JPH0482055A - Recording and reproducing device for digital signal - Google Patents

Abstract

PURPOSE:To prevent dubbing of a source whose dubbing is inhibited by converting a specific discrimination code to another so that the code cannot be decoded on the reproducing side at the time of supplying the specific discrimination code to the recording side. CONSTITUTION:When ID code CD=('2') is supplied, terminals 37d and 37c of a switch circuit 37 are connected. In this case, reproduced data is read out from a deshuffling memory 34 in the shuffling state. As the result, a disordered block pattern, namely, a mere geometrical pattern is seen, and a normal picture cannot be seen. A shuffling pattern which does not actually exist is recorded in the video signal as the ID code CD at the time of dubbing video soft, and thereby, dubbing is prevented without transferring a cipher key.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a digital signal recording and reproducing device, and particularly to a digital signal recording and reproducing device, which performs block encoding on image data during recording, and
The present invention relates to a digital signal recording and reproducing device that performs block decoding to reproduce image data during reproduction.

[Summary of the invention]

In this invention, in a digital signal recording and reproducing device,
It has a switching means for switching characteristics of block encoding, and a means for recording an identification code corresponding to the switching state of the switching means on a recording medium, reproduces the identification code, and decodes the block based on the reproduced identification code. In addition, when a specific identification code is supplied on the recording side, the identification code is converted to a different identification code, making it impossible to decode it on the reproducing side, making it possible to record sources that cannot be dubbed. This is to prevent dubbing.

[Prior art] Conventionally, digital VTRs that perform data compression on image data to reduce the amount of data before recording are analog VTs.
Compared to R, it has the advantage that there is no deterioration in image quality during dubbing.

[Problem to be solved by the invention]

By the way, there is no problem when the user dubs the software he/she has shot by himself/herself, but some kind of countermeasure is desired for dubbing sources that are not allowed to be dubbed (hereinafter referred to as video software).

Therefore, an object of the present invention is to provide a digital signal recording and reproducing apparatus that can easily and reliably prevent dubbing of video software.

[Means to solve the problem]

In this invention, in a digital signal recording and reproducing device,
In a digital signal recording and reproducing device that blocks-encodes a digital signal and records it on a recording medium, and outputs a block-decoded digital signal when reproducing information recorded on the recording medium. It has a switching means for switching encoding characteristics and a means for recording an identification code corresponding to the switching state of the switching means on a recording medium, reproduces the identification code, and performs block decoding based on the reproduced identification code. In addition, when a specific identification code is supplied on the recording side, the identification code is converted to a different identification code, and the reproduction side is configured to be unable to decode it.

[Effect]

When reproducing and recording a digital signal, an identification code is added and recorded according to the switching state of block encoding.

In the case of sources that cannot be dubbed, i.e. video software,
The above-mentioned identification code is converted into a specific identification code and recorded.

During playback, when an identification code that cannot be dubbed is played back, the characteristics of block encoding are switched according to the above-mentioned two identification codes, for example, the shuffling table is switched. Specifically, when an identification code that cannot be dubbed is reproduced, different shuffling tables are specified during recording and during reproduction, or a shuffling table that does not exist during reproduction is specified.

This prevents dubbing of video software.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. In this embodiment, the digital signal recording and reproducing apparatus according to the present invention is applied to a cassette digital recorder. As a premise of this embodiment, it is assumed that the video software has an ID code CD (-(“hi)”) that represents a shuffling pattern recorded in the same position as the identification code of the puffing table. , this I
It is assumed that dubbing is possible or not based on the D code CD.

Before going into the description of one embodiment, the basic idea of this invention will be explained.

One of the characteristics of block encoding is shuffling, and this shuffling is an effective technique as a countermeasure against burst errors. If the shuffling pattern is different between the recording side and the reproducing side, a normal image cannot be reproduced during reproduction, and only a simple geometric pattern image with a disordered block pattern can be reproduced.

So, we decided to use this shuffling pattern as an ID code CD.
By managing the video software, it is possible to prevent dubbing of video software.

First, the recording system 2 of the cassette digital recorder 1 will be explained.

The configuration of the main parts of this cassette digital recorder 1 is shown by solid line A in FIG.

As shown in FIG. 1, this cassette digital recorder 1 is provided with a digital input terminal 3 and an analog input terminal 4 on the input side.

The digital input terminal 3 can be connected to, for example, a digital output supplied from another cassette digital recorder 5, and the analog input terminal 4 can be connected to, for example, another cassette digital recorder 5, a video camera 6, An analog output supplied from the tuner 7 or the like can be connected. Note that 8 is a switch circuit for selecting an analog output.

The digital input terminal 3 described above is connected to the terminal 9a of the switch circuit 9 in the cassette digital recorder 1, and
The analog input terminal 4 is connected to the terminal 9b of the switch circuit 9 via the A/I converter 10. In addition, 9C
is a terminal of the switch circuit 9.

A digital video signal DV supplied from the outside and passed through the switch circuit 9 is supplied to a block encoding circuit 11 and an ID separation circuit 12.

In the block encoding circuit 11, block encoding processing such as ADRC and DCT is performed on the above-mentioned digital video signal DV to form recording data. This block encoded record data is sequentially written into the shuffling memory 13.

On the other hand, the ID code CD is separated from the digital video signal DV supplied to the ID separation circuit 12, and the ID code CD is separated.
The signal is supplied to the modification circuit 14.

In the ID discrimination/change circuit 14, the separated ID code C
Based on D, ID if necessary to prevent dubbing.
Change the code CD. That is, when dubbing video software, during recording, the ID code CD is rewritten to an ID code CD with a shuffling pattern that is not provided in the playback system, which will be described later.

If the reproduced and separated ID code CD is (“0”), that is, if the source is one that can be dubbed, the ID code C
It is supplied to the switch circuit 15 and the ID adding circuit 16 as D=(“θ”).

Similarly, the played and separated ID code CD (“1”
), that is, in the case of video software, the ID code CD=the same 1") is changed to the ID code CD=the same 2') and is supplied to the switch circuit 15 and the ID adding circuit 16.

Furthermore, in the case of the reproduced and separated ID code CD=ji2''), the ID code CD=ji2'') is supplied as is to the switch circuit 15 and the ID adding circuit 16.

In the switch circuit 15, switching control of the switch is performed based on the above-mentioned ID code CD. For example, when ID code CD=("O"), terminals 15a and 15c of switch circuit 15 are connected and shirt ring table 17 is selected.

Also, ID code CD=J1”) or ID code CD
= (“2”), the terminals 15b and 15c of the switch circuit 15 are connected, and the shuffling table 1
8 is selected.

From the shuffling table 17 or 18, each address data of the block-encoded recording data is read out in a shuffled state under the control of a controller (not shown), and is sent to the address generator 19 via the switch circuit 15. Supplied.

The address generator 19 generates pixel-by-pixel address data based on the above-mentioned address data, and this pixel-by-pixel address data is stored in the shuffling memory 13.
supplied to

In the shuffling memory 13, recording data is read out in units of pixels based on address data in units of pixels under the control of a controller (not shown), and is supplied to the ID adding circuit 16.

The ID adding circuit 16 adds an ID code CD1=(“0”) to the recorded data read from the shuffling memory 13.
, (“1”) or (“2”)) is added,
The signal is supplied to the recording processing circuit 20. This ID code CD may be added at the same position as the buffering table identification code described above, or during the vertical blanking period, for example.

In addition, if you do not have an ID code CD, please use the ID code CD (
=(“0”)).

In the recording processing circuit 20, the block-encoded recording data added to the ID coat CD is subjected to frame formation and predetermined signal processing, and is then magnetically recorded onto a magnetic tape (not shown) by a dome 21. be done.

Next, the reproduction system 31 of the cassette digital recorder 1 will be explained.

The RF multiplied signal is reproduced from a magnetic tape (not shown) by the magnetic head 32 and subjected to predetermined signal processing in the RF signal reproduction processing circuit 33 to become reproduced data, which is then supplied to the deshuffling memory 34 and the ID separation circuit 35. Ru.

The reproduced data that has undergone block encoding processing is sequentially written into the deshuffling memory 34.

On the other hand, the ID code CD is separated from the playback data that is supplied to the ID separation circuit 35 and block encoded.
The signal is supplied to the ID discrimination circuit 36.

The ID discrimination circuit 36 controls the switch circuit 37 based on the separated ID code CD, and supplies the ID code CD to the ID addition circuit 38.

If ID code CD = (“0′), it is a source that can be dubbed, so the ID code CD will not be changed.
The ID code CD=ji0'') is supplied to the switch circuit 37 and the ID adding circuit 38.

In addition, if the ID code CD = 1"), the ID code is
The code CD=jido) is supplied to the switch circuit 37 and the ID adding circuit 38.

Furthermore, in the case of a source with ID code CD=("2"), not only dubbing but also normal playback is not possible, so ■D
The code CD=ji2'') is supplied to the switch circuit 37 and the ID adding circuit 38.

In the switch circuit 37, switching control of the switch is performed based on the above-mentioned ID code CD. For example, when ID code CD=(“0”) is supplied, terminals 37a and 37c of switch circuit 37 are connected and deshuffling table 39 is selected.

Further, when the ID code CD- (“1”) is supplied, the terminals 37b and 37c of the switch circuit 37 are connected and the deshuffling table 40 is selected.

When the ID code CD=(“2”) is supplied, the terminals 37d and 37c of the switch circuit 37 are connected. In this case, since there is no target deshuffling table, normal image reproduction is impossible.

From the deshuffling table 39 or 40, the address data of the block-encoded playback data is read out in a deshuffled state under the control of a controller (not shown), and sent to the address generator 41 (1) via the switch circuit 37. Ru.

The address generator 41 generates pixel-by-pixel address data based on the above-mentioned address data, and this pixel-by-pixel address data is transferred to the deshuffling memory 3.
4.

In the deshuffling memory 34, reproduction data is read out in units of pixels based on address data in units of pixels under the control of a controller (not shown), and is supplied to the block encoding circuit 42. This deshuffling memory 34
To read the playback data from the ID code CD=(“
0”), the deshuffling is performed based on the address data from the deshuffling table 39, and the ID code CD
= (“1°), the deshuffling is performed based on the address data from the deshuffling table 40. Then, the ID
In the case of code CD=(“2′”), there is no corresponding deshuffling table, so the deshuffling memory 3
From No. 4 onwards, the reproduced data is read out in the shuffled state.

The block decoding circuit 42 decodes the block-encoded playback data into a pixel-by-pixel digital video signal Dv, and this reproduced digital video signal D
V is supplied to the ID adding circuit 38.

In the ID adding circuit 38, the above-mentioned digital video signal DV
An ID code CD is added to the . This ID code CD may be added at the same position as the buffering table identification code described above, or during the vertical blanking period, for example.

Then, the digital video signal Dν to which the ID code CD has been added is taken out as a digital output from the terminal 43,
Alternatively, after being converted into an analog video signal by the D/A converter 44, it is taken out from the terminal 45 as an analog output.

According to this embodiment, when the terminal 43 or terminal 45 of the reproduction system 31 is connected to a monitor (not shown), the ID code C
If D=JO"), then the deshuffling table 39 is selected for the shirt ring table 17, and if the 10 code C0=("1'), then the shuffling table 1 is selected.
Since the deshuffling table 40 is selected for the deshuffling table 8, the shuffling patterns of the recording system 2 and the reproducing system 31 match, and a normal image can be displayed.

However, when attempting to dub video software, the ID code (CD = 2") is recorded and replayed, so the playback data is read out from the deshuffling memory 34 in a shuffled state, for example. As a result, only a simple geometric pattern with a disordered front pattern can be seen, and a normal image cannot be seen.

In this way, when dubbing video software, by recording a non-existent shuffling pattern in the video signal as an ID code CD, dubbing can be prevented without having to go through the hassle of handing over an encryption key. can.

In this embodiment, as an example of switching the characteristics of block encoding, the shuffling pattern is changed to ID code C.
Although an example of management using D is described, the invention is not limited to this. For example, the dark value bit allocation in the ADRC buffering table can be assigned to a specific ID.
It is also possible to allocate all 0 bits or change the block size depending on the code.

〔Effect of the invention〕

In the digital signal recording and reproducing device according to the present invention, when playing back and recording a digital signal, an identification code is added depending on whether or not dubbing is possible. The code is converted to a specific identification code and recorded, and during playback, the characteristics of block encoding are switched according to the identification code, for example, the shuffling table is switched, so it is possible to prevent dubbing of video software. There is.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. 15.37: Switch circuit, 16.38: ID addition circuit, I7.18: Shuffling table, 20: Recording processing circuit, 21.32: Magnetic head, Dv: Digital video signal, 31: Playback system, 34: Deshuffling 36: ID discrimination circuit, 39.40: Deshuffling table, 42 Niblock decoding circuit. Explanation of main symbols in the drawings 1.5: Cassette digital recorder, 2: Recording system, 11 Ni-block encoding circuit, 12.35: ID separation circuit, 13: Shuffling memory, 14: ID discrimination/change circuit, Agent Patent Attorney Masatoshi Sugiura

Claims (2)

[Claims] (1) In a digital signal recording and reproducing apparatus that blocks-encodes a digital signal and records it on a recording medium, and outputs a block-decoded digital signal when reproducing information recorded on the recording medium. and a means for recording an identification code corresponding to the switching state of the switching means on the recording medium, and reproducing the identification code and recording the reproduced identification code. The characteristics of the block decoding are switched based on the code, and when a specific identification code is supplied on the recording side, the identification code is converted to a different identification code, making it impossible to decode it on the playback side. A recording and reproducing device for digital signals. (2) The digital signal recording and reproducing apparatus according to claim 1, wherein the switching means for switching the characteristics of block encoding is switching of a shuffling table.