KR0176490B1 - Circuit for both recording and reproducing simultaneously with two input source - Google Patents

Abstract

Depending on the recording mode, one sub-sampled output is bypassed or once again sub-sampled to record two input sources simultaneously, and depending on the playback mode, the two interpolated outputs can be bypassed or interpolated once again. Two simultaneous input and simultaneous recording and playback circuits are disclosed, which can simultaneously record and play back two input sources instead of reducing the resolution. Apart from some sources that meet the needs and especially require high resolution, they are suitable for general users as well as monitors that need to check several broadcasts simultaneously.

Description

Simultaneous recording and playback of two input sources

1 is a block diagram showing a recording circuit in a conventional digital VCR.

2 is a block diagram showing a playback circuit in a conventional digital VCR.

3 is a block diagram showing two luminance source simultaneous recording circuits in a digital VCR according to the present invention;

4 is a block diagram showing two chrominance source simultaneous recording circuits in a digital VCR according to the present invention.

5 is a block diagram showing two luminance source simultaneous reproduction circuits in a digital VCR according to the present invention;

6 is a block diagram showing two chrominance source simultaneous reproduction circuits in a digital VCR according to the present invention.

* Explanation of symbols for main parts of the drawings

301, 304, 401, 405: A / D converter 302, 305: subsampling unit

303 and 404: segment generator 306 and 408: image compression encoder

307, 409: outer arc adding portion 308, 410: inner arc adding portion

402 and 406: first sub-sampler 403 and 407: second sub-sampler

501, 601: inner code decoding section 502, 602: outer code decoding section

503 and 603: Image compression decoding unit 504 and 604: Segment restoration unit

505, 507: Interpolation unit 506, 508, 607, 610: D / A conversion unit

605, 608: first interpolation unit 606, 609: second interpolation unit

The present invention relates to simultaneous recording and playback of two input sources in a digital video cassette recorder (hereinafter referred to as D-VCR). Record two input sources simultaneously by bypassing or sub-sampling again, and simultaneously recording two input sources by simultaneously reproducing two input sources by bypassing or interpolating the output once interpolated depending on the playback mode. It relates to a regeneration circuit. In this case, simultaneous recording of two input sources refers to simultaneously recording two broadcasts or recording one broadcast while recording one external source in D-VCR.

1 is a block diagram showing a recording circuit of a conventional D-VCR, which receives an analog input or a digital input signal and records and reproduces in a digital manner. That is, if the composite video signal is an analog video signal, it is converted to a digital signal through an analog / digital (hereinafter, referred to as A / D) conversion unit 101 and then output to the sub-sampling unit 102. If it is a digital video signal, it is directly output to the sub-sampling unit 102.

In this case, the sub-sampling unit 102 samples the luminance signal at 13.5 MHz and the two color difference signals C _R and C _B at 6.75 MHz, and then, in the NTSC (National Television System Committe) method, performs color difference signals in the horizontal direction. In the PAL (Phase Alternating Line) method, the color difference signal is sub-sampled in the line direction and processed in the form of 4: 1: 1 or 4: 2: 0 and output to the segment generator 103. The segment generator 103 extracts a macroblock at a predetermined position on the screen to form a segment. At this time, if the macro blocks are extracted in a row on the screen to form a segment, the image quality is deteriorated. In this case, one segment is composed of five macro blocks, and one macro block is composed of blocks of four luminance components and blocks of two color difference components. Meanwhile, the compression encoder 104 compresses data in units of segments formed by the segment forming unit 103 and outputs the data to the outer code adding unit 105 and the inner code adding unit 106. The outer call adding unit 105 adds a parity code in the horizontal direction for error correction, and the inner call adding unit 106 adds a parity code in the vertical direction and then records the compressed digital video signal on the tape.

FIG. 2 is a block diagram showing a reproducing circuit of the conventional D-VCR, and the operation opposite to that of FIG. That is, the reproduction signal read from the tape through the head performs error correction in the vertical direction using the parity code in the vertical direction in the internal code decoding unit 201, and the internal code decoding unit (202) in the external code decoding unit 202. In step 201, error correction is performed in the horizontal direction including an error that cannot be corrected. At this time, the error correction is performed in the inner code decoder 201 and the outer code decoder 202 in order to increase the error correction capability. The digital video signal in which the error is corrected by the inner code decoder 201 and the outer code decoder 202 is decoded to the original data length by the image compression decoder 203, and then the segment reconstruction unit 204 is executed. Will output The segment restoration unit 204 restores the macroblocks to their original positions on the screen and outputs the macroblocks to the interpolation unit 205. In this case, the luminance signal is sampled at 13.5 MHz in the recording system of FIG. 1, and the two color difference signals CR and CB are sampled at 6.75 MHz, and then the NTSC method is horizontally sampled and the PAL method is subsampled again in the line direction. Since the restoration unit 205 restores the original data by interpolating the data in the horizontal direction and the PAL method in the line direction in the restoration unit 205. In the case of analog VCR, the output of the interpolator 205 is output after being converted into an analog signal by the D / A converter 206, and in the case of D-VCR, the output of the interpolator 205 is output as it is.

However, in the above-described conventional FIGS. 1 and 2, the signal processing path can process only one input at a time without distinction between analog and digital as a single path. In other words, for example, when a television signal is recorded, another broadcast cannot be recorded while recording one channel. In addition, even if the VCR or TV has a Picture In Picture (PIP) function, it is possible to view broadcasts and other broadcasts on the screen, but two broadcast channels cannot be recorded at the same time. In addition to the existing broadcasting system, the number of channels that the user can select rapidly increases due to the practical use of cable broadcasting or satellite broadcasting. However, when programs to be recorded by the user overlap in the same time zone, the user selects and records only one program. If you want to record two input sources at the same time, you need to have more than one VCR system to record.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to enable recording of one input source, while in two input source recording modes, the subsampled output is once again subsampled to provide two input sources. The present invention provides two input source simultaneous recording circuits to enable simultaneous recording.

It is another object of the present invention to provide two input source simultaneous playback circuits capable of simultaneously playing one input source while simultaneously interpolating the output once interpolated in two input source playback modes to allow the simultaneous playback of two input sources. Is in.

A feature of the simultaneous recording and reproducing circuit of two input sources according to the present invention for achieving the above object is that the first digital luminance signal is subsampled and stored in a location where data of the upper predetermined line of the screen is stored during normal recording. And subsampling the second digital luminance signal at a location where data of the lower predetermined line of the screen is stored during normal recording, and extracting a macroblock at a predetermined position where the first and second digital luminance signals are stored to form a segment. Brightness signal recording means for performing data compression of the brightness signal on a formed segment basis; The first digital chrominance signal is successively subsampled and stored at a position where data of the upper predetermined line of the screen is stored during normal recording, and the second digital chrominance signal is successively subsampled so that the data of the lower predetermined line of the screen is normally recorded. Color difference signal recording means for extracting macro blocks at predetermined positions in which the first and second digital color difference signals are stored, storing the data in the stored positions, forming segments, and performing data compression of the color difference signals in units of the formed segments; Decode the error corrected reproduction luminance signal to the original data length, restore the macroblocks of the luminance signal forming the segment to the original position of the screen, and store the data of the upper predetermined line of the screen by the luminance signal recording means. Luminance signal reproducing means for interpolating the first luminance signal stored at a position to be stored and the second luminance signal stored at a position at which data of a predetermined lower line of the screen is stored; Decode the error corrected reproduction color difference signal to the original data length, restore the macroblocks of the color difference signal forming the segment to the original position of the screen, and store the data of the upper predetermined line of the screen by the color difference signal recording means. And a color difference signal reproducing means for interpolating successively each of the first color difference signal stored at the position where the first color difference signal is stored and the second color difference signal stored at the position where the data of the lower predetermined line of the screen is stored.

Hereinafter, a preferred embodiment of two input source simultaneous recording and reproducing circuits according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram showing two luminance source simultaneous recording circuits in a digital VCR according to the present invention. 3, there is a first luminance signal and a second luminance signal. That is, when only one input source is recorded, the first luminance signal line is recorded through the first luminance signal line, and when two input sources are simultaneously recorded, the first and second luminance signal lines are recorded. At this time, in the normal recording mode in which only one input source is recorded, the luminance signal is sampled at 13.5 MHz by the A / D converter 301 and then bypassed without passing through the sub-sampling unit 302 as a digital signal, thereby generating a segment generator ( 303). The segment generator 303 extracts the macroblock at a predetermined position on the screen to form a segment, and outputs the segment to the image compression encoder 306. The image compression encoder 306 uses the segment generator 303 to extract the segment. The data amount is reduced by the formed segment unit, and the data is compressed and then output to the outer call adding unit 307 and the inner call adding unit 308. The outer call adding unit 307 adds a parity code in the horizontal direction for error correction, and the inner call adding unit 308 adds a parity code in the vertical direction and then records the compressed luminance signal on the tape.

On the other hand, in the recording mode in which two input sources are simultaneously recorded, the first luminance signal is sampled at 13.5 MHz by the A / D converter 301 and then output to the sub-sampling unit 302 as a digital signal. The sub-sampling unit 302 sub-samples the digital luminance signal sampled at 13.5 MHz in the horizontal direction and processes it in the form of 2: 1.In the NTSC method, the sub-sampling unit 302 stores data of 0 to 239 lines in normal recording. In the PAL method, the data is stored in a location where 0 to 287 lines of data are stored during normal recording. The second luminance signal is sampled at 13.5 MHz by the A / D converter 304 and then output to the sub-sampler 305 as a digital signal. In the subsampling unit 305, the digital luminance signal sampled at 13.5 MHz is again subsampled in the horizontal direction and processed in the form of 2: 1. In the NTSC method, the data is stored at 240 to 479 lines during normal recording. In the PAL method, the data is stored at a location where 289 to 575 lines of data are stored during normal recording. This process is equivalent to dividing the screen into two and filling the top half with the first luminance signal and the bottom half with the second luminance signal. The segment generator 303 extracts a macroblock at a predetermined position of a screen in which the sub-samplers 302 and 305 respectively store the sub-sampled first luminance signal and the second luminance signal to form a segment, and then compress the image. Output to the encoder 306, and the image compression encoder 306 compresses the data by reducing the amount of data in units of segments formed by the segment forming unit 303, and then the outer code adder 307 and the inner code adder. Output to (308). The outer call adding unit 307 adds a parity code in the horizontal direction for error correction, and the inner call adding unit 308 adds a parity code in the vertical direction and then records the compressed luminance signal on the tape.

4 is a block diagram showing two chrominance source simultaneous recording circuits in a digital VCR according to the present invention. 4, there is a first color difference signal and a second color difference signal. That is, when only one input source is recorded, the first color difference signal line is recorded through the first color difference signal line, and when two input sources are simultaneously recorded, the first and second color difference signal lines are recorded. At this time, in the normal recording mode in which only one input source is recorded, the color difference signal is sampled at 6.75 MHz by the A / D converter 401 and then output to the first sub-sampler 402 as a digital signal. The first sub-sampling unit 402 sub-samples the color difference signal sampled at 6.75 MHz in the horizontal direction in the NTSC method and in the line direction in the PAL method, and then outputs it to the segment generator 404. The segment generator 404 extracts a macroblock at a predetermined position on the screen to form a segment and outputs the segment to the image compression encoder 408. The image compression encoder 408 compresses the data by reducing the amount of data in units of segments formed by the segment forming unit 404, and then outputs the data to the outer code adding unit 409 and the inner code adding unit 410, and then internally. The call and outer call adding units 409 and 410 add parity codes to the horizontal and vertical directions, respectively, and record the compressed color difference signals on the tape.

On the other hand, in the recording mode in which two input sources are simultaneously recorded, the first color difference signal is sampled at 6.75 MHz by the A / C converter 401 and then output to the first sub-sampling unit 402 as a digital signal. The first sub-sampler 402 subsamples the digital color difference signal sampled at 6.75 MHz in the horizontal direction in the NTSC method and in the line direction in the PAL method, and outputs the sub-sampler 403 to the second sub-sampler 403. In the NTSC method, the second sub-sampling unit 403 subsamples the color difference signals sampled in the horizontal direction again in the line direction, and stores them in a location where data of 0 to 239 lines are stored during normal recording. After subsampling in the horizontal direction again with respect to the color difference signal sampled in the line direction, the data is stored in the position where 0 to 287 lines of data are stored during normal recording. At this time, in the NTSC method, the subsampling is performed in the horizontal direction and then subsampled in the line direction. In the PAL method, the subsampling is performed in the line direction and the subsampling is again performed in the horizontal direction. The reason for this is that if the NTSC method subsamples both in the horizontal direction and the PAL method subsamples both in the line direction, the horizontal resolution drops too much in the NTSC method compared to the vertical resolution for the color difference signal, and the vertical resolution in the PAL method. This is because is excessively lower than the horizontal resolution. On the other hand, the second luminance signal is sampled at 6.75 MHz by the A / D converter 405 and then output as a digital signal to the first sub-sampling unit 406. The first sub-sampler 406 subsamples the digital color difference signal sampled at 6.75 MHz in the horizontal direction in the NTSC method and in the line direction in the PAL method, and outputs the sub-sampler 407 to the second sub-sampler 407. In the NTSC method, the second sub-sampler 407 subsamples the color difference signals sampled in the horizontal direction again in the line direction, and stores them in a location where 240 to 479 lines of data are stored during normal recording. After subsampling in the horizontal direction again with respect to the color difference signal sampled in the line direction, the data is stored in a location where 289 to 575 lines of data are stored during normal recording. This process is equivalent to dividing the screen into two and filling the top half with the first color difference signal and the bottom half with the second color difference signal. The segment generator 404 extracts a macroblock at a predetermined position of a screen in which the first color difference signal and the second color difference signal sub-sampled by the second sub-sampling units 403 and 407 are formed to form a segment. The image compression encoder 408 then outputs the result. The image compression encoder 408 compresses the data by reducing the amount of data in units of segments formed by the segment forming unit 404, and outputs the compressed data to the outer code adding unit 409 and the inner code adding unit 410, and The call adding unit 409 and the internal call adding unit 410 add parity codes in the horizontal and vertical directions, respectively, and record the first and second color difference signals compressed on the tape.

5 is a block diagram showing two luminance source simultaneous reproduction circuits in a digital VCR according to the present invention. In other words, the reproduction luminance signal read out from the tape through the head is subjected to error correction in the vertical and horizontal directions by the inner code decoder 501 and the outer code decoder 502, respectively. The luminance signal whose error is corrected through the inner code decoder 501 and the outer code decoder 502 is decoded to the original data length by the image compression decoder 503 and then sent to the segment reconstructor 504. Is output. The segment restoration unit 504 restores the macroblocks of the luminance signal forming the segment to the original position of the screen. In this case, the output of the segment restoration unit 504 is converted into an analog signal through the D / A converter 506 and then output in the normal playback mode in which only one input source is recorded.

On the other hand, in the reproducing mode in which two input sources simultaneously reproduce the recorded data, in the NTSC system, data restored from the segment restoring unit 504 and stored at positions 0 to 239 lines is input to the interpolation unit 505. The executive unit 505 interpolates the data stored in the positions 0 to 239 lines in the horizontal direction, and then outputs the first luminance signal through the D / A converter 506. The data restored by the segment recovery unit 504 and stored at 240 to 479 lines is input to the interpolation unit 507, and the interpolation unit 507 is horizontal to the data stored at 240 to 479 lines. After the interpolation for, the second luminance signal is output through the D / A converter 508. Also, in the PAL method, the data restored in the segment restoration unit 504 and stored at positions 0 to 287 lines are input to the interpolation unit 505, and the interpolation unit 505 stores data stored at positions 0 to 287 lines. After interpolation in the line direction, the first luminance signal is output through the D / A converter 506. Then, the data restored in the segment restoration unit 504 and stored at positions 288 to 575 lines are input to the interpolation unit 507, and the interpolation unit 507 is line direction of data stored at positions 288 to 575 lines. After interpolating for, the second luminance signal is output through the D / A converter 508. At this time, if two screens are to be simultaneously viewed, the first luminance signal is displayed at the upper half position of the playback screen of the VCR, and the second luminance signal is displayed at the lower half position. Then, if one screen is desired, the selected first or second luminance signal is displayed on the entire screen.

6 is a block diagram showing two chrominance source simultaneous reproduction circuits in a digital VCR according to the present invention. That is, the reproduction color difference signal read out from the tape through the head is subjected to error correction in the vertical direction and the horizontal direction in the inner code decoding unit 601 and the outer code decoding unit 602, respectively. The color difference signal whose error is corrected through the inner code decoding unit 601 and the outer code decoding unit 602 is decoded to the original data length by the image compression decoding unit 603 to the segment reconstruction unit 604. Is output. The segment restoration unit 604 restores the macroblocks of the color difference signal forming the segment to the original position of the screen. At this time, the output of the segment restoring unit 604 is input to the second interpolation unit 606 in the normal playback mode in which only one input source plays back the tape. The color difference signal is interpolated and then output through the D / A converter 607.

On the other hand, in the playback mode in which two input sources simultaneously play back a tape, the NTSC method restores data from the segment restoring unit 604 and stores data at positions 0 to 239 to the first interpolation unit 605. The first interpolator 605 interpolates the line direction of data stored at positions 0 to 239 and outputs the data to the second interpolator 606 to interpolate again in the horizontal direction. The first color difference signal is output through the D / A converter 607. Data restored in the segment restoring unit 604 and stored at positions 240 to 479 lines is input to the first interpolation unit 608, and stored at positions 240 to 479 lines in the first interpolation unit 608. After interpolating the data in the line direction, the data is output to the second interpolation unit 609 and interpolated again in the horizontal direction. Then, the second color difference signal is output through the D / A converter 610. Also, in the PAL method, data restored by the segment restoring unit 604 and stored at positions 0 to 287 lines are input to the first interpolation unit 605, and positions 1 to 287 lines in the first interpolation unit 605. After interpolating the data stored in the horizontal direction, the data is output to the second interpolation unit 606 and interpolated again in the line direction, and the first color difference signal is output through the D / A converter 607. Data restored by the segment restoration unit 604 and stored at positions 288 to 575 lines is input to the first interpolation unit 608, and stored at positions 288 to 575 lines at the first interpolation unit 608. After interpolating the data in the horizontal direction, the data is output to the second interpolation unit 609 and interpolated again in the line direction, and the second color difference signal is output through the D / A converter 610. At this time, if the user wants to simultaneously view the two screens, the first color difference signal is displayed at the upper half position of the playback screen of the VCR, and the second color difference signal is displayed at the lower half position. If the user wants to watch a screen, the selected first or second color difference signal is displayed on the entire screen.

As such, this invention can take advantage of the characteristics of digital signals only to simultaneously record two input sources instead of reducing the resolution. Thus, besides some sources that require particularly high resolution, a resolution similar to the current VHS level can be obtained, which is suitable not only for general users but also for monitors that need to check several broadcasts at the same time.

As described above, according to the simultaneous recording and reproducing circuit of two input sources according to the present invention, recording and reproducing of one input source are possible, while in the two input source recording modes, subsampling is performed once more than when one input source is recorded. In the two input source playback mode, the user who wants to simultaneously record and play back two input sources in the same time zone by performing interpolation once more than when playing one input source enables simultaneous recording and playback. It has the effect of improving the quality of products by satisfying the needs of people.

Claims (9)

The first digital luminance signal is subsampled and stored at a position where data of the upper predetermined line of the screen is stored in the normal recording, and the second digital luminance signal is subsampled at a position where data of the lower predetermined line of the screen is stored in the normal recording. Brightness signal recording means for extracting macro blocks at predetermined positions in which the first and second digital luminance signals are stored to form segments, and performing data compression of the luminance signals in units of the formed segments; Subsequently subsampling the first digital chrominance signal to store at the location where the data of the upper predetermined line of the screen is stored during normal recording and subsampling the second digital chrominance signal continuously to save the data of the lower predetermined line of the screen during normal recording Color difference signal recording means for extracting macro blocks at predetermined positions in which the first and second digital color difference signals are stored, storing the data in the stored positions, forming segments, and performing data compression of the color difference signals in units of the formed segments; After decoding the reproduced luminance signal in which the error is corrected to the original data length, restoring the macroblocks of the luminance signal in which the segment is formed to the original position on the screen, the data of the upper predetermined line of the screen is stored by the luminance signal recording means. Luminance signal reproducing means for interpolating the first luminance signal stored at the stored position and the second luminance signal stored at the position where the data of the lower predetermined line of the screen is stored; Decode the error corrected reproduction color difference signal to the original data length, restore the macroblocks of the color difference signal forming the segment to the original position on the screen, and then store the data of the upper predetermined line of the screen by the color difference signal recording means. And two chrominance signal reproduction means for interpolating successively each of the first chrominance signal stored at the position and the second chrominance signal stored at the position where the data of the lower predetermined line of the screen is stored. The display apparatus of claim 1, wherein the luminance signal recording means comprises: a first luminance signal subsampling unit for subsampling a first digital luminance signal and storing the first digital luminance signal at a position of an upper predetermined line of the screen; A second luminance signal subsampling unit for storing at a lower predetermined line position of the segment; a segment forming unit for extracting a predetermined macroblock from a predetermined position of a screen stored in the first and second luminance signal subsampling units to form a segment; And an image compression encoder which performs data compression in units of segments formed by the segment forming unit, and a code adding unit that adds a parity code to the horizontal and vertical directions of the data compressed by the image compression encoder and writes it to a tape. 2 input source simultaneous recording and playback circuit. The method of claim 1, wherein the luminance signal recording means extracts the macroblock at a predetermined position of the screen after bypassing the first digital luminance signal without performing subsampling on the first digital luminance signal in a recording mode for recording only one input source. And forming segments, and performing data compression of the luminance signal in units of the formed segments. 2. The method of claim 1, wherein the luminance signal recording means stores the first digital luminance signal at a location where 0 to 239 lines of data are stored after subsampling in the horizontal direction in the NTSC system, and the second digital luminance signal is horizontal. And two input sources simultaneously recording and reproducing circuits for storing data of 240 to 479 lines after subsampling. The data recording apparatus of claim 1, wherein the luminance signal recording means stores the first digital luminance signal at a position where 0 to 287 lines of data are stored after subsampling in the line direction in the PAL method, and the second digital luminance signal is stored in the line. And two input sources simultaneously recording and reproducing circuits, characterized in that the data is stored in a location where data of 288 to 575 lines is stored after subsampling in the direction. The method of claim 1, wherein the chrominance signal recording means is a recording mode for recording only one input source, and in case of NTSC, the first digital chrominance signal is subsampled in the horizontal direction, and then the macroblock at a predetermined position of the screen is extracted. 2. A simultaneous recording and reproducing circuit of two input sources, characterized by forming a segment and performing data compression of a color difference signal in units of the formed segment. The method of claim 1, wherein the chrominance signal recording means is a recording mode for recording only one input source, and in the PAL method, the first digital chrominance signal is subsampled in the line direction, and then the macroblock at a predetermined position of the screen is extracted. 2. A simultaneous recording and reproducing circuit of two input sources, characterized by forming a segment and performing data compression of a color difference signal in units of the formed segment. The method of claim 1, wherein the chrominance signal recording means stores the first digital chrominance signal by subsampling in the horizontal direction and subsampling again in the line direction in the NTSC system, and stores the data in a position where 0 to 239 lines of data are stored. And the second digital color difference signal is subsampled in the horizontal direction and then subsampled in the line direction and stored at a location where data of 240 to 479 lines is stored. The color difference signal recording unit of claim 1, wherein in the PAL method, the first digital color difference signal is subsampled in the line direction and then subsampled in the horizontal direction, and stored in a location where data of 0 to 287 lines is stored. And the second digital luminance signal is subsampled in the line direction and then subsampled in the horizontal direction and stored in a location where data of 288 to 575 lines is stored.