed. Fourth, a slice layer as shown in FIG. 8D is information common to a small screen for dividing a single screen into an arbitrary length and includes, for example, a quantization characteristic value. The slice layer is a band of macroblocks of any length in the smallest unit of the series of data having a start code, and may not span several pictures. The first and last macroblocks cannot be skipped. In the case of a slice composed of one macroblock, the macroblocks can be skipped. The overlap or skip between the slices is not allowed, the vertical position of the slice is included in the slice start code itself, and the horizontal position of the leading macroblock of the slice is indicated by using the macroblock address of the macroblock layer. Fifth, a macroblock layer as shown in FIG. 8E is a layer in which a plurality of block layers as shown in FIG. 8F are linked. In general, four block layers are linked. The macroblock layer is information common to a recovery block obtained by further dividing the slice layer, and includes motion compensation, a motion vector value, and the like. The macroblock layer is followed by any number of macroblock stuffing, macroblock block escape, macroblock address (MBA), macroblock type, and the like. Finally, a block layer as shown in FIG. 8F is a minimum unit of transmission and compression, includes necessary IDCT coefficients, and ends with an end of block (EOB). The EOB is added even when there are 64 VLCs of the coefficients. Intra DC uses its own VLC, and the others are represented by two-dimensional VLC.

Accordingly, the header analyzing unit 311 separates packets for each layer in the MPEG2 video ES structure having the structure as shown in FIGS. 8A to 8F, and includes a sequence header, a GOP header, and a picture header. header, slice header, and macroblock header are analyzed. And MPEG2 such as frame rate, picture size, picture coding type (I frame, P frame, B frame), GOP sequence (IBBPBBPBBP or IBPBPBPBPBP) according to the header analysis result as described above. Order of I / P / B frames in the standard), etc., and make the result available in the subsequent decoding process.

The buffer 313 stores the actual data from the data separated by the header analyzing unit 311 as described above. In this case, the actual data stored in the buffer 313 includes an index of block data to extract block data in the macroblock mode. At this time, if the data is an I frame (intra frame), this data is input to the variable length decoding unit 315. Then, the variable length decoder 315 performs variable length decoding according to the parsing information transmitted from the header analyzer 311. The variable length decoding method uses the Huffman decoding method proposed by the MPEG2 standard. This method refers to a process of reading each data bit by bit and converting the data into a predetermined standard table. The general variable length decoding method is the first method to perform decoding in the macroblock mode. The variable length decoding unit 315 converts the stored data after being compressed by a variable length coding (VLC) method and converts the stored data into original data. Work continues until the data of one macro block is found.

The result value decoded by the variable length decoder 315 is input to the inverse quantizer 317, where the DC value is extracted from a DCT (discrete cosine transform) which is the core of MPEG2 video compression. The IDCT (inverse discrete cosine transform) unit 319 performs IDCT decoding. In the MPEG2, the IDCT unit is limited to an 8 * 8 pixel area. Therefore, the conversion equation (8 * 8 IDCT conversion equation) is expressed by Equation 1 below.

The two-dimensional transformation of Equation 1 is the same as that of transposing the data that has undergone the transformation on the x-axis and performing the same IDCT on the y-axis, as shown in Equation 2 below. Equation 2 below shows an 8-point IDCT conversion equation on the x-axis, and Equation 3 shows an 8-point IDCT conversion equation on the y-axis.

On the other hand, if the data output from the buffer 313 is a non-intra frame such as a P frame or a B frame (non-intra frame), a motion compensation process is required. In the case of the P frame or the B frame as described above, the motion compensation process is additionally performed and the result is compared with the IDCT final result and output. First, if it is a P frame, the motion compensator 335 compares the image data of the previous frame stored in the previous image storage unit 331 with the input P frame image to calculate a motion vector, and compensates for the motion using the calculated result. . In the second frame B, the motion compensator 335 calculates a motion vector value by comparing the previous frame image stored in the previous image storage unit 331 with the next frame image stored in the next image storage unit 333 and the current B frame image. , The motion compensation of the B frame is performed using the calculated result. In this case, the motion compensation proposed by the MPEG2 standard interpolates by applying a half-pel resolution level, thereby increasing the correlation between frames. That is, motion information transmitted through the channel is calculated as the half-pel resolution. The motion compensation value calculated as described above is output by being combined with the IDCT value previously calculated by the adder 337.

Then, as described above, the IDCT-converted signal (I, B, P frame image) is converted into a signal having a shape suitable for the display unit 150 by the converter 321 and output. At this time, if the display unit 150 is an LCD display unit, the converting unit 321 converts the YUV video signal into an RGB video signal and outputs the RGB video signal.

In this case, a method of scanning a signal on the display unit 150 in the moving picture, particularly a broadcasting video, is divided into two methods. One is a progressive scan method and the other is an interlace scan method. 9A is a diagram showing the characteristics of the progressive scan method, and FIGS. 9B and 9C are diagrams showing the characteristics of the progressive scan method. 9A is a method of scanning an output signal for each line, and a method of scanning a signal by dividing the signal into even lines / odd lines as shown in FIGS. 9B and 9C. to be.

10A and 10B are diagrams illustrating a scanning method which is a method of compressing by converting 8 * 8 pixels into one dimension in a video compression method such as MPEG2. That is, since DCT coefficients are two-dimensional values, they should be converted and encoded in one dimension. At this time, the low frequency signals are bundled with the low frequency signals and the high frequency signals are bundled with the high frequency signals to increase the compression efficiency. Therefore, a method for this is required, which is called scanning. The scanning method includes a zigzag scan method as shown in FIG. 10A used in MPEG1 and 2, and an alternative scan method provided only in MPEG2. 10A and 10B show examples of the order according to the position of each pixel in each scan method.

A portable terminal having a digital broadcast receiver is effective to resize the received video signal. That is, since the size of the display unit 150 is limited, the portable terminal is much smaller than the display unit size of a general digital broadcast receiver. Therefore, it is effective to resize the size of the received video signal to match the size of the display unit 150 of the mobile terminal. In addition, the image signal received by the digital broadcasting receiver may use a forward scanning method and an annular scanning method as shown in FIGS. 9A to 9C. Therefore, it is preferable to resize the received video signal according to the image scanning method of the received video signal. Third, as shown in FIGS. 10A and 10B, the image signal may be resized according to a block scanning method. Fourthly, since the mobile terminal is a miniaturized product unlike the general digital broadcasting receiver, there is a limit in the speed of decoding the digital broadcasting signal. Therefore, it is desirable to resize the video signal according to the processing speed of the digital broadcast signal received by the mobile terminal. Fifth, the screen image may be resized according to the decoding quality that can be displayed on the mobile terminal. Therefore, in the embodiment of the present invention, the resizing factor used as the resizing control signal of the video decoder 230 may be represented as shown in Table 5 below. In addition, other factors than the resizing factors shown in Table 5 may be considered.

At this time, the most resizing factor of the resizing factors in the mobile terminal will be the size of the display unit 150 of the mobile terminal. Therefore, when resizing the image size according to the resizing factors, the image size may be resized in consideration of all the resizing factors as shown in Table 5, and if necessary, one or more resizing factors may be selected to resize the image. You can also perform a resizing of the size. In the embodiment of the present invention, it will be described as resizing the screen by using all the above resizing factors.

The video decoder 230 resizes an image received by the resizing factor as described above. At this time, the configuration for resizing the image size may be a variable length decoder 315, an IDCT unit 319 and a motion compensation unit 335 of the video decoder 230. In this case, the factors for resizing the image size in the variable length decoder 315, the IDCT unit 319, and the motion compensator 335 may be different. The resizing control signals according to the resizing factor may be classified as shown in Tables 6 to 8. The most important resizing control signal is the resizing control signal of the IDCT unit 319, and thus the resizing control signals of the variable length decoder 315 and the motion compensation unit 335 are distinguished. <Table 6> is a resizing control signal of the IDCT unit 319, and the contents described in the description may be screen size, image scanning method, and decoding quality as resizing factors, and accordingly, the resizing size of the IDCT unit 319 (Control signal) is determined.

In addition, the resizing control signal of the variable length decoding unit 315 is determined by the size of the IDCT unit 319 of Table 6 as shown in Table 7 below. Table 7a shows the results of zigzag VLD resizing and effects, and Table 7b shows the contrast of zigzag and alternative VLD resizing and effects.

The resizing control of the motion compensator 335 is determined by the screen size, the decoding quality, and the decoding speed. Table 8 below shows the resizing control signal of the motion compensator 335.

Hereinafter, an operation of resizing an image size according to an embodiment of the present invention in the video decoder 230 will be described in detail.

First, an operation of resizing using the data skip method in the variable length decoding unit 315 will be described.

의 경우 (1/2, 1/4) 만을 예시로 하였지만, 8x8 블록을 갖는 경우에 1/8 ~ 7/8 리사이징이 모두 가능함은 자명하다. 한편

의 경우는 고속 IDCT 알고리즘을 적용하여 보다 빠른 연산이 가능하다. (의견) 예시로 든 것은 1/2^n 뿐이지만 (1/2, 1/4), 1/8 ~ 7/8 까지의 리사이징이 모두 가능하다. 1/2^n을 주로 하는 이유는 2^n 인 경우 Fast Algorithm (Butterfly Algorithm)을 적용 가능하기 때문이다. 예를들어 가로와 세로를 각각 1/2로 줄일 경우 4*4 영역만을 IDCT하게 되면, 상기 4*4 공간 영역 데이터가 추출되는데, 이 데이터는 8*8 IDCT 수행후 평균을 낸 결과와 거의 동일하다. As described above, the standard screen size of DVB-T broadcasting, which is a kind of digital broadcasting, has a 720 * 576 pixel size. In addition, the mobile terminal has a screen size of approximately 176 * 208 pixels. Therefore, when the digital broadcast receiver signal is used in a general digital broadcast receiver, the size of the display unit is large, so that the digital broadcast receiver signal can be reproduced with clear picture quality. However, when the digital broadcast receiver signal is displayed on the mobile terminal, it is not efficient to decode the screen size signal of the general digital broadcast receiver as it is, so that the mobile terminal resizes the received broadcast signal before processing it to reduce the screen size. desirable. In addition, it is efficient to perform the resizing processing operation in a state before compression. Below

In the case of (1/2, 1/4), only 1/8 to 7/8 resizing is possible when having 8x8 blocks. Meanwhile

In the case of, the fast IDCT algorithm is applied for faster computation. (Comment) As an example, it is only 1/2 ^ n (1/2, 1/4), but all 1/8 to 7/8 resizing is possible. The reason why 1/2 ^ n is mainly used is because Fast Algorithm (Butterfly Algorithm) is applicable to 2 ^ n. For example, if the width and length are each reduced to 1/2, if only 4 * 4 region IDCT is extracted, the 4 * 4 spatial region data is extracted, which is almost the same as the averaged result after performing 8 * 8 IDCT. Do.

At this time, it is meaningless to extract values other than the 4 * 4 region. That is, the process of comparing and referring to the table through the variable length decoding may be omitted, and only the end position of the final block may be extracted. If the VLD and IDCT are performed only in the region where the actual decoding is performed, the computation amount may be greatly reduced.

In the following description, only the zigzag scan method will be described. In addition, the effects of the alternate scan method are almost the same as those obtained in the zigzag scan method.

FIG. 11A is a diagram for describing a 4 * 4 scanning method in the case of reducing the width and length to 1/2 respectively. As shown in FIG. 11A, the 4 * 4 scanning method needs to extract only the 24th index in order to extract the 4 * 4 region, which is equivalent to reducing the amount of computation to 25/64. The 4 * 4 scan method may be used in the forward scanning method as shown in FIG. 9A. However, in the case of using the parallel scan method as shown in FIGS. 9B and 9C, the data on the horizontal axis is sufficient while the data on the vertical axis are transmitted only for 1/2 hour of the total time. Therefore, in order to obtain an effect similar to the effect of resizing to 4 * 4 size in the forward scanning method, it is preferable to resizing to 8 * 2 as in FIG. 11B. It also takes advantage of the result of the IDCT empirically and the less data in the lower right part of the natural image.

FIG. 11C shows an example of resizing to 4 * 2 in a parallel scan method. Referring to FIG. 11C, when the horizontal and vertical quarter resizing for an interlace scan or the horizontal and vertical half resizing for a progressinve scan are performed, There is a low frequency and there is a need for reinforcement of vertical axis data in parallel scan. Accordingly, FIG. 11C illustrates a 4 * 2 scan area for reinforcing data on the vertical axis and a characteristic in which data in the lower right end has a low frequency when using the parallel scan method. The scan area as shown in FIG. 11C is equivalent to reducing the amount of computation to 12/64. In addition, the method of creating an optimal shape by combining the above characteristics and the like is a modified 4 * 2 scan method as shown in FIG. 11D, which has an effect of reducing the amount of computation to 10/64. Have

Secondly, the operation of resizing using the zonal filtering method of the IDCT unit 319 according to an embodiment of the present invention will be described.

FIG. 12 shows a zonal filter structure of the IDCT unit 319. FIG.

Referring to FIG. 12, the variable length decoding unit 315 extracts only pixels of a partial region, that is, resizes to perform VLD. In the IDCT unit 319, only some regions are extracted to perform IDCT. A filter that selects (ie, a partial region) is called a zonal filter. As shown in FIG. 12, when n * n regions are extracted and processed from the N * N regions, since they have been resized from N to n, IDCT equations taken in each case are also represented by Equations 4 to 6 below: It can be expressed as Here, Equation 4 is a 2-point IDCT equation, Equation 5 is a 4-point IDCT equation, and Equation 6 is an 8-port IDCT equation.

In Equations 4 to 6, the number of repetitions of taking sigma differs from 2-8 times, but if a butterfly algorithm, which is a fast algorithm, is actually applied, The actual speed of the IDCT part alone is much faster.

On the other hand, when the DCT is processed in the encoding process, when the low frequency component including the DC value is driven to the upper left, most non-zero values exist in the left side of the block. Considering this, if only 8 * 2 part of 8 * 4 selection is performed and other coefficients are assumed to be 0, multiplication, addition, and shift operation used in row processing are mostly performed. Reduced to 1/2 In addition, if only 4 * 2 is processed in the 4 * 4 selection area, the operations of the row processing are reduced to 1/2 like 8 * 4. In this case, the selection area may be the same as setting the scan area as shown in FIGS. 13A to 13C. Here, when performing the IDCT, there is a difference between selecting only an 8 * 2 region and an 8 * 2 IDCT. That is, in the case of selecting the 8 * 2 area, the row process performs 2 * 1 1-D iDCT eight times and the column process performs 8 * 1 1-D IDCT four times. In the case of 8 * 2 IDCT, there is a difference in that row processing is performed 2 * 1 1-D iDCT 8 times and column processing is 8 * 1 1-D IDCT twice.

Table 9 below shows the row IDCT results in 8 * 4 IDCT and 4 * 4 IDCT, and Table 10 shows the row IDCT of the selection in 8 * 4 IDCT and 4 * 4 IDCT. Table showing the results.

Table 10 above shows all IDCT processed values in four blocks after processing row IDCTs of 8 * 4 or 4 * 4 selection areas.Because only 8 * 2 areas are selected, blk [2] or blk [3] is not filled with zeros. That is, in the 8 * 4 or 4 * 4 god IDCT process, the process except for the selection area of the block is assumed to be 0, but the column processing process is performed for the IDCT process of all 8 * 4 blocks. In the case of reducing the horizontal component to one-quarter like 8 * 2 IDCT, too much data is lost in the horizontal direction, so it is very different from the original image even if it is displayed through interpolation for later display. However, by applying this method, we can benefit from the amount of computation while minimizing the loss of image quality.

The above method shows the resizing effect of the IDCT unit in the video decoder which decodes the video signal using the MPEG encoding method. However, even when encoding an image signal using an IT (integer transform) as in H.264 may have a similar resizing effect. In this case, the video decoder may perform a resizing operation using an inverse integer transform (ITT) unit, and a resizing method of the IIT unit will be described later.

Third, the operation of resizing using the minimum motion compensation method in the motion compensator 335 according to an embodiment of the present invention will be described.

In MPEG2's video compression standard, motion compensation allows for higher correlation by applying half-pel resolution levels. That is, the motion information transmitted through the channel has a half-pel resolution as shown in FIG. 14A. As in the present invention, in the zonal filter, only the 8 * 4 or 4 * 4 region is selected among the 8 * 8 blocks, and accordingly, the image is reduced to 1/2 or horizontally vertically by 1/2 respectively. When the decoder is implemented, the motion compensation can be considerably reduced by applying motion compensation through interpolation from the transmitted half-pel resolution motion information to the quarter-pel resolution as shown in FIG. 14B. . Also, in the case of implementing a decoder that selects only 8 * 2 areas of 8 * 8 blocks in the Johnland filter and outputs a horizontally reduced image according to the figure, the motion filter of the transmitted half-pel resolution is shown in FIG. By interpolating to the same octa-pel resolution, motion compensation can be applied to reduce errors in motion compensation. That is, when reduced to 1/2, the lower 2 bits of the transmitted 6-bit motion information can be interpolated to the quarter-pel resolution. When reduced to 1/4, the lower 3 bits of the transmitted 6-bit motion information are reduced. Contains information that can be interpolated at 1 / 8-pel resolution.

14D shows an example of an interpolation technique for motion compensation at quarter-pel resolution. If the half pel bit is Xh, Yh and the bit having quarter-pel information is Xq, Yq, the position from the upper left integer pixel Xdist = 0.5 * Xh + 0.25 * Xq, Ydist = 0.5 * Yh + 0.25Yq. When the motion compensation is performed at the quarter-pel resolution level, the pixel d [i] positioned at the quarter-pel position is located at a distance of Xdist and Ydist from the integrator pixel position of the upper left corner. Therefore, the weights are 1-Xdist and 1-Ydist. Accordingly, in bi-linear interpolation, d [i] may be represented as shown in Table 11 above.

In the embodiment of the present invention, the video decoder 230 resizes and decodes an image encoded by the resizing factor as shown in Table 5. Among the resizing factors as shown in Table 5, the display size, SD: full size, CIF: half size, QCIF: quater size, and quality can be set by the user. The image scan and the block scan may be determined by the received digital broadcast receiver signal, and the decoding speed may be set by the communication environment of the mobile terminal. Therefore, when the digital broadcast receiver receiver processes the digital broadcast receiver signal and displays the configuration shown in FIG. 1 on the display unit 150, the user selects the size and display quality of the screen to be displayed. In this case, the size of the screen may be one of full size (SD: 720 * 576 pixels), half size (CIF: 360 * 288), and quarter size (180 * 244) as described above, and the image quality is high quality. And general definition. In addition, the video decoder 230 determines a resizing factor by analyzing a scan method in the header of the received video ES. The scan method may be a forward scan and a parallel scan as an image scan method (a screen output method), and may include a zigzag scan and an alternative scan method as a block scan method. In the embodiment of the present invention, it is assumed that the block scan method only considers the zigzag scan method. In addition, the controller 100 determines the decoding quality according to the reception speed of the digital broadcast signal (ie, the communication environment). That is, if the digital broadcasting receiver communication environment of the mobile terminal is good, the communication quality is improved. Therefore, the video decoder 230 can decode with high quality decoding quality. If the communication environment is poor, the decoding quality of the received digital broadcasting receiver signal is degraded. do.

As described above, the resizing size of the video decoder 230 may perform resizing of an image encoded by only one or more resizing factors among the resizing factors as shown in Table 5. That is, the resizing operation may be performed only by the screen size factor among the resizing factors. In this case, the resizing of the video decoder 230 may be 8 * 8, 4 * 4, 2 * 2. In addition, when the resizing operation is performed only by the screen size and the image scanning factor among the resizing factors, if the resizing of the video decoder is a forward scan, the resizing may be 8 * 8, 4 * 4, 2 * 2. Resizing can be 8 * 4, 4 * 2, 4 * 2 (modified), and so on. Therefore, the resizing of the video decoder 230 may be used by setting one or more of the resizing factors as shown in Table 5. In the following embodiment of the present invention, it is assumed that the resizing function of the video decoder 230 is performed in consideration of all the resizing factors of Table 5.

15A and 15B illustrate a configuration of a video decoder 230 for resizing and decoding an encoded image according to an embodiment of the present invention. 15A and 15B, R shown in the variable length decoding unit 315, the IDCT unit 319, and the motion compensation unit 335 respectively perform a function of resizing the image according to the resizing control set in the corresponding configuration. 15A illustrates a configuration of a video decoder 230 capable of decoding frame images consisting of I, B, and P frames, and FIG. 15B illustrates a configuration of a video decoder 230 capable of decoding frame images consisting of I and P frames. The configuration is shown.

16 is a flowchart illustrating a procedure of determining resizing factors for resizing control of video decoder 230. FIG. 16 illustrates a procedure of controlling image resizing of the video decoder 230 by analyzing resizing factors in the controller 100.

Referring to FIG. 16, when the broadcast reception mode is set, the controller 100 controls the video decoder 230 by analyzing the resizing factors. In this case, the resizing factors may be five or less as shown in Table 5. First, in step 511, the controller 110 determines the size of the video screen according to the output screen size. In this case, the size of the output screen may be determined by a user input, and the control unit 100 may automatically set the size of the display unit 150 according to the size of the display unit 150. The display unit 150 may vary depending on the type of portable terminal. That is, when the mobile terminal is a telephone, the mobile terminal may have a size of 176 * 208 in the case of the European type, and may have a size of 176 * 200 in the case of the domestic type. In the embodiment of the present invention, it is assumed that the controller 100 automatically determines the size according to the size of the display unit 150 of the mobile terminal.

In addition, the controller 100 checks a screen output method. The information of the image scan method is inserted in the header information of the video image. Accordingly, the header analyzer 311 of the video decoder 230 extracts the image scan information from the header of the received image and transmits the image scan information to the controller 100. In operation 513, the controller 100 may check a screen output method of a video signal currently received. The screen output method may include a progressive scan method as shown in FIG. 9A and an interlace scan method as shown in FIGS. 9B and 9C.

In addition, the controller 300 checks a block scan method. The block scan information is inserted into header information of a video image. Accordingly, the header analyzer 311 of the video decoder 230 extracts the block scan information from the header of the received image and transmits the block scan information to the controller 100. In operation 515, the control unit 100 may check a screen output method of a video signal currently received. Here, the block scan method includes a zig-zag scan method as shown in FIG. 10A and an alternative scan method as shown in FIG. 10B.

In addition, it is possible to select the image quality of the video decoder 230 by the user's selection. Here, the decoding quality may affect the resolution of the screen, and various kinds of image quality may be set. However, in the embodiment of the present invention, it is assumed that the image quality is two kinds of high quality and general quality. Accordingly, the user may select general picture quality or high picture quality when performing the broadcast reception mode. Accordingly, when the type of the image quality is determined, the controller 100 checks the type of the image quality selected in step 517. If the image quality is high, the controller 100 proceeds to step 521 and adjusts the resizing control value upward. In case of the general picture quality, the control unit 100 proceeds to the next step without changing the resizing control value.

In addition, the control unit 100 determines the decoding speed by analyzing the environment of the mobile terminal. If the control unit 100 prioritizes the speed at the time of decoding in step 527, the controller 100 adjusts the resizing control value downward in step 525. Otherwise, the controller 100 does not change the resizing control value. If the speed is given priority, a large number of frame data can be decoded in a unit time.

Determine a resizing control value determined by the resizing factors, and output the determined resizing control values to each of the resizers 410, 420, and 450 of the variable length decoder 315, IDCT unit 319, and motion compensation unit 335, respectively. do. In step 529, the controller 100 controls the video decoder 230 to decode the received video signal of the digital broadcast. The video decoder 230 decodes the video signal of the digital broadcast received according to the resizing control and outputs the decoded video signal to the display unit 150.

In step 531, the controller 100 checks whether a resource for decoding the video signal of the digital broadcast currently received is insufficient. Here, the resource affects the decoding speed of the video decoder 230. That is, when the mobile terminal runs another application while performing the digital broadcast service mode, the resource is insufficient or the decoding information is insufficient in the digital broadcast receiving environment (that is, the communication environment of the mobile terminal is insufficient). Deterioration, and the broadcast reception performance is degraded). Therefore, in step 531, the controller 100 checks the state of the current mobile terminal and if the resource is insufficient or the decoding information is insufficient, the controller 100 proceeds to step 525 to adjust the resizing control value downward. Otherwise, the controller 100 adjusts the current resizing control value. The decoding operation is continued while maintaining the value of.

Referring to the procedure of controlling the resizing according to the resizer factor as described above, the screen size is determined according to the user's selection or the size of the display unit 150 of the mobile terminal, and the screen output method and block according to the stream characteristics of the received digital broadcast signal. The scanning method is determined, and the type of the decoded image quality is determined in consideration of the image quality element by the user's input. The controller 100 may increase the decoding speed by adjusting the resizing control value downward when prioritizing the speed according to its own determination.

The controller 100 determines the resizing control value by analyzing the resizing factors as described above. At this time, the resizing control values of the variable length decoding unit 315, the IDCT unit 319, and the motion compensation unit 335 are shown in Tables 7a, 7b, 6, and 8, respectively. Here, referring to Table 6, an example of determining the resizing control value of the IDCT unit 319 is that the output screen size is a CIF standard, the image scan is a progressive scan method, the decoding speed is general, and the decoding quality is high. In the case of, the controller 100 determines 4 * 4 as the resizing control value as shown in Table 6. In addition, when the output screen size is CIF standard, the image scanning is a progressive scan method, the decoding speed is general, and the decoding quality is high quality, the control unit 100 uses a resizing control value of 8 * as shown in Table 6. Determine 4 The same resizing control value of the IDCT unit 319 is used in the variable length decoding unit 315 in the same way. In addition, the resizing control value of the motion compensator 335 is determined by the screen size, the decoding quality, and the speed. That is, when the screen size is CIF and the decoding quality is high quality, the control unit 100 outputs a quarter-pel control signal as the resizing control value of the motion compensator 335, the screen size is QCIF, and the decoding quality is general quality. If the decoding speed is normal, the controller 100 outputs a half-pel control sensor as the resizing control value of the motion compensator 335.

15A and 15B are diagrams showing an example of the configuration of the video decoder 230 having the resizing function. 15A illustrates an example of a video decoder 230 that decodes I, B, and P frame images, and FIG. 15B illustrates an example of a video decoder 230 that decodes I and P frame images. This will be described with reference to FIG. 15A.

Referring to FIG. 15A, the header analyzer 311 extracts and analyzes header information of a received video signal and transmits the header information to the controller 100. Then, the controller 100 determines the resizing control value while performing the procedure as shown in FIG. 16 and applies these values to the resizers 410, 420, and 450 of the variable length decoder 315, the IDCT unit 319, and the motion compensation unit 335, respectively.

17 is a diagram showing the configuration of the variable length decoding unit 315. FIG.

Referring to FIG. 17, a VLD resizer 410 inputs a resizing control value output from the controller 100, controls an operation of the table converter 413 according to the resizing control value, and controls the table converter 413. Outputs to the output buffer 415. The table converter 413 includes a table for variable length decoding, inputs image data output from the buffer 313, converts the input image data encoded with the variable length into original data, and outputs the resizer 410. The drive is controlled by the control of. The output buffer 415 buffers and outputs the data decoded into the original data by the table converter 413 under the control of the resizer 410.

As illustrated in FIG. 17, the variable length decoder 230 controls a decoding operation according to a resizing control value output from the controller 100. In this case, the resizing control value may be a value as shown in Tables 7a and 7b, and includes information on a block scan method. For example, if the resizing control value is a zigzag scan method of 4 * 4, the resizer 410 controls the table converter 413 to decode variable length coded data up to a 24th pixel data, and the output buffer 415 The 16th pixel data of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 17, 18, and 24th are controlled to be stored. In addition, if the resizing control value is 4 * 4 alternative scanning method, the resizer 410 controls the table converter 413 to decode the variable length coded data up to the 25th pixel data, and 0 to the output buffer 415. 16, data of 1, 2, 3, 4, 5, 6, 7, 8, 9, 18, 19, 10, 21, 24 and 25 are controlled to be stored.

In addition, if the resizing control value is a 4 * 2 zigzag scan method, the resizer 410 controls the table converter 413 to decode the variable length coded data up to the 11th pixel data, and 0 to the output buffer 415. The 8th, 1st, 2nd, 3rd, 4th, 8th, 9th and 11th pixel data are controlled to be stored. In addition, when the resizing control value is 4 * 2 alternative scanning method, the resizer 410 controls the table converter 413 to decode the variable length coded data up to the ninth pixel data, and 0 in the output buffer 415. And 16th, 1st, 2nd, 3rd, 4th, 5th, 8th, and 9th pixel data are stored.

As described above, the variable length decoding unit 315 may perform the variable length decoding only in a predetermined region set by the resizing control value and confirm the result. Therefore, the first VLD is performed and the result is output to the output buffer 415. If the output area is exceeded according to the resizing control value, the input stream is bypassed and the VLD is terminated. In this case, since the bypassed data are data that are not used for decoding, it does not matter at all even if the VLD value is not properly crossed. In this case, when the resizing control value is set, the variable length decoding unit 230 decodes the last pixel data of the set resizing control value, and the last pixel data of the resizing control value depends on the zigzag scan method and the alternative scan method. As shown in Table 7b, it can be seen that the amount of decoding calculation of the variable length decoding unit 230 according to the resizing is greatly reduced.

18 is a diagram showing the configuration of the IDCT unit 319 of the video decoder 230. As shown in FIG.

Referring to FIG. 18, the buffer 421 may be an output buffer 415 of the variable length decoder 315. The IDCT unit 319 first performs DCT of the Y-axis pixels, and then performs DCT of the X-axis pixels. Accordingly, the IDCT unit 319 includes a Y-axis resizer 421 and an X-axis resizer 431, and the scan area of the Y and X resizers is determined by the zonal filter. First, the Y resizer 421 checks the resizing control value of the Y-axis in the resizing control value, and then transfers the data output from the buffer 415 to the corresponding IDCT among the IDCT423-428. Then, the IDCT outputs the IDCT data output from the buffer 415 and stores the data in the buffer 429. When IDCT of Y-axis data is performed as described above, the IDCT is stored in the buffer 429. Secondly, the X resizer 431 checks the resizing control value of the X-axis in the resizing control value, and then transfers the data output from the buffer 429 to the corresponding IDCT among the IDCT433-438. The IDCT then IDCTs the data output from the buffer 429 and outputs the data in the buffer 439. When the IDCT of the X-axis data is performed as described above, the buffer 429 stores the result values of the Y-axis and the X-axis IDCT. 18 illustrates an example in which an IDCT converter selected by the resizing control value of the Y axis performs an IDCT operation, and then an IDCT converter selected by the resizing control value of the X axis performs an IDCT operation to perform resizing IDCT. have. However, first, the IDCT converter selected by the resizing control value of the X axis performs the IDCT operation, and then the IDCT converter selected by the resizing control value of the Y axis performs the IDCT operation to perform the resizing IDCT.

The resizing control value of the IDCT unit 319 is determined as shown in Table 6. Therefore, when the IDCT resizing control value is 8 * 4, the Y resizer 421 transfers data stored in the buffer 415 to 8-point IDCT423, and the 8-point IDCT423 is 8-point Y-axis pixel data transferred from the buffer 415. IDCT them and store them in the buffer 429. The X Resizer 431 transfers the data stored in the buffer 429 to the 4-point IDCT435, and the 4-point IDCT435 IDCTs the x-axis 4-point data (Y-axis IDCT data) output from the buffer 432 to buffer 439. Store in When the IDCT resizing control value is 4 * 2, the Y resizer 421 transfers data to the 4-point IDCT425 and the X resizer 431 transfers the data to the 2-point IDCT437.

As described above, in case of IDCT, according to resizing control values such as 8 * 8, 8 * 4, 8 * 2, 4 * 4, 4 * 2, 2 * 2, 4 * 1, 2 * 1, 1 * 1, etc. Perform the operation of Y-axis and X-axis respectively. In this case, since the 8-point, 4-point, and 2-point IDCT equations are the same, the Y resizer 421 and the X resizer 431 serve to transmit the IDCT coefficient value according to the resizing control value. In this case, as shown in FIG. 12, the IDCT unit 319 extracts only a partial region determined by the resizing control value to perform IDCT on the Y-axis and the X-axis, and does not perform IDCT on the data of the remaining region. Use zonal filter method. Accordingly, in the resizing of the IDCT unit 319, as shown in FIGS. 13A to 13C, if the Y-axis IDCT is performed on the area set by the resizing control value and the X-axis IDCT is performed, the IDCT is performed on the pixels of the remaining area. I never do that. Therefore, the IDCT resizing control values and effects according to the embodiment of the present invention can be represented as shown in Table 6.

19 is a diagram showing the configuration of the motion compensator 335 of the video decoder 230. FIG.

Referring to FIG. 19, an input buffer 461 inputs and buffers a motion vector value of the received video data. The resizer 450 selects a corresponding motion compensator based on the resizing control signal and transmits a motion vector value of the input buffer 461. The motion compensators may be composed of a quarter pel compensator 463, a half pel compensator 465, and an octafel compensator 467. The motion vector and the previous and / or ) Compensates for the motion with the set size using the motion vector value of the next image. The output buffer 469 buffers and outputs the outputs of the quarter-pel compensator 463, the half-pel compensator 465, and the octafel compensator 467 whose motion is compensated.

Referring to the operation of the motion compensator 335, the resizing control of the motion compensator 335 is determined by the screen size, the decoding quality, and the decoding speed, as shown in Table 8. When the motion compensation unit 335 fixes the half pel, the motion compensation may affect decoding quality. For example, in case of compensating for the movement of 1.5 pixels on an 8 * 8 screen, the motion should be compensated for at a 0.75 pixel position on 4 * 4 and 8 * 4 screens. In this case, when the motion is compensated by the half-pel method on the 4 * 4 or 8 * 4 screen, the motion may be compensated by the unit of 0,5 pixel positions, thereby reducing the decoding efficiency. Therefore, the use of the quarter-pel method can improve the motion compensation efficiency of the 8 * 4 screen X-axis motion compensation, the 4 * 4 screen Y-axis and X-axis motion compensation, and the 4 * 2 screen Y-axis motion compensation. Therefore, it is recommended to use the half-pel method when the decoding speed is the priority in 4 * 4, 8 * 4, and 4 * 2, and the quarter-pel method or the octafel method when the image quality is the priority. Also, if the speed is prioritized in the 4 * 2, 8 * 2, and 2 * 2 methods, the half-pel or quarter-pel method should be used, and the octapeel method should be used when the image quality is the priority. In addition, in video decoders such as H.264 that basically use quarter-pel, octape can be used to resize images such as 8 * 4, 4 * 4, and 4 * 2 in half.

The video decoder 230 may be configured in software. In this case, the process 529 of FIG. 16 may be configured as shown in FIG. 20. 20 is a flowchart illustrating a procedure of a video decoding process according to an embodiment of the present invention.

Referring to FIG. 20, the controller 100 determines the resizing control values of the variable length decoder 315, the IDCT unit 319, and the motion compensator 335 while performing the procedure of FIG. 16. Thereafter, when the encoded video data is received, the header of the video strm received in step 611 is analyzed, and the video data received in step 613 is stored in a buffer. In step 615, the frame is analyzed.

If the frame image is an I-frame image, the control unit 100 detects it in step 615 and resizes the decoding area of the video data received by the determined VLD resizing control value in step 617, and the variable length existing in the resized area. The encoded pixel data is decoded into original data with reference to the variable length decoding table. In step 621, the control unit 100 dequantizes the variable length decoded video data and extracts a DC coefficient. After performing the dequantization process, the controller 100 resizes the dequantized video data according to the determined IDCT resizing control value in step 623 and then performs IDCT calculation on the resized Y-axis and X-axis video data. In this case, the resizing of the IDCT unit 319 may be different from or the same in the resizing area of the Y axis and the X axis. Accordingly, IDCT calculation is performed using the point IDCT corresponding to the number of pixels on the resized Y-axis and the X-axis. After performing the IDCT procedure as described above, the control unit 100 stores in step 625.

The operations in steps 617 to 623 are performed in block units (8 * 8) as shown in FIG. 8F. Accordingly, the variable length decoding, inverse quantization, and IDCT operations are performed on image data in units of blocks, and the data decoded in units of blocks is stored in step 623. In this case, when the decoding operation on the video data having the size of one frame is terminated by repeating the decoding operation as described above, the control unit 100 detects this in step 623, and the decoded video data having the one frame size is converted into the RGB data in step 625. To convert. That is, since the input data is YUV data, the input data is converted into RGB data that can be displayed on the display unit 150. In this case, if the received video data is RGB data, step 625 may be omitted.

However, if the current frame image data is a P frame or a B frame in step 615, variable length decoding, inverse quantization, and IDCT operations are performed in the same manner as in step 627 through step 631 in step 623. In step 633, the controller 100 compensates for the movement of the currently received frame data, adds the motion compensated video data to the decoded video data, and stores the same in step 623.

Herein, operations 617 to 635 are performed in block units (8 * 8) as shown in FIG. 8F. Accordingly, the variable length decoding, inverse quantization, and IDCT operations are performed on image data in units of blocks, and video data whose motion is compensated in units of blocks is added to and stored in the IDCT data. In this case, when the decoding operation on the video data having the size of one frame is ended by repeating the decoding operation as described above, the control unit 100 detects it in step 623 and detects the decoded video data having the one frame size on the display unit 150 in step 625. Convert to a form that can be displayed (eg RGB data). At this time, if the received data is P frame data in the motion compensation process of step 633, compensation is performed according to the difference of motion compared to previous frame data, and if it is B frame data, the motion difference is compared to previous and next frame data. Perform rewards accordingly.

As described above, the video decoder 230 may be implemented in hardware as illustrated in FIGS. 15A and 15B, and may be implemented in software in the controller 100 as illustrated in FIG. 20.

As described above, the digital broadcast receiver according to the embodiment of the present invention resizes the encoded video data inputted according to the size of the display unit of the portable terminal before decoding it. The resizing of the input video data may be variably set according to one resizing factor. The largest resizing factor may be the screen size of the display unit 150, and the priority of the remaining resizing factors is an image scan signal (interlace scan, progressive scan) or block scan (zig-zag scan, alternative scan) of the digital broadcast signal. , Decoding speed, decoding quality, and the like.

21A to 21D show screen output examples of an 8 * 8 video decoder and a 4 * 4 video decoder according to an embodiment of the present invention. 21A and 21B are screen examples showing the results of decoding the received digital broadcast news using an 8 * 8 and 4 * 4 video decoder, respectively, and FIGS. 21C and 21D illustrate a received digital broadcast advertisement ( An example of a screen showing the result of decoding an advertisement using an 8 * 8 and 4 * 4 video decoder, respectively. In the comparison of the 8 * 8 video decoder and the 4 * 4 video decoder, the 4 * 4 video decoder includes a VLD control and a resize part, and motion compensation is an example of using a half-pel method.

22A to 22B illustrate screens of outputs of a video decoder including motion compensation units using a half-pel method and a quarter-pel method, respectively, according to an embodiment of the present invention. It can be seen that the two image screens of FIGS. 22A and 22B do not show a big difference.

The experimental results of FIGS. 21A to 22B are performed to objectively compare image quality by measuring the PSNR (peak signal noise ratio) of the video decoder 230 with the configuration as shown in FIG. 23. As shown in the configuration as shown in FIG. 23, the reference image is a full resolution image calculated by 8 * 8 IDCT, so that the degradation of image quality of about 3-4 dB is basically generated when resizing 4 * 4 lights. May appear. In view of the above, the PNSR comparison table is shown in FIGS. 24A to 24D. FIG. 24A is a diagram showing PNSR characteristics of 8 * 8 and 4 * 4 video decoders of digital broadcasting news, and FIG. 24B is a diagram showing PNSR characteristics of 8 * 8 and 4 * 4 video decoders of digital broadcasting advertisements. As shown in FIGS. 24A and 24B, the results of comparing the resolution of the 8 * 8 video decoder with the PSNR of the 4 * 4 video decoder resized according to the embodiment of the present invention are shown. Here, it can be seen that the additional degradation other than the PSNR degradation due to the decrease in resolution is hardly seen. 24C is a diagram showing PNSR characteristics of 4 * 4 and 4 * 2 video decoders of digital broadcasting news, and FIG. 24D is a diagram showing PNSR characteristics of 4 * 4 and 4 * 2 video decoders of digital broadcasting advertisements. . Here, the 4 * 2 video decoder is a fast algorithm that can significantly reduce the computational amount compared to the 4 * 4 video decoder, whereas the image quality is hardly deteriorated.

Tables 12 to 15 show a comparison of the number of operations when resizing the video decoder 230 according to an embodiment of the present invention. Operations in software can be largely divided into shift / add / multiply / if and for constructs. <Table 12> is a table showing the comparison of the calculation amount in the variable length decoding unit 315, <Table 13> is a table showing the comparison of the calculation amount in the IDCT unit 319, <Table 14> is a table showing the comparison of the calculation amount in the inverse quantization unit 317 <Table 15> is a table showing the amount of computation before and after optimization in the motion compensator 335.

In addition, the decoding speed of the video decoder 230 is proportional to the amount of computation, but when implemented on a computer and an embedded system, the performance of the actual system is compared as shown in Tables 16 and 17. In this case, the high-speed processing engine on the computer may generate a higher speed, and in an embedded system, a better performance may be obtained. In the case of the embedded system, it is difficult to calculate the perfect frame rate, and thus the approximate values are shown. In comparison with the embedded system environment, when the 2 * 2 video decoder is used, the performance improvement is about 5-8 times higher than the 8 * 8 video decoder.

In general, digital broadcasting of a mobile terminal has a standard of digital video broadcasing (DVB) and digital multimedia broadcasting (DMB). The DVB system includes a terrestrial broadcast standard DVB-T and a satellite broadcast standard DVT-H. The video used in the DMB and DVB schemes may use MPEG and H.263 schemes. The MPEG method uses a discrete cosine transform (DCT) method, and the H.263 method uses an integer transform (hereinafter, referred to as IT) method. Therefore, a portable terminal having a digital broadcast receiver should have an IDCT or inverse integer transform (ITT) for inverting the DCT or IT transformed image. Accordingly, in the case of a mobile terminal having a digital broadcast receiver, the video decoder 230 preferably has a function of decoding the DCT video data and the IT video data.

In addition, the DMB and DVB schemes preferably consider a mobile environment. In the mobile environment, the CIF image 355 * 288 is transmitted in addition to the SD image 720 * 576. In this case, even when transmitting the CIF-class image, it is preferable to resize in order to express a frame rate suitable for the display unit (LCD, etc.) of the mobile terminal. In the case of a general portable terminal, the display unit 150 has a resolution of 176 * 208, and thus, in the case of a general portable terminal, the CIF image cannot be expressed. Therefore, in the case of the general mobile terminal as described above, the received image is preferably represented by 1/2 resizing image (176 * 144), and in the case of channel selection and ESG (electronic service guide), 1/4 resizing image (88). 72) is desirable. The red dotted line image of FIG. 25A is an image displayed on the display unit 150 when the CIF image of the ESG is resized to 1/4, and the red dotted line image of FIG. 25B is 1/4 of the channel selection UI image. This is an image displayed on the display unit 150 when resizing. FIG. 25C illustrates an image in which an image 176 * 144 resized by half of a CIF image is displayed on the display unit 150 in FIG. 25C. In fact, since the display unit 150 is not properly utilized by the reception state of the terminal and the menu UI, it is not a device that processes digital image data exclusively (a digital broadcast receiver capable of processing images equal to or higher than the CIF level). In such cases, it may be efficient to use a resizing technique.

As described above, when video data is transmitted through the video encoder using the DCT scheme at the transmitting side of the digital broadcast, the video decoder 230 of the portable terminal can be configured as shown in FIG. 15A or 15B. However, when transmitting the video data through the video encoder using the IT method at the transmitting side of the digital broadcast, the video decoder 230 of the portable terminal may be configured as shown in Fig. 26a or 26b. 26A and 26B illustrate a configuration of a video decoder which receives and decodes a signal obtained by encoding an image signal using an IT (integer transform) in a digital broadcast transmitter. In order to decode the IT signal into an original signal, An inverse integer transform (IIT) unit 710 is provided. Here, the operation of the IIT unit 710 will be described first before explaining FIGS. 26A and 26B.

In general, in the case of mobile digital broadcasting (eg, DVB-H), a 4 * 4 converter can be used since the size of the video signal is CIF or less. In this case, the transformation method of the converter may be a DCT (discrete cosine tramsform) and an IT (integer transform). Here, the 4 * 4 converter will be described as an example.

First, let's look at the operation of the DCT converter.

The following transformation is an example of a 4 * 4 DCT transformation scheme, where X is a spatial domain image and Y is a frequency domain image. That is, the following equation is an example of using a four-point DCT converter, where Y represents a DCT conversion result, X is a 4 * 4 input image, and the transformation matrix 1 and the transformation matrix 2 are arranged at left and right sides of the input image X, respectively. . The transformation matrix 2 is a matrix in which the transformation matrix 1 is transposed diagonally.

Here, the DCT transform coefficient values of each matrix are as follows.

In case of receiving the 4 * 4 DCT as described above, the IDCT unit 319 of the receiver converts the inverse, and this is expressed as follows.

The coefficient values of each matrix of the 4 * 4 IDCT converter are as follows.

The reason why it is expressed as above is because the transpose matrix value is equal to the inverse of A, which is represented by the following formula.

이때 상기 Y가 하기와 같은 신호가 입력된다고 가정하면, 리사이징하지 않는 경우에 X는 하기와 같이 얻어진다.

At this time, assuming that Y is input as follows, X is obtained as follows when not resizing.

Therefore, in the case of 1.2 resizing, a 2 * 2 scan area may be set in the 4 * 4 area of the Y matrix, and the following equation is implemented.

The equation is the same as the following equation, the amount of calculation is reduced to 25%,

In the case of 1/4 resizing, a 1 * 1 scan area may be set in the 4 * 4 area of the Y matrix, and thus implemented by the following equation.

And the said formula becomes the following formula.

Second, we look at the integer transform method.

The DCT transform and IDCT transform schemes described above are transform schemes used in the mpeg encoder and decoder. However, for H.264, an integer transform method and an inverse integer transform method may be used. Here, the integer transform method is a modification of the DCT transform method. The integer transform method has the same form as the DCT transform method, and only the coefficient value is changed. That is, the 4 * 4 integer transform can be expressed as follows, and the transform type has the same structure as the DCT, except that the coefficient values of each matrix are different. In the following equation, X is also a spatial-domain image and Y is a frequency-domain image. In the following equation, Y is a result of performing the integer transform, X is a 4 * 4 input image, and the transformation matrix 1 and the transformation matrix 2 are positioned at the left and right sides of the input image X, respectively. In this case, when the coefficient value of the transformation matrix is converted to a = 1, b = 2, and c = 1 in the DCT transformation method, it can be seen that the integer transformation method is obtained. Therefore, it can be seen that the operation of the integer transform method is simpler than the operation of the DCT conversion method.

The video decoder which receives the video data of the IT method as described above should perform an inverse transform procedure for finding the original video signal X from the Y, which can be expressed as an inverse integer transform (IIT).

If it is assumed that Y is input as follows, X` can be obtained as follows when not resizing. Therefore, X ′ of the following equation may be an example of a case where the CIF image is processed without resizing.

However, in the case of 1/2 resizing, a 2 * 2 scan area may be set in the 4 * 4 area of the Y matrix, and thus X` in the case of 1/2 resizing can be obtained by the following equation. That is, in the case of 1/2 resizing, a 2 * 2 (y11, y12, y21, y22) zonal filter is used as shown in the following equation.

The 1/2 resizing result is the same as the following equation, in which case the amount of computation is reduced by 25%.

In the case of 1/4 resizing, a 1 * 1 scan area may be set in the 4 * 4 area of the Y matrix, and thus X` in the case of 1/4 resizing can be obtained by the following equation.

And the formula of the 1/4 resizing result as described above is the same as the following formula.

As described above, the video decoder 230 includes an inverse transformer to convert image data in a 2D frequency domain into image data in a 2D spatial domain. In this case, the inverse converter of the video decoder 230 may use the IDCT unit 319 and the IIT unit as described above. In the embodiment of the present invention, as described above, the IDCT unit or the IIT unit may be used as the inverse transformer, and the IDCT unit 319 and the IIT unit may each perform a resizing function of the image data.

26A and 26B show a configuration of a video decoder 230 that performs a resizing function using the IIT unit 710. FIG. Here, FIG. 26A illustrates a configuration example of a video decoder 230 that decodes I, B, and P frame images, and FIG. 26B illustrates an example of a configuration of the video decoder 230 that decodes I and P frame images. 26A and 26B have the same configuration as those of FIGS. 15A and 15B except for the IIT unit 710, and the operations thereof are performed in the same manner.

This will be described with reference to FIG. 26A.

Referring to FIG. 26A, the header analyzer 311 extracts and analyzes header information of a received video signal and transmits the header information to the controller 100. Then, the controller 100 determines the resizing control value while performing the procedure as shown in FIG. 16 and applies these values to the resizers 410, 420, and 450 of the variable length decoder 315, the IIT unit 710, and the motion compensation unit 335, respectively.

In this case, the operations of the variable length decoder 315 and the motion compensation unit 335 are performed in the same manner as the operation of FIG. 15A. The IIT unit 710 of the video decoder 230 may have a structure similar to that of FIG. 18. The IIT unit 710 may have four-point and two-point IIT units for resizing the Y-axis pixels, and may also have four-point and two-point IIT units for resizing the X-axis pixels. The Y resizer of the IIT unit 710 checks the resizing control value of the Y-axis from the resizing control value, and then transfers the variable length decoded data to the IIT corresponding to the confirmed Y resizing control value. The IIT then IIT and store the data. Secondly, the X resizer checks the resizing control value of the X axis in the resizing control value, and then transfers the resized data on the Y axis to the IIT corresponding to the X axis resizing control value. The IIT then IIT and store the data. When the IIT of the X-axis data is performed as described above, the data becomes a result of performing the Y-axis and the X-axis IIT.

As described above, the inverse transformed data in the IIT unit 710 is determined by the resizing control value as described above, and the result is a zonal filter, and the result is an original image, a 1/2 resizing image, or a 1/1 resizing image. It can be data.

The digital broadcast receiver according to the embodiment of the present invention as described above may be implemented in a portable terminal. 27 shows the configuration of a mobile terminal having a digital broadcast receiver. The portable terminal may be a mobile phone, a PDA, a smart phone, or the like. Here, it will be assumed that the mobile terminal is a mobile phone.

FIG. 27 is a diagram illustrating a configuration of a digital broadcasting receiver of a mobile terminal according to an embodiment of the present invention. 27 illustrates a configuration in which the mobile terminal includes the RF tuner 110, the demodulator 120, and the decoder 130 of the digital broadcast. The decoder 130 may be implemented in the controller 100 of the portable terminal. In this case, the decoder performance of the digital broadcasting receiver may be implemented in software. In FIG. 25, the control unit 100 is an MSM of a mobile phone, and in addition to the overall control of the mobile phone, a modem (MODEM) function for modulating and demodulating voice and data communicated with the mobile phone, and encoding and decoding. and a codec function for decoding. In addition, the modem and codec functions of the portable terminal may be separated and independent of the controller 100 using a digital signal processor (DSP). In addition, when the portable terminal includes a multimedia processor (for example, DM 270, etc.) for processing multimedia data in addition to the MSM, the multimedia processor may be the controller 100. In addition, when the video decoder is independently implemented, the video decoder may be processed by the controller of the video decoder itself. As described above, the mobile terminal is assumed to be a mobile phone, and the control unit 100 is assumed to be an MSM.

Referring to FIG. 27, the RF communication unit 195 performs a wireless communication function of a mobile phone. The RF communication unit 195 includes an RF transmitter for upconverting and amplifying a frequency of a transmitted signal, and an RF receiver for low noise amplifying and downconverting a received signal.

The control unit 100 processes voice and data transmitted and received by the mobile phone, and also performs a function of performing overall control of the mobile phone.

First, the control unit 100 includes a transmitter for encoding and modulating a transmitted signal and a receiver for demodulating and decoding the received signal in order to process communication data. In addition, the control unit 100 may independently implement a data processing unit including a modem and a codec as described above. The data processor may process channel data in a CDMA method, a UMTS method, or a GSM method.

The key input unit 170 includes keys for inputting numeric and character information and function keys for setting various functions. In addition, the function key includes keys for selecting a function such as channel selection for digital broadcast reception, broadcast reception mode control, etc. according to an embodiment of the present invention.

The memory 190 may include program memory and data memories. The program memory includes programs for controlling the general operation of the cellular phone and programs for selecting a digital broadcast channel and processing a broadcast signal of the selected channel according to an embodiment of the present invention. In addition, the data memory is a non-volatile memory (NVM) for storing non-volatile data (e.g., bitmap, font, phonebook, etc.) and RAM for temporarily storing data generated while executing the programs. It may be configured as.

The display unit 150 displays information according to the operation of the mobile terminal under the control of the controller 100, and also displays a broadcast video signal processed by the decoder 130 in the digital broadcast reception mode. The audio processor 160 includes a speaker and a microphone, is used as a handset of a mobile terminal in a communication mode, and plays a function of reproducing a broadcast audio signal in a digital broadcast reception mode.

The RF tuner 110 generates a broadcast frequency signal of the channel selected by the channel control data of the controller 100, and down-converts the frequency of the broadcast signal of the selected channel to generate an intermediate frequency signal. A demodulator demodulates the modulated digital broadcast signal into an original signal.

The decoder 130 separates the broadcast signal demodulated by the demodulator 120 into video and audio, and decodes and outputs the separated video and audio signals, respectively. The decoder 130 may have a configuration as shown in FIG. 2, and the video decoder 230 may have a configuration as illustrated in FIG. 15A or 15B. In addition, as shown in FIG. 20, the video decoder 230 may include a video decoding program and may be processed in software.

The image memory 180 includes buffers for storing header information and broadcast data for decoding in a decoding operation according to an embodiment of the present invention. The image memory 180 also stores various tables for decoding broadcast data received according to an embodiment of the present invention. The image memory 180 stores the broadcast signal output from the decoder 130 under the control of the controller 100 in the recording mode, and outputs the broadcast signal selected by the control unit 100 to the decoder 130 in the playback mode.

In the 27, the digital broadcast reception signal of the mobile terminal may be a signal in a VHF (174 MHz-230 MHz: C5-C12) region and a UHF (470 MHz-862 MHz: C21-C69) region. However, it can be L-Band (1GHz-2.6GHz) and S-Band (2.6GHz-3.95GHz) signals of higher frequency bands as needed. At this time, when the user selects a broadcast channel, the controller 100 outputs control data corresponding to the channel selected by the RF tuner 110. The RF tuner 110 generates and mixes an RF frequency according to the channel data, thereby generating an intermediate frequency signal of the selected channel. In this case, the intermediate frequency (IF) may be 36.17 MHz.

The analog intermediate frequency signal is applied to the demodulator 120. Then, the demodulator 120 demodulates the received analog signal by analog to digital conversion, and then demodulates the demodulated signal in the set method. Here, the modulation scheme of the digital broadcast receiver may use coded orthogonal frequency division multiplexing (CODFM). In an embodiment of the present invention, the demodulator 120 uses an MT352 manufactured and sold by Zarlink. In this case, the signal demodulated by the demodulator 120 is output as 8-bit MPEG-2 TS data, that is, the demodulator 120 converts the signal of the selected channel output from the RF tuner 110 into digital data. It is controlled according to the number of carriers, additional symbols, etc., and goes through a fast fourier transform (FFT) circuit. It is output as MPEG-2 TS.

The MPEG-2 TS signal output from the demodulator 120 is applied to the decoder 130. The decoder 130 then separates the received MPEG-2 TS signal into video, audio and data, respectively, and decodes each of the received MPEG-2 TS signals and outputs the video and audio signals. In this case, the video signal may be a signal such as RGB or YUV, and the audio signal is generally output in the form of PCM stereo sound. The video signal output from the decoder 130 is output and displayed on the display unit 150, and the audio signal is applied to the speaker 160 and reproduced.

At this time, the controller 100 determines a resizing control value for resizing the video data input to the video decoder 230 of the decoder 130. One or more resizing factors of the video decoder 230 may use these factors. Among the resizing factors, the most important resizing factor may be the screen size of the display unit 150. That is, the received digital broadcast signal has a resolution that can be displayed on a general digital television. In this case, it is preferable to resize the digital broadcast signal so that it can be properly displayed on the display unit 150 before decoding the digital broadcast signal. Do. In addition, even when the broadcasted resolution is broadcasted in a size suitable for the portable terminal, each portable terminal has a different display resolution and requires resizing according to the decoding speed and image quality.

In addition to the screen size, other resizing factors may include image scanning methods, block scan methods, decoding speeds of the decoder 230, and types of decoding quality according to the state of the mobile terminal. The controller 100 determines the resizing control value of the decoder 120 by referring to at least one or more of the above resizing factors.

Then, the decoder 130 resizes the encoded digital broadcast signal received by the resizing control value output from the controller 100, decodes the resized digital broadcast signal, and outputs the decoded digital broadcast signal to the display unit 150 for display.

As described above, the digital broadcast receiver according to the embodiment of the present invention resizes the received video signal according to the size of the displayed screen, thereby greatly reducing the image processing time, thereby simplifying the configuration of the receiver. Can be implemented. In particular, when the digital broadcasting receiver is implemented in the portable terminal, the digital broadcasting receiver of the portable terminal can be efficiently implemented by resizing and decoding the decoding region of the received video signal according to the display unit size of the portable terminal before decoding the encoded video data. There is an advantage to this. In addition to the size of the screen displayed on a digital broadcast receiver or a portable terminal including a digital broadcast receiver, a scanning method (image scanning method and / or block scanning method) of a received broadcast signal, image quality and decoding processing speed of an image to be decoded By resizing the area to be decoded before decoding the received video data in consideration of the above, there is an advantage that the video data decoder can be adaptively downsized and processed quickly while maintaining the performance of the video decoder.

Claims (50)

In the video decoder of the digital broadcasting receiver, A resizing controller for generating a control signal for resizing the received video data; A header analyzer for analyzing the header information from the demodulated video stream and separating and outputting the video data; A variable length decoder which decodes the video data output from the header analyzer to the original pixel data size by a variable length table; An inverse quantization unit for inversely quantizing the decoded video data; An inverse transform unit for resizing the video data of the inverse quantized frequency domain into video data of a two-dimensional space domain by the resizing control signal; And a motion compensator configured to motion-compensate and add motion compensation data among the inversely converted video data and the separated video data. The apparatus as claimed in claim 1, wherein the inverse transform unit is an inverse discrete cosine transform unit. The method of claim 2, wherein the inverse discrete cosine transform unit, A Y-axis resizer for selecting a point inverse discrete cosine converter set by the Y-axis control signal of the resizing control signal; The Y-axis inverse discrete transformers having a number corresponding to a plurality of points, the inverse discrete transformers of the selected point inversely discretely transforming Y-axis video data of a resized region, An X-axis resizer for selecting a point inverse discrete cosine converter set by the X-axis control signal of the resizing control signal; A number corresponding to a plurality of points, wherein the inverse discrete cosine transformer of the selected point comprises the inverse discrete cosine transformers for inverse discrete cosine transforming the X-axis video data of the resized region stored in the Y buffer. Said device. The apparatus of claim 3, wherein the variable length decoder further comprises a resizer for resizing the separated video data by the resizing control signal. A table converter for decoding the received variable length coded video data into video data having an original length; A buffer for storing video data decoded by the table converter; And the resizer for controlling the table converter to decode data of a block included in the resizing area set by the resizing control signal, and controlling to store video data of the resizing area in the buffer. . The method of claim 4, wherein the motion compensation unit, A buffer for storing the received motion compensation vector value; A previous image storage unit for storing a previous frame image to compare the motion vector values; A next image storage unit for storing a next frame image to compare the motion vector values; A motion compensator for inputting the motion vector value and an output of a previous image storage part and a motion compensation selection signal driven by a motion compensation selection signal to respectively perform half-pel, quarter-pel and octapel motion compensation; And a resizer for selecting one of the half pel, quarter pel or octapel compensators by the resizing control signal. 6. The apparatus as claimed in claim 5, wherein the resizing control unit determines the resizing control value according to the size of the display unit of the digital broadcast receiver. 6. The apparatus as claimed in claim 5, wherein the resizing control unit determines the resizing control value by the display unit screen size of the digital broadcast receiver and the image scanning method analyzed by the header analyzer. 6. The apparatus as claimed in claim 5, wherein the controller determines the resizing control value by a display unit screen size of the digital broadcast receiver, an image scan method analyzed by the header analyzer, and a block scan method. The method of claim 5, wherein the control unit determines the resizing control value based on the display unit screen size of the digital broadcast receiver, the image scan method and the block scan method analyzed by the header analyzer, and the decoding speed selected by the user. Said device. 6. The method of claim 5, wherein the control unit is configured to determine the screen size of the digital broadcasting receiver by the display unit size, the image scanning method and the block scanning method analyzed by the header analyzing unit, the decoding speed selected by the user, and the decoding speed of the digital broadcasting receiver. And determining a resizing control value. The apparatus as claimed in claim 1, wherein the inverse transform unit is an inverse integer transform unit. The method of claim 11, wherein the inverse integer conversion unit, A Y axis resizer for selecting a point inverse integer converter set by the Y axis control signal of the resizing control signal; The Y-axis de-integrator converters having a number corresponding to a plurality of points, the inverse-inverter converters of the selected point de-integrating the Y-axis video data of the resized region, An X-axis resizer for selecting a point de-integrator converter set by the X-axis control signal of the resizing control signal; A number corresponding to a plurality of points, wherein the inverse integer converter of the selected point is configured to inversely transform the X-axis video data of the resized region stored in the Y buffer; The device. Claim 13 was abandoned upon payment of a registration fee. The apparatus of claim 12, wherein the variable length decoder further comprises a resizer for resizing the separated video data by the resizing control signal. A table converter for decoding the received variable length coded video data into video data having an original length; A buffer for storing video data decoded by the table converter; And the resizer for controlling the table converter to decode data of a block included in the resizing area set by the resizing control signal, and controlling to store video data of the resizing area in the buffer. . Claim 14 was abandoned when the registration fee was paid. The method of claim 13, wherein the motion compensation unit, A buffer for storing the received motion compensation vector value; A previous image storage unit for storing a previous frame image to compare the motion vector values; A next image storage unit for storing a next frame image to compare the motion vector values; A motion compensator for inputting the motion vector value and the output of a previous image storage part and a motion compensation selection signal driven by a motion compensation selection signal to perform half-pel, quarter-pel and octa-fel motion compensation; And a resizer for selecting one of the half pel, quarter pel or octapel compensators by the resizing control signal. Claim 15 was abandoned upon payment of a registration fee. 15. The apparatus as claimed in claim 14, wherein the resizing control unit determines the resizing control value according to the size of the display unit of the digital broadcast receiver. Claim 16 was abandoned upon payment of a setup registration fee. The apparatus of claim 15, wherein the resizing controller determines the resizing control value by a display unit screen size of the digital broadcast receiver and an image scan method analyzed by the header analyzer. Claim 17 was abandoned upon payment of a registration fee. 17. The method of claim 16, wherein the control unit determines the resizing control value by the display unit screen size of the digital broadcast receiver, the image scan method and the block scan method analyzed by the header analyzer, and the decoding speed selected by the user. Said device. Claim 18 was abandoned upon payment of a set-up fee. In the video decoder of the digital broadcasting receiver, A resizing controller for generating a control signal for resizing the received video data; A header analyzer for analyzing the header information from the demodulated video stream and separating and outputting the video data; The table converter decodes the video data output from the header analysis unit to the original pixel data size by a variable length table, and decodes the data of a block included in the resizing area set by the resizing control signal when the variable length decoding is performed. After controlling the variable length decoding unit for controlling to store the video data of the resizing area in the buffer, An inverse quantization unit for inversely quantizing the decoded video data; An inverse transform unit for resizing the video data of the inverse quantized frequency domain into video data of a two-dimensional space domain by the resizing control signal; And a motion compensator for at least one resizing, wherein the motion compensator is selected by the resizing control signal, and the selected motion compensator motion-compensates motion compensation data among the inversely converted video data and the separated video data. Motion compensation unit to add up, And a color converting unit converting outputs of the inverse converting unit and the motion compensating unit into display data. 20. The resizing control signal of claim 19, wherein the inverse transform unit is an inverse discrete cosine transform unit, and the inverse discrete cosine transform unit includes at least one Y-axis inverse cosine cosine transformer and an X-axis inverse cosine cosine transformer for resizing transformation. And a corresponding Y-axis and X-axis inverse discrete cosine converter are driven to resize the variable length decoded video data and perform inverse transformation. 21. The apparatus of claim 20, wherein the inverse transform unit is an inverse integer transform unit, and the inverse integer transform unit includes at least one Y-axis de-integrator converter and an X-axis de-integrator converter for resizing transformation, and corresponds to the resizing control signal. And a Y-axis and an X-axis inverse integer converter are driven to resize the variable length decoded video data and perform inverse transformation. In the digital broadcasting receiver, A controller for generating a channel selection signal according to a user's selection and generating a control signal for resizing video data of a received broadcast signal; A tuner for selecting a channel of a digital broadcast signal received by channel selection of the controller; A demodulator for demodulating a signal of the selected digital broadcasting channel; A demultiplexer for separating audio and video streams from the demodulated digital broadcast signal, a video decoder for decoding data of the separated video stream, and an audio decoder for decoding data of the separated audio stream; The decoder includes: a decoder for resizing the decoding area of the video data received by the resizing control signal output from the controller and decoding the video data of the resized area; A display unit for displaying the decoded video data; And a memory configured to store a digital broadcast signal output from the demodulator in a recording mode and to temporarily store data processed by the decoder. The method of claim 22, wherein the video decoder, A header analyzer for analyzing the header information from the demodulated video stream and separating and outputting the video data; A variable length decoding unit for resizing the separated video data by the resizing control signal and decoding the resized video data to original pixel data size by a variable length table; An inverse quantization unit for inversely quantizing the decoded video data; An inverse transform unit for resizing the video data of the inverse quantized frequency domain into video data of a two-dimensional space domain by the resizing control signal; A motion compensator for compensating for the movement of the pixel data at a pixel movement interval set by the resizing control signal; An adder which adds an output of the inverse transform unit and an output of the motion compensation unit; And a color converting unit converting video data output from the adding unit into display data of a display unit. 24. The apparatus as claimed in claim 23, wherein the inverse transform unit is an inverse discrete cosine transform unit. The method of claim 24, wherein the inverse discrete cosine transform unit, A Y-axis resizer for selecting a point inverse discrete cosine converter set by the Y-axis control signal of the resizing control signal; The Y-axis inverse discrete transformers having a number corresponding to a plurality of points, the inverse discrete transformers of the selected point inversely discretely transforming Y-axis video data of a resized region, An X-axis resizer for selecting a point inverse discrete cosine converter set by the X-axis control signal of the resizing control signal; A number corresponding to a plurality of points, wherein the inverse discrete cosine transformer of the selected point comprises the inverse discrete cosine transformers for inverse discrete cosine transforming the X-axis video data of the resized region stored in the Y buffer. Said device. The apparatus of claim 23, wherein the inverse transform unit is an inverse integer transform unit. The method of claim 26, wherein the inverse integer conversion unit, A Y axis resizer for selecting a point inverse integer converter set by the Y axis control signal of the resizing control signal; The Y-axis de-integrator converters having a number corresponding to a plurality of points, the inverse-inverter converters of the selected point de-integrating the Y-axis video data of the resized region, An X-axis resizer for selecting a point de-integrator converter set by the X-axis control signal of the resizing control signal; A number corresponding to a plurality of points, wherein the inverse integer converter of the selected point is configured to inversely transform the X-axis video data of the resized region stored in the Y buffer; The device. The method of claim 23, wherein the variable length decoding unit, A table converter for decoding the received variable length coded video data into video data having an original length; A buffer for storing video data decoded by the table converter; And a resizer configured to control the table converter to decode pixel data included in the resizing area set by the resizing control signal, and to store video data of the resizing area in the buffer. The method of claim 23, wherein the motion compensation unit, A buffer for storing the received motion compensation vector value; A previous image storage unit for storing a previous frame image to compare the motion vector values; A next image storage unit for storing a next frame image to compare the motion vector values; A motion compensator for inputting the motion vector value and an output of a previous image storage part and a motion compensation selection signal driven by a motion compensation selection signal to respectively perform half-pel, quarter-pel and octapel motion compensation; And a resizer for selecting one of the half pel, quarter pel or octapel compensators by the resizing control signal. 24. The apparatus as claimed in claim 23, wherein the control unit determines the resizing control value based on the display unit screen size of the digital broadcast receiver. 24. The apparatus as claimed in claim 23, wherein the controller determines the resizing control value by the display unit screen size of the digital broadcast receiver and the image scanning method analyzed by the header analyzer. 24. The method of claim 23, wherein the control unit is configured to determine the screen size of the digital broadcasting receiver by the display unit size, the image scanning method and the block scanning method analyzed by the header analyzer, the decoding speed selected by the user, and the decoding speed of the digital broadcasting receiver. And determining a resizing control value. An RF communication unit for up-converting a transmission signal to an RF band, down-converting a received RF signal to a baseband signal, and a data processor for encoding and modulating the transmission signal and demodulating and decoding the received baseband signal. In the digital broadcasting receiver of a mobile terminal having a, A control unit for generating a channel selection signal according to a user's selection and generating a control signal for resizing video data of the digital broadcasting signal received according to the display unit screen size of the mobile terminal; A tuner for selecting a channel of a digital broadcast signal received by channel selection of the controller; A demodulator for demodulating a signal of the selected digital broadcasting channel; A demultiplexer for separating audio and video streams from the demodulated digital broadcast signal, a video decoder for decoding data of the separated video stream, and an audio decoder for decoding data of the separated audio stream; The decoder includes: a decoder for resizing the decoding area of the video data received by the resizing control signal output from the controller and decoding the video data of the resized area; A display unit for displaying the decoded video data; And a memory configured to store a digital broadcast signal output from the demodulator in a recording mode and to temporarily store data processed by the decoder. The video decoder of claim 33, wherein the video decoder comprises: A header analyzer for analyzing the header information from the demodulated video stream and separating and outputting the video data; The table converter decodes the video data output from the header analysis unit to the original pixel data size by a variable length table, and decodes the data of a block included in the resizing area set by the resizing control signal when the variable length decoding is performed. After controlling the variable length decoding unit for controlling to store the video data of the resizing area in the buffer, An inverse quantization unit for inversely quantizing the decoded video data; An inverse transform unit for resizing the video data of the inverse quantized frequency domain into video data of a two-dimensional space domain by the resizing control signal; And a motion compensator for at least one resizing, wherein the motion compensator is selected by the resizing control signal, and the selected motion compensator motion-compensates and adds motion compensation data among the inversely converted video data and the separated video data. With the motion compensation part to do, And a color converting unit converting outputs of the inverse converting unit and the motion compensating unit into display data. 35. The apparatus according to claim 34, wherein the inverse transform unit selects a point inverse discrete cosine transformer set by the Y axis control signal of the resizing control signal; The Y-axis inverse discrete transformers having a number corresponding to a plurality of points, the inverse discrete transformers of the selected point inversely discretely transforming Y-axis video data of a resized region, An X-axis resizer for selecting a point inverse discrete cosine converter set by the X-axis control signal of the resizing control signal; An inverse discrete cosine transformer having an inverse number corresponding to a plurality of points, the inverse discrete cosine transformer of the selected point performing inverse discrete cosine transforming of the X-axis video data of the resized region stored in the Y buffer The apparatus, characterized in that the discrete conversion unit. The method of claim 34, wherein the inverse transform unit, A Y axis resizer for selecting a point inverse integer converter set by the Y axis control signal of the resizing control signal; The Y-axis de-integrator converters having a number corresponding to a plurality of points, the inverse-inverter converters of the selected point de-integrating the Y-axis video data of the resized region, An X-axis resizer for selecting a point de-integrator converter set by the X-axis control signal of the resizing control signal; An inverse integer transform having a number corresponding to a plurality of points, wherein the inverse integer transformer of the selected point is configured to inversely transform the X-axis video data of the resized region stored in the Y buffer; Disclaimer, characterized in that the device. The method of claim 34, wherein the variable length decoding unit, A table converter for decoding the received variable length coded video data into video data having an original length; A buffer for storing video data decoded by the table converter; And a resizer configured to control the table converter to decode pixel data included in the resizing area set by the resizing control signal, and to store video data of the resizing area in the buffer. The method of claim 34, wherein the motion compensation unit, A buffer for storing the received motion compensation vector value; A previous image storage unit for storing a previous frame image to compare the motion vector values; A next image storage unit for storing a next frame image to compare the motion vector values; A motion compensator for inputting the motion vector value and an output of a previous image storage part and a motion compensation selection signal driven by a motion compensation selection signal to respectively perform half-pel, quarter-pel and octapel motion compensation; And a resizer for selecting one of the half pel, quarter pel or octapel compensators by the resizing control signal. 35. The apparatus as claimed in claim 34, wherein the control unit determines the resizing control value based on the display unit screen size of the digital broadcast receiver. 35. The method of claim 34, wherein the control unit determines the resizing control value by adding a resizing factor according to a scan method according to an image scan method analyzed by the header analyzer to the resizing control signal determined by the screen size of the display unit. Said device. 35. The method of claim 34, wherein the control unit determines an image scanning method and a block scanning method analyzed by the header analyzing unit in response to the resizing control signal determined by the screen size of the display unit, a decoding speed selected by a user, and decoding of a digital broadcast receiver. The resizing control value is determined by adding a resizing factor such as speed. In the method for decoding the video data encoded in the digital broadcast receiver, Determining a control signal for resizing the received video data; Parsing and outputting video data by analyzing header information in the demodulated video stream; Resizing the separated video data by the resizing control signal, and decoding the resized video data to the original pixel data size by a variable length table; Dequantizing the decoded video data; An inverse transform process of resizing the video data of the inverse quantized frequency domain into video data of a two-dimensional space domain by the resizing control signal; Motion compensating and summing motion compensation data among the inversely converted video data and the separated video data; And converting the motion compensated video data into data for display on a display unit. 43. The method as claimed in claim 42, wherein the inverse transform process sets a scan area of the Y matrix set by the resizing control signal and inverse discrete cosine transforms the data of the set scan area. 43. The method as claimed in claim 42, wherein the inverse transform process sets a scan area of the Y matrix set by the resizing control signal, and inversely transforms the data of the set scan area. The method of claim 42, wherein the variable length decoding process, Decoding and storing the received variable length coded video data into video data having an original length; Stopping the decoding operation when decoding up to pixel data included in the resizing area set by the resizing control signal; And outputting decoded video data of the resizing area from the stored decoded data. The method of claim 42, wherein the motion compensation process, Storing a previous frame image, a next frame image, and a received motion vector value to compare the motion vector values; The motion compensation method comprises the step of compensating for the motion vector value, the previous image and the previous image through a motion compensator selected by the resizing control signal. 43. The method of claim 42, wherein determining the resizing control signal, And determining a control signal that can be resized to select an area including pixel data having a size corresponding to a screen size of the display unit. 43. The method of claim 42, wherein determining the resizing control signal, The resizing control signal is determined by the screen size of the display unit of the digital broadcasting receiver, the image scanning method and the block scanning method included in the header information, the decoding speed selected by the user, and the decoding speed of the digital broadcasting receiver. The method. In the image processing method of the digital broadcast receiver, Generating a channel selection signal according to a user's selection, and generating a control signal for resizing video data of the received broadcast signal; Selecting a channel of the digital broadcast signal received by channel selection of the controller; Demodulating the signal of the selected digital broadcasting channel; The decoding region of the video data received by the resizing control signal is a process of separating the audio and video stream from the demodulated digital broadcast signal, decoding the data of the separated video and audio stream, respectively, and decoding the video data. Resizing and decoding video data of the resized area; And displaying and playing the decoded video and audio data. In the broadcast signal processing method of a mobile terminal having a wireless communication unit for wireless communication, Generating a channel selection signal according to a user's selection, and generating a control signal for resizing the video data of the digital broadcasting signal received according to the display unit screen size of the mobile terminal; Selecting a channel of the digital broadcast signal received by the channel selection signal; Demodulating the signal of the selected digital broadcasting channel; The audio and video streams are separated from the demodulated digital broadcast signal, and the data of the separated video and audio streams are decoded, respectively. The video decoding process resizes the decoding area of the video data received by the resizing control signal. Decoding video data of the resized area; And displaying and playing the decoded video and audio data.

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