JPH04260287A - Recorder - Google Patents

Abstract

PURPOSE:To realize the recorder by increasing number of still pictures able to be recorded on a recording medium and reducing the capacity of a buffer RAM. CONSTITUTION:A MUSE signal from a BS tuner 2 is digitized and fed to RAM 6A, 6B. Four fields of the MUSE signal are written in the RAM 6A, 6B alternately as in the unit of a still picture data. In this case, the write of the data undesired for still picture display is omitted. For example, only a color signal, a luminance signal and part of a control signal are written. A synchronizing pattern signal PS is added to a head of the data by 4 fields read alternately from the RAM 6A, 6B and fed to a DAT 50, in which the signal is recorded. The quantity of the still picture data is reduced and the still picture number able to be recorded onto the recording medium is increased, the capacity of the buffer RAM is small and the picture reproduction time interval is reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus for recording MUSE signals as still image data.

0002

[Prior Art] As a method for compressing the transmission signal band of television signals, MUSE (Multiple Sub-
nyquist Sampling Encoding
) is known. In the MUSE encoder, band compression is performed by line offset subsampling in the motion system, and by field offset and frame offset subsampling in the stationary system. On the other hand, in the MUSE decoder, in the motion system, an image is reproduced using only the signal of the current field by interpolation, and in the stationary system, the image is reproduced using the signals of the current field and the previous three fields by interframe and interfield interpolation.

[0003] In the MUSE system, high-definition television signals are transmitted. According to the high-definition standard, the number of scanning lines per frame is 1125, the interlace ratio is 2:1, the aspect ratio is 16:9, the field frequency is 60 Hz, and the line frequency is 33,750 Hz.

FIG. 7 shows the format of a television signal (hereinafter referred to as "MUSE signal") transmitted using the MUSE method. The MUSE signal has 480 samples of data on each of 1125 horizontal lines, with a frame pulse added to the beginning of each frame and a horizontal synchronization signal added to the beginning of each line.

[0005]

By the way, it is conceivable to record such a MUSE signal as still image data, for example, on a DAT (digital audio tape recorder).

As described above, in a still system, images are reproduced using signals of four fields, so when recording MUSE signals as still image data, it is desirable to record in units of four fields.

[0007] Although not mentioned above, the MUSE signal is 16.2MH
If sampled in z and there are 4 fields (2 frames), then 1125 x 2 x 480 = 1,080,000 samples. If one sample is 8 bits, 8,640,
000 bits (≒8.24 Mbits).

[0008] If this one screen worth of still image data is recorded on a DAT, the data recording speed on the DAT is 1,
536,000 bits (48kHz x 2 channels x 16
bit)/second, so it will take 5.625 seconds. This limits the number of still images that can be recorded on the DAT.

Furthermore, the transmission speed of the MUSE signal is much faster than the data recording speed of the DAT, and when the DAT records the MUSE signal as still image data, the data of the MUSE signal is temporarily stored in a buffer (RAM). It is necessary to keep it. Therefore, as mentioned above, the MUSE signal is
When recording in field units, a buffer with a capacity of approximately 8.24 Mbits is required.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a recording apparatus that increases the number of still images that can be recorded on a recording medium and that requires less buffer RAM.

[0011]

[Means for Solving the Problems] The present invention provides a recording device for recording MUSE signals as still image data.
The apparatus is equipped with data identification means for identifying data necessary for still image display from the USE signal, and data identified as necessary data by the data identification means or data related to this data is recorded.

0012

[Operation] Not all data of the MUSE signal is recorded, and recording of data unnecessary for still image display is omitted. This increases the number of still images that can be recorded on a recording medium. Furthermore, the capacity of the buffer that temporarily stores the data of the MUSE signal during recording can be reduced. Furthermore, the time interval between capturing still image data and reproducing the image during reproduction can be shortened.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. This example is an example in which the MUSE signal is recorded as still image data using DAT.

FIG. 1 shows the configuration of the recording system. In the figure, a satellite broadcast signal captured by a satellite broadcast (BS) antenna 1 is supplied to a BS tuner 2. B.S.
The MUSE signal output from the tuner 2 is band-limited by a low-pass filter 3, further converted into a digital signal by an A/D converter 4, and then transferred to sides a and b of a changeover switch 5.
It is supplied to RAMs 6A and 6B as buffers via the side.

The output signal of the A/D converter 4 is supplied to a synchronization detection circuit 7, and the frame pulse signal and horizontal synchronization signal detected by the synchronization detection circuit 7 are supplied to a controller 8.

Writing and reading to and from the RAMs 6A and 6B are controlled by the controller 8, and the MUS
Four fields of the E signal are written. In this case, M
All data of the USE signal is not written,
Necessary data is written as still image data, and writing of unnecessary data is omitted.

Data is omitted either on a line-by-line basis or on a sample-by-sample basis.

■ Omission of line units a. Line No. 3-42, 565-604 Since it is still image recording, audio cannot be recorded continuously, and audio signals are unnecessary. 480 samples x 160 lines x 8 bits = 6
This results in the omission of 14,400 bits.

b. Line No. 564 Not used. 480 samples x 2 lines x 8 bits = 7,68
The 0 bit is omitted.

c. Line No. The 563 and 1125 control signals are each written redundantly on the previous four lines. Further, the clamp level is fixed data. 48
0 samples x 4 lines x 8 bits = 15,360 bits are omitted.

d. Line No. The 1st and 2nd frame pulses are fixed data. The VIT signal can be omitted on the condition that an equalizer is not used during reproduction. 480 samples x 4 lines x 8 bits = 15,360 bits are omitted.

By omitting the above a to d, writing of 81,600 samples x 8 bits = 652,800 bits in 4 fields is omitted.

① Omission of sample units The most omitted example will be shown. The required samples are as follows.

a. Color signal (C signal) and luminance signal (Y
M signal) 468 samples x 516 lines x 4 fields x 8 bits = 7,727,616 bits b. Bit No. of control signal. 9,10,1
6,17 4 samples x 4 fields x 8 bits = 128 bits The control signal has 2 samples as 1 bit,
Multiplexed as a binary signal. The code format is expanded Hamming (
8,4) is the code. The generation matrix and binary levels are defined as shown in FIG. However, the left 4 bits of the generation matrix are used as information points, and the right 4 bits are used as inspection points, and are transmitted from the left.

The control signal has 32 bits in total, and when divided into 4 bits each, it becomes 8 blocks, which are sent three times in a row. FIG. 3 shows the multiplexing positions of control signals, and the portion E is not used in a normal MUSE decoder. FIG. 4 shows the contents of the 32-bit control signal.

The total of a and b above (965,968 samples x 8 bits = 7,727,744 bits) is the necessary data, and writing of data other than this is omitted. In other words, writing of (1,080,000-965,968) samples×8 bits=912,256 bits is omitted.

When one of the RAMs 6A and 6B is in a write state, the other is in a read state. In other words,
When 4 fields worth of data (omitted data) of the MUSE signal are written to RAM6A or 6B as still image data, the DA is written from RAM6B or 6A, respectively.
T50 data recording speed (1,536,000 bits/
Four fields of data are read out in synchronization with the second). The controller 8 is supplied with a system clock CLK of 48 kHz×4=192 kHz from the DAT 50 in order to synchronize with the DAT 50.

Here, while data for four fields is read from one RAM at a recording speed of DAT50, many field signals are supplied as write signals to the other RAM, and the data contents are sequentially updated. Four fields of data are always stored.

After the reading of four fields of data from one RAM is completed, the writing and reading states of the RAMs 6A and 6B are switched. At this time, data for four fields immediately before switching is stored in the other RAM.

The four fields of data read out from the RAMs 6A and 6B are respectively placed on the a side of the changeover switch 9,
It is supplied to the a side of the changeover switch 10 via the b side. Switching of the changeover switches 5 and 9 is controlled by a controller 8. The changeover switch 5 is connected to the a side when the RAM 6A is in the write state, and is connected to the b side when the RAM 6B is in the write state. The changeover switch 9 is a RAM
When 6A is in the read state, it is connected to the a side and the RAM
When 6B is in the read state, it is connected to the b side.

Reference numeral 11 denotes a synchronization generation circuit, and a synchronization pattern signal PS outputted from this synchronization generation circuit 11 is supplied to a fixed terminal on the b side of the changeover switch 10. The operation of the synchronization generating circuit 11 and the switching of the changeover switch 10 are controlled by the controller 8. In other words, the synchronization pattern signal PS is output from the synchronization generation circuit 11 immediately before four fields of data are supplied to the a side of the changeover switch 10. Although not mentioned above, the readout of four fields of data from RAM6A, 6B is performed using this synchronization pattern signal P.
It will start after the output of S. Further, the changeover switch 10 is connected to the a side when data for four fields is supplied to the a side, and is connected to the b side when the synchronization pattern signal PS is supplied to the b side.

Therefore, the changeover switch 10 outputs the synchronization pattern signal P at the beginning of each of the four fields of data.
The output with S added is output (shown in Figure 5), which is D
The signal is supplied to the AT 50 and recorded.

Next, FIG. 6 shows the configuration of the reproduction system. In the figure, four fields of data (still image data) sequentially reproduced from the DAT 50 are transferred to the RAM 22 as a buffer via the a side and b side of the changeover switch 21.
A and 22B are alternately supplied and written.

The reproduction signal of the DAT 50 is transmitted to the synchronization detection circuit 23.
supplied to This synchronization detection circuit 23 uses a synchronization pattern signal PS added to the beginning of four fields of data.
is detected, and the detection signal SD is sent to the controller 24.
It is supplied as a signal (cue signal) indicating the start timing of a field's worth of data. Further, the controller 24 is supplied with a 192 kHz system clock CLK from the DAT 50.

Writing and reading of RAMs 22A and 22B are controlled by controller 24 based on detection signal SD and system clock CLK. Changeover switch 2
1 is controlled by the controller 24, and R
When the AM 22A is in the write state, it is connected to the a side, and when the RAM 22B is in the write state, it is connected to the b side.

When one of the RAMs 22A and 22B is in a write state, the other is in a read state. That is, when data for four fields of the MUSE signal (omitted data) is written to RAM 22A or 22B, 16.
Synchronized with 2MHz clock and each data is MUSE
Four fields of data are repeatedly read out at timings that match the signal format (shown in FIG. 7). In this case, after writing 4 fields worth of data to one of the RAMs 22A and 22B,
The write and read states can be switched.

Data output from the RAMs 22A and 22B is supplied to the fixed terminal on the a side of the changeover switch 26 via the a side and b side of the changeover switch 25. Changeover switch 2
5 is controlled by the controller 24, and R
When the AM 22A is in the read state, it is connected to the a side, and when the RAM 22B is in the read state, it is connected to the b side.

27 is an additional signal generating circuit. This additional signal generation circuit 27 outputs data such as frame pulses, horizontal synchronization signals, clamp levels, etc. that are not recorded in the recording system at a timing that matches the format of the MUSE signal, and this data is sent to the b side of the changeover switch 26. is supplied to the fixed terminal of The operation of the additional signal generation circuit 27 and the changeover switch 26 are controlled by the controller 24. In other words, the changeover switch 26 is connected to the a side when data output from the RAMs 22A and 22B is supplied to the a side, and the additional signal generation circuit 27 is connected to the b side.
When data output from the terminal is supplied, it is connected to the b side.

Therefore, from the changeover switch 26, the MU
Repeated data (still image data) of four fields of data according to the format of the SE signal is output, and this still image data is supplied to the MUSE decoder 28. The video signals (for example, R, G, B signals) output from the MUSE decoder 28 are supplied to the monitor television 29, and a still image is displayed on the monitor television 29.

In this way, according to the present example, four fields of the MUSE signal are treated as one unit of still image data on the DAT5.
When recording with 0, all data of the MUSE signal is not recorded, but data unnecessary for still image display is omitted and recorded, thereby increasing the number of still images that can be recorded on the magnetic tape. Furthermore, since data unnecessary for still image display is omitted and recorded, the capacity of the RAMs 6A, 6B or 22A, 22B as buffers for the recording and reproducing system can be reduced. In addition, since the capacity of one screen worth of still image data recorded with DAT50 can be reduced, DAT50 can
The time interval at which still image data is played back and images are played back can be shortened compared to the AT50.

In the above embodiment, the synchronization pattern signal PS is added to the beginning of four fields of data, but the recording system adds dummy data of a predetermined length (for example, 128 level continuous data , 0 level and 2
It is also possible to add 55 levels of alternating continuous data, etc.), and the reproduction system can detect the end of this dummy data and recognize the start of four fields of data.

[0042] Furthermore, the examples of omission in the above-described embodiments are merely examples, and it goes without saying that the present invention is not limited thereto. In short, all or part of data unnecessary for still image display may be omitted and recorded. Also, as an example of omitting the sample unit, the bit number of the control signal. 9,10,1
Although it has been described that the data of 6 and 17 is recorded as 8-bit data without being decoded, it is also possible to decode it into binary data and record it. In this case, the amount of data is only 16 bits in 4 fields (16 bits in the above example).
28 bit). However, in this case, a decoder is required in the recording system, and an encoder is required in the reproduction system to restore the original state.

[0043]Also, in the above-mentioned embodiment, 4 fields are used as one unit of still image data, but the same applies to cases where 2 fields or 1 field are used as 1 unit of still image data. Can be applied.

Furthermore, in the above embodiment, two RA
Although M6A and 6B (22A, 22B) are used, it is also possible to use one or three or more. However, when there is only one, the recording system
It becomes difficult to continuously supply still image data to the AT 50.

Furthermore, in the above embodiment, MUSE
Although the signal is recorded as still image data on the DAT 50, it can be similarly applied to recording on other recorders.

[0046]

According to the present invention, all the data of the MUSE signal is not recorded, but data unnecessary for still image display is omitted and recorded, so the number of still images that can be recorded on the recording medium can be reduced. It can be increased and temporarily set to M when recording.
The capacity of the buffer for storing the data of the USE signal can be reduced, and the time interval between capturing still image data and reproducing the image during reproduction can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a recording system according to an embodiment.

FIG. 2 is a diagram for explaining the format of a control signal of a MUSE signal.

FIG. 3 is a diagram showing multiplexing positions of control signals of MUSE signals.

FIG. 4 is a diagram showing the contents of a control signal of the MUSE signal.

FIG. 5 is a diagram showing the structure of recorded data of DAT.

FIG. 6 is a block diagram showing the configuration of a reproduction system of the embodiment.

FIG. 7 is a diagram showing the format of a MUSE signal.

[Explanation of symbols]

2 BS tuner 6A, 6B, 22A, 22B RAM 7, 23 Synchronization detection circuit 8, 24 Controller 11 Synchronization generation circuit 27 Additional signal generation circuit 28 MUSE decoder 29 Monitor TV 50 DAT

Claims (2)

[Claims] 1. A recording device for recording a MUSE signal as still image data, comprising data identification means for identifying data necessary for displaying a still image from the MUSE signal,
A recording device configured to record data identified as necessary data by the data identifying means or data related to this data. 2. The recording apparatus according to claim 1, wherein the necessary data is part of a luminance signal, a color signal, and a control signal.