JPH0898143A - Optical disk device - Google Patents

Abstract

PURPOSE: To provide an optical disk device which can certainly secure prescribed recording time in one optical disk even if a variable rate in which a recording rate changes in accordance with the movement of a picture is adopted. CONSTITUTION: A video signal division means dividing digital video signals which are sequentially inputted into the video signal of a low-order layer, which can solely reproduce video information, and the video signal of a high-order layer, which can realize reproduction as video information by combining it with the video signal of the low-order layer, a recording means recording the divided video signal of the low-order layer and the video signal of the high-order layer on a disk-like recording medium 113 and a detection means detecting the unrecorded area of the disk-like recording medium 113 are provided. When the detection means detects the lack of the unrecorded area in the disk-like recording medium 113, the video signal of the low-order layer, which is inputted to a next stage is overwritten and recorded on the video signal of the high-order layer in the recorded area of the disk-like recording medium 113.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for recording a compressed moving image on a disk-shaped recording medium such as an optical disk.

[0002]

2. Description of the Related Art As the compression technology of digital video information advances, the compression information is recorded on a disk-shaped recording medium such as an optical disk so that the information can be recorded more than a tape-shaped recording medium such as a conventional VTR. It has become possible to realize an extremely easy-to-use video filing device with excellent searchability. Further, since such a disk file device handles digital information, there is no deterioration of information due to dubbing as compared with the case of recording an analog signal, and since it is optical recording / reproducing, it is contactless and highly reliable. It is a very good thing that a system can be constructed.

A conventional optical disk device will be described below with reference to the drawings. FIG. 18 is a circuit block diagram of a conventional optical disk device for recording a compressed moving image on an optical disk or reproducing the compressed moving image from the optical disk.

In the figure, 1 is an A / D conversion means for converting an analog signal such as an input audio signal or video signal into a digital signal, and 2 is information for compressing the signal digitally converted by the A / D conversion means 1. A compression unit 3, an encoder (encoding unit) that encodes the signal compressed by the information compression unit 2, and 4 converts the encoded signal into a predetermined modulation code in order to reduce intersymbol interference in the recording medium. Modulating means 5 for driving the laser in accordance with the above-mentioned modulation code, 6 an optical head for emitting a light beam corresponding to a modulation signal by the laser driving means, and recording information on the optical disk 7, 8 an optical head A tracking actuator for tracking the light beam from 6.
Reference numeral 9 is a traverse motor that reciprocates the optical head 6 in the radial direction of the optical disk 7, 10 is a disk motor that rotates the optical disk 7 at a predetermined frequency, and 11 is a motor that controls the tracking actuator 8, the traverse motor 9 and the disk motor 10. It is a driving means.

Further, 12 is a reproduction amplifier for amplifying the reproduction signal from the optical head 6, 13 is demodulation means for demodulating the reproduction signal modulated by the modulating means 4, and 14 is a reproduction signal encoded by the encoder 3. A decoder (decoding means) for decoding the information, 15 is an information expansion means for expanding the reproduction signal compressed by the information compression means 2, and 16 is an original video signal by converting a digital signal into an analog signal. It is a D / A conversion means for obtaining an audio signal and the like.

FIG. 19 shows an MP currently being standardized for compressing digital moving image information for transmission / storage.
This is a simplified representation of the data array structure (layer structure) of the EG method. In the figure, 17 is a GOP (Group of pictur) composed of a plurality of predetermined frame information.
e). In this example, one GOP is composed of 15 pieces of frame information.

Reference numeral 18 is a GOP layer representing one piece of frame information, and is composed of several picture layers. A picture layer 19 has a slice structure in which one picture is divided into several blocks. Here, Y represents luminance information, and Cb and Cr represent color information.

Further, 20 is a Slice layer composed of several macroblocks (MB), 21 is a macroblock layer composing a macroblock, and 22 is 8 ×.
It is a block layer composed of 8 pixels.

FIG. 20 shows 1G from frame information of 10 frames.
The coding structure when an OP is constructed is shown in the figure, where 23 is an intra-frame DCT (discrete cosine transform).
I picture, which is video information compressed by
Adds motion compensation using the I picture 23, which is located in the forward direction in time, as a reference screen to the I picture 23.
The P picture which is the video information that has been subjected to the above information compression, and 25 are the I pictures 23 and P which are temporally positioned before and after.
This is a B picture which is video information in which motion compensation using the picture 24 as a reference screen is subjected to DCT coding and information compression of the P picture 24 or more is performed.

By adopting such an encoding structure,
It is possible to improve the encoding efficiency and the data recording capacity of the optical disc 7.

However, since the I picture 23 performs the intra-frame DCT, it is possible to reproduce the image information by this frame alone. However, the P picture 24 has the motion compensation in the forward direction in addition to the intra-frame DCT. Since the I picture 23 is reproduced, the image can be reproduced only after the I picture 23 is reproduced.
Since it is a prediction screen using motion compensation in both the front and back directions, there is a drawback that it cannot be reproduced until both I picture 23 and P picture 24 have been reproduced. Therefore, if the number of B-pictures 25 is increased, the amount of buffer memory in the processing circuit is increased and the delay time from data input to video reproduction is increased. However, in storage media such as the optical disk 7, it takes a long time. While an encoding method having a high compression efficiency is desired for recording, the delay time of the video reproducing process does not cause a problem so much, and thus such an encoding structure is suitable.

FIG. 21 shows 1 GOP when the compression information is recorded on the optical disk 7 with a variable data length depending on the design so that the image quality of all images is constant.
6 is a schematic diagram showing a ratio of a data amount per hit to a recording area of the optical disc 7. FIG. In the figure, 26 are 1G each
The amount of data per OP is shown.

FIG. 22 shows a case where a compressed image is recorded in the recording area of the optical disk 7 at the same variable rate as in FIG. 21 (a).
And (b) when recording at a fixed rate. In the figure, 27 is the entire recording area of the optical disk 7, 28 is the innermost circumference of the disk which is the start point of the entire recording area 27, and 29 is the outermost circumference of the disk which is the end point of the recording area 27.

FIG. 23 is a plot of the amount of data per GOP required to keep the quality of a reproduced image constant regardless of the image, with the horizontal axis representing time. In the figure, a
Indicates the maximum data amount per GOP, and b indicates the average data amount of each GOP.

In FIG. 24, the image S / N indicating the image quality is plotted on the abscissa, and the amount of data per GOP required to realize a predetermined image S / N for each image type is plotted on the ordinate. It is a thing.

Next, the operation of the conventional optical disk device will be described. Conventionally, in order to record compressed moving image information on an optical disc, a method of recording digital compressed moving image information such as MPEG system shown in FIG. 19 on an optical disc recorder as shown in the block diagram of FIG. 18 has been adopted. . At this time, the image information digitized by the A / D converting means 1 is processed by the information compressing means 2, for example, MPE.
It is converted into a standard compressed moving image system such as G. This compression information is encoded by the encoder 3 and the modulation means 4
After being subjected to a predetermined modulation in order to reduce the influence of intersymbol interference on the optical disk 7, the laser driving means 5
Recording is performed on the optical disk 7 by the optical head 6 driven by the.

At this time, if recording is performed at a fixed rate such that the amount of data in each GOP unit is almost the same, the recording time per disc of the optical disc 7 is divided by distributing the information to sectors equal to an integral multiple of the frame period. Can be kept constant.

On the other hand, at the time of reproduction, the video information recorded on the optical disk 7 is amplified by the reproduction amplifier 12, restored to the original video information by the demodulation means 13 and the decoder 14, and further expanded by the information expansion means 15. , D / A conversion means 16 so that the original analog video information signal can be displayed on a monitor (not shown) or the like.

When the MPEG method is used as the digital moving picture compression method in such an optical disk apparatus, as shown in FIG. 20, the I picture 23 which is the compressed video information by the intra-frame DCT and the I picture 23 which is located in the forward direction in time. P-picture 24, which is compressed video information obtained by adding motion compensation using the I picture 23 as a reference screen to DCT encoding, and motion compensation using the I picture 23 and the P picture 24, which are temporally preceding and following, as the reference screen. The B picture 25, which is the compressed video information added to the encoding, is recorded on the optical disc 7 as an encoding structure that is combined as shown in FIG.

However, when the fixed rate recording method is adopted, the recording time per one optical disk 7 can be kept constant as described above, but as shown in FIG. A recording method using a variable rate in which the amount of data per GOP is variable (see FIG. 22).
Compared to (a)), since more data recording area is generally required to record the image information of the same number of frames, the recordable time becomes shorter, and depending on the type of data to be recorded and the recording rate selected. There is a problem that a predetermined recording time (for example, 2 hours) cannot be secured.

This is more apparent from FIGS. 23 and 24. That is, since a general video file has different image fineness and movement amount depending on the design, as shown in FIG. 24, if the same image S / N is obtained for all images, it is The amount of data varies greatly depending on each image.

Therefore, in order to prevent the image quality of all the patterns from being less than a certain level, the recording rate is fixed to the maximum value of the data amount per 1 GOP, that is, the rate of a in the figure, as shown in FIG. It is necessary to keep it. as a result,
A GOP having a large amount of data is unnecessarily present, and a large amount of data recording area is required.

On the other hand, in the recording at the variable rate, since the recording rate according to the type of each image is selected, the recording rate of b in FIG. 23 can be recorded as the average recording rate. . Therefore, the problem of the above fixed rate does not occur, and as a result, it becomes possible to lengthen the recording time by the difference from the maximum recording rate a.

Taking advantage of such a variable rate, 1
In a read-only type optical disc device capable of evaluating one entire video file in advance, the average recording rate of the entire video file is adjusted by repeating encoding, and as a result, the image quality of the entire video file is maintained constant.
The recording time of one optical disk 7 is lengthened to obtain a predetermined recording time.

[0025]

However, when the recording at the variable rate as described above is applied to an optical disk capable of recording, unlike the case where a read-only optical disk is manufactured, the following problems occur. . That is, when a reproduction-only optical disc is manufactured, when recording an image, information such as the fineness of the pattern of the video file to be recorded and the speed of movement is already known. Therefore, it is possible to predict in advance the average recording rate for recording information for a predetermined time on a single optical disc with a constant image quality. However, for a recordable optical disc for recording a TV movie or the like, for example, Usually, it is not possible to know in advance information such as the fineness of the pattern of a video file to be recorded and the speed of movement, and it is not possible to predict the average recording rate in advance. Therefore, the recording time of an optical disk having a limited disk capacity is variable depending on the fineness of the pattern of the video to be recorded, the speed of movement, etc., and the recording time of the optical disk cannot be predetermined. It causes the problem of being lost.

The present invention has been made in order to solve the above problems, and in a recording apparatus employing a variable rate in which the recording rate changes according to the movement of an image,
Even when recording image information on a disc that does not allow the user to know in advance information such as the fineness of the picture pattern of the video file to be recorded and the speed of movement, the recordable time is reduced while minimizing the deterioration of the image quality. It is an object of the present invention to obtain an optical disk device that can reliably secure a predetermined recording time for one optical disk by increasing the time.

[0027]

According to a first aspect of the present invention, in an optical disk device, a sequentially input digital video signal is a lower layer video signal capable of independently reproducing video information and a video of the lower layer. Video signal dividing means for dividing into an upper layer video signal that can be reproduced as video information only when combined with a signal, and the divided lower layer video signal and upper layer video signal are recorded on a disc-shaped recording medium. Recording means for recording and detection means for detecting an unrecorded area of the disk-shaped recording medium are provided, and when the detection means detects a shortage of the unrecorded area of the disk-shaped recording medium, it is input to the next stage. The video signal of the lower layer is overwritten on the video signal of the upper layer of the already recorded area of the disc-shaped recording medium.

According to a second aspect of the present invention, in the optical disc apparatus, the digital video signal is composed of an I picture which is two-dimensional compressed video information information-compressed in a frame and an I picture which is forward in time. A P picture, which is three-dimensional compressed video information that is information-compressed with motion compensation, and a B picture, which is three-dimensional compressed video information, which is information-compressed with motion compensation by I and P pictures that are temporally forward and backward. It is composed of a video information block having a unit of several to several tens of frames in which

Further, in the optical disk device according to a third aspect of the present invention, the video signal dividing means converts the input digital video signal into a video signal having a large number of pixels and a small number of pixels. A layering means for layering is included, a video signal having a small number of pixels lines is a lower layer video signal, and a video signal having a large number of pixels lines is an upper layer video signal.

According to a fourth aspect of the present invention, in the optical disc device, the video signal dividing means includes discrete cosine converting means for converting an input digital video signal into a spatial frequency in the vertical / horizontal directions, and / A low frequency region divided into two by a horizontal frequency is used as a lower layer video signal, and a high frequency region is used as an upper layer video signal.

According to a fifth aspect of the present invention, there is provided an optical disc device, wherein I picture forming the video information block,
The P picture and the B picture are divided into upper layer data and lower layer data, and the divided upper layer data and lower layer data of each picture are consolidated and arranged in the recording area of the disc-shaped recording medium. It is the one.

According to a sixth aspect of the present invention, the optical disk device divides the I picture, P picture, and B picture forming the plurality of video blocks into upper layer data and lower layer data, and also divides them. The upper layer data and the lower layer data of each picture are consolidated and arranged in the recording area of the disc-shaped recording medium.

According to a seventh aspect of the present invention, in the optical disc apparatus, a digital video signal having several to several tens of frames as one unit is a lower layer video signal capable of independently reproducing video information and the lower layer. Video signal dividing means for dividing the video signal into an upper layer video signal which can be reproduced as video information for the first time when combined with the video signal, and a motion vector amount for comparing the motion vector amount of the digital video signal with a predetermined reference value. Determining means, flag adding means for adding an overwritable flag to the digital video signal whose motion vector amount is determined to be less than or equal to the reference value by the motion vector amount determining means, and the divided lower layer video signal and A recording means for recording the video signal of the upper layer on the disc-shaped recording medium; and a detection means for detecting an unrecorded area of the disc-shaped recording medium, When the detection means detects a shortage of the unrecorded area of the disk-shaped recording medium, the digital video signal input to the next stage is the upper layer data of the video signal of the already-recorded area of the disk-shaped recording medium, In addition, the digital video signal to which the overwritable flag is added is overwritten and recorded.

Further, in the optical disk device according to the eighth aspect of the present invention, the digital video signal input to the next stage after the detection means has detected the shortage of the unrecorded area of the disk-shaped recording medium is the video signal. In addition to dividing into a lower layer video signal capable of independently reproducing the video information by the signal dividing means and an upper layer video signal capable of being reproduced as the video information only by combining with the lower layer video signal, The motion vector amount determining means compares the motion vector amount with a predetermined reference value, and when the motion vector amount is less than or equal to the predetermined reference value, only the divided lower layer video signal is overwritten and recorded to the predetermined reference value. When the value is equal to or larger than the value, the video signals of both the lower layer and the upper layer are overwritten and recorded.

According to a ninth aspect of the present invention, in the optical disc device, the video signal dividing means converts an input digital video signal into a video signal having a large number of pixels and a small number of lines. A video signal having a small number of lines of pixels is used as a video signal of a lower layer, and a video signal having a large number of lines of pixels is used as a video signal of an upper layer.

According to a tenth aspect of the present invention, in the optical disk device, the video signal dividing means includes discrete cosine converting means for converting an input digital video signal into a spatial frequency in the vertical / horizontal directions, and / A low frequency region divided into two by a horizontal frequency is used as a lower layer video signal, and a high frequency region is used as an upper layer video signal.

According to claim 11 of the present invention, in the optical disk device, the video information block forming the digital video signal is temporally combined with an I picture which is two-dimensional compressed video information information-compressed in a frame. To the P picture, which is three-dimensional compressed video information that is information-compressed by adding motion compensation by the I picture in the forward direction, and
It is assumed that a B picture, which is three-dimensional compressed video information that is information-compressed by adding motion compensation by a picture and a P picture, is mixed, and the I picture, P picture, and B picture are upper layer data and lower layer data, respectively. It is divided into two parts, and the upper layer data and the lower layer data of each divided picture are fixed and arranged in the recording area of the disc-shaped recording medium.

According to a twelfth aspect of the present invention, in the optical disk device, the video information block forming the digital video signal is temporally combined with an I picture which is two-dimensional compressed video information information-compressed in a frame. To the P picture, which is three-dimensional compressed video information that is information-compressed by adding motion compensation by the I picture in the forward direction, and the I picture in the forward and backward direction in terms of time.
It is assumed that a picture and a B picture, which is three-dimensional compressed video information that is information-compressed by adding motion compensation by the P picture, are mixed, and an I picture, a P picture, and a B picture forming a plurality of the video information blocks are placed in a higher order. The layer data and the lower layer data are divided into two, and the upper layer data and the lower layer data of each divided picture are consolidated and arranged in the recording area of the disc-shaped recording medium.

According to the thirteenth aspect of the present invention, in the optical disc device, information is added by adding motion compensation by an I picture which is two-dimensional compressed video information information-compressed in a frame and an I picture which is forward in time. The number of P-pictures, which are the compressed 3D-compressed video information, and the B pictures, which are the 3D-compressed video information, which are information-compressed by adding motion compensation by the I-picture and the P-picture, which are temporally forward and backward. Rearranging means for rearranging and outputting a digital video signal composed of video information blocks each having several tens of frames as one unit so as to be fixedly recorded for each picture on the recording area of the disc-shaped recording medium, and Recording means for recording the output of the rearranging means on a disk-shaped recording medium, and a motion vector for comparing the motion vector amount of the digital video signal with a predetermined reference value. Amount determining means, flag adding means for adding an overwritable flag to the digital video signal whose motion vector amount is determined to be less than or equal to the reference value by the motion vector amount determining means, and unrecorded on the disc-shaped recording medium. A detection means for detecting an area, and when the detection means detects a shortage of an unrecorded area of the disc-shaped recording medium, a digital video signal input to the next stage is recorded on the disc-shaped recording medium. It is configured such that a part of the B picture of the digital video signal to which the overwrite flag of the area is added is overwritten and recorded.

According to a fourteenth aspect of the present invention, in the optical disc device, the digital video signal is constituted by a plurality of video information blocks as one unit.

[0041]

According to the optical disk device of the first aspect of the present invention, the digital image signal is first combined as the image information by combining the lower layer image signal capable of reproducing the image information and the lower layer image signal. When the recordable area is insufficient, the digital video signal of the next stage is overwritten on the video signal of the upper layer of the already recorded area. I decided to do it.

Further, according to the optical disk device of the second aspect of the present invention, the digital video signal to be recorded is composed of a video block in which image data of several to several tens of frames is one unit, and further, this video is recorded. An I picture, which is two-dimensional compressed video information in which a block is information-compressed in a frame, a P picture, which is three-dimensional compressed video information in which information is compressed by adding motion compensation by a temporally forward I picture, and a time Recording is performed after adding motion compensation using I-pictures and P-pictures in the front-back direction and converting it into a B-picture, which is information-compressed three-dimensional compressed video information.

According to the optical disk device of the third aspect of the present invention, the hierarchizing means hierarchizes the input digital video signal into two hierarchies according to the number of pixels and the number of lines.

Further, according to the optical disk device of the fourth aspect of the present invention, the discrete cosine transform means divides the inputted digital video signal into two hierarchies in the range of the spatial frequency in the vertical / horizontal direction.

Further, according to the optical disk device of the fifth aspect of the present invention, the I, P and B pictures constituting the video block are each divided into upper layer data and lower layer data, and the upper layer of each picture is divided. The layer data and the lower layer data are fixed and recorded in the video block.

According to the sixth aspect of the present invention, there are provided a plurality of optical disc devices in which the upper layer data and the lower layer data of each picture are fixed and recorded in a video block as described above. It was done in the video block of.

Further, according to the optical disk device of the seventh aspect of the present invention, the image is not first formed by combining the lower layer video signal with the lower layer video signal capable of independently reproducing the digital video signal. In addition to being layered in advance with an upper layer video signal that can be reproduced as information, the digital signal is recorded when the magnitude of the motion vector amount of the digital video signal is less than a predetermined reference value. When the recordable area is insufficient, the digital video signal in the next stage is overwritten on the video signal of the upper layer to which the overwriteable flag is added in the recorded area. I chose

According to the eighth aspect of the present invention, when the motion vector amount of the digital video signal recorded in the next stage is equal to or less than the predetermined reference value, only the lower layer data is overwritten. All the upper and lower video signals are overwritten and recorded when the value is higher than a predetermined reference value.

According to the optical disk device of the ninth aspect of the present invention, the hierarchizing means hierarchizes the input digital video signal into two hierarchies according to the number of pixels and the number of lines.

According to the optical disk device of the tenth aspect of the present invention, the discrete cosine transforming means divides the input digital video signal into two layers in the range of the spatial frequency in the vertical / horizontal directions.

Further, according to the optical disc apparatus of the eleventh aspect of the present invention, the digital video signal to be recorded is composed of a video block in which image data of several to several tens of frames is one unit, and further, this video is recorded. An I picture, which is two-dimensional compressed video information in which a block is information-compressed in a frame, a P picture, which is three-dimensional compressed video information in which information is compressed by adding motion compensation by a temporally forward I picture, and a time By adding motion compensation by I and P pictures in the front-back direction and converting it into a B picture which is information-compressed three-dimensional compressed video information, and the I, P and B pictures are data of upper layer and lower layer respectively. The data is divided into two and the upper layer data and the lower layer data of each picture are fixedly recorded in the video block.

According to the twelfth aspect of the present invention, the I, P and B pictures converted in units of a plurality of video blocks are divided into upper layer data and lower layer data, respectively. The upper layer data and the lower layer data of each picture are fixed and recorded in each of the plurality of video blocks.

Further, according to the optical disk device of the thirteenth aspect of the present invention, the digital video signal is converted into I, P and B pictures for each video block, and each picture is fixed and recorded, and When the motion vector amount of the video signal is equal to or less than the reference value, when it is detected that the recordable area of the recording medium is insufficient in the recording area to which the overwritable flag is added, the digital signal input to the next stage is detected. The video signal B of the video signal with the overwritable flag added
Overwriting was recorded on a part of the picture.

According to the fourteenth aspect of the optical disk device of the present invention, recording on the recording medium is performed by a digital video signal in units of a plurality of video blocks.

[0055]

【Example】

Example 1. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a configuration of a recording system of an optical disc device according to a first embodiment of the present invention.

In the figure, 101 is an A / D conversion means for converting an input analog video signal into a digital signal,
Reference numeral 102 is a motion detecting means for detecting a motion vector of a digitized video signal, and 103 is one of band compression methods for converting the digital video signal into vertical / horizontal spatial frequencies for data compression. Cosine transform means (DCT coding means), 104 is an adaptive quantization means for quantizing the transformed digital video signal, 105 is an inverse quantization means, and 106 is for restoring the original digital video signal from the spatial frequency component. Inverse discrete cosine transforming means (IDCT decoding means), 107 motion detecting means 102
A frame memory for storing a reference image based on the motion vector from the above, 108 is a variable length coding means for coding the quantized digital video signal, 109 is a buffer memory, 110 is a data array of the coded digital video signal. Is recombined on the buffer memory 109 to form upper and lower two-layer data in layers, and format information is added by adding header information such as address information and attribute data to the layered signal. Modulating means 112 for applying modulation for preventing intersymbol interference on the optical disk to the formatted and hierarchical digital video signal, 112 is a modulating means 11
1 is a laser modulation means for modulating the recording laser based on the information from 1; 113 is an optical disc on which information is recorded by a method such as magneto-optical recording or phase change recording; 114 is a recording laser modulated by the laser modulating means 112. An optical head for recording information on the optical disk 113, a feed motor 115 for moving the optical head 114 in the radial direction of the optical disk 113, a disk motor 116 for rotating the optical disk 113 at a predetermined frequency, and 117 for the optical head 114.
Servo circuit for performing focus / tracking control, feed motor 115 control, and disk motor 116 control, 118 is a system controller for integrally controlling the entire apparatus by generating control signals for the servo circuit 117, format encoder 110, and the like. Is a reproduction amplifier for reproducing the header information of the video data recorded on the optical disk 113, and 120 is a header recognition means for recognizing the overwritable area from the reproduced header information.

FIG. 2 is a schematic structural diagram showing the structure of a reproducing system for reproducing information from the optical disc 113 on which the digital video signal is recorded as described above. In the figure, 1
Reference numeral 21 is a reproduction amplifier for reading the information recorded on the optical disk 113, 122 is a data detection and PLL circuit for extracting data from the signal read by the reproduction amplifier 121, 1
Reference numeral 23 is an error correction means for detecting and correcting an error in the extracted data, and 124 is a header detection / data for reproducing the header information from the error-corrected data and separating and outputting the data for each hierarchical data. Dividing means, 125
Denoted at 126 are decoders for decoding the divided hierarchical data.

FIG. 3 is a block diagram showing a concrete structure of the decoder 125. Although not shown, the decoder 126 has a similar configuration. In the figure, 12
Reference numeral 7 is a variable length decoding means for decoding the upper layer data divided by the header detection / data division means 124 as an input,
Reference numeral 128 is an inverse quantization means, 129 is an inverse discrete cosine transform means, and 130 is a motion compensation means for performing motion compensation of the digital data decoded by the variable length decoding means based on the reference image stored in the frame memory 107. .

FIG. 4 shows a data arrangement structure of a digital video signal, which is basically the same as that described in FIG. 19 of the conventional example. Here, in the figure, (a)-
(G) shows a new file block obtained by dividing the macroblock layer of the DCT-coded digital video signal with respect to the spatial frequency in the vertical / horizontal direction. Here, the closer to (a), the closer to the DC component, and the closer to (g), the closer to the high frequency region. 1
Reference numeral 31 is a slice, 132 is a slice layer, and 133 is a macroblock layer.

FIGS. 5A to 5C are conceptual diagrams for time-sequentially explaining the concept of data overwriting, which is a feature of the present invention. Here, for example, 12
The case where 0-minute video data is recorded at a variable rate is described as an example. In the figure, S indicates the recording start time of the video data, E indicates the recording end time of the video data, I indicates the innermost circumference of the recording area of the optical disc 113, and O indicates the outermost circumference of the recording area of the optical disc 113.

FIGS. 6A and 6B are diagrams showing a specific procedure of the data overwriting method of the present invention explained in FIG. 5 on the recording area of the optical disk 113, and FIG. In the state in which it is not overwritten, (b) recognizes that the recording time is insufficient due to the adoption of the variable rate based on the information from the header recognizing means 120, and overwrites the recorded area (hatched portion). It shows the state of having gone. here,
The GOP structure of the present invention has the same structure as that shown in FIG. 20 of the conventional example, and in the figure, the lower part shows the lower layer of the hierarchical data divided into two, for example, pixel Small video data with several lines (for example, 360 pixels x
240 lines) or low frequency data in DCT coded data, and the upper layer indicates the upper layer of the divided hierarchical data, for example, video information having a large number of pixels (for example, 720 pixels × 480 lines). ) Or high frequency data in DCT encoded data.

Further, GOPm represents the m-th GOP, and each GOP is a GOP header 134, I picture lower data 135, I picture upper data 136, P picture lower data 137, P picture upper data 138, B.
Picture lower data 139, B picture upper data 14
It is recorded in order of 0. Here, in the case of overwriting, according to the present invention, not only the lower data which is the essential information in the video data reproduction but the upper data which is the detailed data in the video reproduction is overwritten, and the data to be overwritten is also Only the lower data of the picture is overwritten and recorded. Here, 141 to 146 are the GOP header of the n-th GOP to be overwritten, the I picture lower data, the P picture lower data, and the B picture lower data, respectively. It should be noted that the data to be overwritten is divided and overwritten on the data to be overwritten according to the necessity of the individual information amount or the like.

Next, the operation of this embodiment will be described. In the MPEG system, which is currently being adopted as an international standard, recording is performed by a combination of the encoding system and the optical disc drive device as described in FIG.

In the video signal digitized by the A / D conversion means 101, the motion detection means 102 detects the motion amount of the video for each screen (frame) in the form of a motion vector, and the discrete cosine conversion means 103 detects the vertical direction. /
The adaptive quantizing means 10 is converted into a horizontal spatial frequency.
4 adaptively quantized.

In the present invention, the video information is recorded by the GOP which forms one video information unit with several to several tens of frames. However, as described in the conventional example, it is compressed by one video itself. A three-dimensional compressed video (P picture, B) in which a compression operation is performed by adding a two-dimensional compressed video (I picture) in which the motion is performed and a prediction screen using motion vectors from temporally forward or backward video. (Picture) is mixed. The purpose is to mix the two-dimensional compressed image that is effective at the time of retrieval because it can be reproduced with one image and the three-dimensional compressed image that has excellent compression efficiency instead of being reproduced with one image. It is to achieve both searchability and compression efficiency. Therefore, as shown in FIG. 1, the prediction screen necessary to obtain the three-dimensional compressed image is restored from the video data from the adaptive quantization means 104 by the inverse quantization means 105 and the inverse discrete cosine transform means 106. , The motion detection means 10 on the frame memory 107
It is obtained by correcting with the motion vector from 2.

Next, the adaptive-quantized compressed digital video data is subjected to variable-length coding according to the motion vector amount by the variable-length coding means 108, and is temporarily stored in the buffer memory 109. The compressed digital video data stored in the buffer memory 109 is recombined with the data array in each GOP by the format encoder 110 instructed by the system controller 118 to be layered, and information such as a header is added. Then, it is output from the format encoder 110.

The digital video information thus formatted / hierarchized is modulated by the modulation means 111 so as to eliminate intersymbol interference on the optical disk 113, and is passed through the laser modulation means 112 to the optical head 114.
And is recorded on the optical disk 113 by.

As the recording proceeds in sequence, the optical disk 11
3 shows that the recordable area is reduced (FIGS. 5A and 5B) and the recordable area is lost.
When 18 is detected (FIG. 5B), the header of the previously recorded video data is read from the header recognizing means, and based on the header, the video data input to the next stage with respect to the upper layer data of the recorded video data. The data in the lower layer is sequentially overwritten from the innermost circumference of the recording area of the optical disc (FIG. 6). By doing this, the recordable time is lengthened, and even if the predetermined recording time is insufficient under the variable rate, the shortage time can be supplemented by overwriting and the predetermined recording time can be surely obtained. Fig. 5 (c)). It should be noted that the read data rate and the record data rate at this time must be faster than the normal video signal data rate.

Next, the hierarchical structure of the video data and the operation of the reproducing system for realizing the above-mentioned overwrite operation will be described. At present, the MPEG system in which the international standard is being adopted employs a hierarchical structure called a scalable structure. This is a method of dividing the video data into video data of a lower layer of 360 pixels × 240 lines and video data of an upper layer from which video data of 780 pixels × 480 lines can be obtained by combining the above data. In the video data divided in this way, the video data of the upper layer and the video data of the lower layer are combined by the decoding method as shown in FIGS. 2 and 3, and 780 pixels × 480 lines which are digital video information of the upper layer. It is possible to obtain the decoded video screen of.

That is, the video signal read by the reproducing amplifier 121 is reproduced by the data detecting / PLL means 122, error-detected / corrected by the error correcting means 123, and then the header-detecting / data-dividing means 124 performs 7
80 pixels x 480 lines of upper layer video data, and 36
It is divided into 0 pixels × 240 lines of lower layer video data. The divided lower layer video data is decoder 126.
And the lower layer decoded screen can be obtained, and the upper layer video data is decoded by the decoder 125 and then added to the lower layer video data to obtain the upper layer decoded screen. be able to.

As another data layering method, for example, as shown in FIG. 4, a method of dividing data into low frequency / high frequency DCT coefficients and layering the data may be considered. This division method is a method called data partitioning in the MPEG standard. In a standard digital moving image video compression method represented by MPEG, JPEG, or the like, as shown in FIG. 4, an I picture has a picture layer 131 in which one screen is divided into several slices, and how many slices are included in each picture layer 131. Macro block (MB)
The slice layer 132 is divided into two, and the macroblock layer 133 is formed by dividing one macroblock in the slice layer. Here, the macroblock layer 133 is composed of image data corresponding to a DCT coefficient of 8 × 8 pixels, and data obtained by zigzag scanning by dividing the spatial frequency in DCT coding in the macroblock in vertical / horizontal directions. It has an array structure. Here, the DCT coded data of 63 in the figure is divided into 7 units in units of 9 units.
It is decomposed into two blocks (a) to (g).

In the recording using the data partitioning, the data recording is not performed by sequentially recording, for example, I picture data in units of slices, but instead of (a) to (a).
The data is sequentially recorded in the unit of (g), and header information, a parity signal, etc. are added to the head of the block divided in units of the frequency range. By recording in this way, even in the case of data having a relatively large amount of information, such as an I picture, the low frequency component of the DCT encoded data, that is, a DC component, is relatively close, without reproducing the entire I picture data. An image can be obtained by reproducing only the data. In the present invention, the video data is hierarchically divided into upper and lower two layers by this data partitioning, and the data is overwritten on the upper layer, that is, the data relatively close to the high frequency component, thereby increasing the recordable time, The required recording time can be reliably obtained even under a variable rate.

In the video data hierarchized by the above method, for example, even a lower layer data composed of a small number of pixels lines or low frequency component data of the DCT coefficient can tolerate some deterioration in image quality. Video can be played back, for example. By utilizing this point, the present invention can secure a predetermined recording time by overwriting the upper layer data of the video data of the previously recorded area when the recording time is short due to the variable rate recording. It is the one. Embodiment 2. FIG.

Next, a second embodiment of the present invention will be described with reference to the drawings. In the first embodiment described above, the upper layer data of all screens (frames) is overwritten, but this has the following drawbacks. That is, the video data can be roughly classified into fast-moving video data and slow-moving video data based on the motion of the image, but the fast-moving video data is lost by overwriting. Since the upper layer data has a large effect on the image quality of the reproduced image, deleting it can easily cause the viewer to recognize the deterioration of the image quality.

Therefore, in the present embodiment, it is possible to eliminate the drawbacks of the first embodiment by making a distinction as to whether to overwrite the fast moving video data and the slow moving video data. Has an aim.

FIG. 7 shows the optical disk recording / recording according to this embodiment.
It is a schematic block diagram which shows the structure of the recording system of a reproducing | regenerating apparatus. In the figure, the same or corresponding components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 142 is a motion vector amount determination means, which is a characteristic configuration of the present embodiment, and which outputs a signal when it is detected that the motion vector amount from the motion detection means 102 is less than or equal to a predetermined value.

FIG. 8 shows the data recording structure of the video data recorded by the recording apparatus of FIG. 7, particularly the header portion of the GOP and the header portion provided at the beginning of each hierarchical data.

In the figure, 143 is a GOP header including an I picture lower header, 144 is I picture lower layer data, 145 is I picture upper layer data, 146 is P picture lower layer data, 147 is P picture upper layer data,
Reference numeral 148 is an I picture upper header, 149 is a P picture lower header, and 150 is a P picture upper header. Also, 151 to 160 are GO excluding the I picture lower header.
A structure of the P header 143, where 151 is a video GOP address for storing the current address, 152
Is video attribute data which is data for describing the I picture data amount and the like and determining a required buffer memory amount at the time of reproduction, and 153 is a pixel number or line of the screen by providing an area in which the attribute in the digital moving image is described. Scalability mode indicating whether or not a hierarchical structure corresponding to the number is formed, 154 is the number of frames for recording the number of frames forming a GOP, 155 is an I picture in the GOP,
A GOP structure indicating the arrangement structure of P-pictures and B-pictures, 156 is an overwritable flag in which a flag is recorded when the motion vector amount determination means 142 determines that it is less than or equal to a predetermined motion vector amount, and 157 is in the GOP. The detailed attribute data that records whether the image is pan, zoom, or data that includes a scene change is a time code that is data that describes the elapsed time from the start of recording or the start of a movie. For example, it is used for screen display by a character generator or the like. Reference numeral 159 is a jump destination address in which the next overwritable address is recorded, and 160 is a spare area in which other information is recorded.

FIG. 9 shows an operation sequence from recording standby to recording start in the optical disk recording apparatus according to the present embodiment. Further, FIG. 10 shows an operation sequence of the recording apparatus when the user selects the overwrite mode in which the user overwrites in the process of the operation sequence of FIG. 9, and FIG. 11 does not overwrite the user, contrary to FIG. 6 shows an operation sequence of the recording device when the normal recording mode is selected.

FIG. 12 is a conceptual diagram showing the concept of overwrite recording by the recording apparatus of this embodiment. In the figure,
S is the recording start time of the video data, E is the recording end time of the video data, I is the innermost circumference of the recording area of the optical disc 113,
O indicates the outermost circumference of the recording area of the optical disk 113.

FIGS. 13A and 13B show the specific procedure of the data overwriting method explained in FIG.
3A and 3B are diagrams shown in the recording area of FIG. 3, where FIG. 7A is a recording state of data when overwriting is not performed, and FIG.
This shows a state in which the recorded area is overwritten (hatched portion) based on the information from the header recognition unit 120 and the presence or absence of the flag recorded in the header of each GOP. In the figure,
Overwriteable flag is GOPm, GOPm + 3, GOPm
+4, GOPm +7 when set to +7
The upper layer data of OP is overwritten with the lower layer data of GOPn and GOPn + 1.

Next, the operation of this embodiment will be described. Also in this embodiment, the digital video data has a GOP structure composed of a plurality of screens. As shown in FIG. 20 of the conventional example, I picture, B picture,
The P picture has a format in which a two-dimensional compressed screen and a three-dimensional compressed screen are mixed.

First, in the video signal digitized by the A / D conversion means 101, the motion detection means 102 detects the motion amount of the video for each screen (frame) in the form of a motion vector, and the discrete cosine conversion means 103. Is converted into a vertical / horizontal spatial frequency and is adaptively quantized by the adaptive quantizer 104. At this time, in the present embodiment, the motion vector detected by the motion detection means 102 is also sent to the motion vector amount determination means 142, where the motion vector amount of each video screen is compared and determined with a predetermined value. The output signal is sent to the system controller 118 when it is detected that the motion vector amount is less than or equal to a predetermined value (that is, when the image has slow motion).

On the other hand, the compressed digital video data quantized by the adaptive quantization means 104 is subjected to variable length coding according to the motion vector amount by the variable length coding means 108, and is temporarily stored in the buffer memory 109. To be done. The compressed digital video data stored in the buffer memory 109 is recombined with the data array in each GOP by the format encoder 110 instructed by the system controller 118 to be layered, and information such as a header is added. However, if there is an output from the motion vector amount determination means 142, the overwrite flag is added to the header information.

The digital video information thus formatted / hierarchized is modulated by the modulation means 111 so as to eliminate intersymbol interference on the optical disk 113, and is passed through the laser modulation means 112 to the optical head 114.
And is recorded on the optical disk 113 by.

As the recording proceeds in sequence, the optical disk 11
When the system controller 118 detects through the outputs of the reproduction amplifier 119 and the header recognition means 120 that the recordable area of No. 3 is reduced and the recordable area is lost,
The header of the previously recorded video data is read from the header recognizing means, and based on the header, a part of the recorded video data, that is, the upper data for which the overwritable flag is set, of the video data input to the next stage Overwriting of lower layer data is sequentially performed from the innermost circumference of the recording area of the optical disc.
By doing this, even if the predetermined recording time is insufficient under the variable rate, it is possible to supplement the shortage time by overwriting and to reliably obtain the predetermined recording time, and at the same time, if the image quality deterioration due to the overwriting Since the video screen with a large vector amount is not overwritten, and only the video screen with a small motion vector amount that causes little image quality deterioration due to the overwriting can be overwritten, it is possible to obtain video information with excellent image quality as a whole. Note that it is necessary to set the read data rate and the record data rate at this time higher than the normal video signal data rate.
This is the same as in the first embodiment.

Further, in the present embodiment, since it is necessary to overwrite depending on the presence or absence of the overwrite enable flag, as shown in FIG. 8, the header for indicating the top data position of the upper and lower layers of each picture in the structure of data. Since 148, 149, and 150 are provided, it is possible to take out the I picture data independently and the P picture independently. This also has an effect that post-recording and editing can be easily performed in units of GOP. In this case, the audio data is also GOP according to the video information.
It is preferable to arrange in units.

Further, in this embodiment, the scalability mode 153, the number of frames 154, and the GOP structure 155 in which the attribute of the data is described in the digital video data are provided in the GOP header 143, so that it corresponds to a plurality of signal processing methods. It becomes possible. Also, video GOP
Since the current address, the next overwrite address, and time information are recorded in the address 151 and the time code 158, continuous reproduction or special reproduction / search of the overwrite data can be easily performed.

In the above description, the overwriting is performed only on the upper layer data of the GOP for which the overwriting possible flag is set, but conversely, the motion vector amount is determined by the motion vector amount determining means 142. By setting the overwritable flag for fast moving data that exceeds the value,
The same effect can be obtained even if the GOP for which the overwrite-enable flag is set is configured to be prohibited from being overwritten.

Next, the specific operation of the above-mentioned optical disk recording apparatus will be described based on the flowcharts of FIGS. 9 to 11.

First, when the apparatus is turned on to put it in a recording standby state, as shown in FIG. 9, the last recorded last GOP address on the optical disk 113 to be recorded is detected. The number of sectors in the recordable open area on the optical disk 113 is calculated. In this case, even if it is calculated by storing the recording end GOP address at the time of the last recording end in the TOC (Table of content) area in advance, the optical head 114 is actually searched to the open area, The beginning GOP address of the recording start may be read.

Next, when recording is performed as it is, the extent to which the recording area of the optical disk 113 is filled is displayed on the screen as a remaining time by a character generator or the like, and the user is overwritten to be prepared to slightly deteriorate the image quality. Even if the recording time is prioritized or the image quality is prioritized and overwriting is not selected, the recording is then started. In the following, the case where overwriting is selected and the case where overwriting is not selected will be described separately.

FIG. 10 is a flowchart when the overwrite mode is selected. As shown in the figure, first,
When recording is started, it is determined whether or not the overwrite mode is necessary based on the relationship between the data free area on the optical disk 113 and the predetermined recording time. Here, when it is detected that the overwrite mode is selected by the user's selection and the open area is lost, the discrete cosine transform means 103,
In the video encoder including the adaptive quantizing means 104 and the variable length coding means 108, only the lower layer data of the video data is written in the buffer memory 109,
It is formatted and header information is added. Also,
The next overwritable GOP address is assigned to the buffer memory 10
9 is written in the header part.

Next, the header part of the GOP of the recorded area which is about to be overwritten at present is reproduced by the reproduction amplifier 119 and the header recognition means 120, and it is confirmed whether or not the overwriting possible flag is set in the header part, and the overwriting is performed. If possible, the lower layer data written in the buffer memory 109 is written in the upper layer data area of the GOP. On the other hand, if it is not possible to overwrite, the next GOP address is accessed, the presence or absence of the overwrite enable flag is confirmed in the same manner as described above, and if overwrite is possible, the data is overwritten. By repeating this operation, it is possible to easily secure a predetermined recording time even under a variable rate, and it is possible to minimize deterioration in image quality. When performing the overwrite operation, it is necessary to set the data rate for recording / reproducing data on the optical disk 113 to be higher (for example, about twice) than the data rate required to reproduce the video information. is there. This is because the portions to be overwritten are not continuously arranged on the optical disc 113 and are apart from each other, and therefore, it is necessary to consider the search time for the track jump and the rotation waiting time.

Further, the confirmation of the presence or absence of the overwrite flag in the present embodiment employs the method of directly confirming by sequentially reproducing the header of the previously recorded GOP as described above, but the entire recording area of the optical disc 113 is used. It is also possible to write all the addresses of the flagged GOP in the TOC area at the end of the first recording, and reproduce and store this address before performing the overwrite recording.

Further, in the present embodiment, the data to be overwritten is only the lower layer data as in the case of the first embodiment, but the data of this overwriting is also judged the magnitude of the motion vector amount to determine the motion. It is effective to overwrite not only lower layer data but also upper layer data for fast video information in order to equalize the quality of reproduced images.

FIG. 11 is a flow chart in the case of normal recording in which overwrite is not selected. In this case, the format encoder 110 performs hierarchization / formatting of the upper / lower layers, and the motion vector amount determination means 142 determines whether or not the GOP can be overwritten, and the motion vector amount is smaller than a predetermined value and can be overwritten. If it is determined that the overwriting flag is set in the GOP header 143, the picture headers 148, 149 and 150 by the buffer memory 109 and the format encoder 110 that perform format conversion. A normal recording operation is performed by repeating the above operation until the end of recording. Here, when the remaining recording area is insufficient for the predetermined scheduled recording time during recording, the overwrite mode is changed from the middle only when the overwrite approval is obtained from the user. Recording is performed, but in other cases, recording is terminated at that point.

As a result, the overwritten data is shown in FIG.
As shown in (b), G with the overwritable flag set
The data will be overwritten only in the upper layer data portion of the OP. Example 3.

Next, a third embodiment of the present invention will be described. In the above-described first and second embodiments, the video data is divided into the upper layer and the lower layer for each of the I picture, the P picture, and the B picture, and each picture is recorded on the optical disc in the order of the lower and upper layers. However, if this is done, the continuity of the data will be interrupted by overwriting, and it will be necessary to perform playback in consideration of the track jump of the optical head and the rotation waiting time of the optical disc during playback. The processing system will be burdened. The present embodiment solves the problem of such a device, and will be described below with reference to the drawings.

FIG. 14 is a diagram showing a data array on the recording area of the optical disc recorded according to this embodiment.
(A) shows the data arrangement state before overwriting, and (b) shows the data arrangement state after data overwriting.

In the figure, 161 is header information of the m-th GOP and includes a picture header of I picture lower layer data 162. 162 is I picture lower layer data of the m-th GOP, 163 is P picture lower layer data,
164 is B picture lower layer data, 165 is I, P, B
Picture upper layer data, 166 is a P picture lower layer header, 167 is a B picture lower layer header, 168 is I,
P and B picture upper layer headers, 169 is the m + 1th G
OP header information, which is I picture lower layer data 1
Includes 70 picture headers. 170 is the m + 1st G
OP I picture lower layer data, 171 P picture lower layer data, 172 B picture lower layer data, 173
Is a P picture lower layer header, and 174 is a B picture lower layer header. Further, 175 is header information of the n-th GOP overwritten in this embodiment, and includes the picture header of the I picture lower layer data 176. 176
Is I picture lower layer data of the nth GOP to be overwritten, 177 is P picture lower layer data of the nth GOP to be overwritten, 178 is a P picture lower layer header, 17
9 is header information for the remaining data when the nth GOP information cannot be recorded in the upper layer data area of the mth GOP information and is overwritten and recorded in the upper layer data area of the m + 1th GOP information. And a picture header of P picture lower layer data 180, which is a subheader of an overwrite GOP having Reference numeral 180 is the P picture lower layer data of the nth GOP to be overwritten, 181 is the B picture lower layer data of the nth GOP to be overwritten, and 182 is the B picture lower layer header.

In this embodiment, as shown in the same figure, each picture divided into upper layer data and lower layer data is converted into one GO.
This is characterized in that the upper layer data that is overwritten and the lower layer data that is not overwritten in P are arranged after being solidified. With this configuration, even if overwriting is performed, it is possible to maintain the continuity of data in each GOP, simplify the search operation of the overwriting area at the time of recording, and perform the optical operation at the time of reproducing the overwriting data. It is possible to reduce the number of track jumps of the head, and it is also less necessary to perform reproduction while considering the rotation waiting time of the optical disk. Example 4.

Next, a fourth embodiment of the present invention will be described. In the above-described third embodiment, the upper layer data and the lower layer data of each picture in one GOP are consolidated and arranged, but in this embodiment, a plurality of GOPs are arranged. It is characterized in that the upper layer data and the lower layer data of each picture in units of are united and arranged. 15A and 15B are views showing the data arrangement on the recording area of the optical disc recorded according to the present embodiment. FIG. 15A shows the data arrangement state before the overwriting, and FIG. 15B shows the data arrangement state after the data overwriting. Shows. Further, for convenience of explanation, a unit of two GOPs will be shown in this embodiment.

In the figure, 183 is header information of the m-th GOP, which is the first I-picture lower layer data 18
4 picture headers are included. 184 is the first I picture lower layer data of the m-th GOP, 185 is the second I picture lower layer data, 186 is the first P picture lower layer data, 187 is the second P picture lower layer data, 188.
Is the first B picture lower layer data, 189 is the second B picture lower layer data, 190 is the upper layer data of the first I, P, B pictures, and 191 is the upper layer of the second I, P, B pictures. Layer data, 192 is a second I picture lower layer header, 193 is a first P picture lower layer header, 194 is a second P picture lower layer header, 195 is a first B picture lower layer header, and 196 is a first layer. The second B picture lower layer header, 197 is the first I, P, B picture upper layer header, and 198 is the second I, P, B picture upper layer header. In addition, 199 is n overwritten in this embodiment.
It is the header information of the th GOP and includes the picture header of the first I-picture lower layer data 200. 200 is the first I picture lower layer data of the overwritten nth GOP, 201 is the second I picture lower layer data of the overwritten nth GOP, and 202 is the first I picture lower layer data of the overwritten nth GOP. P picture lower layer data, 203 is the second P picture lower layer data of the overwritten nth GOP, and 204 is the first B of the overwritten nth GOP.
Part of picture lower layer data, 205 is a second I picture lower layer header, 206 is a first P picture lower layer header, 207 is a second P picture lower layer header, and 208 is a first B picture lower layer. It is a header.

In this embodiment, as shown in the figure, each GO divided into upper layer data and lower layer data is divided into two GOs.
The upper layer data that is overwritten and the lower layer data that is not overwritten in P are arranged after being hardened respectively. With this configuration, it is possible to maintain the data continuity in each GOP even if overwriting is performed, reduce the number of track jumps of the optical head during reproduction, and rotate the optical disc. There is less need to perform playback after considering the waiting time. Further, since the two GOPs are new GOPs of one unit, the continuity of the data in the larger data area can be provided. It is possible to reduce the number of track jumps and the number of data searches of the optical head to half that in the case of the third embodiment in units of 1 GOP. However, in this embodiment, a plurality of GOPs
Since format conversion and inverse conversion are performed as a unit, a buffer memory for holding data also needs to have a large capacity accordingly. Therefore, it is appropriate to set several GOPs as one unit. Example 5.

Next, a fifth embodiment of the present invention will be described. The present embodiment is characterized in that a B picture in a slow moving GOP is overwritten and partially rewritten. This is based on the fact that in a slow-moving GOP, even if the B picture is partially deleted, the deterioration in the image quality of the reproduced image is not so recognized by the viewer. Here, the screens to be deleted are B-pictures because some B-pictures become unreproducible when I-pictures or P-pictures are deleted. This is not the case when the B picture of is deleted.

FIG. 16 shows the arrangement of each picture data according to this embodiment. In the figure, I is an I picture, B is a B picture, P is a P picture,
The subscript number indicates the number of each picture in 1 GOP. Also, in this embodiment, the original 1
The data array of each picture in the GOP is I, B1, B2, P1, B3, B4, P2, B as shown in FIG.
They are arranged like 5, B6, P3. (FIG. 16 (a)) where 209 is a B picture overwrite header and 210 is P
A picture header, 211 is a B picture header.

In this embodiment, such a data array is used as the format encoder 110 and the buffer memory 10.
9, I, P1, P on the recording area of the optical disk 113
2, P3, B1, B3, B5, B2, B4, B6 are rearranged (FIG. 16 (b)), and the B picture overwrite header 2
09 is provided. Then, based on the overwrite header 209, B2, B4, and B6 in the GOP data are overwritten. In this case, one of the three playback screens
Since the frames are deleted, the image quality will deteriorate, but
Since this screen is a GOP that does not move much, the viewer will not notice much. In this way, in this embodiment, even if the recordable area runs short under the variable rate, it is possible to easily secure the predetermined recording time. It should be noted that if the GOP is data with almost no movement such as a still image, even if all the B pictures of the GOP are deleted, the viewer will feel a slight deterioration in reproduced image quality. Is a still image, so there is no problem. Example 6.

FIG. 17 shows the arrangement of the fifth embodiment, in which data is arrayed on the recording area of the optical disc using a plurality of GOPs as new units, as in the case of the fourth embodiment. Therefore, the data array state before overwriting is shown here. Further, for convenience of explanation, a unit of two GOPs will be shown in this embodiment.

In the figure, reference numeral 212 denotes GOP header information, which includes the picture header of the I picture data 213 of the first GOP. 213 is I picture data of the first GOP, 214 is P picture data of the first GOP,
215 is I picture data of the second GOP, 216 is P picture data of the second GOP, and 217 is the first GOP.
B1 picture data, 218 is B3 picture data of the first GOP, 219 is B5 picture data of the first GOP, 220 is B1 picture data of the second GOP, and 22
1 is B3 picture data of the second GOP, 222 is the second
GOP B5 picture data, 223 is the first GOP
B2 picture data, 224 is B4 picture data of the first GOP, 225 is B6 picture data of the first GOP, 226 is B2 picture data of the second GOP, 22
7 is the B4 picture data of the second GOP, 228 is the second
B6 picture data of GOP. Also, 229 is the P picture header of the first GOP, and 230 is the second GO.
An I picture header of P, 231 is a P picture header of the second GOP, 232 and 234 are B picture headers of the first GOP, 233 and 235 are B picture headers of the second GOP, and B picture header 2
34 to the B6 picture data 228 of the second GOP are the overwrite range.

In this embodiment, such a data array is formed by rearrangement by the format encoder 110 and the buffer memory 109 as in the fifth embodiment. Then, B2, B4, and B6 in the first and second GOP data are overwritten based on the headers 234 and 235. In this case as well, one of the three playback screens will be deleted, and the image quality will be degraded, but this screen is a GOP with little movement, so the viewer does not notice much. Will be things. In this way, in this embodiment, even if the recordable area runs short under the variable rate, the predetermined recording time can be easily secured.

Furthermore, in the present embodiment, since two GOPs are new one unit GOPs, it is possible to provide data continuity in a larger data area. Therefore, at the time of overwriting or reproduction of overwriting data. At this time, the optical disk rotation waiting time, the number of optical head track jumps, and the number of data searches can be reduced to half of those in the fifth embodiment in units of 1 GOP. However, in the present embodiment, format conversion and inverse conversion are performed with a plurality of GOPs as one unit, and accordingly, a buffer memory for holding data is also required to have a large capacity. Therefore, it is the same as the fourth embodiment that it is appropriate to set several GOPs as one unit.

In the present invention described above, when the variable rate is adopted and the recordable area becomes insufficient and the predetermined recording time becomes insufficient, the predetermined area is overwritten by overwriting. Although the purpose is to secure the recording time, by applying the configuration of the present invention to an optical disc recording / reproducing apparatus adopting a fixed rate,
It is also possible to lengthen the recording time accordingly.

[0114]

According to the optical disk device of the first aspect of the present invention, the recordable time of one optical disk can be extended while suppressing the deterioration of the image quality of the reproduced image to a slight extent, and the variable rate Even if the recording is performed according to, there is an effect that the predetermined recording time can be surely secured.

Further, according to the optical disk device of the second aspect of the present invention, in the invention of the first aspect, it is possible to achieve both the information searchability of the optical disc on which information is recorded and the compression efficiency of video information.

According to the optical disk device of the third aspect of the present invention, in the invention of the first aspect, overwriting can be performed while ensuring the minimum number of pixels and the number of lines required for reproducing the video signal. Has the effect.

According to the optical disk device of the fourth aspect of the present invention, in the invention of the first aspect, it is possible to perform overwriting while keeping the number of pixels and the number of lines in the reproduction of the video signal as they are. .

Further, according to the optical disk device of the fifth aspect of the present invention, in the invention of the second aspect, the continuity of the data of the picture data to be overwritten and the picture data left without being overwritten can be maintained. It is possible to reduce the number of optical head track jumps during playback,
Further, there is an effect that it is possible to shorten the rotation waiting time of the optical disc.

According to the sixth aspect of the present invention, compared to the fifth aspect of the invention, the number of track jumps of the optical head during reproduction is further reduced, and the optical disc rotation waiting time is shortened. There is an effect that can be done.

Further, according to the optical disk device of the seventh aspect of the present invention, overwriting is not performed for a fast moving image whose image quality is deteriorated by overwriting, and slow moving image data with a small image quality deterioration by overwriting is not performed. Only the overwriting can be performed, so that the recordable time can be lengthened and the predetermined recording time can be reliably ensured even under the variable rate while improving the image quality of the entire video information.

According to the eighth aspect of the present invention, in the seventh aspect of the invention, the uniformity of the reproduced image quality between the video data left without being overwritten and the overwritten video data is improved. The effect that it can be maintained over the entire area of one optical disk is achieved.

According to the ninth aspect of the present invention, in the seventh aspect of the invention, it is possible to perform overwriting while ensuring the minimum number of pixels and the number of lines required for reproducing the video signal. Has the effect.

According to the optical disk device of the tenth aspect of the present invention, in the invention of the seventh aspect, there is an effect that it is possible to perform overwriting while keeping the number of pixels and the number of lines in the reproduction of the video signal as they are. .

According to the eleventh aspect of the present invention, in the invention of the seventh aspect, it is possible to maintain continuity between the picture data to be overwritten and the picture data left without being overwritten. As a result, the number of track jumps of the optical head at the time of reproduction can be further reduced, and the rotation waiting time of the optical disk can be shortened.

According to the optical disk device of the twelfth aspect of the present invention, the number of track jumps of the optical head during reproduction is further reduced as compared with the eleventh aspect of the invention.
This has the effect of shortening the rotation waiting time of the optical disc.

Further, according to the optical disk device of the thirteenth aspect of the present invention, the recordable time is lengthened while the deterioration of the image quality of the reproduced image is kept to a slight extent, and the recording is surely performed even under the variable rate recording. An effect that a predetermined recording time can be secured is exhibited.

According to the optical disk device of the fourteenth aspect of the present invention, in the invention of the thirteenth aspect, it is possible to reduce the number of track jumps of the optical head at the time of reproduction and shorten the rotation waiting time of the optical disc. It also has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a recording system of an optical disc device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a reproduction system of the optical disc device according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a decoder of the optical disc device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a data structure of a digital video signal according to the first embodiment of the present invention.

FIG. 5 is a conceptual diagram showing in time series the concept of data overwriting by the optical disc device according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a data recording state in which data is overwritten and recorded by the optical disc device according to the first embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a recording system of an optical disc device according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a data arrangement structure of a digital video signal according to a second embodiment of the present invention.

FIG. 9 is a flowchart showing an operation sequence of the optical disc device according to the second embodiment of the present invention.

FIG. 10 is a flowchart showing an operation sequence when the overwrite mode is selected in the optical disc device according to the second embodiment of the present invention.

FIG. 11 is a flowchart showing an operation sequence when the normal recording mode is selected in the optical disc device according to the second embodiment of the present invention.

FIG. 12 is a conceptual diagram showing the concept of overwrite recording by the optical disk device of the second embodiment of the present invention.

FIG. 13 is a diagram showing a recording state of data overwritten and recorded by the optical disc device according to the second embodiment of the present invention.

FIG. 14 is a diagram showing a data arrangement structure and a recording state of overwritten data in an optical disc device according to a third embodiment of the present invention.

FIG. 15 is a diagram showing a data arrangement structure and a recording state of overwritten data in an optical disk device according to a fourth embodiment of the present invention.

FIG. 16 is a diagram showing a data arrangement structure by an optical disc device according to a fifth embodiment of the present invention.

FIG. 17 is a diagram showing a data arrangement structure by an optical disc device according to a sixth embodiment of the present invention.

FIG. 18 is a block diagram showing a configuration of a conventional optical disc device.

FIG. 19 is a diagram showing a data structure of a conventional digital video signal.

FIG. 20 is a diagram showing the concept of a GOP structure of a recorded video signal.

FIG. 21: 1 GO when recording at a variable rate
FIG. 3 is a schematic diagram showing a ratio of a data amount per P to a recording area of an optical disc.

FIG. 22 is a comparison diagram comparing a case where recording is performed at a variable rate and a case where recording is performed at a fixed rate in the recording area of the optical disc.

[Fig. 23] Fig. 23 is a diagram illustrating a data amount per GOP necessary for keeping the quality of a reproduced image constant regardless of the image.

FIG. 24 is a diagram showing the amount of data per GOP required to obtain a predetermined image quality according to the type of image.

[Explanation of symbols]

101: A / D conversion means, 102: motion detection means, 10
3: DCT encoding means, 104: adaptive quantization means, 10
5: Dequantization means, 106: IDCT decoding means, 10
7: frame memory, 108: variable length coding means, 10
9: buffer memory, 110: format encoder, 111: modulator, 112: laser modulator, 11
3: optical disc, 114: optical head, 115: feed motor, 116: disc motor, 117: servo circuit, 1
18: system controller, 119: reproduction amplifier, 1
20: header recognition means, 121: reproduction amplifier, 122:
Data detection and PLL circuit, 123: error correction means, 1
24: Header detection / data division means, 125, 126:
Decoder 127: Variable length decoding means, 128: Inverse quantization means, 129: IDCT decoding means, 130: Motion compensation means, 142: Motion vector amount determination means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G11B 20/10 301 Z 7736-5D H04N 7/32 (72) Inventor Yoshinori Asamura Nagaokakyo Baba, Kyoto Prefecture No. 1 in the drawing room, Mitsubishi Electric Corporation Video System Development Laboratory

Claims (14)

[Claims] 1. Digital video signals that are sequentially input are
Video signal dividing means for dividing into a lower layer video signal capable of independently reproducing video information and an upper layer video signal capable of being reproduced as video information for the first time by combining the lower layer video signal with the lower layer video signal. Recording means for recording the lower layer video signal and the upper layer video signal on a disc-shaped recording medium, and a detection means for detecting an unrecorded area of the disc-shaped recording medium. When a shortage of the unrecorded area of the disk-shaped recording medium is detected, the lower layer video signal input to the next stage is overwritten on the upper layer video signal of the already recorded area of the disk-shaped recording medium. An optical disk device characterized by the above. 2. The digital video signal is a three-dimensional compression that is information-compressed by adding motion compensation by an I-picture, which is two-dimensional compressed video information information-compressed in a frame, and an I-picture in a temporally forward direction. A number of frames to several tens of frames in which a P picture which is video information and a B picture which is three-dimensional compressed video information that is information-compressed by adding motion compensation by temporally forward and backward I pictures and P pictures are mixed.
The optical disk device according to claim 1, wherein the optical disk device is composed of video information blocks as a unit. 3. The video signal dividing means includes a hierarchizing means for hierarchizing an input digital video signal into a video signal having a large number of pixels lines and a video signal having a small number of pixels lines. 3. The video signal having a small number is used as a lower layer video signal, and the video signal having a large number of pixels lines is used as an upper layer video signal.
The optical disk device described. 4. The video signal dividing means includes a discrete cosine transforming means for converting an input digital video signal into a vertical / horizontal spatial frequency, and a low frequency region divided into two by the vertical / horizontal frequency. 3. The optical disk device according to claim 1, wherein the lower layer video signal is used and the high frequency region is used as the upper layer video signal. 5. The I picture, P picture, and B picture forming the video information block are divided into upper layer data and lower layer data, and the upper layer data and lower layer data of each divided picture are divided. The optical disk device according to any one of claims 2 to 4, wherein the optical disk device is solidified and arranged in a recording area of the disk-shaped recording medium. 6. An I picture, a P picture, and a B picture forming a plurality of the video blocks are divided into upper layer data and lower layer data, and upper layer data and lower layer data of each divided picture. 5. The optical disk device according to claim 2, wherein each of them is solidified and arranged in a recording area of the disk-shaped recording medium. 7. A digital video signal having a unit of several to several tens of frames is combined as a video information for the first time by combining a video signal of a lower layer capable of independently reproducing the video information and a video signal of the lower layer. A video signal dividing means for dividing into a reproducible upper layer video signal, a motion vector quantity judging means for comparing the motion vector quantity of the digital video signal with a predetermined reference value, and a motion by the motion vector quantity judging means. Flag adding means for adding an overwritable flag to the digital video signal whose vector amount is determined to be less than or equal to the reference value; and recording the divided lower layer video signal and upper layer video signal on a disc-shaped recording medium. Recording means and a detection means for detecting an unrecorded area of the disc-shaped recording medium, wherein the detection means is unrecorded on the disc-shaped recording medium. When the lack of the area is detected, the digital video signal input to the next stage is the digital data which is the upper layer data of the video signal of the already recorded area of the disc-shaped recording medium and to which the overwritable flag is added. An optical disk device characterized by being overwritten and recorded on a video signal. 8. The digital video signal input to the next stage is a video image only by combining the video signal of the lower layer and the video signal of the lower layer capable of independently reproducing the video information by the video signal dividing means. It is divided into an upper layer video signal that can be reproduced as information, and the motion vector amount determination means compares the motion vector amount with a predetermined reference value, and the motion vector amount is less than or equal to the predetermined reference value. In this case, the overwriting recording is performed only on the divided lower layer video signal, and when the predetermined reference value is exceeded, the overwriting recording is performed on both the lower layer and upper layer video signals. The optical disk device according to claim 7. 9. The video signal dividing means includes a hierarchizing means for hierarchizing an input digital video signal into a video signal having a large number of pixels and a small number of pixels and a number of pixels. 9. The optical disk device according to claim 7, wherein a video signal having a small number of lines is used as a lower layer video signal and a video signal having a large number of pixels and lines is used as a higher layer video signal. 10. The video signal dividing means includes a discrete cosine transforming means for converting an input digital video signal into a vertical / horizontal spatial frequency, and a low frequency region divided into two by the vertical / horizontal frequency. 9. The optical disk device according to claim 7, wherein the lower layer video signal is used and the high frequency region is used as the upper layer video signal. 11. The video information block constituting the digital video signal is information-compressed within a frame.
Information compression is performed by adding motion compensation using an I picture that is dimensional compressed video information and an I picture that is temporally forward.
P pictures, which are three-dimensional compressed video information, and B pictures, which are three-dimensional compressed video information that have been information-compressed by adding motion compensation by temporally front and rear I and P pictures, are mixed. The I picture, the P picture, and the B picture are each divided into upper layer data and lower layer data, and the divided upper layer data and lower layer data of each picture are consolidated and recorded in the recording area of the disc-shaped recording medium. The optical disk device according to any one of claims 7 to 10, wherein the optical disk device is arranged in the optical disk device. 12. The video information block constituting the digital video signal is information-compressed within a frame.
Information compression is performed by adding motion compensation using an I picture that is dimensional compressed video information and an I picture that is temporally forward.
P-pictures, which are three-dimensional compressed video information, and B pictures, which are three-dimensional compressed video information that are information-compressed by adding motion compensation by temporally preceding and following I and P pictures, are mixed. Of the I picture, P picture, and B picture forming the video information block are divided into upper layer data and lower layer data, and the upper layer data and lower layer data of each divided picture are fixed respectively. 11. The optical disk device according to claim 7, wherein the optical disk device is arranged in a recording area of a disk-shaped recording medium. 13. An I picture, which is two-dimensional compressed video information information compressed in a frame, and a P picture, which is three-dimensional compressed video information information-compressed by adding motion compensation by an I picture that is forward in time. And I in the front-back direction in terms of time
A disc is provided with a digital video signal composed of a video information block in which one unit is several to several tens of frames in which a B picture, which is three-dimensional compressed video information that is information-compressed by adding motion compensation by pictures and P pictures, is mixed. Rearranging means for rearranging and outputting so that each picture is fixedly recorded on the recording area of the recording medium, recording means for recording the output of the rearranging means on a disc-shaped recording medium, and the digital video A motion vector amount determination means for comparing the motion vector amount of the signal with a predetermined reference value, and an overwritable flag is added to the digital video signal determined by the motion vector amount determination means to be less than the reference value. Flag adding means for detecting the unrecorded area of the disk-shaped recording medium, and detecting means for detecting an unrecorded area of the disk-shaped recording medium. When it is detected that the unrecorded area of the disk-shaped recording medium is insufficient, the B picture of the digital video signal to which the overwriting enabled flag of the already-recorded area of the disk-shaped recording medium is added to the digital video signal input to the next stage. An optical disk device characterized in that a part of the data is overwritten. 14. An optical disk device, wherein the digital video signal is composed of a plurality of video information blocks as one unit.