JP2004030890A - Record medium and reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain edit processing in the unit of GOP by simple and high speed processing and even special reproduction such as high speed fast-forward and reverse reproduction in the unit of GOP by the simple and high speed processing in the case of recording digital image data subjected to high efficiency encoding on a disk recording medium such as a mini disk. <P>SOLUTION: Clusters being a unit of reproduction each comprising a plurality of sectors, on which a prescribed data quantity can be recorded, are provided to the outer circumferential side in a recording data area of the disk recording medium such as a mini disk as a reproduction exclusive area, each frame of a group of pictures comprising a prescribed number of consecutive frames of a moving picture and subjected to image compression processing is recorded in a first sector area comprising a prescribed number of sectors 0 to 31 of the clusters and compression data Is adopting a prescribed system of a frame P12 required for reproducing frames B1, B2 of an adjacent group of pictures are recorded on a second sector area comprising other sectors 32 to 35 of the clusters. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recording medium suitable for recording highly efficient encoded digital image data, and a reproducing apparatus suitable for reproducing highly efficient encoded digital image data on the recording medium. It is.
[0002]
[Prior art]
As is well known, a CD-ROM (Compact Disc Read Only Memory) is standardized on the basis of a music CD (Compact Disc Digital Audio: hereinafter abbreviated as CD-DA).
First, the physical format will be briefly described. The physical format refers to a format in which data can be physically read at least when a CD-ROM disc is mounted on a CD-ROM drive.
[0003]
One disc can include up to 99 music or data tracks. Information about the track is recorded at the head of the disc, which is called TOC (Table Of Contents), that is, at the innermost circumference of the disc. The part where the TOC is recorded is called a lead-in track (Leadin Track). On the other hand, the last track, that is, the part where the last song ends in CD-DA, is called a lead-out track (Leadout Track).
[0004]
In the CD-DA, a stereo audio signal is digitized and recorded at a sampling rate of 16 bits and 44.1 kHz, so that in one second, 2 (stereo) × 2 (16 bits) × 44,100 = 176,400 This means that byte data is recorded. In a CD-ROM, a sector obtained by dividing one second into 75 is handled as a minimum unit, and thus one sector is 2,352 bytes.
[0005]
In the case of CD-ROM MODE-1, SYNC data (12 bytes) and a header (4 bytes) for synchronization, ECC (Error Correction Coding: 276 bytes) and EDC (Error) for error correction are included in one sector. (Detect Coding: 4 bytes), and the other 2048 bytes are recorded as user data. For data that does not require strict error correction due to data interpolation processing, such as audio and image data, the ECC and EDC are omitted, and 2,336 bytes excluding SYNC and header are included in one sector as user data. Be recorded. This is called CD-ROM MODE-2.
[0006]
In recent years, a personal audio device capable of recording and reproducing has been developed and commercialized, which is called a minidisc (trademark) system.
[0007]
In this mini-disc, EFM (Eight to Fourteen Modulation) is used as a modulation method for writing to the disc, and CIRC (Cross Interleave Reed-Solomon Code) is used as an error correction code. In this format, audio data compressed by ATRAC (Adaptive Transform Acoustic Coding) is recorded. The compressed data is collectively recorded for each block called a cluster as shown in FIG. The format is very close to the above-described CD-ROM MODE-2.
[0008]
The CD-ROM has 98 sectors of a CD as one sector. Converted to the playback time, it is 13.3 ms. The interleave length of CIRC is 108 frames (14.5 ms). It is longer than one sector of a CD-ROM. In order to record data using the CIRC error correction code, it is necessary to secure at least three extra sectors. This area is called a link area. Before starting to write data, a link area of 108 frames (1 sector + α) or more must be secured. Even after the data has been written, it is necessary to secure an area of 108 frames or more in the same manner.
Otherwise, the error correction interleave will not be completed.
[0009]
If data can be written from an arbitrary location, the link areas are distributed to various parts of the disk, and the data recording / reproducing efficiency deteriorates. Therefore, data is written for each recording unit which is relatively large. In a mini disc, this recording unit is called a cluster. One cluster is composed of 36 sectors. Rewriting is always performed at an integral multiple of one cluster. The data to be recorded is temporarily stored in the RAM and written to the disk. This RAM can be shared with a shock-proof memory for realizing a function of preventing vibration during reproduction.
[0010]
In a magneto-optical disk type mini disk capable of recording and reproduction, three sectors in one cluster (= 36 sectors) are set as link sectors, and the next one sector is reserved for sub data. The compressed data is recorded in the remaining 32 sectors.
[0011]
When recording data, writing is started in the middle of the second link sector of the previous cluster. When the 36th sector has been written, data for error correction must be written halfway between the first link sector and the second link sector.
[0012]
In a minidisk similar to a read-only CD, there is no need to consider rewriting in cluster units, and since data is recorded continuously, three sectors in the link area are unnecessary. All four sectors, which are the three sectors plus one sub data sector, are allocated for sub data so that graphics data and the like can be stored.
[0013]
As described above, in the mini-disc, the sub data capacity of the recording disc and the reproduction-only disc are different, and if the sub-data is included, it is impossible to completely copy the reproduction-only disc to the recording disc.
[0014]
In the case of rewriting a part of the data already recorded on the recording disk, it is necessary to rewrite the entire cluster even if the update data is small. This is because interleaving is performed in units of clusters.
[0015]
On the other hand, as a method for encoding an image signal with high efficiency, a high-efficiency encoding method for image signals for digital storage media is specified in accordance with a standardization plan by MPIG1 (Moving Picture Image Coding Experts Group Phasel). Here, the storage medium targeted by the method is one having a continuous transfer speed of about 1.5 Mbit / sec or less, such as a CD, a DAT (Digital Audio Tape), or a hard disk. It is also assumed that this is connected not only directly to the decoder but also via a transmission medium such as a computer bus, a LAN (local area network), and telecommunications. Special functions such as random access, high-speed reproduction, and reverse-order reproduction as well as normal-order reproduction are also considered.
[0016]
The principle of such a high-efficiency encoding method of an image signal by MPEG1 is as follows (for example, see Non-Patent Document 1).
[0017]
In this high-efficiency coding method, first, the redundancy in the time axis direction is reduced by taking the difference between images, and then, the discrete cosine transform (DCT) processing and the variable-length coding processing are used to reduce the redundancy in the time axis direction. To reduce the degree of redundancy.
[0018]
First, the redundancy in the time axis direction will be described below.
In general, in a continuous moving image, the temporally preceding and succeeding images are very similar to the currently focused image (image at a certain time). Therefore, for example, as shown in FIG. 16, if the difference between the image to be encoded and the image ahead in time is obtained and the difference is transmitted, the redundancy in the time axis direction is reduced. To reduce the amount of information to be transmitted. The image coded in this way is called a forward-predicted coded image (P-picture or P-frame) described later. Similarly, if the difference between the image to be coded from now and the interpolated image generated from the front or the rear or the front and the back in time is taken, and the difference of a small value among them is transmitted. Thus, it is possible to reduce the amount of information to be transmitted by reducing the redundancy in the time axis direction. The image encoded in this manner is referred to as a bidirectionally predictive encoded image (B-picture or B-frame) described later. In FIG. 16, an image denoted by reference numeral I in the figure indicates an intra-coded image (intra-coded picture: I-picture or I-frame) described later, and an image denoted by reference numeral P in FIG. Indicates a P picture, and an image indicated by a symbol B indicates a B picture.
[0019]
In addition, motion compensation is performed to generate a predicted image.
According to this motion compensation, for example, a block of 16 × 16 pixels (hereinafter referred to as a macroblock) constituted by a unit block of 8 × 8 pixels is extracted, and one block is located near the position of the corresponding macroblock in the previous image. By searching for a macroblock with a small number difference and taking the difference from the searched macroblock, it is possible to reduce the data to be sent. Actually, for example, in a P picture (forward prediction coded image), the difference between the predicted image after the motion compensation and the difference between the predicted image after the motion compensation and the Are encoded in units of macroblocks of 16 × 16 pixels.
[0020]
However, in the case described above, for example, a large amount of data must be transmitted for an image portion such as a background that appears after an object moves. Therefore, for example, in the case of a B picture (bidirectional predictive coded image), an already decoded temporally forward or backward image after motion compensation and an interpolated image generated by adding both of them will now be encoded. And the image which does not take this difference, that is, the image with the smallest data amount among the four images to be encoded from now on is encoded.
[0021]
Next, the redundancy in the space axis direction will be described below.
The difference of the image data is not transmitted as it is, but is subjected to discrete cosine transform (DCT) for each unit block of 8 × 8 pixels. The DCT expresses an image not at a pixel level but by how many frequency components of a cosine function are included. For example, by a two-dimensional DCT, data of an 8 × 8 pixel unit block is converted to an 8 × 8 pixel unit block. 8 is converted into a coefficient block of the component of the cosine function. Generally, an image signal of a natural image captured by a television camera often becomes a smooth signal. In this case, by performing DCT processing on the image signal, the data amount can be efficiently reduced.
[0022]
That is, in the case of a smooth signal such as the above-described image signal of a natural image, by performing DCT processing, a large value is concentrated near a specific coefficient. When these coefficients are quantized, most of the 8 × 8 coefficient blocks become 0, and only large coefficients remain.
[0023]
Therefore, when transmitting the data of the 8 × 8 coefficient block, a Huffman code is used in which a non-zero coefficient and a 0 run indicating how much 0 continues before the coefficient are set in a zigzag scan order. By transmitting, the amount of transmission can be reduced. On the decoding side, the image is reconstructed in the reverse procedure.
[0024]
Here, FIG. 17 shows the structure of data handled by the above-described encoding method. The data structure shown in FIG. 17 includes, in order from the bottom, a block layer, a macroblock layer, a slice layer, a picture layer, a group of pictures (GOP: Group Of Picture) layer, and a video sequence layer. Hereinafter, description will be made in order from the lower layer of FIG.
[0025]
First, in the block layer, each unit block of the block layer is composed of 8 × 8 pixels (8 lines × 8 pixels) having adjacent luminance or color difference. The DCT described above is performed for each unit block.
[0026]
In the macroblock layer, each macroblock is composed of four luminance blocks (luminance unit blocks) Y0, Y1, Y2, and Y3 adjacent to each other on the left and right and up and down, and a color difference block (corresponding to the same position as the luminance block on the image). (A color difference unit block) Cr and Cb. The order of transmission of these blocks is Y0, Y1, Y2, Y3, Cr, Cb. Here, in the present encoding method, what is used for a predicted image (a reference image for obtaining a difference) or whether or not the difference need not be transmitted is determined in units of macroblocks.
[0027]
The slice layer is composed of one or a plurality of macroblocks connected in the scanning order of the image. In the header of this slice, the difference between the motion vector and the DC (direct current) component in the image is reset, and the first macroblock has data indicating the position in the image, and thus an error has occurred. Even if you can return. Therefore, the length and start position of the slice are arbitrary, and can be changed depending on the error state of the transmission path.
[0028]
In the picture layer, a picture, that is, an image one by one, is composed of at least one or a plurality of slices. Each of the above-described intra-coded images (I-pictures or I-frames), forward prediction-coded images (P-pictures or B-frames), and DC intra-coded images (DC coded (D) pictures) according to the coding method. Are classified into four types of images.
[0029]
Here, in the above-described intra-coded image (I-picture), at the time of coding, only closed information in one image is used. Therefore, in other words, when decoding, an image can be reconstructed using only the information of the I picture itself. Actually, encoding is performed by DCT processing without taking a difference. Although this encoding method is generally inefficient, random insertion and high-speed reproduction are possible if this I picture is inserted everywhere.
[0030]
In the forward prediction coded image (P picture), an I picture or P picture which is located temporally earlier in the input and has already been decoded is used as a prediction image (a reference image for taking a difference). In practice, the more efficient one of encoding the difference from the motion-compensated predicted image and encoding the difference as it is (intra) without taking the difference is selected for each macroblock.
[0031]
In the bidirectional predictive coded image (B picture), three types of an I picture or a P picture that is temporally located earlier as a predicted picture and an interpolated picture generated from both of them are used. . As a result, the most efficient one of the above three types of difference coding after motion compensation and intra coding can be selected in macroblock units.
[0032]
The DC intra-coded image is an intra-coded image composed only of DCT DC coefficients, and cannot exist in the same sequence as the other three types of images.
[0033]
The group of pictures (GOP) layer is composed of one or more I-pictures and zero or more non-I-pictures.
[0034]
Here, the input order to the encoder is, for example,
1I, 2B, 3B, 4P * 5B, 6B, 7I, 8B, 9B, 10I, 11B, 12B, 13P, 14B, 15B, 16P * 17B, 18B, 19I, 20B, 21B, 22P The output of the encoder, that is, the input of the decoder is, for example, 1I, 4P, 2B, 3B * 7I, 5B, 6B, 10I, 8B, 9B, 13P, 11B, 12B, 16P, 14B, 15B * 19I, 17B, 18B. , 22P, 20B, and 21B.
[0035]
The reason why the rearrangement of the order is performed in the encoder is that, for example, when the above B picture is encoded or decoded, a temporally later I picture or P picture serving as a predicted image is first. This is because it must be encoded. Here, the interval between I pictures (for example, 9) and the interval between I pictures or B pictures (for example, 3) can be set arbitrarily. Further, the interval between the I picture and the P picture may be changed inside the group of picture layer. Note that the breaks in the group of picture layer are represented by the above-mentioned “*”, and the I indicates an I picture, P indicates a P picture, and B indicates a B picture.
[0036]
The uppermost video sequence layer in FIG. 17 includes one or a plurality of group of picture layers having the same image size, image rate, and the like.
[0037]
[Non-patent document 1]
The Institute of Television Engineers of Japan, "Multimedia Selection MPEG", First Edition, Ohmsha, April 20, 1996, pp. 85-109.
[0038]
[Problems to be solved by the invention]
By the way, when it is assumed that digital image data encoded at a high efficiency according to the above-described MPEG1 method is recorded on the above-described mini-disc, the following problem may occur.
1. When the recording unit of a GOP is set to an arbitrary size irrespective of a cluster, there is a possibility that image data of one GOP is recorded over two or more clusters. In this case, the GOP starts or ends in the middle of the cluster, making it difficult to perform editing processing such as replacing the GOP with another GOP as a cut unit. Even so, there is a problem that the average transfer rate decreases.
[0039]
2. When a P-picture or B-picture having the last frame of the immediately preceding GOP as a prediction image (reference image) is arranged at the beginning of the GOP, the preceding GOP is decoded to decode the P-picture or B-picture of the GOP. This also requires decoding, which causes a problem that rapid image reproduction becomes difficult during seek reproduction such as fast-forward or reverse-forward reproduction.
[0040]
SUMMARY OF THE INVENTION An object of the present invention is to make it possible to perform editing processing in units of GOPs by a simple and quick processing when recording highly efficient encoded digital image data on a disk-shaped recording medium such as a mini disk. Another object of the present invention is to make it possible to perform special reproduction such as high-speed fast-forward or reverse-forward reproduction by a simple and quick process.
[0041]
[Means for Solving the Problems]
In the recording medium according to the present invention, a cluster serving as a unit of reproduction in which a plurality of sectors capable of recording a predetermined amount of data are connected is provided on the outer peripheral side in the recording data area of the disc for reproduction only, and a predetermined number of continuous moving images is provided. Each frame of the group of pictures composed of the following frames is subjected to image compression processing and recorded in a first sector area composed of a predetermined number of sectors of a cluster, and in a second sector area composed of other sectors of the cluster, It is characterized in that compressed data of a predetermined method of a frame necessary for reproducing a frame of an adjacent group op picture is recorded.
[0042]
Also, the method of compressing a frame necessary for reproducing a frame of an adjacent group of pictures is intra-picture encoding.
[0043]
Further, in the reproducing apparatus according to the present invention, a cluster serving as a unit of reproduction in which a plurality of sectors capable of recording a predetermined data amount are connected is provided on the outer peripheral side in the recording data area of the disc for reproduction only, and a continuous moving image is provided. Each frame of a group of pictures composed of a predetermined number of frames is subjected to image compression processing and recorded in a first sector area composed of a predetermined number of sectors of a cluster, and a second sector area composed of other sectors of the cluster A reproducing unit for reading data in cluster units from a recording medium, wherein the reproducing unit reproduces a recording medium on which compressed data of a predetermined method required for reproducing a frame of an adjacent group of pictures is recorded; Storage means for storing the data read by the decoding means; decoding means for decoding the image-compressed data reproduced by the reproduction means; The reproducing means is controlled so that a group of pictures to be read is read from the recording medium to the storage means, and data of a predetermined sector of a cluster in which a group of pictures adjacent to the group of pictures to be decoded are read. Moving means is reproduced based on the data recorded in the second sector area of the reproduced adjacent group of pictures and the group of pictures read from the recording medium to be decoded. Control means for controlling the decoding means as described above.
[0044]
According to the recording medium and the reproducing apparatus of the present invention having the above configuration, each frame of the group of pictures is image-compressed and recorded in the first sector area of the cluster, and is necessary for reproducing frames of the adjacent group of pictures. Image data of a particular frame is recorded in the second sector area of this cluster, and a moving image is recorded based on the group of picture to be decoded and the data recorded in the second sector area of the adjacent group of pictures. Since reproduction can be performed, editing processing in units of GOPs and special reproduction such as fast forward and reverse fast forward reproduction can be performed, and higher quality images can be reproduced at high speed.
[0045]
BEST MODE FOR CARRYING OUT THE INVENTION
First, an external configuration of an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view showing an external configuration of an embodiment of a disk recording medium and a disk recording / reproducing apparatus according to the present invention. A mini-disk (usually called a mini-disc including the cartridge 1) including a magneto-optical disk or an optical disk is housed inside the cartridge 1 shown in FIG. Digital data can be recorded and reproduced magneto-optically. An insertion hole 3 is formed on a front surface of the disk recording / reproducing device 2. A loading mechanism for loading or unloading the cartridge 1 with a mini-disc inserted in the insertion hole 3 is provided in the disk recording / reproducing device 2. It is provided inside. Various operation keys 4 are arranged on the front right side of the disk recording / reproducing apparatus 2 so that various instructions can be input to the disk recording / reproducing apparatus 2. In addition, a color LCD (liquid crystal display) 5 is provided above and in front of the disk recording / reproducing apparatus 2, and a color moving image reproduced and decoded from the mini disk is displayed on the color LCD 5. ing.
[0046]
FIG. 2 is a perspective view showing an external configuration of another embodiment of the disc recording / reproducing apparatus according to the present invention. In this embodiment, the color LCD 5 in the embodiment of FIG. 1 is omitted, and the video signal output from the disk recording / reproducing device 2 is supplied to the color CRT display / monitor 12 via the cable 11 and displayed. Has become. That is, the embodiment shown in FIG. 1 is a portable disk recording / reproducing apparatus, whereas the embodiment shown in FIG. 2 is a stationary disk recording / reproducing apparatus.
[0047]
Next, FIG. 3 shows an electrical configuration inside the disk recording / reproducing apparatus 2. The MD (mini-disc) drive device 20 records and reproduces digital data on the mini-disc 1a stored in the cartridge 1.
[0048]
The MD drive device 20 is originally designed based on a mini-disk system developed for use in portable, stationary, or in-vehicle personal audio equipment. In this mini-disc system, a small and thin recording medium called a mini-disc is used. The mini-disc can be any of a read-only optical disc having a diameter of 64 mm, a rewritable MO (magneto-optical) disc, or a hybrid disc (also called a partial ROM disc) in which a rewritable area and a read-only area are provided in a mixed manner. (W × L × H = 72 mm × 68 mm × 5 mm). Data is read from a mini-disc containing a read-only optical disc according to the same principle as a CD (Compact Disc). On the other hand, data is recorded on a mini-disc containing an MO disc or a hybrid disc by a magnetic field modulation direct overwrite method. The magnetic field modulation direct overwrite method irradiates a rotating disk with a high-power laser beam from below, and raises the magneto-optical film of the part to be recorded to the Curie temperature at which the coercive force of the magnetic material disappears. In this method, data is written from above a disk by a magnetic head.
[0049]
In the development process of such a mini-disc system as a personal audio device, the integration of each circuit element and the optimization of each mechanical component have been achieved, and the miniaturization and weight reduction of the entire device have been achieved. Battery operation is possible due to power consumption. Furthermore, in addition to the feature that it has almost the same storage capacity (140 Mbytes) as the existing 3.5-inch MO disk and that the recording medium can be exchanged, the recording medium can be compared with other MO disks due to the mass production effect. Of course, the manufacturing cost of the drive unit itself is also reduced. In addition, reliability has been sufficiently demonstrated based on the results of use as personal audio equipment.
[0050]
The detailed configuration of the MD drive device 20 will be described later with reference to FIG. This MD drive device 20 is connected to a bus line via an I / O interface circuit 21 as shown in FIG.
[0051]
3, an MPU (microprocessor unit) 22 supplies necessary addresses and data to each unit via a bus line, and controls each unit. The main memory 23 includes a ROM in which a program executed by the MPU 22 is stored in advance, and a RAM in which various data are temporarily stored as a work area. The main memory 23 is addressed from the MPU 22 or the like via a bus line. Along with this, various data are written and read.
[0052]
The DMAC (direct memory access controller) 24 directly controls the input and output of data to and from the main memory 23 without going through the MPU 22 to perform DMA transfer.
[0053]
An audio AD / DA (analog digital / digital / analog) conversion circuit 25 A / D converts an analog audio signal input to an analog audio input terminal Ain and supplies the analog audio signal to an audio encoder / decoder 26, while the audio audio signal is supplied to the audio encoder / decoder 26. The digital audio data supplied from the encoder / decoder 26 is D / A converted and output to an analog audio output terminal Aout. The audio encoder / decoder 26 encodes and compresses the digital audio data supplied from the audio AD / DA conversion circuit 25 in a predetermined format defined by the MPEG audio standard, and encodes the encoded audio data. The data is temporarily stored in the main memory 23 under the control of the DMAC 24. Further, the coded audio data read from the main memory 23 is decoded to restore the original digital audio data, and is supplied to the audio AD / DA conversion circuit 25. The transfer of encoded audio data between the main memory 23 and the audio encoder / decoder 26 is controlled by the DMAC 24.
[0054]
The video encoding unit 27 converts the analog video signal input to the analog video input terminal Vin into an A / D converter 27a, and converts the digital video data converted by the A / D converter 27a into MPEG1 data. And an MPEG video encoder 27b for encoding and compressing based on the standard. The encoded video data encoded by the MPEG video encoder 27b is temporarily stored in the main memory 23 under the control of the DMAC 24.
[0055]
The digital video data converted by the AD converter 27a is also supplied to an LCD controller 28, and is displayed on the LCD 5 under the control of the LCD controller 28. In the configuration without the LCD 5, as shown in FIG. 2, it is supplied to the CRT display / monitor 12 via the external cable 11 and displayed.
[0056]
The video decoder 29 decodes the coded video data read from the main memory 23 to restore the original digital video data, and the MPEG video decoder 29b decodes the decoded video data. And a D / A converter 29a for D / A converting the digital video data and outputting it to an analog video output terminal Vout.
[0057]
The digital video data decoded by the MPEG video decoder 29b is also supplied to the LCD controller 28, and is displayed on the LCD 5 under the control of the LCD controller 28.
[0058]
The transfer of encoded video data between the MPEG video encoder 27b and the MPEG video decoder 29b and the main memory 23 is also controlled by the DMAC 24.
[0059]
Further, the exchange of various data between the main memory 23 and the MD drive device 20 via the I / O interface 21 is also controlled by the DMAC 24.
[0060]
The operation panel controller 30 supplies various instruction data input by the operation keys 4 to the MPU 22 via a bus line.
[0061]
Here, a specific configuration example of the MPEG video encoder 27b will be described with reference to FIG. The blocked digital video signal from the input terminal 61 is supplied to a subtractor 62 and a motion vector detection circuit 72. This block digital video signal is a digital video signal composed of discrete pixel data strings, for each screen, pixel data arranged in the horizontal and vertical directions of the screen, for example, in an 8 × 8 matrix. Is a signal that has been time-series converted so as to be subdivided into a plurality of unit block signals composed of
[0062]
In the subtractor 62, a unit block signal of the blocked digital video signal and a unit block signal having a pixel data configuration similar to the unit block signal, that is, a prediction unit block signal, obtained from the motion compensation circuit 71. Subtraction with the one is performed.
[0063]
A difference unit block signal (sometimes not a difference unit block signal but a unit block signal) which is a subtraction output of the subtracter 62 is converted to a two-dimensional discrete cosine transform circuit (two-dimensional DCT) which is a kind of orthogonal transform circuit. (Circuit) 63 for cosine conversion. The transform coefficients obtained from the two-dimensional DCT circuit 63 are supplied to a quantization circuit (requantization circuit) 64 and quantized.
[0064]
The quantized transform coefficients are supplied to a variable-length coding circuit 65, where they are coded, and then variable-length coded at an output terminal 66 and output as quantized transform coefficients (coded data). .
[0065]
Then, the unit block signal constituting the frame signal stored in the frame memory 70 is supplied to the motion compensation circuit 71, and the motion compensation circuit 71 is controlled by the detection output from the motion vector detection circuit 72, and The unit block signal having the highest correlation is determined, and the unit block signal having the highest correlation is output from the motion compensation circuit 71 as a predicted unit block signal, and supplied to the subtractor 62 and the adder 69, respectively.
[0066]
Next, a specific configuration example of the MPEG video decoder 29b will be described with reference to FIG. Variable-length coded and quantized transform coefficients (coded data) corresponding to the output signal of the output terminal 66 in FIG. 4 are supplied from the input terminal 81 to the variable-length decoding circuit 82 and decoded. The quantized transform coefficients from the variable length decoding circuit 82 are supplied to an inverse quantization circuit 83 and are inversely quantized. The obtained quantized transform coefficient from the transform quantization circuit 64 is supplied to the inverse quantization circuit 67, where it is inversely quantized and the transform coefficient is output. The transform coefficient is supplied to a two-dimensional discrete cosine inverse transform circuit (two-dimensional discrete IDCT circuit) 68 to obtain an original difference unit block signal.
[0067]
The difference unit block signal is added by the adder 69 to the prediction unit block signal from the motion compensation circuit 71. The unit block signal from the adder 69 is supplied to the frame memory 70, and all the unit block signals constituting the frame signal to which the unit block signal belongs are stored.
[0068]
In the motion vector detection circuit 72, a unit block signal corresponding to each unit block signal of the blocked digital video signal from the input terminal 61 in the frame memory 70 for each unit block signal of the blocked digital video signal from the input terminal 61. , A unit block signal having the highest correlation is detected.
[0069]
Then, a block signal constituting the frame signal stored in the frame memory 70 is supplied to the motion compensation circuit 71, and the motion compensation circuit 71 is controlled by the detection output from the motion vector detection circuit 72, and The correlation of each block signal is determined, and the block signal having the highest correlation is output from the motion compensation circuit 71 as a prediction block signal, and supplied to the subtractor 62 and the adder 69, respectively.
[0070]
Next, a specific configuration example of the MPEG video decoder 29b will be described with reference to FIG. A variable-length coded and quantized transform coefficient (encoded data) corresponding to the output signal of the output terminal 66 in FIG. 4 is supplied from the input terminal 81 to the variable-length decoding circuit 82 and is subjected to variable-length decoding. . The quantized transform coefficients from the variable length decoding circuit 82 are supplied to an inverse quantization circuit 83 and are inversely quantized. The obtained transform coefficient is supplied to a two-dimensional discrete inverse cosine transform circuit (two-dimensional IDCT circuit) 84 and inversely transformed to obtain a differential unit block signal (sometimes a unit block signal instead of a differential unit block signal). ) Is obtained.
[0071]
When a unit block signal (a unit block signal of an I picture) is output from the two-dimensional IDCT circuit 84 instead of the difference unit block signal, the movable contact m of the changeover switch 85 is switched to the fixed contact a, and the unit is changed. The block signal is output to the output terminal 86 through the changeover switch 85.
[0072]
When the difference unit block signal is output from the two-dimensional IDCT circuit 84, the movable contact m of the changeover switch 85 is switched to the fixed contact b. In this case, the difference unit block signal from the two-dimensional IDCT circuit 84 is supplied to the adder 93 and added to the predicted unit block signal from the changeover switch 92, and the unit block signal from the adder 93 is changed to the changeover switch. The signal is output to an output terminal 86 through 85.
[0073]
The prediction unit block signal from the adder 93 is supplied to the frame memory 87 through the fixed contact b and the movable contact m of the changeover switch 85. In the frame memory 87, all the unit block signals constituting the frame signal to which the prediction unit block signal belongs from the adder 93 are stored.
[0074]
The frame signal read from the frame memory 87 is supplied to another frame memory 90 and stored. The frame signals before and after a predetermined frame from the frame memories 87 and 90 are respectively supplied to the motion compensation forward prediction circuit 88 and the motion compensation backward prediction circuit 91, respectively, and the average of the frame signals before and after the predetermined frame is supplied. Is supplied to the motion compensation forward / backward prediction circuit 89.
[0075]
In the prediction circuits 88, 91, and 89, the unit block signal of a certain frame is a unit block signal near the unit block signal of a certain frame, the unit block signal of a frame before and after a predetermined frame and an average unit thereof. When the prediction unit block signal having the highest correlation among the block signals is selected and the forward prediction unit block signal (prediction unit block signal of the P picture) is obtained, the movable contact m of the changeover switch 92 is set to the fixed contact c side. , And the unit block signal having the highest correlation is supplied to the adder 93 and added to the difference unit block signal from the two-dimensional IDCT circuit 84.
[0076]
When obtaining a bilateral prediction block signal (a prediction unit block signal of a B picture), the prediction unit block signal having the highest correlation among the three prediction unit block signals having the highest correlation is switched. The switch 92 is selected by switching the movable contact m of the movable contact m with respect to the fixed contacts c, d, and e, supplied to the adder 93, and added to the difference unit block signal from the two-dimensional IDCT circuit 84.
[0077]
Incidentally, specific circuits of the MPEG video encoder and the decoder described with reference to FIGS. 4 and 5 are described in detail in Japanese Patent Application Laid-Open No. 05-95545.
[0078]
Next, the operation of the disk recording / reproducing apparatus having the above configuration will be described.
When a predetermined one of the keys 4 is operated to instruct recording of the input audio signal and video signal, this instruction is supplied to the MPU 22 via the bus line by the operation panel controller 30. In response to this command, the MPU 22 controls each unit according to the procedure described below, and records the encoded audio data and the encoded video data encoded based on the MPEG1 standard on the mini-disc 1a.
[0079]
Here, the audio signal input to the analog audio input terminal Ain is A / D converted by the audio AD / DA conversion circuit 25 and supplied to the audio encoder / decoder 26. The audio encoder / decoder 26 temporarily stores the encoded audio data in the RAM having one cluster (32 sectors).
[0080]
Then, when encoded audio data (approximately 64 KBytes) for one cluster is generated by the audio encoder / decoder 26, the data is DMA-transferred and stored in the main memory 23 under the control of the DMAC 24. . What is the data for one cluster stored in the main memory 23? The data is read by the DMAC 24 at a predetermined timing, DMA-transferred to the MD drive device 20 via the I / O interface circuit 21, and recorded on the mini disk 1a.
[0081]
Here, in the MD drive device 20, data for one cluster is interleaved in units of clusters and recorded on the mini-disc 1a. That is, in a magneto-optical disk type mini disk capable of recording and reproduction, as shown in FIG. 6, three sectors in one cluster are set as link sectors, and the next one sector is reserved for sub data. Data is recorded in the remaining 32 sectors. When recording data, writing is started in the middle of the second link sector of the previous cluster. When the 36th sector has been written, data for error correction is written halfway between the first link sector and the second link sector.
[0082]
In this embodiment, as shown in FIG. 6, one cluster is composed of 36 sectors, of which the first 32 sectors record substantial data, and the last 4 sectors contain substantial data. It is not recorded. In the link sectors of the first three sectors of the last four sectors, data for error correction of data recorded in the adjacent cluster is recorded. The last one sector is a sub-data sector, and spare graphic data and the like corresponding to the data recorded in the first 32 sectors can be recorded. No data is recorded. In each sector, address information and data are recorded.
[0083]
Similarly, the video signal input to the analog video input terminal Vin is A / D converted by the A / D conversion circuit 27a, supplied to the MPEG video encoder 27b, and encoded. This coded video data is also temporarily stored in a RAM for one cluster (32 sectors), similarly to the coded audio data described above. When encoded video data for one cluster is generated by the MPEG video encoder 27b, the data is DMA-transferred and stored in the main memory 23 under the control of the DMAC 24. The data for one cluster stored in the main memory 23 is read out at a predetermined timing by the DMAC 24, DMA-transferred to the MD drive device 20 via the I / O interface circuit 21, and subjected to interleave processing in cluster units. After that, it is recorded on the mini disc 1a.
[0084]
In this embodiment, the encoded video data and the encoded audio data are cluster-interleaved and recorded on the minidisc 1a as shown in FIG. That is, the MPU 22 controls the coded video data indicated by the reference numeral V and the coded audio data indicated by the reference A in such a manner that they are alternately arranged in different clusters. Then, if necessary, predetermined data D such as programs and character data other than the encoded video data V and the encoded audio data A, and the encoded video data V or the encoded audio data A are recorded. Is recorded in a cluster different from the cluster that As described above, only the related data having a strong correlation is recorded in the same cluster, that is, the encoded video data V, the encoded audio data A, and the other data D are recorded in different clusters. Thereby, the processing speed at the time of recording and reproduction can be improved.
[0085]
However, in order to enable high-speed reproduction during a seek operation, the corresponding coded video data V, coded audio data A, and other data D are arranged in relatively close clusters. This is because these related data need to be reproduced at approximately the same time.
[0086]
The digital video data converted by the A / D converter 27a during the recording operation described above is supplied to the LCD controller 28, and is displayed on the LCD 5 under the control of the LCD controller 28. Alternatively, in a configuration without the LCD 5, as shown in FIG. 2, the data is supplied to the CRT display / monitor 12 via the external cable 11 and displayed. This allows the user to monitor the image being recorded.
[0087]
Next, the operation at the time of reproduction will be described. When the reproduction is instructed by operating the key 4, this instruction is supplied to the MPU 22 via the operation panel controller 30. At this time, the MPU 22 controls the MD drive device 20 to reproduce data recorded on the mini disc 1a. This reproduced data is DMA-transferred to the main memory 23 via the I / O interface circuit 21. Of the data stored in the main memory 23, the encoded audio data is DMA-transferred to the audio encoder / decoder 26, and the encoded video data is DMA-transferred to the video decoding unit 29, respectively.
[0088]
The encoded audio data for one cluster supplied to the audio encoder / decoder 26 is decoded, D / A converted in the audio AD / DA conversion circuit 25, and output from the analog audio output terminal Aout. Is done.
[0089]
On the other hand, the encoded video data for one cluster supplied to the video decoding unit 29 is also supplied to the LCD controller 28 after being decoded, and is displayed on the LCD 5 under the control of the LCD controller 28. Alternatively, in the configuration without the LCD 5, after the D / A conversion is performed by the DA converter 29a, the D / A conversion is supplied from the analog video output terminal Vout to the CRT display monitor 12 via the external cable 11 shown in FIG. Is displayed.
[0090]
Next, the configuration of the MD drive device 20 will be described with reference to FIG.
By applying a modulation magnetic field in accordance with recording data by the magnetic head 41 in a state in which the optical disk 44 irradiates a laser beam to the mini-disc 1a rotated by the spindle motor 46 shown in FIG. Data is optically reproduced by performing magnetic field modulation overwrite recording along the upper recording track and tracing the target track on the mini-disc 1a with the laser light by the optical pickup 44.
[0091]
The optical pickup 44 includes, for example, a laser light source such as a laser diode, an optical component such as a collimator lens, an objective lens, a polarizing beam splitter, a cylindrical lens, and a photodetector divided into a predetermined arrangement. Is positioned by the feed motor 45 at a position opposed to the magnetic head 41 with respect to.
[0092]
When recording data on the mini-disc 1a, the optical pickup 44 drives the magnetic head 41 by the magnetic head driving circuit 43 and applies a laser beam to a target track of the mini-disc 1a to which a modulation magnetic field according to the recording data is applied. By irradiating, data recording is performed by thermomagnetic recording.
[0093]
Further, the optical pickup 44 detects a focus error by, for example, an astigmatism method by detecting a laser beam applied to a target track, and detects a tracking error by, for example, a push-pull method, and a read-only type. When a reproduction signal is detected by utilizing the diffraction phenomenon of light in a pit row of a target track of the mini-disc 1a and data is reproduced from the writable mini-disc 1a, the polarization angle of the reflected light from the target track ( A difference in the car rotation angle is detected to generate a reproduction signal.
[0094]
The output of the optical pickup 44 is supplied to an RF amplifier 47. The RF amplifier 47 extracts a focus error signal and a tracking error signal from the output of the optical pickup 44 and supplies the extracted signal to the servo control circuit 48, binarizes the reproduction signal, and supplies it to the address decoder 49. The address decoder 49 decodes an address from the supplied binary reproduction signal and supplies the decoded signal to the EFM / CIRC encoder / decoder 51.
[0095]
The servo control circuit 48 includes, for example, a focus servo control circuit, a tracking servo control circuit, a spindle motor servo circuit, a thread servo circuit, and the like.
[0096]
The focus servo control circuit controls the focus of the optical system of the optical pickup 44 so that the focus error signal becomes zero. The tracking servo control circuit controls the feed motor 45 of the optical pickup 44 so that the tracking error signal becomes zero.
[0097]
Further, the spindle motor servo control circuit controls the spindle motor 46 to rotate and drive the mini disc 1a at a predetermined rotation speed (for example, a constant linear speed). The thread servo control circuit moves the magnetic head 41 and the optical pickup 44 to the target track position of the mini disk 1a specified by the system controller 50 by the feed motor 45.
[0098]
The EFM / CIRC encoder / decoder 51 performs coding processing for error correction, that is, coding processing of CIRC (Cross Interleaved Reed-Solomon Code), on the data supplied via the I / O interface 21, A modulation process suitable for recording, that is, an EFM (Eight to Fourteen Modulation) encoding process is performed.
[0099]
The encoded data output from the EFM / CIRC encoder / decoder 51 is supplied to the magnetic head drive circuit 43 as recording data. The magnetic head drive circuit 43 drives the magnetic head 41 so as to apply a modulation magnetic field according to the recording data to the mini disk 1a.
[0100]
When receiving a write command from the MPU 22 via the I / O interface 21, the system controller 50 controls the recording position on the mini disc 1a so that the recording data is recorded on a predetermined recording track of the mini disc 1a. I do. The recording position is controlled by controlling the recording position information on the mini disk 1a obtained from the encoded data output from the EFM / CIRC encoder / decoder 51 by the system controller 50, and recording from the system controller 50 on the mini disk 1a. This is performed by supplying a control signal specifying the recording position of the track to the servo control circuit 48. As a result, coded audio data, coded video data, and other digital data to be added as necessary are stored on the mini-disc 1a in cluster units by the so-called magnetic field modulation magneto-optical recording method, as described above. Recorded in.
[0101]
At the time of reproduction, the EFM / CIRC encoder / decoder 51 performs EFM demodulation processing and CIRC decoding processing for error correction on the input binary reproduction data, and performs I / O interface 21 Output to
[0102]
Further, when receiving a read command from the MPU 22 via the I / O interface 21, the system controller 50 controls a reproduction position with respect to a recording track of the mini disc 1a so that reproduction data is continuously obtained. The reproduction position is controlled by controlling the recording position information on the mini-disc 1a obtained from the reproduction data by the system controller 50, and servo-controlling the control signal for specifying the reproduction position of the recording track of the mini-disc 1a from the system controller 50. This is done by supplying the circuit 48.
[0103]
Next, a relationship between a GOP and a cluster according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, as shown in FIG. 9, for example, when a GOP is composed of seven frames (or fields) of images, the first frame image is defined as an I picture I0, and the fourth frame is defined as an I picture I0. The image is assumed to be a P picture P1 which is a forward prediction image from the image I0 of the first frame. Further, the picture of the final seventh frame is set as a P picture P4 which is a forward prediction picture from the P picture P1 of the fourth frame. The images of the second and third frames are assumed to be B pictures B2 or B3 which are bidirectional prediction images from the preceding I picture I0 and the subsequent P picture P1, respectively. Similarly, the images of the fifth and sixth frames include a B picture B5 or B6, which is a bidirectional prediction image from the P picture P1 of the fourth frame and the P picture P4 of the seventh frame. I do.
[0104]
Then, in the present embodiment, as shown in FIG. 10, the encoded video data of one GOP is encoded so as to fit in 32 sectors of one cluster, and recorded on the minidisc 1a. In this case, in the read-only ROM type mini-disc 1a, when encoded video data based on the MPEG standard is generated, encoding is performed in advance in units of 1 GOP so as to be recorded in each cluster. Based on the coded video data thus generated, stamping and the like are performed through the same manufacturing process as that for a CD, and a large number of minidiscs 1a on which the same coded video data is recorded are produced.
[0105]
Also, in a writable RAM type or a hybrid type (partial ROM type) mini-disc 1a in which a writable area and a read-only area are mixed, the MPEG video encoder 27b of the video encoding unit 27 uses one GOP as a unit. Encoding is performed so as to be recorded in each one cluster, and the encoded video data thus generated is DMA-transferred to the MD drive device 20 and recorded on the minidisc 1a.
[0106]
Here, the encoding order is indicated by a numeral in FIG. That is, the images of the respective frames sequentially input in the order of I0, B2, B3, P1, B5, B6, and P4 are sequentially encoded in the order of I0, P1, B2, B3, P4, B5, and B6. Then, the encoded video data is arranged in each sector in one cluster in the order of the encoding.
[0107]
However, in exceptional cases, when the encoded video data of one GOP cannot be arranged in 32 sectors in one cluster, the encoded video data of the GOP is recorded in a plurality of continuous clusters. You. If the recording position of the coded video data corresponding to the last frame of the GOP does not correspond to the last sector of the cluster, the remaining sectors of the cluster have substantially invalid dummy data such as "0". Data is additionally recorded.
[0108]
Thus, in the present embodiment, the first frame of one GOP is encoded as an I picture, and the last frame is encoded as a P picture. Then, the leading I picture is always located at the head of the cluster. By doing so, for example, even in a case where the minidisk 1a is sought and an image of a predetermined cluster is intermittently extracted and reproduced, an I picture is always arranged at the head of each cluster. , It is possible to completely decode at least one frame of the extracted cluster. Further, since encoded video data of different GOPs are not arranged in the same cluster, editing in cut units such as replacing encoded video data with other encoded video data in units of 1 GOP is performed. This can be easily performed.
[0109]
FIGS. 11 and 12 show the relationship between GOPs and clusters in another embodiment of the present invention. In this embodiment, as shown in FIG. 11, for example, as shown in FIG. 11, one frame is composed of 15 frames, and among the sequentially input frames, the image of the third frame is defined as an I picture I0, and the sixth frame is Is a P picture P3 that is a forward prediction image from the third frame image I0, and a ninth frame image is a P picture P6 that is a forward prediction image from the sixth frame image P3. It is said. The image of the twelfth frame is a P picture P9 which is a forward prediction image from the image P6 of the ninth frame. Then, the picture of the last 15th frame is a P picture P12 which is a forward prediction picture from the P picture P9 of the twelfth frame.
[0110]
The image of each frame located between the I picture and the P picture is a B picture, and is predicted from the I picture or the B picture located before and after the frame. That is, the images of the fourth and fifth frames are B pictures B4 and B5, which are bidirectional predicted images from the I picture I0 of the third frame and the P picture P3 of the sixth frame. . The images of the seventh and eighth frames are B pictures B7 and B8 from the P pictures P3 and P6 of the sixth and ninth frames, respectively, and the images of the tenth and eleventh frames. The images are B pictures B10 and B11 from the P pictures P6 and P9 of the ninth and twelfth frames. Further, the images of the thirteenth and fourteenth frames are B pictures B13 and B14 from the P pictures P9 and P12 of the twelfth and fifteenth frames.
[0111]
Then, the images of the first two frames of the GOP are the last P picture P12 of the immediately preceding GOP and the B pictures B1 and B2 from the I picture I0 of the corresponding GOP.
[0112]
However, if a GOP is configured in this manner, the B pictures B1 and B2 of the first two frames cannot be decoded when only the cluster corresponding to the same GOP is reproduced. This is because the P picture P12, which is one image serving as a reference for predicting the B pictures B1 and B2, belongs to the immediately preceding GOP and is recorded in the immediately preceding cluster.
[0113]
Therefore, in the present embodiment, as shown in FIG. 12, the coded video data for 15 frames constituting the GOP is encoded in the first 32 sectors out of 36 sectors constituting one cluster. The encoded video data corresponding to the P picture P12, which is an image for predicting the B pictures B1 and B2 of the first two frames of the immediately succeeding GOP, is placed in the last four sectors in order. It is recorded as an I-picture Is encoded by intra-coding, which can reconstruct an image only with its own data without using it. This I picture Is is, of course, redundant data that overlaps with the P picture P12 in the same cluster.
[0114]
However, by recording the redundant I picture Is in this way, it becomes possible to decode the original image only from the encoded video data for the last four sectors of the GOP. That is, it is not necessary to decode all GOPs in the immediately preceding cluster from the beginning. Therefore, from the I pictures Is of the last four sectors of the GOP immediately before the GOP to be reproduced and the third I picture I0 of the GOP to be reproduced, the B pictures B1 and B2 sandwiched therebetween. Can be decoded.
[0115]
However, as described above, in the case of the writable mini-disc 1a (hereinafter referred to as MO cluster including the writable area of the partial ROM disk), three of the last four sectors of each cluster are set as link sectors. It is stipulated in the standards to secure. However, in the read-only mini-disc 1a (hereinafter referred to as a ROM cluster including a read-only area of a partial ROM disk), all these four sectors can be freely used as sub data sectors. Therefore, in the case of the read-only mini-disc 1a, the sub data sectors of the last four sectors of each cluster (however, in this specification, these sub data sectors and the link sector are collectively referred to as a link sector. Then, the predicted images of the B pictures B1 and B2 of the first two frames of the immediately following GOP are recorded as I picture Is.
[0116]
FIG. 13 is a flowchart showing a procedure for creating data of one group of pictures for the read-only mini-disc 1a (ROM cluster) in one embodiment of the present invention.
[0117]
In this figure, in this case, the ROM cluster is not limited to the case where the entire disk is a ROM area, for example, a predetermined area of an inner circumference of one disk is a ROM cluster, and the outer circumference thereof is recordable. Also includes a partial ROM that is an MO cluster.
[0118]
First, in step S1 in FIG. 13, the picture format of the first frame of the GOP is determined on the assumption that the cluster to be recorded is a ROM cluster. If the first frame of the GOP to be recorded is an I picture as shown in FIG. 10, for example, the process proceeds from step S2 to step S3, and nothing is recorded in the last four sectors. (However, data for completing the interleaving is actually recorded), and the process is terminated.
[0119]
On the other hand, in step S1, for example, as shown in FIG. 11, when the first frame is composed of a B picture or a P picture other than an I picture, the process proceeds from the next step S2 to step S4, where the last four sectors of the cluster are stored. It is determined whether or not the capacity is such that the I picture IS (the predicted image of the first two frames of the immediately following GOP) corresponding to the P picture P12 can be recorded.
[0120]
If the capacity is determined to be recordable, the process proceeds to step S5, and the I picture IS is recorded. On the other hand, when it is determined that the data amount of the I picture IS is too large to record the data of the I picture IS in four sectors, the process proceeds to step S3, and the I picture IS is not recorded.
[0121]
In this way, taking into account the last four sectors of the cluster and the data amount of the I picture IS, encoding and encoding are performed so as to obtain a higher quality image by using an algorithm using the immediately preceding GOP as much as possible. A record is made.
[0122]
FIG. 14 is a flowchart showing a recording process procedure for one group of pictures on the writable mini-disc 1a in one embodiment of the present invention. In the case where it is determined in step S11 in FIG. 11 that the cluster to be recorded is an MO cluster, the last four sectors of each cluster are required to have three sector link sectors. See Japanese Patent Application No. 2-222821 (JP-A-4-105271) and the corresponding US Pat. No. 5,243,588. Therefore, in this case, the process proceeds to step S13, on the assumption that the prediction process from the immediately preceding GOP is impossible, the first frame of the GOP is set to an I picture, and the last frame is set to a P picture. Is processed as Then, the process proceeds to step S14, in which no data is recorded in the last four sectors of the cluster. As a result, encoded video data is recorded in the format of the embodiment shown in FIGS.
[0123]
FIG. 15 is a flowchart showing a procedure of a reproduction process for one group of pictures on the mini disc 1a in one embodiment of the present invention.
[0124]
First, in step S21, it is determined whether or not the cluster to be reproduced is a ROM cluster. If it is determined that the cluster is a ROM cluster, the process proceeds to step S22, and it is determined whether the I picture Is is recorded in the last four sectors of the immediately preceding cluster. If the I picture Is has been recorded, the process proceeds to step S23, and the B pictures B1 and B2 of the first two frames of the next GOP are decoded using the I picture Is.
[0125]
If it is determined in step S22 that the I picture Is is not recorded in the last four sectors of the cluster, the process proceeds to step S24, where data obtained by decoding the immediately preceding GOP picture P12 (I picture (Which is data) is determined. For example, when a search operation is being performed, the immediately preceding GOP does not necessarily decode all the clusters from the first sector. In such a case, the P picture P12 is often not decoded. Therefore, in this case, the process proceeds to step S26, in which the B pictures B1 and B2 of the first two frames of the GOP are not substantially decoded (even if decoded, they are not displayed). This prevents a distorted image from being displayed.
[0126]
On the other hand, in a case where normal playback is performed instead of the search operation, each cluster is sequentially played back. Therefore, in step S24, it is determined that the P picture P12 of the immediately preceding GOP has been decoded. Is determined. In this case, the process proceeds from step S24 to step S25, and the B pictures B1, B2 of the first frame of the next GOP are decoded using the decoded P picture P12.
[0127]
On the other hand, if it is determined in step S21 that the cluster to be reproduced is not a ROM cluster (if it is determined to be an MO cluster), the process proceeds from step S21 to step S27, and the cluster to be reproduced is determined. The decryption is performed only with the data in. That is, in this case, as described in step S2 of FIG. 13, the I picture is arranged at the head of the cluster, and the P picture is arranged at the end of the cluster. As a result, decoding can be performed only with the data in the cluster.
[0128]
In the above description, the case where MPEG digitally compressed video data is recorded on a mini-disc has been described as an example. However, the present invention is also applied to the case where digital video data processed by another compression method is recorded on another disc. It is possible.
[0129]
【The invention's effect】
As described above, according to the recording medium and the reproducing apparatus of the present invention, each frame of the group of picture is image-compressed and recorded in the first sector area of the cluster, and the reproduction of the adjacent frame of the group of picture is performed. Is recorded in the second sector area of this cluster, and a moving image is generated based on the group of pictures to be decoded and the data recorded in the second sector area of the adjacent group of pictures. Since images can be reproduced, editing processing in units of GOPs and special reproduction such as fast-forward and reverse-fast-forward reproduction can be performed. Can be reproduced at high speed.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external configuration of a disk recording / reproducing apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing an external configuration of a disk recording / reproducing apparatus according to another embodiment of the present invention.
FIG. 3 is a block diagram showing an electrical configuration of a disk recording / reproducing apparatus according to one embodiment of the present invention.
FIG. 4 is a block diagram showing a specific configuration example of an MPEG video encoder 27b shown in FIG.
FIG. 5 is a block diagram showing a specific configuration example of an MPEG video decoder 29b shown in FIG.
FIG. 6 is a conceptual diagram for explaining a recording format of a mini disc applied to one embodiment of the present invention.
FIG. 7 is a conceptual diagram illustrating cluster interleaving applied to one embodiment of the present invention.
FIG. 8 is a block diagram showing an electrical configuration of an MD drive device applied to one embodiment of the present invention.
FIG. 9 is a conceptual diagram illustrating a group of pictures applied to an embodiment of the present invention.
FIG. 10 is a conceptual diagram illustrating a relationship between a group of pictures and a cluster applied to an embodiment of the present invention.
FIG. 11 is a conceptual diagram illustrating another configuration example of a group of pictures applied to an embodiment of the present invention.
FIG. 12 is a conceptual diagram for explaining another relationship between a group of pictures and a cluster applied to one embodiment of the present invention.
FIG. 13 is a flowchart showing a procedure for creating data of one group of pictures for a read-only type mini-disc in one embodiment of the present invention.
FIG. 14 is a flowchart showing a recording process procedure for one group of pictures on a writable mini-disc in one embodiment of the present invention.
FIG. 15 is a flowchart showing a reproduction processing procedure for one group of pictures on the mini-disc 1a in one embodiment of the present invention.
FIG. 16 is a diagram showing prediction between images.
FIG. 17 is a diagram showing a data structure.
[Explanation of symbols]
1a: Mini disk, 2: Disk recording / reproducing device, 5: Color LCD, 20: MD drive device, 21: I / O interface, 22: MPU, 23: Main memory 24 DMAC 26 Audio encoder / decoder 27 Video encoder 29 Video decoder 28 LCD controller 50 System controller , 51 ... EFM / CIRC encoder / decoder

Claims (3)

A cluster which is a unit of reproduction in which a plurality of sectors in which a predetermined amount of data can be recorded is linked is provided exclusively for reproduction on the outer peripheral side in the recording data area of the disk,
Each frame of a group of pictures composed of a predetermined number of continuous frames of a moving image is subjected to image compression processing and recorded in a first sector area including a predetermined number of sectors of the cluster,
A recording medium in which compressed data of a predetermined format of a frame necessary for reproducing a frame of an adjacent group op picture is recorded in a second sector area including another sector of the cluster. 2. The recording medium according to claim 1, wherein the frame compression method required for reproducing the adjacent group of picture frames is intra-picture encoding. A cluster which is a unit of reproduction in which a plurality of sectors in which a predetermined amount of data can be recorded is linked is provided exclusively for reproduction on the outer peripheral side in the recording data area of the disk,
Each frame of a group of pictures composed of a predetermined number of continuous frames of a moving image is subjected to image compression processing and recorded in a first sector area including a predetermined number of sectors of the cluster,
In a reproducing apparatus for reproducing a recording medium in which compressed data of a predetermined format of a frame necessary for reproducing a frame of an adjacent group of pictures is recorded in a second sector area including another sector of the cluster,
Reproducing means for reading data in cluster units from the recording medium;
Storage means for storing data read by the reproduction means;
Decoding means for decoding the image-compressed data reproduced by the reproducing means,
Controlling the reproducing means so that the group of pictures to be decoded is read from the recording medium to the storage means; Is controlled so that is read out, the data recorded in the second sector area of the reproduced adjacent group of pictures and the group of pictures read from the recording medium to be decoded are And a control means for controlling the decoding means so that a moving image is reproduced based on the video signal.

Images