JPH07143517A - Video signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide a comparatively in expensive video signal recording and reproducing device for which picture quality degradation caused by image compression is eliminated and handling is simplified. CONSTITUTION:This device is provided with an A/D converter 4 for sampling a first video signal at a field frequency 60Hz at a sampling frequency f1 and making it into digital data, channel dividing circuit 5 for dividing the digital data into N channels per field, and rate converting circuit 6 for converting the clock frequency of digital data into the 6/5-fold frequency of a sampling frequency f2 of a second video signal at a field frequency 50Hz and adding dummy data to a blank period generated by the conversion, the video data signals provided by the conversion are recorded onto a magnetic tape 11 as recording signals and at the time of reproduction, the first video signal is reproduced by performing the inverse conversion of the rate converting circuit 6 to the reproduced signal of a recording and reproducing circuit for the second video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal recording / reproducing apparatus for recording / reproducing a high-definition video signal by using a plurality of PAL digital VTR signal processing systems.

[0002]

2. Description of the Related Art Broadcasting Technology Development Council Standard BTA S-0
According to 01, when trying to record a high-definition signal using a digital VTR, the effective image data is 1
The luminance signal (Y) per line is 1920 samples, the color difference signals (PB, PR) are 960 samples, and the number of recording lines is 1035 lines / frame, and if the user's area is included, it is 1040 lines / frame. This has about four times the amount of information as a video signal of the current system such as NTSC or PAL.

Therefore, this HDTV digital V
In order to realize TR, it is common to record a high-definition signal by dividing it into several channels. This method is based on the HDTV digital V currently on the market.
According to the method adopted by TR, looking at the specifications, the video signal is divided into 8 channels and recorded on a 1-inch open reel tape. Therefore, NTSC, PAL
Compared with the current type digital VTR, the mechanical system and the signal processing system have complicated configurations.

Contrary to the above method, the image compression is performed by utilizing the correlation of the image data of the high-definition signal itself to reduce the amount of data and the digital VTR of the current system.
There is a way to record. For example, if a high-definition signal having an information amount of 1.2 Gbps is image-compressed to a quarter, the data rate becomes almost the same level as the NTSC and PAL systems, and the high-definition VTR can be realized relatively easily.

[0005]

First, when a high-definition signal is divided and recorded, the number of channels and the number of segments are larger than those of the current system digital VTRs such as NTSC and PAL. Recording technology is required. Therefore, in order to solve these problems, it becomes very expensive, and it is necessary to pay close attention to the maintenance.

Further, when image compression is performed for recording,
In terms of capacity, at least 1 / of the original data
Since there is a need to compress about four, depending on the compression algorithm, there is a drawback that the image quality is not a little deteriorated due to image compression. This problem is a great disadvantage in the case of a broadcasting VTR that requires severe image quality.

In view of the above problems, an object of the present invention is to provide a video signal recording / reproducing apparatus such as a high-definition digital VTR which is free from image quality deterioration due to image compression, is easy to handle, and is relatively inexpensive.

[0008]

In view of the above problems, according to the present invention, a luminance signal and a luminance signal with a field frequency of 60 Hz are used.
Means for sampling the first video signal, which is a color difference signal of a kind, at a predetermined sampling frequency f1 to convert it into digital data;
Means for dividing the channel (N is an integer), and the clock frequency of the digital data is a field frequency 50H.
Video obtained by a video signal conversion circuit including at least means for converting the sampling frequency f2 of the second video signal of z to 6/5 times, and means for adding dummy data to the blank period generated by the clock conversion. A data signal is recorded on the magnetic tape as a recording signal, and the second signal is recorded during reproduction.
A high-definition signal is reproduced by performing reverse conversion of the reproduction signal of the video signal recording / reproducing circuit by the video signal converting circuit. Further, in order to improve the operability, a part or all of the dummy data is reproduced. Are recorded by replacing them with time code and channel identification data, and at the time of reproduction, the time code is searched to control the reproduction start point of the magnetic tape, and the channel identification data is detected and the channel is integrated based on the information. Is to control.

When the first video signal is divided into N channels, the luminance signals are adjacent to each other in the horizontal direction of the screen.
The color difference signal is distributed to each channel for each sample. The color difference signal is distributed to the same channel as the luminance signal for each of the two samples forming the same pixel, and the luminance signal and the color difference signal are sequentially distributed to each channel in the vertical direction of the screen.

[0010]

As described above, by operating the signal processing system of a plurality of current type digital VTRs, it becomes possible to relatively easily record and reproduce a high-definition signal having an enormous amount of information.

Since all the N magnetic tapes recorded by the present invention are recorded with the system clock increased by 6/5 times, the recording pattern on the magnetic tape is a normal PA.
It is recorded in the same way as the magnetic tape recorded by the L method. Therefore, if one of the magnetic tapes recorded according to the present invention is reproduced by a normal PAL digital VTR, it is possible to monitor a high-definition video thinned to a quarter by a PAL TV receiver. It is possible.

[0012]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 is a diagram showing a circuit configuration of a video signal recording apparatus according to a first embodiment of the present invention.

In FIG. 1, 1 is a Y signal input terminal, 2 is a PB signal input terminal, 3 is a PR signal input terminal, 4 is an A / D converter, 5 is a channel dividing circuit, 6A to 6D are rate converting circuits, 7 is a PAL wide mode signal recording processing circuit, 8
Is a system clock conversion circuit, 9 is a synchronizing signal, 10 is a recording head, 11 is a magnetic tape, 12 is a reproducing head, and 13
Is a PAL wide mode signal reproduction processing circuit, 14 is a PAL
Wide mode signal output terminal, 15A-15D rate reverse conversion circuit, 16 channel integration circuit, 17 D / A converter, 18 Y signal output terminal, 19 PB signal output terminal, 20 PR signal output / input terminal , B to D are the same signal processing circuits as A including the constituent elements 7 to 14.

FIG. 2 is a diagram showing a high-definition signal for recording and reproducing in the first embodiment. In FIG. 2, white circles and black circles represent sample positions, i (1 ≦ i ≦ 1920) is a Y pixel number in the horizontal direction of the screen, and j (1 ≦ j ≦ 520) is a line number. The sampling frequency of each signal is 74.25 MHz for Y and 37.125 MHz for PB and PR.
The sampling rate ratio is 4: 2: 2. Here, since the numbering in the horizontal direction is performed by the pixel number of Y, the PB and PR signals are numbered only by odd numbers.

On the other hand, FIG. 3 shows PAL per field.
It is a figure which shows a wide mode signal. In FIG. 3, white circles and black circles represent sample positions of effective image data, i
(1 ≦ i ≦ 960) is the Y pixel number in the horizontal direction of the screen, j
(1 ≦ j ≦ 304) is a line number. The sampling frequency of each signal is 18MHz for Y and 9MH for CB and CR.
sampled at z. Here, since the horizontal numbering is performed with the pixel number of Y, the CB and CR signals are numbered only with odd numbers.

FIG. 4 is a diagram showing the relationship between a high-definition screen and a PAL wide mode screen per field screen. For convenience of explanation, FIG. 4 shows the number of samples of the Y signal, but the same applies to the color difference signal. The PB signal of high-definition is the CB signal of PAL and the PR signal is the CR signal.
Corresponding to the signal. As shown in FIG. 4, it is possible to cover the entire high-definition screen by using four screens in the PAL wide mode. Here, the PAL wide mode is shown as an example in consideration of the compatibility with the high-definition screen, but the PAL of the conventional screen with an aspect ratio of 4: 3 is shown.
The method is also acceptable.

First, the high-definition signals input from the input terminals 1 to 3 are sampled and digitized by the A / D converter 4 as shown in FIG. As shown in FIG. 4, since the high-definition screen is composed of the PAL wide mode 4 screen, the number of channels is set to N = 4, and the channel division circuit 5 sets each sample shown in FIG.
, Samples within the range of 1 ≦ i ≦ 960, 1 ≦ j ≦ 260, and for channel B 961 ≦ i ≦ 1920, 1 ≦ j ≦
Samples in the range of 260 are assigned to channel C as 1 ≦ i ≦
Samples in the range of 960, 261 ≤ j ≤ 520, 961 ≤ i ≤ 1920, 261 ≤ j ≤ 52 for channel D.
Distribute samples in the 0 range.

At this time, the PB and PR signals are multiplexed into one system and transmitted to the next block by two systems of the Y signal and the color difference signal (PB, PR) signal. The clock frequency of the sample distributed to each channel is 74.25 / 4 = 18.5625 MHz because it is divided into four by two systems.

Then, in the rate conversion circuits 6A to 6D of the respective channels, dummy data corresponding to the shaded area in FIG. 4 is added before and after the effective image data, and all the samples per field are 1/60 seconds (high-definition Converts the clock rate so that it can be transmitted to the reciprocal of the field frequency. The insertion positions of the dummy data are distributed and arranged before and after the effective image data. The rate conversion circuits 6A to 6D can be easily configured by using a memory. The clock frequency on the read side of this memory is 60/50 = 6/5 of the original PAL wide mode sampling frequency.
Set to double. Therefore, the frequency is 18 × 6/5 =
It becomes 21.6 MHz.

Since the PAL word mode screen generated in this manner is created based on the high-definition signal, its field frequency is 60 Hz, and in order to process these video data as a recording signal, P
The system clock frequency of the AL wide mode recording signal processing circuit 7 may be increased by 6/5. Therefore, this processing is performed by the system clock conversion circuit 8.

In this embodiment, the system clock is 1
By changing from 8 MHz to 21.6 MHz, apparently a field frequency of 60 Hz is supported without changing the internal operation of the PAL wide mode signal recording circuit 7. Further, since it is necessary for the PAL wide mode signal recording processing circuit 7 of four channels to operate in synchronization with the high definition signal, the synchronization signal 9 synchronized with the input high definition signal is supplied to each channel as an external synchronization signal. . Then, each channel is converted into a signal suitable for recording and recorded on the magnetic tape 11 via the recording head 10. At this time, the system clock of the mechanism control system (not shown) for recording on the magnetic tape 11 is also multiplied by 6/5 as in the signal processing system.

Next, the operation during reproduction will be described. At the time of reproduction, the PAL wide mode signal reproduction processing circuit 13 is operated synchronously, and a reproduction signal is taken out from the four magnetic tapes via the reproduction head 12. The reproduced signal taken out is PAL wide mode signal reproduction processing circuit 13 for each channel.
The PAL wide mode reproduction signal is obtained by signal processing in which the field frequency is apparently converted to 60 Hz. Then, the rate reverse conversion circuits 15A to 15D delete the dummy data added at the time of recording from this signal, extract only the video data, and further convert the transmission clock from 21.6 MHz to 185625 MHz. The video data thus signal-processed is combined into four channels by the channel integration circuit 16, the high-definition screen data is aligned, and the high-definition signal is reproduced through the D / A converter 17.

In the tape pattern of the magnetic tape recorded as described above, all system clock frequencies are 6
Since it is multiplied by / 5, the recording wavelength does not change, so recording is performed with the same tape pattern as in the current format. Therefore, when the magnetic tape 11 corresponding to any of the channels is independently reproduced at the time of reproduction, if the system clock frequency is restored and reproduced, a normal PAL wide mode video signal having a field frequency of 50 Hz is output from the output terminal 20. As it can be taken out, D for PAL
By using the / A circuit (not shown), it is possible to monitor the 1/4 screen of the high definition shown in FIG. 4 with the PAL wide receiver.

Next, a second embodiment of the present invention will be described.
In the first embodiment, dummy data is added during recording,
The channel identification data of the signal is added instead of the dummy data recorded at the beginning or the end of each field. For example, if the video signal level is 8-bit data and the black level is 16 and the white peak level is 235, the first sample (1 byte) of the dummy data is assigned.
Data other than 16 to 235 is used for channel identification data. When black level data is transmitted as dummy data, channel identification data is 11 for channel A, 12 for channel B, and 1 for channel C.
Data of 3 and channel D are added and transmitted.

When such processing is performed, the channel identification data is recorded at the beginning of the field on each of the four magnetic tapes. Therefore, by detecting this signal at the time of reproduction, the channel identification of the reproduction signal can be easily performed. be able to. In the case of the first embodiment, a correct video cannot be reproduced unless the reproduction processing circuit having four channels and the channels of the magnetic tape match. However, Example 2
In the case of, even if the channels of the reproduction processing circuit and the magnetic tape do not match, the rate reverse conversion circuit 15A shown in FIG.
If the channel identification data is detected at 15D and the channel is selected by the channel integration circuit 16 based on this information, the combination of the reproduction processing circuit and the magnetic tape may be any combination.

In the above-mentioned embodiment, an example in which 1 byte of channel identification data is added to the beginning of the field has been described.
The recording position may be at the end of the field. Further, the dummy data itself may be treated as the channel identification data, in which case the channel identification data is repeatedly recorded, so that the channel identification can be surely performed.

The third embodiment of the present invention is a case where a time code is recorded in addition to the channel identification data of the second embodiment. The data assigned to this time code is the second embodiment.
Data other than 16 to 235 to which video data is assigned is used. Basically, it suffices to be able to identify the numbers from 0 to 9. Therefore, in this embodiment, 0 to 9 are assigned as they are, and the time and frame number are identified by the recording position. This time code is used for searching during reproduction and controlling the reproduction start point.

In this case, the rate inverse conversion circuit 15A shown in FIG.
.About.15D to identify the time codes 21A to 21D, and based on the information, the magnetic tape of each channel is fast forwarded or rewound to the point where the respective time codes match. As a result, the reproduction points of the four channels can be matched.

Further, as a fourth embodiment of the present invention, a case where the channel division circuit 6 of FIG. 1 is subjected to a division method different from that of the first embodiment will be described. In the second embodiment, as shown in FIG. 5, every two samples for the luminance signal in the horizontal direction of the screen, and for the color difference signal, the samples of the same pixel as the luminance signal are in the same channel.
In the vertical direction, channel division is performed so that any signal is sequentially assigned to each channel.

In this case, the recording / reproduction of the high-definition signal is exactly the same as that of the first embodiment, but if only one of the above-mentioned magnetic tapes of one channel is reproduced in the PAL wide mode, then it is a quarter of the high-definition screen. The horizontal and vertical resolutions are not 1/4, and the horizontal and vertical resolutions are 1/4, and aliasing noise occurs, but it is possible to easily monitor the entire high-definition screen in the PAL wide mode.

Since the channel identification data recorded in the second embodiment is a signal below the black level, the reproduced image is clipped to the black level, and only the black portions at the top and bottom of the screen are reproduced. Does not affect the image.

In this embodiment, the high-definition signal is divided into four parts. However, it may be divided into more parts, and a video signal other than the high-definition signal may be used as the first video signal.

[0033]

According to the present invention, a high-definition signal is added to the current system (PAL) by adding some additional circuits.
Recording and reproduction can be performed by directly using the four systems of the recording and reproducing circuit of the wide mode). Further, the recorded magnetic tape can monitor an image of a quarter of a high-definition screen even when reproduced by a normal PAL wide mode reproducing apparatus.

Further, when the high-definition signal is divided into four, if the channels are sequentially distributed in the horizontal and vertical directions of the screen, it is possible to easily monitor the entire high-definition screen by the PAL wide mode reproducing device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a video signal recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a high-definition signal according to the first embodiment.

FIG. 3 is a diagram showing a PAL wide mode signal in the first embodiment.

FIG. 4 is a diagram showing a relationship between a high definition screen and a PAL wide mode screen of the first embodiment.

FIG. 5 is a diagram showing a method of dividing a high-definition signal channel according to a fourth embodiment.

FIG. 6 is a configuration diagram of a video signal recording / reproducing apparatus according to a third embodiment.

[Explanation of symbols]

 1 Y signal input terminal 2 PB signal input terminal 3 PR signal input terminal 4 A / D converter 5 channel division circuit 6A to 6D rate conversion circuit 7 PAL wide mode signal recording processing circuit 8 system clock conversion circuit 9 synchronization signal 10 recording head 11 magnetic tape 12 reproducing head 13 PAL wide mode signal reproduction processing circuit 14 PAL wide mode signal output terminal 15A to 15D rate reverse conversion circuit 16 channel integration circuit 17 D / A circuit 18 Y signal output terminal 19 PB signal output terminal 20 PR signal I / O terminal

Claims (3)

[Claims] 1. A luminance signal at a field frequency of 60 Hz and 2
Means for sampling the first video signal, which is a color difference signal of a kind, at a predetermined sampling frequency f1 to convert it into digital data;
Means for dividing the channel (N is an integer), and the clock frequency of the digital data is a field frequency 50H.
A video signal conversion circuit including at least means for performing clock conversion for converting the sampling frequency f2 of the second video signal of z to 6/5 times, and means for adding dummy data to a blank period generated by the clock conversion. The obtained video data signal is recorded on a magnetic tape as a recording signal, and at the time of reproduction, the reproduction signal of the recording / reproducing circuit of the second video signal is reverse-converted by the video signal converting circuit to reproduce the first video signal. A video signal recording / reproducing apparatus characterized by performing reproduction. 2. A part or all of the dummy data is replaced with a time code and channel identification data for recording, and at the time of reproduction, the time code is searched to control the reproduction start point of the magnetic tape, and further the channel identification data is recorded. 2. The video signal recording / reproducing apparatus according to claim 1, wherein the video signal recording / reproducing apparatus detects the channel and controls the channel integration based on the information. 3. When the first video signal is divided into N channels, in the horizontal direction of the screen, the luminance signal is distributed to each adjacent two samples, and the color difference signal is divided into two samples constituting the same pixel. Allocate to the same channel as the luminance signal, the luminance signal in the vertical direction of the screen,
The video signal recording / reproducing apparatus according to claim 1, wherein the color difference signals are sequentially distributed to each channel.