JPH11205745A - Device and method for recording and reproducing, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent added information of copyright protection signal, etc., from being easily altered. SOLUTION: Added information to supply for an encoder 12 from an inputting device 11 is converted to a proper code and a control signal for select-switching the mode of a discrete cosine(DCT) transformation according to this bit array is supplies for a DCT part 13. The part 13 is provided with a frame DCT part 13a and a field DCT part 13b and by switching a switch 14 according to the control signal, switches a mode by each encoding unit to DCT-process a picture signal. The control signal is written at a proper position as a motion flag according to a format by a motion flag fitting-in part 15. Thereby, added information can be recorded in a recording medium in a form inseparable from a video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording and reproducing apparatus and a recording and reproducing method for recording and / or reproducing compression-encoded image data.

[0002]

2. Description of the Related Art As one system of consumer digital video,
In recent years, a so-called DV system standard has been used in which digital image data is compressed to about 1/5 the data amount using a discrete cosine transform (DCT) and recorded on a magnetic tape.

In such a DV system standard, information for copyright protection of a video signal includes a video AUX (VAUX) area which is an area in a video sector in which video AUX information accompanying the compressed image data is recorded. Is recorded. As described above, the information for copyright protection is recorded together with the image data in order to protect the rights of the copyright holder by prohibiting the duplication of the work.

[0004]

Devices such as a digital video cassette recorder (VCR) based on the DV system generally have a digital interface terminal, so that image data can be easily taken into a personal computer or the like. There is a risk that the information for copyright protection of may be altered.

[0005] In addition, the copyright holder does not always want to prohibit the copying of his or her own literary works, and tries to widely distribute copies without deterioration in image quality and the like by taking advantage of digital media. It is possible. In this case, it is necessary to be able to prove that the user is the author in some form (for example, a "watermark").

However, even if such a signal for copyright-related information is newly defined, if it is recorded in the VAUX area, there is a risk that the signal is relatively easily modified by means such as the personal computer described above. is there.

[0007] The present invention has been made to solve the above-described problems, and has been developed by making additional information such as a copyright protection signal inseparable from a video signal, thereby making the information inseparable. An object of the present invention is to provide a recording / reproducing apparatus and a recording / reproducing method which are not easily modified.

[0008]

SUMMARY OF THE INVENTION A recording / reproducing apparatus according to the present invention proposed to solve the above problem records and compresses image data compressed by an encoding method capable of selectively switching at least two modes. And / or a recording / reproducing apparatus for inputting and inputting additional information embedded in the image data, converting the additional information into a code of a predetermined format, and compression-encoding the image data based on the additional information. An encoder for generating a control signal for selecting a mode, and compression encoding means for compressing and encoding the image data in the mode selected by the control signal.

Another recording / reproducing apparatus of the present invention proposed to solve the above-mentioned problem records and / or records image data compressed and encoded by an encoding method capable of selectively switching at least two modes. In a recording / reproducing apparatus for reproducing, a flag indicating a motion detection result of the compressed image data is detected, and flag detection means for extracting additional information recorded by being set in the flag, and a mode selected according to the additional information. A decompression decoding means for decompressing and decoding the compressed image data.

A recording / reproducing method according to the present invention proposed to solve the above-mentioned problem records and / or reproduces image data compressed and encoded by an encoding method capable of selectively switching at least two modes. In the recording / reproducing method, an input step of inputting additional information to be embedded in image data, converting the additional information into a code of a predetermined format, and selecting a mode for compression-encoding the image data based on the additional information. And a compression encoding step of compression encoding the image data in a mode selected by the control signal.

Another recording / reproducing method according to the present invention proposed to solve the above-mentioned problem is to record and / or record image data compressed and encoded by an encoding method capable of selectively switching at least two modes. In the recording / reproducing method for reproducing, a flag indicating a motion detection result of the compressed image data is detected, and a flag detecting step of extracting additional information recorded by being inserted into the flag, and a mode selected according to the additional information. A decompression decoding step of decompressing and decoding the compressed image data.

According to another aspect of the present invention, there is provided a recording medium on which an image display program is recorded, wherein the image display program indicates a motion detection result of the compressed image data. A flag detecting step of detecting a flag and extracting additional information recorded by being set in the flag; and selecting a decompression decoding mode corresponding to a compression encoding mode of the image data for each encoding unit using the additional information. And a decompression decoding step of switching and decompressing and decoding the compressed image data.

According to the present invention, it is possible to provide a recording / reproducing apparatus and a recording / reproducing method in which additional information such as copyright-related information is not easily changed, and a recording medium on which an image display program is recorded.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

First, prior to the description of a specific embodiment of the present invention, a configuration of a digital VCR apparatus as a typical example to which the recording / reproducing apparatus and the recording / reproducing method of the present invention are applied will be described.

FIG. 1 is a functional block diagram showing a configuration example of a main part of a digital VCR device which is a recording / reproducing device according to an embodiment of the present invention.

First, the operation of the recording system of the digital VCR will be described assuming the DV system.

The input video data is first sampled at a predetermined sampling frequency by a sampling section 41, and a block of (8 × 8) pixels serving as a basic unit of a discrete cosine transform (DCT) by a blocking / shuffling section 42. And a shuffling process is performed to equalize the amount of information included in the video segment.

In the DV system, six blocks composed of the above (8 × 8) pixels are processed as one unit, and are called macro blocks. In addition, five macroblocks constituting one video segment are collected by shuffling according to a predetermined rule from within one screen.

The motion detector 43 detects the motion of the video data from the blocking / shuffling unit 42.
This motion detection is performed, for example, by comparing the sum of absolute values of differences between fields with a predetermined threshold value, and the detection result is indicated by a motion flag.

A DCT (Discrete Cosine Transform) unit 44 selectively switches between two DCT modes according to the motion detection result of the motion detection unit 43 and compresses the image data to about 1/5.

Here, the two DCT modes which are selectively switched are a basic mode called "still mode" and a mode called "movement mode".

The “stationary mode” is also called “frame DCT mode” or “8 × 8 DCT mode”.
(8 × 8) DCT is applied to (× 8) pixels.

On the other hand, the "motion mode"
Also called a “CT mode” or “2 × 4 × 8 DCT mode”, this mode is used when a subject is moving or a camera is panning or zooming. This DC
In the T mode, an (8 × 8) block is divided into (4 × 8) blocks of a first field and a second field, and (4 × 8) DCT is applied to each (4 × 8) pixel. Is a mode for preventing an increase in high frequency components in the vertical direction and preventing a decrease in compression efficiency.

Next, the DCT coefficients obtained by the DCT unit 44 are converted into a one-dimensional coefficient sequence by a zigzag scan by a zigzag scan unit 45, and are classified into classes by a classifying unit 46. The data is temporarily stored in the memory 48.

In the meantime, the data amount estimating section 47 selects a quantizer for quantizing the video segment.

The quantizer 49 quantizes the video segments sequentially supplied from the FIFO 48 by the quantizer selected by the data amount estimator 47.

The quantized video data is converted into a variable-length code by a VLC (variable-length coding) unit 50, subjected to framing processing by a framing unit 51, and subjected to a deshuffling unit 5.
In 2, deshuffling, which is the reverse of shuffling, is performed. In the deshuffling unit 52, audio data, subcode data, DIF data, and the like are also multiplexed with video data.

Next, after the parity is added by the parity generation section 53 and the time axis is corrected by the TBC (time axis correction) section 54, a predetermined coding is performed by the recording coding section 55 to obtain recording data. It is recorded on a magnetic tape as a recording medium.

On the other hand, the operation of the reproduction system of the digital VCR basically performs the reverse of the above-mentioned processing in the recording system.

That is, the reproduction data read from the magnetic tape is decoded by the reproduction decoding unit 56 and sent to the error correction unit 57 via the TBC unit 54.

After error correction is performed by the error correction section 57, the audio data, the subcode data,
DIF data and the like are separated, subjected to a process reverse to that at the time of recording, and output as video data.

Next, a recording system including an image compression block of the recording / reproducing apparatus according to the embodiment of the present invention will be described with reference to a specific example.

FIG. 2 shows an example of the configuration of a main part of a recording system including an image compression block, which is applied to the VCR apparatus shown in FIG.

The input device 11 receives additional information input by a user and supplies the additional information to the encoder 12. The input from the user is character or image information.

The encoder 12 converts an input from the input device 11 into an appropriate code, and generates a control signal for selecting a DCT mode. Image data is NTS
In the case of the C (SD mode) method, the number of processing units composed of 8 × 8 pixels is 8,100 per frame. For this reason, recording the same information for each frame has the advantage that information can be correctly picked up even if a concealing process, which is a process unique to the digital VCR, is performed. The information amount of 8100 bits is ASC
When converted to the number of 1-byte code characters such as II code
Since this corresponds to 01.25 characters, information of 101 characters can be recorded.

For example, the user inputs “ABC” from the input device.
When the character string "D" is entered, the corresponding ASCI
The I code is as follows. However, in this example, a space (20h) is provided in a blank portion of the 101 characters.

The encoder 12 supplies a control signal to the discrete cosine transform (DCT) unit 13 so that the mode of the discrete cosine transform is selected according to the bit arrangement.

The discrete cosine transform (DCT) section 13 includes a frame DCT section 13a and a field DCT section 13b. The DCT unit 13 switches the switch 14 according to the control signal from the encoder 12 so that the first processing of the frame is performed by the frame DCT.
In the mode, the next processing is the field DCT mode, the next processing is the frame DCT mode, and so on, and the mode is switched to perform the discrete cosine transform (DCT) processing. Note that FIG. 2 illustrates a case where the frame DCT unit 13a and the field DCT unit 13b are configured as independent blocks, but it is also possible to share a part of these circuits. .

The motion flag fitting section 15
Writes the above control signal at an appropriate position as a motion flag according to the format. Thus, the input additional information is embedded in the image data in an inseparable form.

FIG. 3 shows a specific example of bits defined as a motion flag.

In the DV format, FIG.
As shown in FIG.
Two bits are used as a DCI part, followed by an AC part. Further, a DC error code to be replaced when an error is found in the data part, a motion flag indicating which DCT mode was used for processing, a class number, and the like are arranged.

FIG. 3B shows the contents of the DCI part. Of these bits, bits from “b8” to “b0” are DC coefficient values, and “m0”
Is a motion flag, and "c0" and "c1" are class numbers. The motion flag “m
“0” indicates that, for example, when the value is 0, the frame DCT mode (8 × 8 DCT mode) is selected, and when the value is 1, the field DCT mode (2 × 4 × 8 DCT mode) is selected.
Mode) is selected. The class numbers “c0” and “c1” are used for selecting a quantization table at the time of requantization, and a portion where the image is rich is quantized roughly, and a portion where the image is little changed is finely quantized. For example, it is possible to select an efficient quantization table using characteristics of human vision.

The above-described recording system is applied to a so-called DV digital VCR, and a DCT processing block performs processing in a frame DCT mode or processing in a field DCT mode according to additional information converted into a predetermined code. Have been to do. The coded additional information is recorded on the magnetic tape in a form inseparable from the image data as a motion flag indicating which DCT mode has been processed.

Next, a reproducing system including a compressed image decompression block of the recording / reproducing apparatus according to the embodiment of the present invention will be described with reference to a specific example.

FIG. 4 shows a digital V as exemplified in FIG.
2 shows a configuration example of a main part of a reproduction system including a compressed image decompression block applied to a CR device.

This reproducing system corresponds to the recording system illustrated in FIG. 2, and is adapted to select a mode of the inverse DCT processing according to a motion flag into which additional information is set at the time of recording. That is, of the compressed image data, coding units processed in the field DCT mode are subjected to field inverse DCT processing, and coding units processed in the frame DCT mode are subjected to frame inverse DCT processing. Specifically, the motion flag detection unit 21 detects a motion flag from the reproduction data and sends the motion flag to the decoder 22, and generates a control signal for the DCT unit 23 from the above detection result. Note that only the AC coefficient in the data is subjected to reverse zigzag scanning, and the portion where the motion flag is written is separately processed.

Then, in the decoder 22, the motion flags from the motion flag detecting section 21 are collected for each frame, and the additional information is detected. here,
Input during recording and set in motion flag of image data Signal sequence of the additional information appears.

Inverse discrete cosine transform (IDCT) unit 23
Comprises a frame IDCT unit 23a and a field IDCT unit 23b. This IDCT unit 23
By switching the switch 24 in response to the control signal from the decoder 22, the part processed in the field DCT mode is subjected to the field inverse DCT processing, and the part processed in the frame DCT mode is subjected to the frame inverse DCT processing.

The display device 25 is for displaying the additional information decoded by the decoder 22, and is, for example, a display device of a computer.

In the above description, the recording system and the reproducing system of a recording / reproducing apparatus such as a digital VCR have been described as an example. However, the recording system and the reproducing system are each configured as an independent recording apparatus and a reproducing apparatus. You may.

The recording / reproducing method according to the present invention described above is not only applied to a digital VCR device, but its processing procedure can be recorded on a recording medium as an image display program and used as appropriate. is there.

As described in the above embodiment, when compressing and encoding image data in the DV system, a D-value is applied to a square area on a screen composed of 64 pixels.
Frame DCT and field DCT as CT operation
And a flag indicating which mode the processing was performed is recorded together with the compressed data. By applying the recording / reproducing apparatus and the recording / reproducing method according to the present invention to such a DV system and determining in which mode the processing is performed for each processing unit in accordance with a predetermined pattern, an additional method is provided. Information can be recorded / reproduced in a manner inseparable from the video signal.

[0054]

According to the recording / reproducing apparatus, the recording / reproducing method, and the recording medium of the present invention, the coded additional information is written in the flag indicating the compression encoding mode of the image data. And the like can be recorded in an inseparable form from the video signal, and can be prevented from being easily altered.

[Brief description of the drawings]

FIG. 1 is a functional block diagram illustrating a configuration example of a recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an example of a configuration of a main part of a recording system including an image compression block in the recording and reproducing apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram for describing a motion flag.

FIG. 4 is a block diagram showing an example of a configuration of a main part of a reproduction system including an image expansion block in the recording / reproduction device according to the embodiment of the present invention.

[Explanation of symbols]

11 input device, 12 encoder, 13 discrete cosine transform (DCT) unit, 13a frame DCT
Unit, 13b field DCT unit, 14 switch, 15 motion flag insertion unit

Claims (14)

[Claims] An input means for inputting additional information embedded in image data in a recording / reproducing apparatus for recording and / or reproducing image data compressed and encoded by an encoding method capable of selectively switching at least two modes. An encoder for converting the additional information into a code of a predetermined format and generating a control signal for selecting a mode for compression-encoding the image data based on the additional information; and a mode selected by the control signal. And a compression coding means for compression coding the image data. 2. The recording / reproducing apparatus according to claim 1, further comprising a flag inserting means for inserting the code into a flag indicating a motion detection result of the image data for recording. 3. The compression-encoded image data is DV
2. A method according to claim 1, wherein said compression coding means switches said compression coding mode to a frame discrete cosine transform mode or a field discrete cosine transform mode for each coding unit by said control signal. The recording / reproducing apparatus according to claim 1. 4. A recording / reproducing apparatus for recording and / or reproducing image data compressed and encoded by an encoding method capable of selectively switching at least two modes, wherein a flag indicating a motion detection result of the compressed image data is detected. ,
Recording / reproduction comprising flag detection means for extracting additional information recorded in the flag, and expansion decoding means for expanding and decoding the compressed image data in a mode selected according to the additional information. apparatus. 5. The recording / reproducing apparatus according to claim 4, further comprising display means for displaying said additional information. 6. The compressed image data is image data of a DV system, and the decompression decoding means changes the mode of the decompression decoding based on the control signal for each coding unit in a frame inverse discrete cosine transform mode or a field inverse discrete cosine transform mode. The recording / reproducing apparatus according to claim 4, wherein the mode is switched to a mode. 7. A recording / reproducing method for recording and / or reproducing image data compressed and encoded by an encoding method capable of selectively switching at least two modes, an input step of inputting additional information embedded in the image data. An encoding step of converting the additional information into a code of a predetermined format and generating a control signal for selecting a mode of compression-encoding the image data based on the additional information; A compression encoding step of compressing and encoding the image data in a mode. 8. A recording / reproducing method according to claim 7, wherein said code is inserted into a flag indicating a motion detection result of said image data and recorded. 9. The compression-encoded image data is DV
8. The image data according to claim 7, wherein said compression encoding step switches said compression encoding mode to a frame discrete cosine transform mode or a field discrete cosine transform mode for each encoding unit by said control signal. The recording / reproducing apparatus according to claim 1. 10. A recording and reproducing method for recording and / or reproducing image data compressed and encoded by an encoding method capable of selectively switching at least two modes, wherein a flag indicating a motion detection result of the compressed image data is detected. ,
Recording / reproducing, comprising: a flag detecting step of extracting additional information recorded in the flag, and an expansion decoding step of expanding and decoding the compressed image data in a mode selected according to the additional information. Method. 11. The compressed image data is DV-type image data, and in the decompression decoding step, the mode of the decompression decoding is set to a frame inverse discrete cosine transform mode or a field inverse discrete cosine transform for each coding unit by the additional information. The recording / reproducing method according to claim 10, wherein the mode is switched to a mode. 12. The recording / reproducing apparatus according to claim 10, further comprising a display step of displaying said additional information on a display means. 13. A recording medium on which an image display program is recorded, wherein the image display program detects a flag indicating a motion detection result of the compressed image data,
A flag detecting step of extracting additional information recorded by being embedded in the flag; and selecting and switching a decompression decoding mode corresponding to a compression encoding mode of the image data for each encoding unit using the additional information. A decompression decoding step of decompressing and decoding the compressed image data. 14. The image display program according to claim 13, further comprising a display step of displaying, on a display means, the content of the additional information recorded in the flag indicating the motion detection result. recoding media.