JPH0570830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a video signal recording and reproducing device for recording and reproducing a CRT display outputted to a computer using a VTR device.

(Prior art) As a method for recording and reproducing CRT displays output by a computer using a general VTR device,
(a) Convert the video signal output from the computer to an NTSC signal using a frame synchronizer, and convert it into an NTSC signal.
A method of recording and playing back with a VTR device, (b) a telecine method of shooting a CRT screen on cine film such as 16mm film, and recording and playing it with a VTR device;
(c) There are methods such as recording and playing directly on a VTR device using a TV camera.

(Problems to be Solved by the Invention) However, all of the above methods have a problem in that the quality of reproduced images deteriorates significantly due to the limitation of the video frequency band of the VTR device (maximum 4.5 MHz). Particularly in the case of color images, the chroma band is even lower (0.5-1.5MHz), so the color reproduction of details is extremely degraded. Although some of these phenomena are caused by deterioration within the VCR device, most of them are
This is because it complies with standards established by the NTSC system or PAL system.

The same reason is why the image quality of a home TV using an RF converter is inferior to the image quality of a personal computer or the like using RGB separate video signals.

The present invention has been made in view of these problems, and its purpose is to realize a video signal recording and reproducing device that does not cause deterioration in video quality even though it uses a general VTR device.

(Means for Solving the Problems) The present invention, which solves the above-mentioned problems, includes a screen buffer memory for inputting a raster scan system separate color video signal and capturing the color video signal in real time, and A means for dividing and transmitting information in a format that complies with NTSC or PAL standards so that one screen is composed of multiple frames; a VTR device for recording signals transmitted from this means;
A reproduction display screen buffer memory for sequentially storing information divided into a plurality of frames reproduced by a VTR device, and means for reading out information stored in the reproduction display screen buffer memory according to the format of a separate color video signal. It is characterized by having the following.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a device according to an embodiment of the present invention. Here, a case is shown in which a raster scan type separate color video signal output from a computer is recorded and reproduced.

In the figure, numeral 1 is a computer, from which, for example, separate color video signals of raster scan type for data display, that is, R, G, B color signals and horizontal and vertical synchronization signals H-
SYNC and V-SYNC are output respectively.
SW is a changeover switch, 2 is a color CRT which inputs a separate color video signal through the changeover switch, and the part surrounded by a broken line is the video signal recording/reproducing apparatus of the present invention.

In this device, 3 is R from computer 1,
A shift register 4 converts each G and B color video signal (serial signal) into a parallel signal; 4 a dual port screen buffer memory for capturing and storing each parallel color video signal from the shift register 3 in real time; 5 are horizontal and vertical synchronization signals H-SYNC and V from computer 1.
-SYNC is input, a timing signal that is the same as the timing of the video signal generated inside the computer 1 is generated, and the timing signal is transferred to the shift register 5.
and a first timing generator that supplies the screen buffer memory 4 with information equivalent to the contents of the display refresh memory inside the computer 1.

Reference numeral 6 indicates a shift register that reads information from the capture screen buffer memory 4 and converts it into a serial signal. 7 indicates a shift register that generates a timing signal in NTSC (or PAL) format, and transmits the timing signal to the screen buffer memory 4, shift register 6, and encoder. 8. The encoder 8 inputs the R, G, and B color video signals read out from the screen buffer memory 4 by the shift register 6 and converted into serial signals, and the timing signal from the second timing generator 7. , horizontal and vertical synchronization signals, a burst flag, etc., and encodes it into an NTSC (or PAL) system color video signal.The color video signal from here is applied to the VTR device 9.

1 stored in the capture screen buffer memory 4
The video signal for a raster is usually 10 times the video signal for one raster that can be expressed using the NTSC (or PAL) system.
It has ~20 times the amount of information. Therefore, the shift register 6 and the second timing generator 7 are
It is a format that complies with the NTSC (or PAL) standard, and is read out by dividing it into as many frames as necessary so that one screen is made up of multiple frames.

10 is a decoder that inputs the reproduced information from the VTR device 9; 11 is a shift register that inputs the color video signal from the decoder 10 and converts it into a parallel signal; 12 is a dual register that sequentially stores the video signal from the shift register 11; 13 is a third timing generator that generates a timing signal to be applied to the shift register 11 and the screen buffer memory 12 for playback display; 14 reads information from the screen buffer memory 12 for playback display and serially converts the information to the screen buffer memory 12 for playback display; A shift register 15 for converting into a signal is a fourth timing generator that generates a timing signal in accordance with the format of the separate video signal and provides the timing signal to the screen buffer memory 12 for playback and display and the shift register 14.

The R, G, and B color separate video signals from the shift register 14 and the timing signal from the fourth timing generator 15 are all sent to the separate video color CRT 2 via a switch SW.
is applied to

To explain the operation of the device configured in this way,
It is as follows. The timing of the video signal generated inside the computer 1 is known, and a timing signal that is the same as that timing is generated by the first timing generator 5, and a display reflex built in the computer 1 is generated. Information equivalent to the contents of the screen memory is stored in the capture screen buffer memory 4. Therefore, the image information stored here is
There is a 1:1 correspondence with the displayed content. The information stored in the capture screen buffer memory 4 is an NTSC (or
PAL) format timing signal and is converted into an R, G, B color video signal by a shift register 6.

At this time, 1 in the capture screen buffer memory 4
The video signal for a raster is usually 10 times the video signal for one raster that can be expressed using the NTSC (or PAL) system.
It has ~20 times the amount of information. Therefore, this device divides and reads the data as many times as necessary.

FIG. 2 is a conceptual diagram of the structure of information read out from the capture screen buffer memory 4, and FIG. 3 is a waveform diagram of the output signal from the encoder 8 (NTSC system). Here, one screen is horizontal x vertical = 320 x 256
This is a dot configuration, which is divided into 40 dots as one unit, and one raster is divided into eight. A predetermined number of divisions is selected depending on the system.

The encoder 8 adds horizontal and vertical synchronization signals and burst flags to the R, G, and B color video signals output from the shift register 6, as shown in FIG. 3, and encodes them into NTSC color signals.
Output to VTR device 9. Moreover, the encoder 8 is
Normal horizontal and vertical synchronization signals (H-SYNC, V-
SYNC), a special synchronization signal F-SYNC,
It is added every time one frame of the original image is transferred, so that the original image can be reproduced.

As mentioned above, if multiple frames are divided and transferred to the VTR device 9 so that one screen is constructed,
Although the number of times the display screen is updated per unit time is lower than 30 times/second, the number of times that a normal computer display can be updated is about 1 time/second, so this is not a practical problem.

The VTR device 9 records the NTSC color signal output from the encoder 8 as shown in FIG.

In order to reproduce the image information recorded in the above manner, it is sufficient to switch the switch SW to the recording/reproducing apparatus side and perform the conversion opposite to the above-mentioned conversion. That is, the image information reproduced from the VTR device 9 and divided into a plurality of frames is sequentially stored in the screen buffer memory 12 for reproduction and display via the shift register 11. On the other hand, this screen buffer memory 1
The original image information reconstructed into CRT 2 is read out via the shift register 14 in accordance with the format of the original separate color video signal, and sent via the switch SW to the separate video color CRT 2.
is applied to reproduce the original image.

(Effects of the Invention) As explained above, the present invention expands the time axis of a video signal from a computer via a buffer memory, and converts it into an NTSC (or PAL) signal that matches the frequency band of general VTR equipment. The converted, recorded, and reproduced video signal is passed through the buffer memory again and subjected to time-axis compression by a conversion that is completely opposite to the time-axis expansion described above, and the original image is reproduced. Therefore, according to the present invention, it is possible to prevent loss of recorded information in the high frequency range, and to realize an inexpensive video signal recording and reproducing device that does not cause deterioration in video quality even though it uses a general VTR device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the configuration of an apparatus according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of the configuration of information read out from a capture screen buffer memory, and FIG. 3 is a waveform diagram of an output signal from an encoder. 1...Calculator, 2...Color CRT, 3,6,
11, 14... Shift register, 4... Screen buffer memory for capture, 5, 7, 13, 15... Timing generator, 8... Encoder, 9...
VTR device, 10... decoder, 12... screen buffer memory for playback display, SW... changeover switch.

Claims (1)

[Claims] 1. A screen buffer memory that inputs a raster scan type separate color video signal and captures the color video signal in real time, and the information in this screen buffer memory is formatted in accordance with the NTSC or PAL standards, and multiple frames are converted into one screen. means for dividing the transfer so as to configure the
A VTR device that records signals transferred from this means, a screen buffer memory for playback display that sequentially stores information divided into multiple frames played back by this VTR device, and a screen buffer memory for playback display that sequentially stores information divided into multiple frames that are A video signal recording and reproducing apparatus comprising: means for reading out information according to the format of a separate color video signal.