JPH07184163A - Information recording medium, information reproduction device and information reproducing method - Google Patents

Abstract

PURPOSE:To reproduce a video image in the forward direction or the reverse direction at a high speed by detecting a position of an in-frame coding picture with a memory of a small capacity at a higher speed. CONSTITUTION:An information recording medium 1 is constituted of plural file areas 101 recording compressed video audio data and a file information area 100 managing the areas 101. A directory entry 110 managing the area 101 by one to one is recorded in the area 100. The area 101 is made up of plural segments 120. Each segment 120 consists of variable numbers of sectors 130 recording compressed video and audio data. The sector 130 is constituted of a sector address 140, control data 141, user data 142 and an error correction check code 143. Since the data 141 are recorded just after the address 140, the address 140 is detected and immediately acquired. A segment is retrieved in a binary tree retrieval way for an object segment at a high speed by recording the segment after integrated number of 2s in the data 141.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium in which video and audio are compressed and recorded in sector units on an information recording medium,
The present invention relates to an information reproducing apparatus and an information reproducing method for reproducing an image from the information recording medium at high speed.

[0002]

2. Description of the Related Art As one of video and audio compression techniques,
The well-known international standard MPEG (Mov
ing Picture Expert Group.
ISO / IEC 11172).

In MPEG, video and audio are separately compressed, and multiplexed to generate one compressed bit stream.

In MPEG, each audio frame forming audio is an intra-coded audio which is compressed using only the information in the video frame. On the other hand, each video frame which is an image forming each video is compressed into the following three types as illustrated in FIG. 7 in order to achieve a high compression rate and high image quality.

I-picture (Intra coded p
image) is an intra-frame coded image compressed using only the information in the video frame.

P-picture (Predictive co)
A ded picture) is an inter-frame coded image that is compressed using not only the information in the video frame but also the difference between the information of the preceding I picture or the preceding P picture and the information in the video frame.

Then, a B picture (Bidirecti)
only-predictive coded p
In addition to the information in the video frame, the difference between the information in the front I picture or the front P picture and the information in the video frame, and the information in the rear I picture or the rear P picture and the information in the video frame. It is an inter-frame coded image compressed by using the difference from the information in the video frame.

As described above, the P picture and the B picture achieve high image quality with a small amount of data by compressing using the difference between video frames.

Next, let us consider reproducing the image at high speed in the forward or reverse direction. Since the I picture is an intra-frame coded image, it can be expanded independently. Therefore, by skipping other P-pictures and B-pictures and reproducing and expanding only the I-picture, the video can be reproduced at high speed in the forward or reverse direction.

As for the position of the I picture to be reproduced, if the video and audio are compressed so that the interval between the I pictures is fixed,
It can be easily calculated by proportional calculation.

However, in order to compress the I picture so that the interval becomes a fixed length, it is necessary to increase the compression rate in order to keep it within that range, and the image quality deteriorates. Enormous processing time is required to compress at an optimum ratio so as not to deteriorate image quality. Further, if the interval between I-pictures is set to be large, useless empty areas will occur.

Therefore, it is conceivable to compress and record video and audio with variable intervals of I pictures and record the position information of all I pictures on the information recording medium.

The position information of all I pictures are collectively I
When the picture management information is recorded in the first or last area of the information recording medium, the reproduction speed becomes slow if the I picture management information is read every time the I picture is accessed. Further, in order to read the I picture only at the beginning, a large capacity memory for storing the entire I picture management information is required.

A method of reproducing only an I picture, that is, an intra-frame coded image in a small-capacity memory is disclosed in Japanese Patent Laid-Open No. Hei 4-
It is disclosed in Japanese Patent No. 58686.

In this method, the position information of the next intra-frame coded image is recorded at the beginning of the intra-frame coded image. Since the position of the next intra-frame coded image can be known immediately after playing the intra-frame coded image, high-speed video playback can be realized by sequentially searching and playing only intra-frame coded images. You can

[0016]

However, in the method disclosed in Japanese Patent Laid-Open No. 4-58686, the position information of the next intra-frame coded image is added only to the beginning of the intra-frame coded image. Therefore, for example, the rear 4
Even if one intra-frame coded image is skipped and the fifth intra-frame coded image is to be played back, all the beginnings of the four intra-frame coded images in between must be played back, and therefore the playback speed is It had the problem of being limited.

According to the present invention, the information recording medium, the information recording / reproducing apparatus, and the information recording which can detect the position information of the preceding and following intra-frame coded images at a higher speed and reproduce the video forward or backward at a high speed. The purpose is to provide a reproducing method.

[0018]

In order to achieve the above object, the present invention is directed to frame encoding in which frame encoded images obtained by variable length compression of video frames are continuously recorded in a data area of a sector having a fixed data capacity. The information recording medium is characterized in that an image position area for recording image numbers and position information of preceding and following frame encoded images is formed in all sectors.

Further, according to the present invention, frame-encoded images obtained by variable-length-compressing video frames are continuously recorded in a data area of a sector having a fixed data capacity, and the frame-encoded image number and the preceding and following frame-encoded images are recorded. From the information recording medium in which the position information is recorded in the image position areas of all the sectors, is an information reproducing apparatus for reproducing the frame-encoded image in a scattered manner, and head moving means for moving the reproducing head toward the target sector position, Sector detecting means for detecting a sector position, target sector detecting means for detecting a target sector position, sector reproducing means for reproducing a sector and transmitting reproduced data, and a predetermined number backward or predetermined number of frames in the reproduced data The head moving means is executed with the sector position indicated by the position information of the encoded image as the target sector position, and The moving reproduction means for repeating the reproduction of the detected sector by the sector reproduction means, and the target sector detection means after the movement reproduction means are executed, and the frame encoded image is reproduced from the target sector position by the sector reproduction means. Then, the information reproducing apparatus is provided with a high-speed image reproducing means for executing again from the repetition of the moving reproducing means.

Further, according to the present invention, frame-encoded images obtained by variable-length-compressing video frames are continuously recorded in a data area of a sector having a fixed data capacity, and the frame-encoded image number and the preceding and following frame-encoded images are recorded. From the information recording medium in which position information is recorded in the image position area of all sectors,
An information reproducing method for reproducing a frame-encoded image intermittently, wherein reproduction data is reproduced from a sector in which a frame-encoded image for starting reproduction is recorded, and a predetermined number backward or a predetermined number of frame codes in the reproduction data are reproduced. The target sector position is detected after repeatedly moving the target sector at the sector position indicated by the position information of the encoded image and reproducing the reproduction data from the first sector detected after the movement, and reproducing data from that sector. Is reproduced and the frame encoded image is transmitted, and thereafter, it is repeatedly executed from the sector position indicated by the position information of the frame encoded image of a predetermined number backward or a predetermined number in the reproduced data as a target. This is the information reproducing method.

Finally, according to the present invention, frame-encoded images obtained by variable-length-compressing video frames are continuously recorded in the data area of a sector having a fixed data capacity, and the position information of the current frame-encoded image and one A method for reproducing information in which the frame-coded image is reproduced from the information recording medium in which the position information of the backward frame-coded image is recorded in the image position areas of all sectors The reproduced data is reproduced from the recorded sector, the sector position where the frame coded image of a predetermined number of backwards or a predetermined number of frames is recorded is predicted, the predicted sector position is moved as a target, and first detected after the movement. The reproduction data is reproduced from the sector, and the sector position of the frame-encoded image that is one behind in the reproduction data and the sector position of the current frame-encoded image are recorded. Moves with the nearer sector position as the target, detects the target sector position, reproduces the reproduced data from that sector, and sends out a frame-encoded image. This is an information reproducing method characterized in that a sector position in which an image is recorded is predicted, and the predicted sector position is moved as a target to repeatedly execute.

[0022]

According to the present invention, according to the above-described structure, first, after reproducing data from a sector in which an intra-coded image is recorded, an intra-frame coded image which is a predetermined number of backwards or a predetermined number of forwards in the reproduced data is reproduced. By repeating the process of moving toward the sector position where is recorded and reproducing the reproduction data from the first detected sector after the movement, the sector in which the target intra-frame encoded image is recorded is searched. It becomes possible to reproduce.

Secondly, according to the present invention, after reproducing the reproduction data from the sector in which the intra-frame coded image is recorded, the sector position in which the intra-frame coded image which is the next reproduction target is recorded is predicted. , The target sector is moved as the target, and the reproduced data is reproduced from the first detected sector after the movement. Then, by moving the sector position of the intra-frame coded image that is one behind in the reproduction data and the sector position closer to the sector position of the current intra-frame coded image as a target, the frame in the vicinity of the target frame is moved. It becomes possible to retrieve and reproduce the sector in which the inner coded image is recorded.

[0024]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the area structure of an information recording medium 1 according to an embodiment of the present invention. In this embodiment, the information recording medium 1
Will be described assuming that data is recorded and reproduced in sector units.

FIG. 1A is an area configuration diagram of the information recording medium 1. The information recording medium 1 includes a plurality of file areas 101 in which compressed video / audio data is recorded and files for managing the respective file areas 101. It is composed of the management information area 100.

FIG. 1B shows a file management information area 100.
In the file management information area 100, a directory entry 110 for managing each file area 101 on a one-to-one basis is recorded. The directory entry 110 includes a file area name, a file area size,
The location information of the file area and the creation time of the file area are recorded.

FIG. 1C is an area configuration diagram of each file area 101, and the file area 101 is composed of a plurality of segments 120. Each segment 120 is shown in FIG.
As shown in (d), it is composed of a variable number of sectors 130 in which compressed video and compressed audio are recorded.

FIG. 2 shows a data structure diagram of compressed video and compressed audio in the segment 120. First, one variable-length-compressed intra-frame coded image 200 is arranged at the beginning of the segment 120, one or more variable-length-compressed inter-frame coded images 201 are arranged, and finally the frame-coded audio 202. One or more are arranged.

FIG. 1E is a data structure diagram in the sector 130. The sector 130 includes a sector address 140 of the sector 130, control data 141 that is management information of the sector 130, compressed video and audio, user data 142 such as the directory entry 110, and user data 142. It is composed of an error correction detection code 143 for improving reliability.

Since the control data 141 is recorded immediately after the sector address 140, the sector address 1
As soon as 40 is detected, it can be obtained. Further, the control data 141 is efficiently recorded, for example, by using a free area generated for adding the error correction detection code 143.

FIG. 1F is a data structure diagram of the control data 141. The control data 141 is a stream ID 15 indicating the type of the user data 142.
0 and the first segment 120 in the file area 101
From the segment number 151, the current segment position 158, the one segment position 152 behind, the two segment positions 153 behind, the four segment positions 154 behind, and the one segment ahead. The segment position 155, the segment position 156 two forwards, and the segment position 157 four segments ahead. In addition,
The front segment position (155 to 157) is not recorded in the control data 141 in the first segment 120 of each file area 101.
The control data 141 in the last segment 120 of 01 includes the rear segment position (from 152 to 15).
4) is not recorded.

In the present embodiment, the head sector address of the segment 120 is set in the segment positions (152 to 157).

In the stream ID 150, the user data 142 includes video, audio, and directory entry 11.
0, and, in the case of video, whether it is the intra-frame coded image 200 or the inter-frame coded image 201. By checking the stream ID 150 during reproduction of the intra-frame coded image 200, it is possible to determine the end of the sector 130 in which the intra-frame coded image 200 is recorded.

In FIG. 3, the current segment position 158 in the control data 141, the segment position 152 one backward, the segment position 153 two backwards, the segment position 154 backwards, and the segment position one forward. The positional relationship between the segment position 155, the segment position 156 two forwards, the segment position 157 four forwards, and the segment 120 is shown.

These plural posterior segment positions are for searching an arbitrary number of posterior segment positions. For example, the search operation of the segment position 10 ahead is
The segment position 154 located four behind is searched and reproduced, and the segment position 1 located four more behind in the sector 130 is searched.
54 is searched and played back, and finally 2 in the sector 130 is searched.
This can be done by searching the segment position 153 backward by one.

By recording the segment positions behind the power of 2 in this way, the target segment can be detected at high speed by binary search.

The plurality of front segment positions are similarly used to search for an arbitrary number of front segment positions.

Further, rear and front segment positions,
Since the segment number 151 is recorded in all the sectors 130, a new target segment position can be calculated from the target segment position even if the target segment position is not reached in one search. , The segments 120 can be searched one after another.

Next, FIG. 4 shows the information recording medium 1 shown in FIG.
FIG. 3 is a block configuration diagram of an information reproducing apparatus that searches for and reproduces an intra-frame coded image 200 from a high speed.

In this embodiment, the information recording medium 1 is in the shape of a disk, such as an optical disk or a magnetic disk, and is composed of a number of tracks composed of sectors 130 for one round of the disk.

In FIG. 4, reference numeral 2 is an information reproducing apparatus for reproducing the data recorded on the information recording medium 1, and 3 is a control of the information reproducing apparatus 2 for reproducing the file area 101 designated by the user and expanding the reproduced data. Host computer to use, 4
Is a display for displaying the video frame signal 408 received from the host computer 3, 40 is a microcontroller for controlling the entire information reproducing apparatus 2 by the firmware stored therein, and 41 is recorded in the sector 130 of the information recording medium 1. Read signal and play signal 4
A head for sending out 05, 42 is a seek control circuit for moving the head 41 to the vicinity of the target sector position, 43 is for demodulating the reproduction signal 405 and executing error correction processing to obtain the sector address 140, the control data 141 and the user data 142. , A control data memory circuit for temporarily storing the control data 141, a user data memory circuit for temporarily storing the user data 142, and a SCSI (Small)
Computer System Interfac
This is a host interface control circuit that controls transfer operations such as device commands, reproduction data, and command status with the host computer via the host interface 400 as in e).

Further, 47 is a microcontroller 4 for storing the number of search segments for designating how many backward or forward intra-frame coded images 200 are reproduced.
0 is a search segment number register inside 0, 48 is a search segment number register for storing the segment number to be searched next and reproduced, and 49 is a target sector address register for storing the sector address of the target sector to be reproduced.

The operation of the information reproducing apparatus of one embodiment of the present invention constructed as above will be described below.

FIG. 5 shows a procedure in which the information reproducing apparatus 2 receives a start command from the host computer 3 and reproduces a predetermined number of backward frame-encoded images 200 while accurately skipping them to perform high-speed reproduction processing. It is a flowchart explaining.

The host computer 3 specifies the start sector address of the file area 101 to be reproduced, the number of search segments which specifies how many backward or forward segments 120 the intra-frame coded image 200 existing at the beginning is reproduced, and the backward segment. A direction indicator that indicates which direction to search, ie, forward or backward, is set in the start command and sent. (Step 500) The microcontroller 40 sends the device command 4 from the host interface control circuit 46.
When the start command is received as 01, the direction indicator in the start command indicates backward,
Know that high-speed playback processing to the rear has been requested.

Then, the microcontroller 40 sets the start sector address and the number of search segments in the start command in the target sector address register 49 and the number of search segment registers 47, respectively, and then the command status indicating that the high speed reproduction process is started. The start command execution is completed by setting 402 in the host interface control circuit 46 and transferring it to the host computer 3. (Step 501) The microcontroller 40 activates the seek control circuit 42 by sending out the seek control signal 403 in which the address of the track where the target sector address in the target sector address register 49 exists is set as the target track address.

The seek control circuit 42 uses the head control signal 40.
4 is sent to move the head 41 toward the target track address.

When the movement of the head 41 is completed, the reproducing circuit 43 reproduces the reproduced signal 405 sent from the head 41 to change the sector address 140 to the sector address signal 40.
Send to 6. (Step 502) If the sector address 140 received from the reproducing circuit 43 is not the sector address on the target track A, the microcontroller 40 proceeds to Step 5
The processing is repeated from 01. (Step 503) If the sector address 140 received from the reproducing circuit 43 is the sector address on the target track, the microcontroller 40 rotates the information recording medium 1 and detects the target sector address.
The control data 141 and the user data 142 sent from are stored in the control data memory circuit 44 and the user data memory 45 circuit via the data bus 407, respectively.

Then, the microcontroller 40 uses the stream ID 15 in the control data memory circuit 44.
While 0 indicates the intra-frame coded image 200, the user data 142 stored in the user data memory circuit 45 is sent to the host interface control circuit 46 and transferred to the host computer 3, whereby the intra-frame coded image 200 is displayed. Reproduce. (Step 504) The microcontroller 40 sends the segment number 15 from the control data memory circuit 44.
1 is taken out and the search segment number obtained by adding the number of search segments in the search segment number register 47 and this segment number 151 is stored in the search segment number register 48 as the segment number to be searched next. (Step 505) The microcontroller 40 uses the segment number 15 in the control data memory circuit 44.
The difference in segment number from 1 to the search segment number stored in the search segment number register 48 is obtained.

If there is a segment position backward by the number matching the segment number difference in the control data memory circuit 44, the microcontroller 40 sets the segment position in the target sector address register 49, and then in Step 501. Repeat from processing. For example, when the difference between the segment numbers is 4, the segment position 154 four behind in the control data memory circuit 44 is set in the target sector address register 49. When the segment number difference is 0, the current segment number 158 is set to the target sector address register 49.
Set to.

The microcontroller 40 exists in the control data memory circuit 44 and is smaller than the difference in the segment number if the segment position backward by the number corresponding to the difference in the segment number does not exist in the control data memory circuit 44. Among the segment positions behind the number, the segment position with the largest number backward is set in the target sector address register 49. For example, when the difference between the segment numbers is 3, the segment position 153 two behind in the control data memory circuit 44 is set in the target sector address register 49. (Step 506) The microcontroller 40 activates the seek control circuit 42 by sending out the seek control signal 403 in which the address of the track where the target sector address in the target sector address register 49 exists is set as the target track address.

The seek control circuit 42 uses the head control signal 40.
4 is sent to move the head 41 toward the target track address.

When the movement of the head 41 is completed, the reproducing circuit 43 reproduces the reproduced signal 405 sent from the head 41 to change the sector address 140 to the sector address signal 40.
Send to 6.

Then, the microcontroller 40 stores the control data 141 in the control data memory circuit 44 via the data bus 407, and then, Step
The processing from step 505 is repeated. (Step 507) The microcontroller 40 sets St
When a stop command is received as the device command 401 from the host interface control circuit 46 after executing the processing of ep503, this high-speed reproduction processing is terminated, and a command status 402 indicating that high-speed reproduction processing has been performed is issued to the host interface control circuit. 46
And the transfer to the host computer 3 completes execution of the stop command.

As described above, the information reproducing apparatus 2 can acquire the segment number of the seek position and the succeeding segment position without waiting for the rotation immediately after the completion of the seek operation, so that the frame existing at the head of the segment 120 can be obtained. The operation of reproducing a predetermined number of the inner coded images 200 while accurately skipping them can be realized at high speed.

The forward intra-frame coded image 200
Also, with respect to the first segment position 155, the second segment position 156 and the fourth segment position 157, it is possible to reproduce while skipping a predetermined number.

FIG. 6 shows a procedure in which the information reproducing apparatus 2 receives a start command from the host computer 3 and reproduces the backward intra-frame coded images 200 while skipping a number close to a predetermined number to perform high-speed reproduction processing. It is a flowchart explaining.

Note that, in FIG. 6, Step 600 to Step 603 and Step 606 are respectively t in FIG.
The description is omitted because it is the same as ep500 to Step 503 and Step 507. The specification of the start command is also the same as the start command used in the description of FIG. (Step 604) The microcontroller 40 predicts a segment position in the search segment number register 47, which is behind the search segment number. For example, each segment 12
When 0 is composed of about 100 sectors 130, if the number of search segments is 4, then 400 (100 x
4) Sector 130 behind is used as the predicted segment position. Then, the predicted segment position is set in the target sector address register 49. (Step 605) The microcontroller 40 sends out the seek control signal 403 in which the address of the track in which the target sector address in the target sector address register 49 exists is set as the target track address to activate the seek control circuit 42.

The seek control circuit 42 uses the head control signal 40.
4 is sent to move the head 41 toward the target track address.

When the movement of the head 41 is completed, the reproducing circuit 43 reproduces the reproduced signal 405 sent from the head 41 to change the sector address 140 to the sector address signal 40.
Send to 6. Then, the microcontroller 40 stores the control data 141 in the control data memory circuit 44 via the data bus 407.

The microcontroller 40 fetches the segment position 152 one behind and the current segment position 158 from the control data memory circuit 44, calculates the difference between each of them and the sector address 140, and calculates the segment position with the smaller difference. Is set in the target sector address register 49. For example, the sector address 140 is 480, the segment position 152 one behind is 520,
If the current segment position 158 is 405, the difference is 40
The next segment position 152, which is smaller by 1, is set in the target sector address register 49.

Then, the microcontroller 40 uses St
The process from ep601 is repeated. In this way, the information reproducing apparatus 2 can obtain the position of the closest intra-frame encoded image without waiting for rotation immediately after predicting the target track and completing the seek operation. The operation of reproducing while skipping a number close to a predetermined number can be realized at high speed.

In addition, the method of FIG.
Since only 0, the segment position 152 one behind and the current segment position 158 need to be recorded in each sector 130, the present invention can be applied even when the area for recording the control data 141 is small.

The forward intra-frame coded image 200
Similarly, it is possible to reproduce while skipping a number close to a predetermined number.

[0066]

As described above, according to the present invention,
By detecting the position of the intra-frame coded image at a higher speed with a small-capacity memory, the video can be reproduced at a high speed in the forward direction or the reverse direction, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is an area configuration diagram of an information recording medium in an embodiment of the present invention.

FIG. 2 is a data structure diagram of a segment 120.

FIG. 3 is a positional relationship diagram between segment position information in control data 141 and one segment 120.

FIG. 4 is a block diagram of an information reproducing apparatus according to an embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation in which the information reproducing apparatus 2 reproduces the backward intra-frame coded image 200 while accurately skipping a predetermined number.

FIG. 6 is a flowchart illustrating an operation in which the information reproducing apparatus 2 reproduces a backward intra-frame coded image 200 while skipping by a number close to a predetermined number.

FIG. 7 is a diagram showing an example of a video frame sequence compressed by MPEG.

[Explanation of symbols]

 1 Information Recording Medium 2 Information Reproducing Device 3 Host Computer 4 Display 40 Microcontroller 41 Head 42 Seek Control Circuit 43 Reproducing Circuit 44 Control Data Memory Circuit 45 User Data Memory Circuit 46 Host Interface Circuit 47 Search Segment Number Register 48 Search Segment Number Register 49 Target sector address register 100 File management information area 101 File area 120 Segment 130 Sector 140 Sector address 141 Control data 142 User data 143 Error correction detection code 150 Stream ID 151 Segment number 152 One backward segment position 153 Two backward segment position 154 4 backward segment position 155 1 forward segment position 156 2 previous Segment position 157 three front segments located 200 intra-frame coded picture 201 inter-coded image 202 frame coding speech

Front page continuation (72) Inventor Hiroshi Hamasaka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. Frame-encoded images obtained by variable-length-compressing video frames are continuously recorded in a data area of a sector having a fixed data capacity, and a frame-encoded image number and position information of preceding and following frame-encoded images are recorded. An information recording medium characterized in that an image position area to be formed is formed in all sectors. 2. The information recording medium according to claim 1, wherein the image position area is formed immediately after the area in which the sector address is recorded. 3. The information recording medium according to claim 1, wherein the image position area is allocated to an area which is additionally generated for adding the error correction detection code to the frame encoded image. 4. A frame-coded image obtained by variable-length-compressing a video frame is continuously recorded in a data area of a sector having a fixed data capacity, and a frame-coded image number and position information of preceding and following frame-coded images are all recorded. Is an information reproducing apparatus for reproducing a frame-encoded image from the information recording medium recorded in the image position area of the sector, the head moving means for moving the reproducing head toward the target sector position, and the sector for detecting the sector position. Detecting means, target sector detecting means for detecting the target sector position, sector reproducing means for reproducing the sector and transmitting the reproduced data, and position information of the frame-encoded image in the reproduced data by a predetermined number of backwards or a predetermined number of forwards. Execute the head moving means with the sector position indicated by as the target sector position, and set the sector first detected by the sector detecting means to the sector. The moving reproduction means for repeating the reproduction by the reproducing means and the moving reproduction means, the target sector detecting means is executed, the frame encoded image is reproduced from the target sector position by the sector reproducing means, and then the moving reproduction is performed. An information reproducing apparatus comprising: a high-speed image reproducing means for repeating the processing from the repetition of the means. 5. A frame coded image obtained by variable length compression of a video frame is continuously recorded in a data area of a sector having a fixed data capacity, and the frame coded image number and position information of preceding and following frame coded images are all recorded. An information reproducing method for reproducing a frame-coded image from an information recording medium recorded in the image position area of a sector of a sector, in which reproduction data is reproduced from a sector in which a frame-coded image for starting reproduction is recorded. The target is moved after the target position is moved to the sector position indicated by the position information of the frame-encoded image that is backward or forward by a predetermined number in the data, and the reproduction data is reproduced from the first sector detected after the movement. The sector position is detected, the reproduction data is reproduced from that sector, and the frame-coded image is transmitted. Alternatively, an information reproducing method is characterized in that it is repeatedly executed by moving with a sector position indicated by position information of a predetermined number of frame encoded images as a target. 6. A frame-encoded image obtained by variable-length-compressing a video frame is continuously recorded in a data area of a sector having a fixed data capacity, and position information of the current frame-encoded image and a frame-encoded image one frame behind. From the information recording medium in which the position information of is recorded in the image position areas of all the sectors, the frame coded image is reproduced in a scattered manner. Reproduce the reproduction data, predict the sector position where the frame-coded image is recorded a predetermined number of backwards or a certain number of forwards, move the target sector position as the target, and reproduce the reproduction data from the first detected sector after the movement. Then, the sector position of the next frame-encoded image in the reproduction data and the sector position closer to the sector position of the current frame-encoded image are set to Move to the target, detect the target sector position, reproduce the playback data from that sector, and send the frame-encoded image. An information reproducing method characterized in that a position is predicted, and the predicted sector position is moved as a target to repeatedly execute the process.