JPH0877755A - Reproducing device for compressed image information - Google Patents

Abstract

PURPOSE: To attain a quick access by storing reproducing points of intera-frame and moving based on the address information at the time of a fast forwarding/ fast rewinding reproduction. CONSTITUTION: A signal recorded on a medium 1 is inputted to a reproducing signal processing circuit 5 via an optical pickup 2. The processing circuit 5 obtains address information of the medium 1 being a present reproducting point to output the information to a control circuit 6. In the case of intra-frame (I frame), an image signal processing circuit 8 detects it and outputs type of image information to a control circuit 6. The circuit 6 stores successively inputted information in a memory 7. Besides, the signal is outputted from the processing circuit 5 as an image and audio output signals via the processing circuit 8 and an audio signal processing citcuit 9. In the fast forwarding/fast rewinding reproducing, the quick access is made possible by reproducing specified I frame while reading out address information of reproducing points from the memory 7 and controlling a driving circuit 4 with the control circuit 6 according to the mode of an operation input.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reproducing compressed image information which enables high speed access to a medium in which an image signal or the like is compressed and recorded.

[0002]

2. Description of the Related Art A video signal which requires an information amount of 100 to 200 Mbps requires an information amount which is almost 100 times that of an audio signal which has an information amount of 1 to 2 Mbps. Therefore, package media such as optical discs have a capacity of 1000M.
Since it is ~ 5000 Mbytes, if the video signal is recorded as it is without being compressed, it will be 40 as shown in (Equation 1).
It can be stored only in seconds to 7 minutes.

[0003]

[Equation 1]

In order to solve this, a technique for compressing an image for a package medium has been established and standardized in recent years by a working group of the compression technique called MPEG.
Using this technology, images can be compressed to 1/100 to 1/150 and can be recorded on a compact disc with a capacity of 640 MB in 74 minutes.

Generally, a video signal of a television or the like is composed of 30 (frame) still images per second.
Most of these continuous frame images are similar to the preceding and following frame images except when the scenes are different. These compression techniques take advantage of the fact that the amount of the entire data can be considerably reduced by adding the difference data of the previous frame image to the next frame image with respect to a certain frame image. This is achieved by reducing redundancy.

FIG. 6 is a schematic diagram showing a structure of compression information of a moving image frame. An intra-frame is a self-contained image frame in which the screen is composed of only the image information of itself, regardless of the previous and next frames, such as when a scene changes. In addition, a frame that can form a screen by the difference information of the image of an intra frame (hereinafter, abbreviated as I frame) like a little screen change in the same scene is called a P frame, and is sandwiched between the I frame and the P frame. A frame that can form a screen from the information of both frames is called a B frame. The arrow in FIG. 6 indicates the reference destination of each frame for constructing each image.

A conventional reproducing method of such compressed information will be described below with reference to the drawings. FIG. 4 shows a structure of a conventional reproducing method of an image recorded by using such a compression technique.
In FIG. 4, the separated unit means a frame on a television screen. The medium is reproduced in the direction of point 10 → point 11 → point 12 during reproduction. At the time of fast-reverse reproduction, if the current point is point 11, reproduction is performed in the direction of point 11 → point 10. During fast forward playback, if the current point is point 11,
Playback is performed in the direction from point 11 to point 12. Therefore, in normal reproduction, all I frames, B frames, B frames, and P frames are reproduced, but in order to reproduce at high speed, only I frames that do not require image information of preceding and succeeding frames are reproduced. .

FIG. 3 is a diagram showing the configuration of a recording / reproducing apparatus for compressed information in a conventional example. Reference numeral 1 is a medium on which a compressed image or the like is recorded, 2 is an optical pickup for reading a signal from the medium 1, and 3 is at least one for driving the medium 1 and the optical pickup 2 in order to move the optical pickup to an arbitrary position on the medium 1. A motor 4, a drive circuit for driving the motor 3, 5 a reproduction signal processing circuit for demodulating a signal from the optical pickup 2, 8 an image signal processing circuit for demodulating an image signal from the demodulated reproduction signal, and 9 a demodulation signal An audio signal processing circuit 6 demodulates an audio signal from the reproduced signal, and a control circuit 6 controls the driving circuit 4 to obtain the image type information from the image signal processing circuit 8 and retrieve the storage address of the I frame.

The operation of the conventional compressed information recording / reproducing apparatus configured as described above will be described. Under the control of the control circuit 6 that receives an operation input (not shown), the drive circuit 4 drives the drive motor 3 to move the optical pickup 2 to an arbitrary position on the medium 1. The optical pickup 2 detects the recorded information on the medium 1 and outputs it to the reproduction signal processing circuit 5. The reproduction signal output from the reproduction signal processing circuit 5 is input, the audio signal processing circuit 9 demodulates the audio signal, the image signal processing circuit 8 demodulates the image signal, and the reproduced image type information is displayed. Output to the control circuit 6. Based on this image type information, the control circuit 6 controls the drive circuit 4 according to the operation mode at the present time to perform the reproduction, the fast-forward reproduction, the fast-reverse reproduction, etc. described in detail in FIG.

[0010]

However, in the case of the conventional fast-reverse reproduction, in order to find the I frame,
At the current point 11, it is necessary to search for an I frame some time ago. Unfortunately, if it is not an I frame, the process is repeated until the I frame is found by tracing back to the previous frame. Fortunately, if an I frame such as point 10 is found, point 10 is reproduced and the operation is repeated thereafter. The same applies to fast-forward playback. Therefore, there is a problem that a smooth and high-speed operation cannot be expected depending on the I-frame searching and the backward moving amount.

The present invention solves the above problems,
An object of the present invention is to provide a compressed information recording / reproducing apparatus which stores an address of a reproduction point of an I-frame during normal reproduction and moves at the address during fast-reverse / fast-forward reproduction to enable high-speed access. To do.

[0012]

In order to achieve this object, the present invention is an apparatus for recording / reproducing a medium in which moving image compression information including self-contained image information and control information are recorded and reproduced. A reading means for reading a signal, a driving means for driving the signal so that the signal can be read from an arbitrary position on the medium, a driving circuit means for driving the driving means, and a reproduction signal for demodulating the read signal into a reproduction signal of a predetermined format. The processing circuit means, the image signal processing circuit means for demodulating an image from the obtained reproduction signal and outputting a video signal, the operation input means for inputting the control mode, and the location of the medium read by the reproduction signal processing circuit means Address information
Control circuit means for controlling the drive circuit means by obtaining the type information of the image demodulated by the image signal processing circuit means and the control mode from the operation input means, and the address information of the medium inputted from the control circuit means, And a memory means for storing or reading drive information such as image type information and control mode, and the control circuit means reads out from the memory means address information in which self-contained image information is stored according to the control mode. The drive circuit means is controlled so that the recorded information at the address position on the medium can be read.

[0013]

With this configuration, when the reproduction of the I frame is detected during the normal reproduction, the address indicating the position of the reproduction point of the I frame is sequentially stored in the memory means, and during the fast rewind / fast forward reproduction, the current address is reproduced. From the point, it is possible to move forward and backward based on the address table of this I frame for high speed access.

[0014]

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

FIG. 1 shows the structure of a recording / reproducing apparatus according to an embodiment of the present invention. The same parts as those in FIG. 3 showing the conventional example are designated by the same reference numerals and described. Reference numeral 1 is a medium on which a compressed image or the like is recorded, 2 is an optical pickup as a reading means for reading a signal from the medium 1, and 3 is a driving means for moving the optical pickup to an arbitrary position on the medium 1. At least one motor for driving the pickup 2, 4 a drive circuit for driving the motor 3, 5 a reproduction signal processing circuit for demodulating a signal from the optical pickup 2, 8
Is an image signal processing circuit for demodulating an image signal from the demodulated reproduction signal, 9 is an audio signal processing circuit for demodulating an audio signal from the demodulated reproduction signal, and 6 is an image signal processing circuit 8 for obtaining image type information from the image signal processing circuit 8. It is a control circuit that controls the drive circuit 4 to retrieve the storage address of the I frame. Reference numeral 7 denotes a memory circuit which is a memory means for inputting / outputting and storing the type information and the like of the image with the control circuit 6.

The operation of the compressed image information reproducing apparatus configured as described above will be described with reference to the drawings.

FIG. 2 shows the structure of the reproducing method of the present invention for an image recorded using a compression technique. FIG. 5 is a diagram showing the flow of the access.

In FIGS. 1, 2 and 5, it is assumed that the reproducing apparatus is first started. Playback start step 22
Then, in order to start the reproduction state, first, the medium 1 is driven by the drive motor 3
When driven by the optical pickup 2, the signal recorded on the medium 1 is read by the optical pickup 2 and transmitted to the reproduction signal processing circuit 5. The obtained signal is sent to the image signal processing circuit 8 and the audio signal processing circuit 9, and is output as a video signal output and an audio signal output. In normal reproduction, reproduction is performed in the direction of point 10 → point 11 → point 12 in FIG. Since this normal series of operations is not fast reverse reproduction in step 23, the process proceeds to step 24, and the reproduction signal processing circuit 5 acquires the address information of the medium which is the current reproduction point. This address information is used by the control circuit 6
Is transmitted to. In step 25, the image signal processing circuit 8 detects that the points such as the points 10, 11, and 12 are I frames. If it is an I frame, the type information of the image indicating that it is an I frame is transmitted to the control circuit 6. In step 26, when the control circuit 6 receives the type information of the image which is the I frame, it sequentially stores the address information of the medium which is the reproduction point in the memory 7. In step 27, it is sent to the image signal processing circuit 8 and the audio signal processing circuit 9, and is output as a video signal output and an audio signal output. Then, the process returns to step 23 and the operation is repeated.

When the fast reverse reproduction is selected, step 23
And branch to step 28. Assuming that the reproduction point at this point is the point 11, in the fast-reverse reproduction, the reproduction is performed while advancing in the direction of the point 10. In step 28, the address of this point 11 is obtained and stored. In step 30, the access mode input in step 29 is judged. Here, an example in which three of mode 1, mode 2, and mode 3 can be selected is shown.

[0020]

[Table 1]

Table 1 shows each access point (marked with a circle) from the current point 11 (marked with a circle) for each mode. Mode 1 is a case where fast rewind reproduction is performed for every I frame from point 11 to point 10 direction, and mode 2 similarly fast rewind reproduction is performed for two I frame intervals from point 11 to point 10 direction. This is the case, and Mode 3 is a case where fast reverse reproduction is similarly performed in the direction from point 11 to point 10 for each I frame closest to a certain set time.

If the mode 1 input is selected in step 29, the process proceeds to step 31 and the address of the point 10 immediately before the current point 11 is obtained. The address of point 11 from (Table 1) is 32 minutes 50 seconds 23.
Point 1 which is a frame and is the previous I frame
We get a 32 minute 45 second 12 frame with an address of 0.

Then, in step 37, the control circuit 6 instructs the drive circuit 4 to move to the access point of 32 minutes 45 seconds 12 frames based on the value of this address. The drive circuit 4 moves the optical pickup 2 via the drive motor 3. When you move to the address of the command,
In step 38, the I frame at point 10 is reproduced. Next, in step 39, the fast-reverse release is detected. When the release is detected, the process returns to step 22 for starting the reproduction and the operation from the start of the reproduction is repeated. When the cancellation of the fast rewind is not detected, the process returns to step 31 to repeat the fast rewind reproduction, and next, the fast rewind reproduction is performed in the order of point 9, point 8, point 7, point 6 and point 5.

If the mode 2 input is selected in step 29, the process proceeds from step 30 to step 32.
The address of the point 9 that is N = 2 before the current point 11 is obtained. From Table 1, the address of point 11 is 32
It is 32 minutes 05 seconds 68 frames, which is the address of the point 9 that is the I frame that is N = 2 previous I frames, which is minutes 50 seconds 23 frames. From this address value, the process proceeds to step 37, where the control circuit 6 instructs the drive circuit 4 to be 32 minutes 05 seconds 68.
Command to move to the frame's access point. The drive circuit 4 moves the optical pickup 2 via the drive motor 3. After moving to the commanded address, the I frame at point 9 is reproduced in step 38. Next, in step 39, the fast-reverse release is detected. When the release is detected, the process returns to step 22 for starting the reproduction and the operation from the start of the reproduction is repeated. If the cancellation of the fast rewind is not detected, the process returns to step 32 to repeat the fast rewind reproduction, and next, the fast rewind reproduction is performed in the order of point 7 and point 5.

When the input of mode 3 is selected in step 29 as the last mode, the process proceeds from step 30 to step 33, and (Table 1) shows an example in which the set time is 70 seconds. First, the address of the current point 11 is 32 minutes 50
Get 23 frames per second. Subtracting the set time of 70 seconds from this value gives 31 minutes, 40 seconds and 23 frames. Address of point 10 which is one point before the current point 11 32 minutes 4
Get 12 seconds for 5 seconds. Further, the address 32 minutes 05 seconds 68 frames of the point 9 which is two points before the current point 11 is obtained.

[0026]

[Table 2]

Current point 11 value of the above (Table 2) -7
The value of 0 second and the value of the previous point 10 are compared, and the value of the current point 11 value-70 seconds and the point 9 two points before are compared to determine whether the point 10 is closer or the point 9 is closer. calculate. In step 34, it is determined whether the content value of the previous one is closer. in this case,
The point 9 two points before is closer. In that case, the process proceeds to step 35, and the address of the comparison table is +
Increment by 1. The above value is obtained again in step 33.

[0028]

[Table 3]

As shown in Table 3, in this case also, 3
The last point, point 8, is closer. Also in that case, the process proceeds to step 35, and the address of the comparison table is +
Increment by 1. The above value is obtained again in step 33.

[0030]

[Table 4]

In step 34, it is determined whether the content value of the previous one (in this case, three before the beginning) is closer. In this case, the point 8 three points before is closer. In that case, the process proceeds to step 36, and the 31 minutes 30 seconds 00 frame of the address of the point 8 is obtained. Based on the value of this address, the process proceeds to step 37, and the control circuit 6 instructs the drive circuit 4 to move to the access point of 31 minutes 30 seconds 00 frames. The drive circuit 4 moves the optical pickup 2 via the drive motor 3.
After moving to the commanded address, the I frame at point 8 is reproduced in step 38. Next, in step 39, the fast-reverse release is detected. When the release is detected, the process returns to step 22 for starting the reproduction and the operation from the start of the reproduction is repeated. If cancellation of the fast-reverse is not detected, the process returns to step 33 again to repeat the fast-reverse reproduction operation.

If cancellation of the fast-reverse is not detected, the next point is obtained from (Table 5) because the current point is the point 8 again in step 33.

[0033]

[Table 5]

In this case, the process proceeds to step 35 and the address of the comparison table is incremented by +1. Then, in step 33 again, the above values are obtained as shown in (Table 6).

[0035]

[Table 6]

In this case, the process proceeds to step 36, and the 30 minutes 29 seconds 62 frame of the address of the point 6 is obtained.
After this, the process proceeds to step 37, where the control circuit 6 drives the drive circuit 4
To the access point of 31 minutes 30 seconds 00 frames. The drive circuit 4 is the drive motor 3
The optical pickup 2 is moved via. After moving to the commanded address, the I frame at point 8 is reproduced in step 38. Next, in step 39, the fast-reverse release is detected. Step 2 to start playback when release is detected
Return to 2 and repeat the operation from the start of reproduction. If cancellation of the fast-reverse is not detected, the process returns to step 33 again to repeat the fast-reverse reproduction operation.

As described above, according to this embodiment (Table 1)
The address of the playback point of the I-frame is stored during normal playback, as described above, and during fast-reverse / fast-forward playback, each I-frame in mode 1 or 2 I-frames in mode 2, or the set time (this example). For every 70 seconds), the address of the next access point can be easily obtained from the table, and the target address can be moved and reproduced at high speed.

Although FIG. 5 shows the flow of the fast-reverse reproduction, the same flow can be used for the fast-forward reproduction if the I-frame position ahead of the current reproduction point is stored in the memory 7. Further, although the fast-reverse reproduction for each I-frame and the second I-frame has been described in the embodiment, by setting every N I-frames (N is an integer), fast-forward / fast-reverse reproduction of N times speed and mode 3 are performed. The example of every 70 seconds was given, but it goes without saying that this time can be set freely. If a file system is provided, it is possible to manage the table representing the position of the I address stored in the memory 7 as a file.

In the embodiment, the medium 1 is a disk on a disk, but the medium 1 is not limited to this. For example, the same effect can be obtained by using a magnetic tape as the medium 1 and a magnetic head as the reading means.

[0040]

As described above, according to the present invention,
At the time of normal reproduction, the address of the reproduction point of the I frame is stored in the memory means, and at the time of fast-reverse / fast-forward reproduction, the target address is obtained and moved under various conditions based on the address table of the memory means to move at high speed. It is possible to provide an accessible reproduction device of compressed image information, which does not require reproduction search while finding an I frame in the conventional fast-reverse / fast-forward reproduction, and has no time required for search, and its practical effect is great. .

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a reproducing method of the present invention for an image recorded using a compression technique.

FIG. 3 is a diagram showing a configuration of a recording / reproducing apparatus in a conventional example.

FIG. 4 is a diagram showing a configuration of a conventional reproduction method of an image recorded using a compression technique.

FIG. 5 is a diagram showing an access flow.

FIG. 6 is a schematic diagram showing the structure of an image frame.

[Explanation of symbols]

 1 medium 2 optical pickup 3 drive motor 4 drive circuit 5 reproduction signal processing circuit 6 control circuit 7 memory 8 image signal processing circuit 9 audio signal processing circuit 10 operation input

Claims (1)

[Claims] 1. An apparatus for recording / reproducing a medium in which moving image compression information including self-contained image information and control information are recorded, the reading means for reading a signal from the medium and the signal from an arbitrary position of the medium. Driving means for driving so as to be readable, driving circuit means for driving the driving means, reproduction signal processing circuit means for demodulating a read signal into a reproduction signal of a predetermined format, and demodulating an image from the obtained reproduction signal. Image signal processing circuit means for outputting a video signal, operation input means for inputting a control mode, address information indicating the location of the medium read by the reproduction signal processing circuit means, and demodulation by the image signal processing circuit means. Control circuit means for controlling the drive circuit means by obtaining the type information of the image being displayed and the control mode from the operation input means, and the control circuit hand. Medium of the address information input from,
Memory means for storing or reading drive information such as image type information and control mode, and the control circuit means stores the address information storing self-contained image information according to the control mode in the memory means. A device for reproducing compressed image information, characterized in that the drive circuit means is controlled so that the recorded information at the address position on the medium can be read.