KR100827711B1 - Video encoder and method of transforming image signal - Google Patents

Abstract

The video encoder includes a synchronization signal controller, a motion vector calculator, a modulated signal generator, an image quality corrector, a modulator, and a digital-analog converter. The synchronization signal controller generates a synchronization signal for synchronizing the analog image signal. The motion vector calculator calculates the sum of the motion vectors of the frames. The modulated signal generator generates a carrier sampled at an adjusted sampling frequency based on the sum of the motion vectors of the frames. The image quality correction unit corrects the image quality of the digital image signal to generate a corrected digital image signal. The modulator modulates the corrected digital video signal into a digital signal corresponding to the analog video signal based on the synchronization signal and the carrier wave. The digital-analog converter generates the analog video signal by converting the modulated digital signal into an analog signal. When there is a lot of image change between frames, the number of samples of sine and cosine waves used as carriers for modulation is reduced by a predetermined number of times, thereby reducing memory access time by reducing the amount of data stored in the memory and consuming power. Can be reduced.

Description

VIDEO ENCODER AND METHOD OF TRANSFORMING IMAGE SIGNAL}

1 is a block diagram showing a configuration of a general digital image processing apparatus, a video encoder, and a TV award period.

2 is a block diagram illustrating a conventional video encoder.

3 is a block diagram illustrating a video encoder according to an embodiment of the present invention.

4 and 5 are graphs showing the sum of motion vectors of a frame.

6 is a graph showing a sampling state of a cosine wave signal before the number of sampling of the cosine wave sampling value recorded in the memory is adjusted.

7 is a graph showing a sampling state of a cosine wave signal when the number of sampling of cosine wave sampling values recorded in the memory is reduced to four based on the change in the sum of the motion vectors.

8 is a block diagram illustrating a video encoder according to another embodiment of the present invention.

9 is a block diagram illustrating a video encoder according to another embodiment of the present invention.

10 is a block diagram illustrating a video encoder according to another embodiment of the present invention.

11 is a flowchart illustrating a video signal conversion method according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

120: video encoder 220, 320: image quality correction unit

230, 330: modulator 240, 340: modulated signal generator

360: motion vector calculating unit 830: switching unit

The present invention relates to a video encoder and a video signal conversion method, and more particularly to a video encoder and a video signal conversion method that can be used in a television receiver.

1 is a block diagram showing a configuration of a general digital image processing apparatus, a video encoder, and a TV award period. As shown in FIG. 1, the video encoder 120 converts the digital video signal 112 output from the digital video signal output device 110 into an analog video signal 122 to convert the digital video signal 112 into an analog video signal 122. Display the image. The digital video signal output device 110 may be a digital camera phone, a memory card, a personal computer (PC), a portable multimedia player (PMP), or the like. The video encoder 120 may be included in the TV receiver 130 or included in the digital video signal output device 110 or may be implemented as an independent device as shown in FIG. 1. In FIG. 1, the video encoder 120 is connected to the TV receiver 130, but the video encoder 120 includes a high definition television (HDTV), a plasma display panel (PDP) TV, and a liquid crystal display (LCD). In addition to the TV receiver 130 such as a TV, it may be connected to a projector and used.

2 is a block diagram illustrating a conventional video encoder.

Referring to FIG. 2, a conventional video encoder includes a synchronization signal controller 210, an image quality corrector 220, a modulator 230, a modulated signal generator 240, and a digital-analog converter 250. .

The synchronization signal controller 210 includes a timing controller 212, a sync signal generator 214, and a blank signal generator 216, and includes a vertical sync signal VSYNC, a horizontal sync signal HSYNC, and a field identifier FIELD_ID. And a synchronization signal SYNC signal 211 and a blank signal (or blanking signal 213) for synchronizing the analog TV signal based on the clock CLOCK.

A blank signal may be inserted into the digital image signal passing through the image quality correction unit 220, and a synchronization signal (SYNC signal) may be inserted in the retrace period. The horizontal synchronization signal HSYNC may be inserted in the horizontal blanking period, and the vertical synchronization signal VSYNC may be inserted in the vertical blanking period. To synchronize the analog TV signal, an equalizing pulse is inserted before and after the vertical synchronization signal, a serration pulse is inserted within the vertical synchronization signal period, and the back of the horizontal retrace period of the digital video signal. A burst signal can be inserted into the back porch.

The luminance signal Y, the color signals CB, and CR of the digital image signal 201 pass through the first image quality corrector 222, the second image quality corrector 224, and the third image quality corrector 226, respectively. Oversampled at 222a, 224a, and 226a, and noise components are removed from the low pass filters 222b, 224b, and 226b, thereby improving the quality of the digital video signal.

The modulated signal generator 240 generates a carrier wave for modulating the luminance signal Y 202, the color signal CB 204, and the CR 206 with improved image quality, in order to generate an analog TV signal. Specifically, the modulated signal generator 240 stores the n sampled sine wave sample values and the cosine wave sample values in a memory in advance, reads the sine wave sample values, and generates a sine wave signal 242. Is read to generate a cosine wave signal 244.

The modulator 230 modulates the luminance signal Y 202, the color signal CB 204, and the CR 206 with improved image quality based on the synchronization signal 211, the blank signal 213, and the carrier waves 242 and 244. To generate a digital signal corresponding to the analog TV signal.

The digital-to-analog converter 250 includes three digital-to-analog converters 252, 254, and 256 to digital-analog convert the digital signal output from the modulator 230 to the analog TV signal 258. To convert.

In the video compression codec decoding process, in the case of a video having a very fast scene change or movement between frames in the video screen, the sum of the motion vectors of the video signals increases rapidly.

In the conventional video encoder, as described above, in the case of a video having a very fast scene change or movement between frames, the image enhancement operation is performed in the image quality improvement block 220, or the sine wave sample value and cosine in the memory is modulated by the modulator 230. More time is spent accessing the wave sample value, resulting in increased power consumption.

Accordingly, a first object of the present invention is to provide a video encoder that can reduce power consumption even when there are many changes in an image between frames.

In addition, a second object of the present invention is to provide a video signal conversion method that can reduce power consumption even when there are many changes in the image between frames.

According to an aspect of the present invention, there is provided a video encoder, including: a synchronization signal controller configured to generate a synchronization signal for synchronizing an analog image signal; A motion vector calculator for calculating a sum of motion vectors of frames; A modulated signal generator for generating a carrier sampled at an adjusted sampling frequency based on the sum of the motion vectors of the frames; An image quality corrector configured to correct the image quality of the digital image signal to generate a corrected digital image signal; A modulator for modulating the corrected digital video signal into a digital signal corresponding to the analog video signal based on the synchronization signal and the carrier wave; And a digital-to-analog converter configured to convert the modulated digital signal into an analog signal to generate the analog image signal. The modulating signal generator may further include a memory configured to store a sampling value sampled at a sampling frequency reduced by a predetermined sampling frequency of the carrier. The modulated signal generator may generate a sampled carrier by reducing the number of times of sampling in the π / 2 interval of the carrier when the change of the sum of the motion vectors of the frame is greater than or equal to a predetermined threshold. The modulated signal generator may generate a sampled carrier by reducing the number of times of sampling in the π / 2 interval of the carrier when the slope of the tangent in a predetermined frame on the sum curve of the motion vectors of the frame is greater than or equal to a predetermined threshold. The modulated signal generator may generate a sampled carrier such that the number of times of sampling in the π / 2 interval of the carrier has different values according to a sine value corresponding to a slope of a tangent in a predetermined frame on a sum curve of the motion vectors of the frame. Can be. The modulated signal generator may generate a sampled carrier such that the number of times of sampling in the π / 2 interval of the carrier has a different value according to the total value of the motion vectors of the frame. When the sum of the motion vectors of the frame is greater than a predetermined threshold, the modulated signal generator divides the π / 2 sections of the carrier into sections corresponding to the reduced number of samplings and stores the initial values of the sections in the memory. Can be. When the sum of the motion vectors of the frame is greater than a predetermined threshold, the modulated signal generator divides the π / 2 sections of the carrier into sections corresponding to the reduced number of sampling and samples the intervals between the initial value of each section and zero or one. The difference value may be stored in the memory. If the sum of the motion vectors of the frame is greater than a predetermined threshold may further include a switching unit for controlling at least a portion of the digital image signal does not pass through the image quality correction unit.

According to an aspect of the present invention, there is provided a method of converting a video signal, the method comprising: generating a carrier sampled at an adjusted sampling frequency based on a sum of motion vectors of a frame; Modulating a digital video signal into a digital signal based on a synchronization signal for synchronizing an analog video signal and the sampled carrier; And converting the modulated digital signal into an analog signal to generate an analog image signal.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and one or more other It is to be understood that the present invention does not exclude the possibility of the presence or the addition of features, numbers, steps, operations, components, parts, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

In describing the drawings, similar reference numerals are used for similar components.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. Hereinafter, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

3 is a block diagram illustrating a video encoder according to an embodiment of the present invention.

Referring to FIG. 3, a video encoder according to an embodiment of the present invention includes a synchronization signal controller 310, an image quality corrector 320, a modulator 330, a modulated signal generator 340, and a motion vector calculator ( 360 and a digital-analog converter 350.

The synchronization signal controller 310 includes a timing controller 312, a sync signal generator 314, and a blank signal generator 316. The synchronization signal controller 310 may include a synchronization signal SYNC signal for synchronizing the analog image signal based on the vertical synchronization signal VSYNC, the horizontal synchronization signal HSYNC, the field identifier FIELD_ID, and the clock CLOCK. 311) and a blank signal (or blanking signal 313). Hereinafter, the analog video signal is a concept including both an analog TV signal for output to a TV receiver or an analog video signal for output to a projector.

A blank signal may be inserted into the digital image signal passing through the image quality correction unit 320, and a synchronization signal 311 may be inserted in the retrace period. The horizontal synchronization signal HSYNC may be inserted in the horizontal blanking period, and the vertical synchronization signal VSYNC may be inserted in the vertical blanking period. Equalizing pulses may be inserted before and after the vertical synchronization signal to synchronize the analog image signals. A serration pulse can be inserted within the period of the vertical synchronization signal. A burst signal may be inserted into the back porch of the horizontal retrace period of the digital video signal.

The luminance signal Y, the color signals CB, and CR of the digital image signal 301 pass through the first image quality corrector 322, the second image quality corrector 324, and the third image quality corrector 326, respectively. Oversampling is performed at 322a, 324a, and 326a, and noise components are removed at the low pass filters 322b, 324b, and 326b, thereby improving the image quality of the digital video signal. Here, the digital image signal 301 input to the image quality correction unit 320 is not limited to the luminance signal Y, the color signals CB and CR shown in FIG. 3, and may be an image signal in the RGB format.

The motion vector calculator 360 obtains a motion vector of each frame of the digital image signal 301, calculates a sum of motion vectors for each frame, and modulates the signal generator 340 based on the calculated sum of the motion vectors. The sampling frequency of the sine wave signal and the cosine wave signal, which are generated from the carrier), can be adjusted.

The modulated signal generator 340 generates a carrier wave for modulating a digital image signal having an improved image quality, for example, a luminance signal Y 302, a color signal CB 304, and a CR 306, to generate an analog image signal. Generate. In the memory, sampling values (sine wave signal and cosine wave signal) sampled at a predetermined predetermined number of samples are stored in advance.

The memory stores only the sample values having a reduced sampling number without storing all the sampling values of the conventional N number of carriers (sine wave or cosine wave). For example, k sampling values, which are much smaller than N / 4 in a quarter period of a conventional carrier, are stored. Here, k may be four. Or k may be eight or sixteen.

Here, the modulated signal generator 240 reads the sampled value sampled by the predetermined number of samples reduced from the memory, and the sum of the motion vectors calculated by using the sampled value read by the motion vector calculator 360. The sampling frequency is adjusted based on to generate a carrier-signal wave signal 342 and a cosine wave signal 344 that have been sampled with the adjusted number of sampling. For example, a sampled value with an increased number of samplings is obtained by reading four sampling values within a quarter period from a memory and performing a linear approximation using a straight line between the four sections. Can be generated.

In FIG. 3, the modulation signal generator 240 and the motion vector calculator 360 are illustrated as separate blocks, but the modulation signal generator 340 may be implemented to perform the functions of the motion vector calculator 360. Of course.

The modulator 330 modulates the luminance signal Y 302, the color signal CB 304, and the CR 306 with improved image quality based on the synchronization signal 311, the blank signal 313, and the carrier waves 342 and 344. To generate a digital signal corresponding to the analog video signal.

The digital-to-analog converter 250 includes three digital-to-analog converters 352, 354, and 356 to digital-analog convert the digital signal output from the modulator 330 into an analog image signal 358. To convert. The analog image signal 358 may be provided to a TV receiver 130 or a projector such as a high definition television (HDTV), a plasma display panel (PDP) TV, a liquid crystal display (LCD) TV, or the like. have.

Hereinafter, a method of adjusting the sampling frequency of the sine wave sampling value and the cosine wave sampling value based on the sum of the motion vectors will be described in detail.

If the image of the previous frame is similar to the image of the current frame during decoding of the video compression codec, the sum of the motion vectors of the current frame is small. If the image of the previous frame and the image of the current frame are very different, the sum of the motion vectors of the current frame is different. Increases rapidly than the sum of the motion vectors of the previous frame. That is, in the case of a video having a very fast transition or movement between frames in a video screen, most of the motion vectors constituting the frame change, so the sum of the motion vectors of the frames increases rapidly.

In the video encoder according to an embodiment of the present invention, in the case of a video having a very fast scene change or movement between frames, the sampling frequency of the sine wave sampling value and the cosine wave sampling value used as a carrier for modulation is reduced by a predetermined number of times. By reducing the amount of data of the sine wave sampling value and the cosine wave sampling value stored in the memory, the power consumption can be reduced by reducing the time to access the sine wave sampling value and the cosine wave sampling value.

In one embodiment of the present invention, the number of sampling of the sine wave sampling value and the cosine wave sampling value may be adjusted based on the change of the sum of the motion vectors.

For example, in a graph showing the sum of the motion vectors of the frames of FIG. 4, the sine wave sampling value and the cosine wave when the slope of the tangent in a predetermined frame on the sum curve of the motion vectors at points A1, A2, and A3 is greater than or equal to a predetermined threshold. The number of samplings of the sampling value can be reduced to a predetermined number. Here, the predetermined number may be 4, 6, 8, 16, 32, and the like. FIG. 6 is a graph illustrating a sampling state of a cosine wave signal before a sampling frequency of a cosine wave sampling value recorded in a conventional memory is adjusted, and FIG. 7 is a diagram of a cosine wave sampling value recorded in a memory according to an embodiment of the present invention. It is a graph showing the sampling state of the cosine wave signal when the number of sampling is reduced to four.

All other sine table values can be found in memory by recording a sine table value of 1/4 using the symmetry of sine and cosine values. For example, π / 2 sections of a sine wave (or cosine wave) that is a 1/4 sine wave may be divided into k sections, sampled into k sections, and sampled into k sections, and the initial value of each section may be stored as a sampling value in the memory. Alternatively, the difference between the initial value of each section and 0 (or 1) may be stored in the memory.

Equation 1 below represents a value f (φ) stored in a memory when the π / 2 section of a sine wave is divided into eight sections and sampled into eight sections.

Where? Is 0, 1, 2, 3,... Is an integer value.

Referring to Equation 1, the π / 2 sections of the sine wave are divided into eight sections, sampled into eight sections, and the difference between the initial value of each section and 0 (or 1) is stored in the memory.

That is, in the case of a video having a very fast transition or movement between frames, a π / 2 section of a sine wave (or cosine wave) used as a carrier for modulation is divided into sections corresponding to a reduced number of sampling k. After sampling by the number of sampling k, the initial value of each section or the difference between the initial value of each section and 0 (or 1) is stored in the memory. Thus, for example, when the sampling value is represented by 16 bits without reducing the sampling number of the sine wave (or cosine wave), the π / 2 interval of the sine wave (or cosine wave) corresponds to the reduced sampling number. The initial value of each section obtained by dividing by, or the difference value between the initial value of each section and 0 (or 1) can be expressed by only the lower 8 bits of the 16 bits. That is, the number of bits of data stored in the memory can be reduced, and only the lower 8 bits need to be accessed when the memory is accessed, thereby reducing the memory access time and performing fast operation during modulation.

In another embodiment of the present invention, a sine wave sampling value and a cosine wave sampling according to sine values sinα1, sinα2, and sinα3 corresponding to slopes of tangents at points A1, A2, and A3 in the graph representing the sum of the motion vectors of the frame of FIG. The number of samplings of the values may have different values. For example, when the sine value sinα corresponding to the tangential slope of a predetermined frame on the sum curve of the motion vectors is between sin 0 ° and sin 30 °, the sampling frequency is 4, and the sin value sinα is equal to sin 30 °. When the sin is between 60 °, the sampling frequency is 8, and when the sine value sinα is between sin 60 ° and sin 90 °, the sampling frequency can be 16.

In another embodiment of the present invention, the number of sampling of the sine wave sampling value and the cosine wave sampling value may be adjusted based on the sum of the motion vectors.

For example, in the graph showing the sum of the motion vectors of the frames of FIG. 5, the sampling frequency of the sine wave sampling value and the cosine wave sampling value differs depending on which section the sum of the motion vectors at the points B1, B2, and B3 belongs to. It can have a value. For example, when the sum of the motion vectors at the points B1, B2, and B3 is between C2 and C3 (B1), the sampling frequency of the sine wave sample value and the cosine wave sample value is reduced to 4, and when it is between C2 and C1 ( In B2), the number of samplings of the sine wave sampling value and the cosine wave sampling value is reduced to 8, and in the case of less than C1 (B3), the number of sampling of the sine wave sampling value and the cosine wave sampling value can be used without decreasing.

8 is a block diagram illustrating a video encoder according to another embodiment of the present invention.

The video encoder of FIG. 8 is the same as the video encoder of FIG. 3 except that the switching unit 830 is provided in front of the image quality correction unit 320. In the video encoder of FIG. 8, the color signals CB and CR of the digital image signal 301 do not pass through the image quality correction units 324 and 326 in the case of a video having a very fast scene change or movement between frames. For the image part, power consumption may be reduced by temporarily blocking the image quality correction units 324 and 326. When the sum of the motion vectors of the frames is greater than a predetermined threshold, it may be determined that the video is very fast in changing scenes or moving between frames.

In the case of a moving image having a very quick transition or movement between frames, the disable signal 807 is activated. When the disable signal 807 is activated, the color signals CB and CR of the digital image signals 301 do not pass through the image quality correction units 324 and 326 in the first and second switching units 832 and 834. When the disable signal 807 is inactivated and the disable signal 807 is deactivated, the color signals CB and CR of the digital image signals 301 are corrected by the first and second switching units 832 and 834. The control unit 324 controls the output to the modulator 330 after passing through 324 and 326.

9 is a block diagram illustrating a video encoder according to another embodiment of the present invention.

The video encoder of FIG. 9 differs from the video encoder of FIG. 3 in that it further includes an upscaler 910 and an image signal converter 920. In this case, the remaining configuration for reducing the number of sampling of the sine wave sampling value and the cosine wave sampling value used as a carrier for modulation to a predetermined number is the same as the video encoder of FIG. 3.

An upscaler 910 enlarges the resolution of the digital image signal 360 by upscaling the digital image signal 360 by a predetermined ratio. That is, even when the low resolution digital video signal 360 output from the DMB phone or the like is input, the upscaler 910 may enlarge the resolution of the digital video signal 360 to be suitable for a high resolution TV.

 The video signal converter 920 analyzes the shape of the upscaled digital video signal 362 output from the upscaler 910, and if the video encoder is not a digital video signal suitable for conversion into an analog video signal, the analog video signal. Convert to a digital video signal suitable for conversion. For example, when a digital video signal of YCBCR format is input, it may be converted into a digital video signal of RGB format, or when a digital video signal of RGB format is input, it may be converted into a digital video signal of YCBCR format.

When the size of an image input to the video encoder is increased by the upscaler, the carrier sine wave signal and the cosine wave signal are also upscaled and stored in the memory by the upscaled ratio. In the case of a video having a very quick transition or movement between frames, the amount of data stored in the memory is reduced by reducing the number of sampling times of the sine wave sampling value and the cosine wave sampling value used as a carrier for modulation to a predetermined number of times. The size can be reduced.

10 is a block diagram illustrating a video encoder according to another embodiment of the present invention.

The video encoder of FIG. 10 is the same as the video encoder of FIG. 9 except that the switching unit 830 is provided in front of the image quality correction unit 320. In the video encoder of FIG. 10, the color signals CB 903 and CR 905 of the digital image signals 901, 903, and 905 are the image quality correcting unit 324 in the case of a video having a very fast scene change or movement between frames. By not passing through 326, the power consumption can be reduced by temporarily blocking the image quality correction units 324 and 326 for the high-speed image portion.

11 is a flowchart illustrating a video signal conversion method according to an embodiment of the present invention.

Referring to FIG. 11, first, a sum of motion vectors for each frame of a digital video signal is calculated (step 1101), and it is determined whether the sum of motion vectors exceeds a reference value (step 1103). Here, the determination of whether the sum of the motion vectors exceeds the reference value is performed by determining a sine value corresponding to the slope of the tangent in a predetermined frame on the sum curve of the motion vector and the slope of the tangent in a predetermined frame on the sum curve of the motion vector. Alternatively, it may be determined whether the total value of the motion vectors exceeds a predetermined reference value. In addition, the predetermined reference value may be a plurality of reference value values or a predetermined section instead of one reference value.

If the sum of the motion vectors exceeds the reference value, the sampled value sampled with the reduced sampling number of the carrier wave (sine wave or cosine wave) for modulation is read (step 1105). The memory stores only the sample values having a reduced sampling number without storing all the sampling values of the conventional N number of carriers (sine wave or cosine wave). For example, k sampling values, which are much smaller than N / 4 in a quarter period of a conventional carrier, are stored. Here, k may be four. Or k may be eight or sixteen.

If the sum of the motion vectors does not exceed the reference value, a sampled value having an increased sampling number is generated using the sampled value sampled with the reduced sampling number of the carrier (sine wave or cosine wave) for modulation. (Step 1107). For example, a sampled value with an increased number of samplings is obtained by reading four sampling values within a quarter period from a memory and performing a linear approximation using a straight line between the four sections. Can be generated.

A carrier is generated based on the sampling value (step 1109).

Therefore, the number of times of access of the memory can be greatly reduced, compared to the case of using a memory that stores all the N sampling values in the related art, and thus the power consumed can be greatly reduced.

According to the video encoder and the video signal conversion method as described above, the sampling frequency of the sine wave and the cosine wave used as a carrier wave to modulate the digital video signal based on the sum of the motion vectors of the frame is adjusted, and in particular, between the frames. In the case of many image changes, the number of sine and cosine waves used as a carrier for modulation is reduced by a predetermined number of times, thereby reducing the memory size and reducing the memory access time by reducing the amount of data stored in the memory. In the modulation operation, fast operation can be performed and power consumption can be reduced.

 Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (17)

A video encoder for converting a digital video signal into an analog video signal for displaying an image, A synchronization signal controller for generating a synchronization signal for synchronizing the analog video signal; A motion vector calculator configured to calculate a sum of motion vectors of each frame of the digital video signal; A modulated signal generator for generating a carrier sampled at an adjusted sampling frequency based on the sum of the motion vectors of the frames; An image quality corrector configured to correct the image quality of the digital image signal to generate a corrected digital image signal; A modulator for modulating the corrected digital video signal into a digital signal corresponding to the analog video signal based on the synchronization signal and the carrier wave; And And a digital-to-analog converter configured to convert the modulated digital signal into an analog signal to generate the analog image signal. The video encoder of claim 1, wherein the modulated signal generator further includes a memory configured to store a sampling value sampled at a sampling frequency reduced by a predetermined sampling frequency of the carrier. 3. The method of claim 2, wherein the modulated signal generator generates a sampled carrier by reducing the number of times of sampling in the π / 2 interval of the carrier when the change in the sum of the motion vectors of the respective frames is greater than or equal to a predetermined threshold. Video encoder. 3. The method of claim 2, wherein the modulated signal generator is further configured to reduce the sampling frequency in the π / 2 interval of the carrier when the slope of the tangent in a predetermined frame on the sum curve of the motion vectors for each frame is greater than or equal to a predetermined threshold. Video encoder, characterized in that it generates a generated carrier. 3. The method of claim 2, wherein the modulated signal generator is different in the number of times of sampling in the π / 2 interval of the carrier according to the sine value corresponding to the slope of the tangent in a predetermined frame on the sum curve of the motion vector for each frame And generate a carrier sampled to have a value. 3. The method of claim 2, wherein the modulated signal generator generates a sampled carrier such that the larger the magnitude of the sum of the motion vectors of the respective frames, the smaller the number of times of sampling in the π / 2 interval of the carrier is. Video encoder. The method of claim 2, wherein the modulated signal generator is further configured to divide the π / 2 sections of the carrier into sections corresponding to a reduced number of samples when the sum of the motion vectors of the respective frames is greater than a predetermined threshold, and then sample each section. And store an initial value of in the memory. 3. The method of claim 2, wherein the modulated signal generator is further configured to divide the π / 2 sections of the carrier into sections corresponding to the reduced number of samples when the sum of the motion vectors of the frame is greater than a predetermined threshold, and then start each section. And a difference value between 0 and 1 in the memory. Claim 9 was abandoned upon payment of a set-up fee. The video encoder of claim 1, further comprising a switching unit configured to control at least a portion of the digital image signal not to pass through the image quality correction unit when the sum of the motion vectors of the frame is greater than a predetermined threshold. A video signal conversion method for converting a digital video signal into an analog video signal for displaying an image, Generating a carrier sampled at an adjusted sampling frequency based on the sum of motion vectors of each frame of the digital video signal; Modulating the digital video signal into a digital signal based on a synchronization signal for synchronizing the analog video signal and the sampled carrier; And And converting the modulated digital signal into an analog signal to generate the analog video signal. The method of claim 10, wherein the generating of the carrier comprises: reading a sampling value sampled from a memory at a sampling frequency reduced by a predetermined sampling frequency of the carrier; Generating a carrier having a sampled value sampled with a reduced number of samples read from the memory when the sum of the motion vectors of each frame is greater than or equal to a predetermined threshold; And Generating a carrier having a sampled value having an increased number of sampling using a sampled value with a reduced number of samples read from the memory if the sum of the motion vectors of each frame is less than the predetermined threshold; The video signal conversion method characterized in that. The method of claim 10, wherein the generating of the carrier comprises generating a sampled carrier by reducing the number of samplings in the π / 2 interval of the carrier when the change of the sum of the motion vectors of the respective frames is greater than or equal to a predetermined threshold. A video signal conversion method. The method of claim 10, wherein the generating of the carrier comprises reducing the number of samplings in the π / 2 interval of the carrier when the slope of the tangent in a predetermined frame on the sum curve of the motion vectors of each frame is equal to or greater than a predetermined threshold. And a sampling carrier is generated. Claim 14 was abandoned when the registration fee was paid. The method of claim 10, wherein the generating of the carrier comprises the number of times of sampling in the π / 2 interval of the carrier is different from each other according to a sine value corresponding to a slope of a tangent line in a predetermined frame on a sum curve of a motion vector of each frame. And generating a carrier sampled to have a different value. Claim 15 was abandoned upon payment of a registration fee. The method of claim 10, wherein the generating of the carrier comprises generating a sampled carrier such that the larger the sum of the motion vectors of the respective frames, the smaller the number of samplings in the π / 2 interval of the carrier is. A video signal conversion method. Claim 16 was abandoned upon payment of a setup registration fee. 12. The method of claim 10, wherein the generating of the carrier comprises: after equalizing and sampling the π / 2 interval of the carrier into the interval corresponding to the reduced number of sampling when the sum of the motion vectors of each frame is greater than a predetermined threshold, And storing the initial value of each section in the memory. Claim 17 was abandoned upon payment of a registration fee. 12. The method of claim 10, wherein the generating of the carrier comprises: after equalizing and sampling the π / 2 interval of the carrier into the interval corresponding to the reduced number of sampling when the sum of the motion vectors of each frame is greater than a predetermined threshold, And storing a difference value between the initial value of each section and a difference value between 0 and 1 in the memory.

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