JPH0865670A - Method and device for encoding image - Google Patents

Abstract

PURPOSE: To reproduce a moving image, of which the encoded data amount is variable, composed of plural frames without any trouble by adding the information concerning the encoded data transfer amount as well in addition to encoded data. CONSTITUTION: A moving image signal 4 is converted into image data 6 just for (n) frames by an A/D converting circuit 5 and stored in frame memory 7 later. An image encoding circuit 8 encodes the image data 6 for (n) frames in the frame memory 7 and generates encoded data 9, and a data transfer speed calculating circuit 10 calculates the average data amount of the encoded data 9 and outputs data transfer rate information 11. The data read from a buffer memory 12, where this data transfer rate information 11 is stored, are edited into a format for optical disk by a mastering device 13 and recorded in a master disk 14 of an optical disk and an optical disk 16 is manufactured. Then, the information on the data transfer amount to transfer the encoded data of plural frames to a transmitting medium is added to the encoded data while variably controlling the data transfer amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to encoding, decoding and transmission of digital moving image data, and more particularly to encoding moving images suitable for a moving image reproducing system using package media such as CD-ROM. A method and apparatus.

[0002]

2. Description of the Related Art As a conventional moving picture coding method and apparatus, there is known an image coding transmission system disclosed in Japanese Patent Laid-Open No. 62-164391, or IEE, transaction on communication, or CMO. 32, 3 (March 1984) pp. 225 to 232 (IEEE, Trans. Communications, Vol.
COM-32, No. 3, March 1984, pp225
232) is used.

FIG. 2 is a block diagram showing a moving picture coding transmission system according to these conventional techniques. In the figure, 20 is a moving picture coding device, 22 is an input video signal, 23 is an A / D conversion circuit, 24 is image data, 25 is a frame memory having a capacity of at least one frame,
Reference numeral 26 is an image encoding circuit, 27 is encoded data, 28 is a buffer memory, 29 is an encoded data amount control circuit, and 30 is an encoded data amount control signal. Then, 31 is a transmission medium, 21 is a moving picture decoding device, 32 is encoded data, 33 is a buffer memory, 34 is an image decoding circuit, 3
5 is image data, 36 is a frame memory, 37 is D / A
The conversion circuit 38 is an output video signal. FIG. 3 is a data amount of encoded data generated in the image encoding circuit 26 in the conventional example shown in FIG. 2 (hereinafter, referred to as encoded data amount).
It shows the time variation of.

Next, the operation will be described. In FIG. 2, the input video signal 22 is converted into digital image data 24 by the A / D conversion circuit 23 every 1/30 seconds and stored and held in the frame memory 25.
The image encoding circuit 26 highly efficiently encodes the image data 24 in the frame memory 25 and stores it in the buffer memory 28. The encoded data 27 stored in the buffer memory 28 is, for example, 1 Mbits per second (hereinafter, 1 Mbits).
It is read at a speed of bps) and is output to the transmission medium 31. When the motion of the video content of the input video signal 22 is small, the encoded data amount 40 generated in the image encoding circuit 26 is the same as the frames a, b, c and d in FIG.
1 is determined by the transmission speed of the transmission medium 31
A of the data transfer capacity 41 per frame (here,
1 Mbps × 1/30 second≈32 kbit). In this case, dummy data is inserted and transmitted in order to establish transmission synchronization with the video decoding device 21. on the other hand,
When the video content of the input video signal 22 is violently moving or when there is a scene change, the encoded data amount 40 generated by the image encoding circuit 26 is one frame as in the frames e and f in FIG. Data transfer capacity of 41
It may exceed A. Therefore, in this case, since the data amount in the buffer memory 28 increases, the coded data amount control circuit 29 drops frames like the g frame or changes the coding parameters like the h and i frames. The encoded data amount 40 is controlled to be forcibly reduced by increasing the compression rate.

[0005]

In the above-mentioned prior art, since the transmission speed of the transmission medium is constant, the amount of coded data is forcibly reduced by dropping frames or changing the coding parameters for a moving image. Was going on. For this reason, the image quality of such a video in a moving image may be significantly deteriorated. By the way, from the viewpoint of information transmission regarding human perception, a large amount of important information is generally included in a large moving image as well as a small moving image. Therefore, in the related art in which a moving image with a large motion cannot be faithfully transmitted, its application is significantly limited.

As a means for solving this problem, it is conceivable to increase the transmission speed of the transmission medium, but for example, when the transmission medium is a communication line, the communication cost is greatly increased, and the transmission medium is a CD. -In the case of package media such as ROM, the total recording time of images is greatly reduced.

The present invention is intended to solve the above-mentioned problems, and an image with a large amount of motion is the same as an image with a small amount of motion with a minimum cost increase or a minimum total recording time reduction. The purpose is to ensure image quality and realize transmission of high-quality moving image data.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to variably control a data transfer amount for transferring coded data of a plurality of frames to a transmission medium in a moving image coding method and apparatus, and to code information on the data transfer amount. It is achieved by adding to the encoded data.

[0009]

According to the present invention, since information about the amount of coded data transferred is added in addition to the coded data, the coded data is prevented from becoming insufficient or broken during the reproduction of the moving image in the reproducing apparatus. In addition, it is possible to control the data read operation according to the information regarding the encoded data transfer amount, and it is possible to sequentially decode the encoded data of which the encoded data amount of a plurality of frames is variable, and reproduce the moving image without failure. . As a result, when a video with little motion and a video with a lot of motion are mixed, a part of the data generated in the part with a lot of front and back motion is added to the surplus part of the data transfer capacity in the part with little motion. When the data is transferred and the part with a lot of movement continues for a long time, the data transfer capacity from the recording medium is increased, and more data is transferred. Therefore, image quality deterioration can be reduced.

[0010]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, showing a moving image coding / recording system for an optical disc. In FIG. 1, reference numeral 1 is a moving picture coding apparatus and 2 is an optical disk manufacturing apparatus. Further, 3 is a moving image source such as a silver salt film or VTR, 4 is a moving image signal, 5
Is an A / D conversion circuit, 6 is image data, and 7 is at least n.
A frame memory having a capacity for frames, 8 is an image encoding circuit, 9 is encoded data, 10 is a data transfer rate calculation circuit, 11 is data transfer rate information, and 12 is a buffer memory. Further, 13 is a mastering device for reading the encoded data at a constant speed to create an optical disc master, 14 is an optical disc master, 15 is a press device for manufacturing an optical disc from the optical disc master by pressing, 1
Reference numeral 6 is an optical disk.

FIG. 4 is a diagram showing a change in the amount of encoded data generated in the image encoding circuit 8 in FIG. 1, and FIG. 5 is a reproduction of an optical disk produced by the moving image encoding / recording system shown in FIG. FIG. 3 is a block diagram of a moving picture decoding / playing system that performs In FIG. 4, 45 is the amount of encoded data generated in the image encoding circuit 8, and 46, 47 and 48 are data transfer capacities that change in n frame units. In addition, in FIG.
50 is an optical disk reproducing device, 51 is a moving image decoding device,
Reference numeral 52 is an optical disk on which moving images are coded and recorded, 53 is a servo circuit for controlling a rotation motor and an optical pickup,
54 is a rotary motor, 55 is a motor rotation control signal, 56 is an optical pickup, 57 is a preamplifier for amplifying a signal from the optical pickup, 58 is a data processing circuit for reproducing data, 59 is reproduced encoded data, and 60 is Data transfer rate information, 61 is a buffer memory for storing the encoded data of the reproduced moving image, 62 is an image decoding circuit for decoding the encoded data, 63 is the decoded image data,
Reference numeral 64 is a frame memory, 65 is a D / A conversion circuit, and 66 is an output video signal.

Next, the operation of the moving picture coded recording system shown in FIG. 1 will be described. When the moving image source 3 prepared in advance is encoded and recorded on the optical disk, first, the moving image signal 4 is converted into image data 6 by the A / D conversion circuit 5 for n frames, and then the frame memory 7 is stored. Remember. The image coding circuit 8 codes the image data 6 for n frames in the frame memory 7 to generate coded data 9, and the data transfer rate calculation circuit 10 calculates the average data amount of the coded data 9. And outputs the data transfer rate information 11. That is, the calculated data transfer rate is V (t) and the encoded data amount in each frame is D
(I)

[0013]

[Equation 1]

V (t) is determined so that For example, in FIG.
As shown in, when i = 1 to n, V (t) = α (bps) i = (n + 1) to 2n V (t) = β (bps) i = (2n + 1) to 3n V (t) = γ (bps). The data transfer rate information 11 is stored in the buffer memory 12 together with the encoded data 9. Then, the data read from the buffer memory 12 is edited by the mastering device 13 into an optical disc format and recorded on the optical disc master 14, and the press device 15 manufactures the optical disc 16.

Next, the operation of the moving picture decoding / reproducing system shown in FIG. 5 will be described. The data stored in the optical disc 52 is read by the optical pickup 56, amplified by the preamplifier 57, and waveform-shaped. Then, after being demodulated by the data processing circuit 58, data error correction processing is performed according to a predetermined procedure. The reproduced data is separated into encoded data 59 and data transfer rate information 60. The servo control circuit 53 outputs a motor rotation control signal 55 for controlling the rotation of the rotary motor 54 according to the data transfer speed information 60 reproduced by the data processing unit 58. Here, the servo is operated so that the data transfer rate from the preamplifier 57 becomes constant. That is,
CLV (constant linear velocity) rotation control is performed so that the data transfer rate is determined by the data transfer rate information 60.
For example, as described above, the data transfer rate changes in three stages of α, β and γ (bps). Then, the data processing circuit 5
The coded data 59 of the moving image reproduced in 8 is stored in the buffer memory 61, decoded into the original image data 63 by the image decoding circuit 62, and written in the frame memory 64. The image data 63 is sequentially read from the frame memory 64 in accordance with the display scanning, converted by the D / A converter 65 into an output video signal 66, and output. By the way, if the maximum data transfer rate is γ (bps), the capacity of the buffer memory 61 is

[0016]

## EQU00002 ## .gamma..times.n.times.1 / 30 (bits) is sufficient, but in reality, considering the response delay when the data transfer rate from the optical disk 52 is changed, a little extra memory is required. Need to have. In this embodiment, the processing is always performed every n frames, but the capacity of the buffer memory 61 can be reduced by, for example, making the value of n inversely proportional to the data transfer rate.

The example in which the data transfer speed is changed by controlling the rotation speed of the optical disk has been described above, but it is also possible to use an optical disk reproducing device having a fixed data transfer speed. For example, a commonly used CD-
By using a ROM reproducing device, it is possible to change the data transfer rate equivalently by devising the method of data transfer. Hereinafter, the example will be described in detail.

CD-ROM (Compact Disc-Read Only)
Memory) is for recording computer data, not digital audio data, on the same optical disc as an audio CD. FIG. 6 shows the structure of this optical disk. This optical disk is a disk having a diameter of 12 cm and a thickness of 1.2 mm, and is provided with one track 70 connected in a spiral shape with a total length of about 5 km. On the track 70, a pit having a width of 0.4 μm and a length of 0.9 to 3.3 μm (its length varies depending on the data) is recorded. Inner diameter 46 mm
The lead-in area 71 starts from, followed by the program area 72 having a diameter of 50 mm to a diameter of 116 mm, and the lead-out area 73 continues to an outer diameter of 120 mm. Then, actual digital audio data and computer data are recorded in the program area.
In addition, TOC (Table Of Content) is displayed in the lead-in area.
The entire table of contents is recorded.

FIG. 7 shows the format of data recorded on the CD-ROM disc. As shown in (a), the minimum unit of data recording is a frame 80 as in the audio CD, and as shown in (b), a frame 808 having a total of 588 bits includes a frame synchronization data 81, a subcode 82 (freely). Usable auxiliary information), 24 bytes of digital data 83, and error correction code ECC 84 by a double-coded Reed-Solomon code. This frame 80 is about 260 in the track 70 on the disc.
0,000 are recorded. Note that the data is not actually recorded in order, but appropriate data rearrangement (interleaving) is performed over a fairly long range in order to enhance the error correction capability for burst errors caused by defects and dirt on the disc. It is recorded after being broken.
In the case of an audio CD, the audio signal is 4
16-bit 2-channel digital audio data sampled at 4.1 kHz is equivalent to 24 bytes for one frame 80
In the case of a CD-ROM, computer data is recorded instead.

As shown in (c), one sector 85 of the CD-ROM is composed of 2352 bytes including 98 frames of digital data 83, in which blocked 2048 bytes of computer data are recorded. . One sector 85 has 12-byte sync data 86 for synchronization, address and mode information 4
Byte header data 87, 2048 bytes computer data 88, 4-byte error detection code EDC89 with 32-bit CRC, 8-byte reserved area 90 for future expansion, 276-byte error with double-coded Reed-Solomon code It consists of a correction code ECC91. To the computer, as shown in (e), it seems that the computer data 88 divided into blocks of 2 kB are arranged.

Although the audio CD has been subjected to strong error correction as already described, the CD-
Since the ROM is intended for computer data, error correction is further performed to improve data quality. The data transfer rate of CD-ROM is 1.2 Mbps,
That is, it is 150 kB / sec, and approximately 540 MB of computer data can be recorded.

FIG. 8 is a block diagram of a moving image coding / recording system for recording a moving image on a CD-ROM, and FIG. 9 is a block diagram of a moving image decoding / reproducing system for reproducing a moving image from a CD-ROM. First, in FIG. 8, 100 is a moving picture coding device, 111 is a CD-ROM manufacturing device, and 112 is a CD-R.
It is an OM disc. In the moving picture coding apparatus 100, 101 is an input video signal, 102 is an A / D conversion circuit, 103 is image data, 104 is a frame memory having a capacity of one frame or more, 105 is an image coding circuit,
106 is encoded data, 107 is data transfer rate information,
108 is a data multiplexing circuit, 109 is a buffer memory, 1
Reference numeral 10 is a data transfer rate information generation circuit. Next, FIG.
In the figure, 120 is a moving picture decoding device, 121 is a CD-ROM disc, and 122 is a CD-ROM reproducing device. Also, in the moving picture decoding device 120, 12
3 is a data separation circuit, 124 is encoded data, 125 is data transfer rate information, 126 is a data transfer control circuit, 1
27 is a buffer memory, 128 is an image decoding circuit, 12
Reference numeral 9 is image data, 130 is a frame memory having a capacity of one frame or more, 131 is a D / A conversion circuit, and 132 is an output video signal.

First, the operation of the moving picture coded recording system shown in FIG. 8 will be described. A video signal output from a TV camera, a video tape recorder, or the like is separated from an NTSC composite video signal into three types of component video signals (for example, luminance Y, color differences RY and BY). Each input video signal 101 is sampled by the A / D conversion circuit 102 at a predetermined sampling frequency (for example, four times the frequency of the color subcarrier frequency of 3.58 MHz) and sequentially converted to digital image data 103. It
Normally, the number of bits of the A / D conversion circuit 102 is set to 8 bits, so the data amount of the image data 103 per pixel is 8 bits for each component component, for a total of 24 bits.
Bit. The frame memory 104 has a capacity capable of storing image data for a plurality of frames, and the digitized image data 103 is sequentially written by a predetermined number of frames. Although it depends on the image coding method, at least two frames are required for interframe coding, for example. The image data 103 stored and held in the frame memory 104 is highly efficiently encoded by the image encoding circuit 105, and the encoded data 10 with reduced redundancy
6 is generated. Although various image coding methods are known, for example, when the motion-compensated interframe coding method is used, data compression can be performed about 1/100 times on average. That is, the image data 103 of 24 bits per pixel can be compressed to about 0.2 bits. However, the data pressure rate changes considerably depending on the ratio of the moving area, the intensity of the movement, the fineness and vividness of the pattern, etc., and the data amount of the encoded data 106 changes for each frame.

Generally, so far, the buffer memory 10
The image encoding circuit 10 changes the encoding parameter according to the data amount of the encoded data 106 stored in the image encoding circuit 10.
5 is used to control the amount of encoded data 106 generated. This is because the amount of data in the buffer memory 109 is kept as constant as possible, and the average value of the amount of data generated per unit time is adjusted to the data transfer rate of the CD-ROM. Conventionally, an encoding device and a decoding device using a communication path of a constant data transfer rate have been mainly developed, and thus a method of controlling the encoded data amount by changing the encoding parameter is generally used. It was However, with this method, the amount of data generated is controlled by changing the coding parameters according to the convenience of data transfer, regardless of the amount of information originally contained in the input image, so the fluctuation in coding error for each frame becomes extremely large. This causes a significant deterioration in image quality. Therefore, in this embodiment, the buffer memory 109
The data transfer rate information generation circuit 110 for generating the data transfer rate information 107 according to the data amount of the encoded data 106 stored in the buffer is provided, and the data transfer rate from the buffer memory 109 to the CD-ROM manufacturing apparatus 111 is set. The control method is adopted. By using this method, it is possible to suppress the fluctuation of the coding error, improve the image quality, and record a moving image for a long time. The specific method will be described in detail later.

The coded data 106 output from the image coding circuit 105 is multiplexed with the data transfer rate information 107 by the data multiplexing circuit 108 and stored and held in the buffer memory 109. Then, the data is sequentially read from the buffer memory 109 and output to the CD-ROM manufacturing apparatus 111 while controlling the data transfer rate. CD-R
Since the OM is not a medium that the user can easily record on the spot, the data to be recorded is stored in the CD-ROM manufacturing apparatus 1
CD-RO after handing over to 11 and making a master disc
It is necessary to manufacture the M disk 112 by pressing.

Next, the operation of the moving picture decoding system shown in FIG. 9 will be described. CD-ROM disc 121 is a CD
-The data reproduced and recorded by the ROM reproducing device 122 is read. The read data is separated by the data separation circuit 123 into encoded data 124 and data transfer rate information 125. This data transfer rate information 12
5, the data transfer control circuit 126 controls the data transfer speed from the CD-ROM reproducing device 122. The specific method will be described in detail later. The encoded data 124 is once written in the buffer memory 127, but since the data transfer rate is controlled, the data amount of the encoded data 124 stored in the buffer memory 127 is kept substantially constant. Then, the encoded data 124 read from the buffer memory 127 is the image decoding circuit 128.
To the image data 129. The decoded image data 129 is stored and held in the frame memory 130, and the analog output video signal 1 is stored in the A / D conversion circuit 131.
It is converted to 32 and displayed on the CTR section.

Then, the method of controlling the data transfer rate from the moving picture coding apparatus 100 to the CD-ROM manufacturing apparatus 111 in FIG. 8 and the data from the CD-ROM reproducing apparatus 122 to the moving picture decoding apparatus 120 in FIG. A method of controlling the transfer speed will be described. The data transfer rate of a CD-ROM is 1.2 Mbps (that is, 150 kB /
Second), and a method of controlling the data transfer rate in two steps, that is, the maximum transfer rate and a slower transfer rate slower than the maximum transfer rate will be described in detail below.

FIG. 10 shows a first example of the data transfer rate control method. In the figure, (a) shows the encoded data 10 recorded in order on the tracks of the CD-ROM disc.
6 is arranged from the moving image encoding apparatus 100 to CD-.
A state of data transfer to the ROM manufacturing apparatus 111, (c) a data transfer speed in the data transfer, (d) a data amount of the encoded data 106 generated by the image encoding circuit 105, (e) a buffer memory 109. It is the data amount of the encoded data 106 stored in.

Since the coded data amount 152 after highly efficient coding of the moving image varies greatly from frame to frame as shown in (d), the data transfer rate is changed to control the data amount 153 in the buffer memory. There is a need. That is, when the encoded data 140 is transferred at the maximum transfer rate, the data amount 153 in the buffer memory becomes lower than the lower limit threshold 154 at time A as shown in (e). Therefore, when the coded data 141 to 149 are transferred by switching to the low transfer rate from the time point A, the data amount 153 in the buffer memory now exceeds the upper limit threshold 155 at the time point B. Therefore, the encoded data 150 is transferred again at the maximum transfer rate. Here, in order to realize data transfer at a low transfer rate, as shown in (a) and (b), sectors 141, 143, 145, 147, and 149 are skipped from time A to time B. , 142, 144, 146, 148 realizes a low transfer rate equivalent to 1/2 of the maximum transfer rate (shown by a dotted line in (c)) equivalently.

When skipping a sector, there is a method of transferring data other than coded data in addition to the method of not transferring data.

FIG. 11 shows a second example of the method of controlling the data transfer rate. In the figure, (a) is a line of encoded data, (b) is the state of data transfer, (c) is the data transfer rate, (d) is the amount of encoded data, and (e) is the amount of data in the buffer memory. is there.

The data transfer rate is changed according to the variation of the encoded data amount 167, and the data amount 1 in the buffer memory is changed to 1.
Control 68. That is, from the time A when the data amount 168 in the buffer memory is below the lower threshold 169 to the time B when it is above the upper threshold 170,
The data transfer of the encoded data 161 to 164 is performed at a low transfer rate. Here, in order to realize data transfer at a low transfer rate, as shown in (a) and (b), from the time point A to the time point B, the sectors 161, 162, 163, 164 start and end. By equivalently pausing for a suitable time, a low transfer rate (shown by a dotted line in (c)) slower than the maximum transfer rate is realized equivalently.

By adjusting the pause time, it is easy to provide more than two stages. Further, it is not necessary to provide a pause for each sector as described above, but it may be provided for each of a plurality of sectors.

FIG. 12 shows a third example of the data transfer rate control method. In the figure, (a) is a line of encoded data, (b) is the state of data transfer, (c) is the data transfer rate, (d) is the amount of encoded data, and (e) is the amount of data in the buffer memory. is there.

The data transfer rate is changed according to the variation of the encoded data amount 187 shown in (d), and the data amount 188 in the buffer memory shown in (e) is controlled. That is,
From the time point A when the data amount 188 in the buffer memory falls below the lower threshold 189, the upper threshold 190
Up to the point of B, which is higher than B, the encoded data 181 to 184
Data transfer at low speed. Here, in order to realize data transfer at a low transfer rate, as shown in (a) and (b), from the time point A to the time point B, first,
The sectors 81 and 183 are skipped and the data is transferred only in the sectors 182 and 184. Then, the seek is performed again up to the point A and the data is transferred only in the previously skipped sectors. By doing so, a low transfer rate (shown by a dotted line in (c)) equivalently slower than the maximum transfer rate is realized.

The ratio between the number of sectors to be skipped and the number of sectors to transfer data may be N instead of 1, and seek for returning from the end to the beginning may be performed N times.

As described above, from the moving picture coding apparatus 100 to the CD-
Three examples of the method of controlling the data transfer rate to the ROM manufacturing apparatus 111 have been described in detail with reference to FIGS. 10 to 12. The data transfer speed from the CD-ROM reproducing device 122 to the moving picture decoding device 120 is in accordance with the data transfer speed information 125, as described above, from the moving picture coding device 100 to the CD-ROM manufacturing device 111. It is variably controlled like the data transfer rate. That is, CD-
The ROM reproducing device 122 equivalently variably controls the data transfer rate by skipping, pausing, or seeking during the reading of data from the CD-ROM. Control of the data transfer rate of the encoded data is performed by the moving picture encoding device 10.
It was supposed to be performed by the amount of data in the buffer memory of 0, but of course it may be controlled by another method. For example, the amount of data in the buffer memory of the moving image decoding apparatus 120 may be predicted and controlled by comparing the amount of data with a predetermined threshold. Also, the image coding circuit 1 is used instead of the data amount in the buffer memory.
The control may be performed according to the encoded data amount generated in 05.
For example, in the moving image encoding apparatus 100, the frame memory 104 is provided for n frames, the captured n frames of image data are collectively encoded to calculate the total encoded data amount, and then the total encoded data amount is calculated. There is a method of controlling the data transfer rate accordingly.

Further, the CD-ROM disk 112 has
It is necessary to record the data transfer rate information 107 together with the encoded data 106. However, the data transfer rate information is embedded and recorded together in the sequence of the encoded data, or only the data transfer rate information is separately recorded. It may be recorded in a predetermined place collectively. It may be recorded in the subcode area shown in FIG. 7B or the reserved area in the sector shown in FIG.

The case of recording encoded data on an optical disk such as a CD-ROM has been described above in detail, but the present invention is not limited to this and other data recording media may be used. For example, a CD-R that the user can freely rewrite
Examples include AM disks, hard disks, and floppy disks. While a CD-ROM has a single spiral track, a hard disk or the like has a plurality of concentric tracks, but the same method as the data transfer rate control method described so far can be applied.

[0040]

As described above, according to the present invention,
Since the information about the encoded data transfer amount is added to the encoded data, the encoded data amount of a plurality of frames can be changed by controlling the data read operation in the reproducing device according to the information about the encoded data transfer amount. It is possible to reproduce a moving image without failure, and it is possible to realize recording and reproduction of a moving image with higher image quality than in the past. Further, if the image quality is the same as the conventional one, the amount of data to be read from the recording medium can be reduced, so that it is possible to realize recording and reproduction of a moving image for a longer time than the conventional one.

[Brief description of drawings]

FIG. 1 is a block diagram of a moving picture coded recording system according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional moving image coding transmission system.

FIG. 3 is a graph showing variations in the amount of encoded data in FIG.

FIG. 4 is a graph showing changes in the amount of encoded data and changes in data transfer capacity in FIG.

FIG. 5 is a block diagram of a moving picture decoding / reproducing system which is paired with FIG.

FIG. 6 is a conceptual diagram showing the structure of a CD-ROM disc, which is a type of optical disc.

FIG. 7 is a conceptual diagram showing a data format of a CD-ROM.

FIG. 8 is a block diagram of a moving picture coded recording system which is another embodiment of the present invention.

FIG. 9 is a block diagram of a moving picture decoding / playing system which is paired with FIG. 8.

10 is a conceptual diagram showing three examples of the data transfer method in FIG.

11 is a conceptual diagram showing three examples of the data transfer method in FIG.

12 is a conceptual diagram showing three examples of the data transfer method in FIG.

[Explanation of symbols]

1, 20, 100 ... Moving picture coding device, 21, 51, 120 ... Moving picture decoding device, 7, 25, 36, 64, 104, 130 ... Frame memory, 12, 28, 33, 61, 109, 127 ... buffer memory, 8, 26, 105 ... image coding circuit, 34, 62, 128 ... image decoding circuit, 10 ... average data transfer calculation circuit, 53 ... servo control circuit, 110 ... data transfer rate information generation circuit, 126 ... Data transfer control circuit.

Claims (10)

[Claims] 1. An image coding method for generating coded data according to a predetermined coding method, wherein the coded data transfer amount information for transferring coded data for each of a plurality of image sets is coded. An image encoding method characterized by adding to data. 2. An image coding method for generating coded data according to a predetermined coding method, wherein the coded data includes information on a coded data transfer amount per unit time for transferring the coded data. An image encoding method characterized by adding. 3. An image coding method for generating coded data according to a predetermined coding method, wherein the coded data amount is calculated from the coded data, and the coded data transfer amount per unit time is plural. The total amount of encoded data for each image set is divided by the time width of the plurality of image sets, and the encoded data transfer amount is set to be a value greater than or equal to the average encoded data amount. An image coding method, characterized in that information on a quantity is added to the coded data. 4. An image coding method for generating coded data according to a predetermined coding method, wherein the coded data amount is calculated from the coded data, and the cumulative total of the coded data amount and the coded data are calculated. An image characterized by setting the encoded data transfer amount such that the difference value from the cumulative total of the transferred amount is always within a predetermined range, and adding information on the encoded data transfer amount to the encoded data. Encoding method. 5. An image coding apparatus for generating coded data according to a predetermined coding method, wherein the coded data transfer amount information for transferring coded data for each of a plurality of image sets is coded. An image encoding device comprising: an addition unit that adds the data. 6. An image coding apparatus for generating coded data by a predetermined coding method, wherein the coded data transfer amount information for transferring coded data for each of a plurality of image sets is coded. An image coding apparatus comprising: an addition unit that adds data, and a control unit that transfers the coded data based on the coded data transfer amount. 7. An image coding apparatus for generating coded data according to a predetermined coding method, wherein the coded data includes information on a coded data transfer amount per unit time for transferring the coded data. An image coding apparatus comprising: an addition unit that adds the image data and a control unit that transfers the coded data based on the coded data transfer amount. 8. An image coding apparatus for generating coded data according to a predetermined coding method, comprising: calculating means for calculating the coded data amount from the coded data; and coded data transfer amount per unit time. A setting means for setting the coded data transfer amount such that the sum of the coded data amounts for each of the plurality of image sets is equal to or greater than the average coded data amount obtained by dividing the sum of the coded data amounts by the time width of the plurality of image sets An addition means for adding information about the encoded data transfer amount to the encoded data,
An image coding apparatus, comprising: a control unit that transfers the coded data based on the coded data transfer amount. 9. An image coding apparatus for generating coded data according to a predetermined coding method, comprising: calculating means for calculating the coded data amount from the coded data; cumulative total of the coded data amount; Setting means for setting the coded data transfer amount so that the difference value from the cumulative total of the coded data transfer amount is always within a predetermined range, and addition for adding information on the coded data transfer amount to the coded data. An image coding apparatus comprising: a means and a control means for transferring the coded data based on the coded data transfer amount. 10. An image coding apparatus for generating coded data according to a predetermined coding method, comprising: a buffer for temporarily storing the generated coded data; and coded data for transferring the coded data. Setting means for setting the transfer amount,
The setting means includes: an addition unit that adds information about the encoded data transfer amount to the encoded data; and a control unit that transfers the encoded data from the buffer based on the encoded data transfer amount. An image coding apparatus, wherein the coded data transfer amount is set according to the degree of sufficiency of the coded data in the buffer.