JP3128492B2 - Access device for image playback equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reproducing apparatus for reproducing a package medium in which video data is recorded in accordance with the moving image compression standard MPEG, by using address data recorded on the medium. The present invention relates to an access device for an image reproducing device.

[0002]

2. Description of the Related Art In an image reproducing apparatus for reproducing a package medium in which video data is digitally recorded by MPEG of a moving image compression standard, a video CD or CD-I player in which video data is recorded by MPEG1 is a product. Has been

Address data is recorded on a medium on which video data is recorded by MPEG, for example, a video CD or a CD-I disc which is the above-mentioned CD system, and image data of such a medium is recorded. In the reproducing apparatus, the cueing by access, program reproduction, or time display is performed using the address data.

Further, in the image reproducing apparatus for a medium in which address data is recorded as described above, a memory input operation is performed at any time during reproduction of a moving image, and the address data at the time of the operation is stored. Is provided with a memory playback function that starts movie playback from the point of memory input operation, or a time designation playback function that performs time designation input operation and starts movie playback from the designated time ing.

[0005] By the way, video data conforming to the MPEG standard is based on screen data (I) that is completed by only one original image because data compression is performed using previous and subsequent screen data.
Picture data) is recorded as a group of several screen data including at least one picture, and additional information called a sequence header is added to the head of each group. Image decoding information necessary for decoding the video data such as the image size and the image rate of the video data is recorded, and the video data can be reproduced for each group.

Therefore, in an image reproducing apparatus for reproducing video data conforming to the MPEG standard, the video data of the group is reproduced only after reading the screen data (I picture) completed by only one image. I can't do it.

[0007] In recent video CD discs, the number of groups recorded so that a sequence header appears twice per second has increased, and the number of recorded discs has been increased. Video CD called
In the case of the predecessor disc, one sequence header is provided at the beginning of each song, and each song is in one group, or in the case of a CD-I movie disc, about once every four minutes Many groups are divided and recorded so that a sequence header appears at a frequency of .times..times..times., And some disks are roughly divided into groups.

[0008]

DISCLOSURE OF THE INVENTION In a disk reproducing apparatus provided with a memory reproducing function and a time-specified reproducing function,
When memory playback or timed playback is performed, if playback is started from the middle of a group, video data decoding is performed immediately before memory playback or timed playback is performed until the next group sequence header is read. Since the decoding is performed according to the sequence header of the group that has been decoded, if the image decoding information based on the sequence header is different in image type such as the image size and the image rate, the sequence header of the next group is read from the start of reproduction. Video data is not decoded correctly until

[0009] Here, if the sequence header appears at a frequency of twice per second, the grouping of the playback disk is fine,
The period during which the video data is not decoded correctly is instantaneous and does not cause any problem.However, when a disc roughly divided into groups is played, the sequence header does not appear for several tens of seconds or several minutes, and during that time the video data is correctly decoded. This can be a problem.

An object of the present invention is to solve such a problem.

[0011]

According to the present invention, there is provided a direct mode for directly accessing video data having address data corresponding to an access target address specified by an address specification, and a track mode of address data corresponding to the access target address. A step mode for accessing video data having the address data after accessing the first track enables selective access, and detects whether or not a sequence header is included in input data input to the video decoder. The access mode can be switched by the detection output. In this way, when the sequence header is detected, the access is performed in the step mode, so that the sequence header is read first, and then the video data corresponding to the access target address is accessed, so that the video data is supported. Decoding can be correctly performed according to the image decoding information included in the sequence header to be decoded.

In this case, the detection state of the sequence header is stored using a flag, and identification indicating that the power is turned on, the disk is exchanged, or the high-definition still image data is being reproduced. When the code is decoded by the video decoder, the flag indicating that the sequence header is not detected is set to 0, and the identification code indicating that the reproduction of the moving image data is being performed is set. When a sequence header is detected in a state where the sequence header is detected by the video decoder, a flag = 1 indicating a state where the sequence header is detected is set.

[0013]

FIG. 1 is a circuit block diagram showing an embodiment of the present invention. FIG.
Video data is recorded in the EG1 format, and the MPE
This is compatible with a video CD on which audio data is recorded in the G system.

In FIG. 1, reference numeral 1 denotes an audio-only CD.
-A CD-R is added to the demodulated CD-ROM data by digital signal processing to the same range as the DA disc format.
A CD-ROM decoder that performs decoding processing by performing digital signal processing unique to OM data, 2 is an MPEG decoder that performs MPEG decoding processing of CD-ROM data output from the CD-ROM decoder 1, and 3 is the MPEG decoder 2 And a RAM used to store the MPEG decoded data in order to align the time series of the output MPEG decoded data.

The MPEG decoder 2 decodes various additional data added to video data and audio data from the CD-ROM data output from the CD-ROM decoder 1 and identifies the attributes in the additional data. A data separation unit 4 for separating video data and audio data into groups (packets) to which identification codes are added, and a video decoder unit for decoding the video data separated by the data separation unit 4 5 and an audio decoder 6 for decoding the audio data separated by the data separator 4.

Reference numeral 7 denotes a sequence header detection circuit for detecting whether or not a sequence header has been read by the data separation unit 4. Reference numeral 8 denotes a flag for setting a flag in accordance with the detection status of the sequence header by the sequence header detection circuit 7. It is a setting circuit.

Numeral 9 performs focusing control for focusing a light beam for reading a signal from the disk on a signal surface of the disk, tracking control for following a signal track of the light beam on the disk, and an optical pickup (not shown) itself. A pickup servo circuit for performing thread feed control for feeding in the radial direction, an access control circuit 10 for controlling the pickup servo circuit 10 to perform an access operation so as to cause a track jump of a disk reading position by an optical pickup, and 11 for detecting a sequence header Access control circuit 10 according to the detection output by circuit 7
Is an access instruction circuit that instructs an access operation according to.

The access command circuit 11 sets address data (track number, minute, second, frame) stored by a memory input operation at any time during reproduction of a moving image as an access target, and performs a memory reproduction operation. A memory reproduction access command for performing an access operation of an access target is issued, and an address command specified by a time specification input operation is set as an access target, and a time-specified reproduction access command for performing the access operation of the access target is performed. It has been made to.

The access command circuit 11 has a direct mode for directly accessing video data having address data to be accessed, and has the address data after accessing the first track of the track number of the address data to be accessed. An access command is issued to selectively operate the access control circuit 10 in an access mode different from the step mode for accessing video data.

Reference numeral 12 denotes an input means for performing a memory input operation in preparation for memory reproduction and a memory reproduction operation for executing memory reproduction, and a time-specified reproduction operation for time-specified reproduction. Is a command decoding circuit for decoding the contents of the operation command input by the above.

The sequence header detecting circuit 7, flag setting circuit 8, access command circuit 11, and instruction decoding circuit 1
Reference numeral 3 denotes a microcomputer 14 for controlling the CD-ROM decoder 1, the MPEG decoder 2, and the RAM 3.

Next, the operation of the circuit block configured as described above will be described. The CD-ROM data output from the CD-ROM decoder 1 is separated into video data and audio data by a data separation unit 4, the video data is decoded by a video decoder unit 5, and the audio data is decoded by an audio decoder unit. 6 is decoded.

Here, the various additional data decoded by the data separation unit 4 has information necessary for decoding video data and audio data, and the video decoder unit 5 and the audio decoder unit 6 Decoding processing according to the additional data is performed.

The video data decoded by the video decoder unit 5 and the audio data decoded by the audio decoder unit 6 are time-aligned, and the video output circuit (not shown) and the audio output circuit (not shown) at the subsequent stage are respectively provided. (Not shown).

Now, a memory input operation is performed by the input means 12, and when that is decoded by the instruction decoding circuit 13, the address data being reproduced at present is taken into a memory (not shown) in the microcomputer 14. And input means 1
2, when the memory reproduction operation is performed, the address data stored in the memory becomes the target address, the access control circuit 10 is operated by a command from the access command circuit 11, and the memory input operation is performed. The recorded data being reproduced is accessed.

When a time designation input operation is performed by the input means 12, time data designated by the input operation is stored in the memory, and the time data becomes a target address to be used by the access instruction circuit 11. The access control circuit 10 is operated by the command, and the recording data having the address specified at the time is accessed.

When such memory reproduction or time-specified reproduction is performed, the access command circuit 11 switches the access mode in accordance with the detection state of the sequence header by the sequence header detection circuit 7 and performs access by the access control circuit 10. Perform the operation.

FIG. 2 is a flowchart showing an access method when memory reproduction or time-specified reproduction is performed. When the flag “1” is set in the flag setting circuit 8 (step a) and the sequence header is detected by the sequence header detection circuit 7, the access command circuit 11 performs the direct mode for directly accessing the target address. An access command for operating the access control circuit 10 is issued. Therefore, access is performed up to the frame which is the minimum unit of the target address (step b), and the recording data of the disk having the address data corresponding to the target address is directly accessed.

On the other hand, if the flag "0" is set in the flag setting circuit 8 (step a) and the sequence header detecting circuit 7 has not detected the sequence header, the access command circuit 11 sets the target address to An access control circuit 1 according to a step mode for stepwise access
An access command to activate 0 is issued. Therefore, first, the head track of the track number of the target address is accessed (step c).

Here, since the sequence header is always recorded at the head of the track number, the head track of the track number of the target address is accessed, and when the head of the track number is read, the sequence is read. The header is read (step d). Then, when the sequence header is detected by the sequence header detection circuit 7 and the flag “1” is set in the flag setting circuit 8, the access command circuit 11 issues a command to perform access to the minimum unit of the target address,
Access to the minimum unit of the target address is performed by the access control circuit 10 (step b), and thus the recording data of the disk having the address data corresponding to the target address is accessed stepwise.

Next, the flag setting condition of the flag setting circuit 8 as the access mode switching condition will be described with reference to the flowchart of FIG. MPEG-decoder 2 with CD-
When the ROM data is input, the attribute of the CD-ROM data is identified by the data separation unit 4 by additional data (packet header) added to the packet for each group, that is, for each packet.

When a memory reproduction execution operation or a time-specified reproduction operation is performed, it is determined whether or not the disk reproduction is being performed at the time of the operation (step A). Then, when the disk is being played,
It is determined from the packet header decoded by the data separation unit 4 whether or not the packet being decoded is a packet in which moving image data is recorded (step B), and it is determined that the packet being decoded is a packet of moving image data. Then, the sequence header detection circuit 7 detects whether or not the data separation unit 4 has read the sequence header (step C), and waits for the data separation unit 4 to read the sequence header. Become. When the sequence header detection circuit 7 detects that the data separation unit 4 has read the sequence header, the flag “1” is set in the flag setting circuit 8 (step D).

On the other hand, if the packet being decoded by the packet header decoded by the data separation unit 4 is a packet other than the moving image data (step B) and the packet in which the high-definition still image data is recorded (step E). The flag "0" is set in the flag setting circuit 8 (step F).

If the packet being decoded by the packet header decoded by the data separation unit 4 is a packet in which data that is neither moving image data nor high-definition still image data is recorded (steps B and E), the flag is set. The flag is not changed while being set by the circuit 8.

On the other hand, if the disc is not being reproduced at the time of performing the memory reproduction execution operation or the time-specified reproduction operation, it is determined whether or not the disk ejection operation has been performed (step G). When the operation is performed, the flag “0” is set in the flag setting circuit 8.
Is set (step F), and if the disc eject operation has not been performed, it is determined whether or not the power-on operation has been performed next (step H).

When the power-on operation is performed, the flag "0" is set in the flag setting circuit 8 (step F). When the power-on operation is not performed, the flag set by the flag setting circuit 8 is set. The flag is not changed as it is.

As described above, the flag setting condition of the flag setting circuit 8 is satisfied, and after the disc is exchanged for performing the disc eject operation and after the power is turned on, the disc reproduction is started. Since the flag “0” is set in the flag setting circuit 8 until the sequence header is detected by the sequence header detection circuit 7, the sequence header before disc replacement is performed or before power is turned off is transmitted to the MPEG decoder 2. When the memory reproduction operation or the time-specified reproduction operation is performed in the remaining state, the access is performed in the step mode. For that reason,
First, the first track of the track number of the target address is accessed, and a new sequence header is read by the MPEG decoder 2. Then, when the flag "1" is set in the flag setting circuit 8 by reading the sequence header, the memory is reproduced or the time-specified reproduction is performed by accessing the minimum unit of the target address. In the state where the sequence header before or at the time of power-off remains in the MPEG decoder 2, the memory reproduction execution operation or the time-specified reproduction operation is not performed, and the video data accessed by the memory reproduction or the time-specified reproduction is not accessed. The decoding is performed according to the image decoding information included in the sequence header in the track number of the newly obtained target address.

Therefore, it is possible to prevent the video data from being decoded by the image decoding information such as the image size and the image rate contained in the old sequence header.
Here, since it is unlikely that video data of different image types are recorded in the same track number in a mixed manner, the same track is recorded in accordance with the image decoding information included in the sequence header recorded at the beginning of the track number. By decoding the video data in the number, correct video data can be decoded.

When the high-definition still image data is reproduced during the reproduction of the disk, the flag "0" is set in the flag setting circuit 8. Therefore, immediately after the reproduction of the high-definition still image data, a memory reproduction execution operation or the like is performed. The access in the step mode is also performed when the time-designated reproduction operation is performed. Therefore, the video data accessed in the memory reproduction or the time-specified reproduction is not decoded by the image decoding information included in the sequence header corresponding to the high-definition still image data, and the accessed video data is not accessed. The decoding is performed according to the image decoding information included in the sequence header in the track number of the target address newly obtained on the way.

Therefore, it is possible to prevent the decoding of the video data accessed in the memory reproduction or the time-specified reproduction by the image decoding information having different image types.

[0041]

As described above, according to the present invention, when the memory reproduction and the time-specified reproduction are performed, the sequence header recorded at the head of the track number of the target address is read by the access in the step mode. After that, access to the minimum unit of the target address can be performed, so that the decoded information included in the sequence header of the data that was decoded immediately before the memory reproduction or the time-specified reproduction is performed Even if the decoding information of the data whose reproduction is started by the reproduction is different, the accessed video data can be decoded according to the image decoding information included in the sequence header within the same track number, and the image decoding of different image types Decoding of video data by information can be prevented.

In this case, at the time of the memory reproduction execution operation or the time-specified reproduction operation, the reproduction of the moving image is detected and the sequence header is detected, and the image of the image decoding information contained in the sequence header is detected. When the type is unlikely to change, access is performed in the direct mode to ensure high-speed access, media to be played are exchanged, and the image type of the image decoding information included in the sequence header is changed. It is highly likely that the access will be made in the stepwise mode when the memory reproduction and the time-specified reproduction are performed at the time of disc replacement and power-on when the disc is exchanged and when the power is turned on. When playback of special high-resolution still image data is performed, By so as to perform a scan, it can be carried out efficiently by fewer conditions to switch to the access stage mode.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart illustrating an access method when memory reproduction or time-specified reproduction is performed in the present invention.

FIG. 3 is a flowchart showing a flag setting condition of a flag setting circuit 8 which is a condition for switching an access mode in the present invention.

[Explanation of symbols]

 Reference Signs List 1 CD-ROM decoder 2 MPEG decoder 4 Data separation unit 5 Video decoder unit 7 Sequence header detection circuit 8 Flag setting circuit 11 Access command circuit

Claims (6)

(57) [Claims] 1. A package medium such as a disk or a tape in which video data is recorded by MPEG of a moving image compression standard, and the video data is recorded by being divided into groups each having several pieces of screen data. A video decoder that decodes video data in accordance with a signal format of recorded video data in an image reproducing device configured to be able to reproduce and access using address data recorded on the medium, Detecting means for detecting a sequence header provided at the head of each group of video data and including image decoding information used when decoding the video data by the video decoder; and track jumping the read position of the medium by the read head. Access control means for performing access by Direct access to video data having address data corresponding to the access target address specified by the address specification, and direct access to the video data having the address data corresponding to the access target address specified by the address specification. Access command means for selectively operating the access control means in a step mode for accessing video data having the address data after accessing the head track of the track number, and wherein the detection means detects a sequence header. An access device for an image reproducing apparatus, wherein the access command means is operated so that the access control means performs access in a step mode when the access is not performed. 2. The apparatus according to claim 1, wherein a detection state of whether or not the detection of the sequence header by the detection unit is performed is stored using a flag. 3. The image reproducing apparatus according to claim 2, wherein when the power is turned on, a flag indicating a state in which the sequence header is not detected by the detecting means is initially set to 0. Access device. 4. The image according to claim 2, wherein when a disk is exchanged, a flag indicating a state in which the sequence header is not detected by the detection means is set to "0". Access device for playback equipment. 5. When reproducing a package medium in which high-definition still image data is recorded, an identification code indicating that high-definition still image data is being reproduced is input to the video decoder. 3. The apparatus according to claim 2, wherein a flag indicating that the sequence header is not detected by the detection means is set to "0" when the data is included in the data. . 6. In a state where it is detected that an identification code indicating that reproduction of moving image data is being performed is included in the input data input to the video decoder, the detecting means detects a sequence header of the sequence header. 3. The access device according to claim 2, wherein, when the detection is performed, a flag indicating a state in which the detection of the sequence header is performed by the detection unit is set to "1".