KR100555643B1 - apparatuses for sending and receiving video signal and method thereof - Google Patents

Abstract

An apparatus and method for transmitting and receiving video signals are disclosed. The preprocessor receives a video signal and outputs a first video signal identical to the received video signal and a second video signal from which a first frame of the received video signal is removed. The normal channel encoding unit receives the first image signal and generates a first image group composed of a plurality of images, and the backup channel encoding unit receives the second image signal and the second image group in which a predetermined number of images of the first image group are transitioned. Create The transmitter transmits the picture group generated by each encoder. The receiver receives and outputs a video signal, and the normal channel decoder decodes the video signal received through the normal channel to output the first video signal, and the backup channel decoder decodes the video signal received through the second channel. 2 Outputs a video signal. The post processor outputs a signal obtained by averaging the first video signal and the second video signal. Generate a GOP having an image array in which a certain number of images are transitioned to the image array in the GOP of the video signal transmitted through the regular channel, and transmit the GOP through the backup channel, and average the video signals received through the normal channel and the backup channel. By outputting it, it is possible to reliably receive an image even when a problem occurs in the regular channel, and at the same time improve the quality of the received image and prevent waste of the channel.

Regular channel, GOP, MPEG, preprocessing, encoding, decoding

Description

Apparatuses for sending and receiving video signal and method

1A is a block diagram showing the configuration of a conventional video signal transmitting apparatus;

1B is a block diagram showing the configuration of a conventional video signal receiving apparatus;

2 is a diagram showing the configuration of a video signal transmission apparatus according to the present invention;

3 is a diagram illustrating an internal configuration of a regular channel encoder and a backup channel encoder;

4 is a block diagram showing the configuration of a video signal receiving apparatus according to the present invention;

5 is a diagram showing the internal configuration of a normal channel decoding unit and a backup channel decoding unit of a video signal receiving apparatus according to the present invention;

6 is a diagram illustrating the structure of a GOP coded by a normal channel encoder and a backup channel encoder of a video signal transmission apparatus according to the present invention;

7 is a flowchart illustrating a video signal transmission method according to the present invention;

8 is a flowchart illustrating a method of receiving a video signal according to the present invention.

The present invention relates to an apparatus for transmitting and receiving a video signal and a method thereof, and more particularly, to an apparatus for transmitting and receiving a same image through a plurality of channels by compressing the same image and transmitting the same image through a plurality of channels. The present invention relates to a receiving apparatus for restoring and outputting an image, a method of encoding and transmitting an image in each apparatus, and a method of decoding a received image.

The current video is compressed and then transmitted for efficient use of the transmission frequency, and is generally encoded using Moving Pictures Expert Group 2: MPEG2. In the case of a video signal transmission and reception device that requires high quality and high reliability, such as an Olympic broadcast, a backup channel is additionally used in case a video cannot be transmitted through a regular channel. In this case, the MPEG video codec is mainly used as the encoder / decoder of the normal channel and the backup channel.

1A is a block diagram showing the configuration of a conventional video signal transmission apparatus.

Referring to FIG. 1A, a conventional video signal transmitting apparatus 100 includes a preprocessor 110, a regular channel encoder 120, a backup channel encoder 130, and a transmitter 140.

The preprocessor 110 outputs the video signal to the normal channel encoder 120 and the backup channel encoder 130 by performing noise reduction on the received video signal. The normal channel encoder 120 and the backup channel encoder 130 encode and output image signals received from the preprocessor 110, respectively. In this case, the same video signal compressed and encoded by the MPEG method is output from the normal channel encoder 120 and the backup channel encoder 130. The transmitter 140 transmits a video signal compressed and encoded by the MPEG method through a normal channel and a backup channel.

1B is a block diagram showing the configuration of a conventional video signal receiving apparatus.

Referring to FIG. 1B, a conventional video signal receiving apparatus 150 includes a receiver 160, a regular channel decoder 170, a backup channel encoder 180, and a post processor 190.

The receiver 160 receives a video signal transmitted from the video signal transmitter 100. The normal channel decoder 170 and the backup channel decoder 180 receive an image signal corresponding to each channel from the receiver 160 and restore the original signal. After the normal channel operates normally, the post processor 190 outputs the reconstructed video signal received from the normal channel decoder 170. If a problem occurs in the normal channel and a video signal cannot be received from the regular channel, the post processor 190 outputs the restored video signal received from the backup channel decoder 180. The post processor 190 includes a switch, and selects an image signal input to the post processor 190 according to whether the normal channel is normally operated.

The conventional video signal receiving apparatus 150 restores and outputs a video signal received through a backup channel when a problem occurs in a regular channel, thereby enabling stable reception of an image. However, when both the normal channel and the backup channel operate normally, the same video signal is received through two channels of the normal channel and the backup channel, thereby causing a waste of the channel.

An object of the present invention is to provide an apparatus and method for transmitting a video signal that can stably receive a video even in the event of a problem with a regular channel and at the same time prevent the waste of the channel. have.

Another object of the present invention is to provide a video signal receiving apparatus and method capable of stably receiving a video even when a problem occurs in a regular channel and at the same time preventing waste of the channel.

According to an aspect of the present invention, there is provided an apparatus for transmitting video signals according to an embodiment of the present invention, wherein the first video signal identical to the video signal received from the video signal and the second image from which the first frame of the video signal is removed are removed. A preprocessor outputting a signal; A first channel encoder for receiving the first image signal and generating and outputting a first image group composed of a plurality of images; And a second channel encoder configured to receive the second image signal and generate a second image group in which a predetermined number of images of the first image group are transitioned.

Preferably, the preprocessor includes a delay unit for delaying the input image signal for a predetermined time and outputting a second image signal from which the first frame of the image signal is removed.

According to an aspect of the present invention, there is provided an apparatus for receiving video signals, comprising: a first channel decoder configured to decode a video signal received through a first channel and output a first video signal; A second channel decoder for decoding a video signal received through the second channel and outputting a second video signal; And a post processor outputting a signal obtained by averaging the first video signal and the second video signal.

The post-processing unit outputs the second video signal when the first video signal is not received, and the second video signal is an image group including an image in which a certain number of images in the image group of the first video signal are transitioned. Do.

According to another aspect of the present invention, there is provided a video signal transmission method comprising: receiving a video signal and outputting a first video signal identical to the received video signal and a second video signal from which a first frame of the received video signal is removed; Pretreatment step; A first channel encoding step of receiving the first image signal and generating and outputting a first image group consisting of a plurality of images; And a second channel encoding step of receiving the second image signal and generating a second image group having a predetermined number of transitions of the images of the first image group.

According to another aspect of the present invention, there is provided a video signal receiving method comprising: a first channel decoding step of decoding a video signal received through a first channel and outputting a first video signal; A second channel decoding step of decoding a video signal received through the second channel and outputting a second video signal; And a post-processing step of outputting a signal obtained by averaging the first video signal and the second video signal.

Generate a GOP having an image array in which a certain number of images are transitioned to the image array in the GOP of the video signal transmitted through the regular channel, and transmit the GOP through the backup channel, and average the video signals received through the normal channel and the backup channel. By outputting the same, it is possible to stably receive an image even when a problem occurs in a regular channel, and at the same time prevent the quality of the received image and the waste of the channel.

Hereinafter, an apparatus and method for transmitting and receiving video signals according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram showing the configuration of a video signal transmission apparatus according to the present invention.

Referring to FIG. 2, the video signal transmitting apparatus 200 according to the present invention includes a preprocessor 210, a normal channel encoder 220, a backup channel encoder 230, and a transmitter 240.

The preprocessor 210 receives a video signal and outputs a first video signal identical to the received video signal and a second video signal from which a first frame of the received video signal is removed. The preprocessing unit 210 delays the input image signal for a predetermined time (for example, a time corresponding to one screen of the first image group) to output a second image signal from which the first frame of the input image signal is removed. Has a portion 215.

On the other hand, the delay unit 215 may be configured as a switch. When the delay unit 215 is a switch, the video signal input by turning on the switch after a predetermined time (for example, a time corresponding to one screen of the first image group) after the video signal is input to the preprocessor 210. The second video signal from which the first frame of is removed is output.

The normal channel encoder 220 outputs the compressed video signal by coding the first video signal received from the preprocessor 210 into a first picture group composed of a plurality of pictures. The backup channel encoder 230 compresses the second video signal received from the preprocessor 210 into a second picture group in which a predetermined number (for example, one) of the pictures of the first picture group is transitioned and compressed. Output the signal.

The transmitter 240 transmits the compressed video signal from the normal channel encoder 220 and the backup channel encoder 230 to each channel.

3 is a diagram illustrating an internal configuration of a regular channel encoder and a backup channel encoder. The regular channel encoder 220 and the backup channel encoder 230 have the same configuration and call this the MPEG encoder 300.

Referring to FIG. 3, the MPEG encoder 300 includes a frame / field memory 305, a complexity predictor 310, a rate adjuster 315, a discrete cosign transfomer 320, a quantizer 325, and an inverse quantization. Group 330, inverse DCT 335, frame memory and motion compensator 340, motion predictor 345, VCL (Variavle length coding) 350, and buffer 355. In the MPEG method, a video signal is compressed using spatial redundancy and temporal redundancy of an image.

The frame / field memory 305 controls the order of data and the order of encoding the input video signal. The video signal output from the frame / field memory is discrete cosine transformed in the DCT 320. The coefficients generated in the DCT 320 are quantized in the quantizer 325, and the VCL 350 performs variable length coding to indicate the quantized coefficients. Finally, the compressed / coded video signal is input to the buffer 355, and the buffer 355 outputs a bitstream of the converted video signal. This process is expressed as spatial redundancy in the MPEG method.

The video signal generated from the frame / field memory 305 is predicted by the complexity predictor 310, and the rate is adjusted by the rate adjuster 315 based on the complexity and the state of the buffer 355. Quantization of quantizer 325 is controlled.

On the other hand, when the image to be encoded is an I (Intra) image coded in the spatial mode, the output signal of the quantizer 325 is input to the inverse quantizer 330 and in turn to the inverse DCT 335 to input the frame / field. The image is restored to the output of the memory 305 and then stored in the frame memory 340 to be used as a reference image. This process is represented by temporal redundancy in the MPEG method.

If the picture to be encoded is a P (predictive) picture configured based on a temporary previous picture based on preceding prediction, the motion predictor 345 encodes an error value and a motion value by motion prediction, and inverse quantization and inverse DCT. The motion compensation is performed by the motion compensator 340 using the reference image stored in the frame memory 340 through the video, and decoded into one image and stored as a new reference image in the frame memory 340.

If the picture to be encoded is a B (bidirectional predictive) picture composed of two temporary previous pictures and subsequent pictures based on the preceding prediction and the subsequent prediction, the motion prediction uses the two reference pictures to obtain the optimal motion prediction. Since the B picture is not used as the reference picture, a separate decoding operation is not necessary.

6 is a diagram illustrating the structure of a GOP coded by a normal channel encoder and a backup channel encoder of the apparatus for transmitting a video signal according to the present invention.

Referring to FIG. 6, the GOP coded by the normal channel encoder 220 has an image array 610 of IBBPBBPBBPBBPBB, and the GOP coded by the backup channel encoder 230 has an image array 620 of BIBBPBBPBBPBBPB. According to FIG. 6, it is understood that the picture array 620 of the GOP coded by the backup channel encoder 230 has one picture transitioned from the picture array 610 of the GOP coded by the normal channel encoder 220. Can be. This is because the video signal input to the backup channel encoder 230 is delayed by one image by the preprocessor 210.

4 is a block diagram showing the configuration of a video signal receiving apparatus according to the present invention.

Referring to FIG. 4, the video signal receiving apparatus 400 according to the present invention includes a receiver 410, a regular channel decoder 420, a backup channel decoder 430, and a post processor 440.

The receiver 410 receives the video signal transmitted from the video signal transmitting apparatus 200 according to the present invention and outputs the video signal to the normal channel decoder 420 and the backup channel encoder 430 according to the channel of the received signal. The normal channel decoder 420 and the backup channel decoder 430 restore the respective image signals input from the receiver 410 to the original image and output the original image to the post processor 440.

5 is a diagram illustrating an internal configuration of a normal channel decoding unit and a backup channel decoding unit of a video signal receiving apparatus according to the present invention. The normal channel decoder 420 and the backup channel decoder 430 have the same configuration and are referred to as an MPEG decoder 500.

The buffer 510 receives an image signal from the receiver 410 and outputs the image signal to the decoder 520. The decoder 520 restores the received signal. In the case of I and P images, the decoder 520 is dequantized by the inverse quantization unit 530 and inverse discrete cosine transformed by the inverse DCT 540 to decode the B image. ) In this case, when the reconstructed signal is a B-image, the signal predicted by the adaptive prediction unit 560 is added to the output of the inverse DCT unit 540 by the adder 550 and then stored in the memory 570. The images stored in the memory 570 are rearranged and output in the same order as the frames of the original image in the frame rearranging unit 580.

The post processor 440 includes a normal channel decoder 420 and a reception signal processor 445 that averages and outputs the signals restored by the backup channel decoder 430. In addition, the post-processing unit 440 outputs an image signal output from the reception signal processing unit 445 when both the normal channel and the backup channel operate normally, and only one of the normal channel and the backup channel operates normally. In this case, the switch 450 is provided to output an image signal output from the decoder for the corresponding channel.

7 is a flowchart illustrating a video signal transmission method according to the present invention.

Referring to FIG. 7, when an image signal is input to the preprocessor 210 (S700), the preprocessor 210 may remove a first image signal identical to the input image signal and a first frame of the received image signal. The video signal is output (S710). The second video signal is a video signal in which the first frame of the input video signal is removed because the input video signal is delayed for a predetermined time (for example, a time corresponding to one screen of the GOP generated by the regular channel encoder 220). to be.

The regular channel encoder 220 receives the first image signal from the preprocessor 210 and generates and outputs a first image group GOP composed of a plurality of images (that is, I image, P image, and B image). The backup channel encoder 230 receives the second image signal from the preprocessor 210 to generate a second image group to which a number of images of the first image group are transitioned (eg, one image). To compress (S730).

The video signal compressed / coded by the regular channel encoder 220 and the backup channel encoder 230 is transmitted through the corresponding channel through the transmitter 240 (S730). In this case, a multiplexing process of multiplexing the compressed / coded video signal by the normal channel encoder 220 and the backup channel encoder 230 may be performed before the video signal is transmitted.

8 is a flowchart illustrating a method of receiving a video signal according to the present invention.

Referring to FIG. 8, when an image signal is received through the receiver 410, the receiver 410 outputs the image signal received for each channel to the normal channel decoder 420 and the backup channel encoder 430 ( S800). The normal channel decoder 420 and the backup channel decoder 430 restore each image signal input from the receiver 410 to the original image and output the original image to the post processor 440 (S820).

The post processor 440 checks whether the video signal is input from the regular channel decoder 420 (S820). If the signal is not input, the post processor 440 checks the signal input from the backup channel decoder 430 (S830). When the video signal is input from the backup channel decoder 430, the post processor 440 outputs the video signal input from the backup channel decoder 430 (S840).

If it is confirmed in step S820 that the video signal is input from the regular channel decoder 420, it is checked whether the video signal input from the backup channel decoder 430 (S850). When the video signal is input only from the normal channel decoder 420, the post processor 440 outputs the video signal input from the normal channel decoder 420 (S860).

If it is determined in step S850 that the video signal is input from both the normal channel decoder 420 and the backup channel decoder 430, the post processor 440 is the normal channel decoder 420 and the backup channel decoder 430. In operation S870, a value obtained by averaging the input video signal is output. Since the images received from the normal channel decoder 420 and the backup channel decoder 430 at the same time have low correlation, an average value of both signals can be obtained to obtain a higher quality image than the respective images.

According to the present invention, a GOP having a picture array in which a predetermined number of pictures are transitioned to a picture array in a GOP of a video signal transmitted through a normal channel is generated and transmitted through a backup channel, and through a normal channel and a backup channel. By averaging and outputting the received video signals, it is possible to stably receive a video even when a problem occurs in a regular channel, and at the same time obtain a quality improvement of the received video and prevent waste of the channel.

Although the present invention has been described in detail through the representative embodiments, those skilled in the art to which the present invention pertains can make various modifications without departing from the scope of the present invention with respect to the embodiments described above. Will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

Claims (7)

A pre-processing unit which receives a video signal and outputs a first video signal identical to the received video signal and a second video signal from which a first frame of the received video signal is removed; A first channel encoder for receiving the first image signal and generating and outputting a first image group composed of a plurality of images; And And a second channel encoder configured to receive the second image signal and generate a second image group in which a predetermined number of images of the first image group are transitioned. 2. The method of claim 1, And the preprocessor includes a delay unit configured to delay the input image signal for a predetermined time and output a second image signal from which the first frame of the image signal is removed. A first channel decoder for decoding a video signal received through the first channel and outputting a first video signal; A second channel decoder for decoding a video signal received through the second channel and outputting a second video signal; And And a post processor which outputs a signal obtained by averaging the first video signal and the second video signal. The method of claim 3, wherein And the second image signal is an image group consisting of images in which a certain number of images in the image group of the first image signal are transitioned. The method according to claim 3 or 4, And the post processor outputs the second video signal when the first video signal is not received. A preprocessing step of receiving a video signal and outputting a first video signal identical to the received video signal and a second video signal from which a first frame of the received video signal is removed; A first channel encoding step of receiving the first image signal and generating and outputting a first image group consisting of a plurality of images; And And a second channel encoding step of receiving the second image signal and generating a second image group in which a predetermined number of images of the first image group are transitioned. 2. A first channel decoding step of decoding a video signal received through the first channel and outputting a first video signal; A second channel decoding step of decoding a video signal received through the second channel and outputting a second video signal; And And a post-processing step of outputting a signal obtained by averaging the first video signal and the second video signal.

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