JP2558973B2 - Optical disk drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for reproducing digital compressed image data.

[0002]

2. Description of the Related Art Recently, it has been proposed to reproduce digital compressed image data from an optical disk by processing within a field or frame, between fields or between frames.

In general, the amount of data coded within a field or frame is several times larger than the amount of data between fields and frames.

On the other hand, at the time of high speed reproduction such as queue (fast forward) and review (reverse fast forward), it is desirable from the viewpoint of decoding to reproduce only the data processed in the field or in the frame.

[0005]

However, usually, the reproduction time of the data of one field or one frame by the above encoding is longer than the output time of one field or one frame after decoding (1 frame = 1/30 sec). Therefore, a section in which the decoded signal is missing occurs. That is, there is a problem that it is impossible to continuously output decoded signals.

[0006]

Means for Solving the Problems The present invention is in the field
Or intra-frame processing and inter-field or inter-frame processing
Optical to reproduce digital image data encoded using
In the disk device, the image data is required to be transferred.
The rate is constantly changing with time in the range of Rmin to Rmax.
Digitally compressed with variable rate coding that varies with
It is digital image data, and high-speed replay of queues and reviews
When live, transfer rate from optical disc is higher than Rmax
Playback at Rhigh and processing in field or frame
Decompressed field or frame encoded data
The same field that was decrypted at the same time
Or, the same frame is displayed once or multiple times.
It is a characteristic. In addition, the present invention is
For intra-frame processing and inter-field or inter-frame processing
An optical disc for reproducing encoded digital image data.
Disk device, wherein the image data has a required transfer rate.
Changes with time in the range from the minimum Rmin to the maximum Rmax.
Digitically compressed by variable rate coding
Tal image data, which is read from the optical disc during normal playback.
The transfer rate of Rmax is approximately Rmax, and high-speed queue and review
During playback, the transfer rate from the optical disc is higher than Rmax.
To high Rhigh, and by in-field or intra-frame processing
Decompressed field or frame encoded data
The same field that was decrypted at the same time
Or, the same frame is displayed once or multiple times.
It is a characteristic.

[0007]

With this, it is possible to prevent the reproduction image from being lost by outputting the same data until the data processed in the next field or in the frame is reproduced. Further, by improving the transfer rate by increasing the number of rotations, the reproduction time of data can be significantly shortened, and high-speed reproduction by displaying once per frame becomes possible.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. (FIG. 1A) shows digital data reproduced from the optical disc, and 0 to 12 are frame numbers. Frames that have undergone intraframe compression processing have frame numbers 0 , 6, and 12. Others are frames that have been subjected to interframe compression processing and have a smaller amount of information than frames that have been subjected to intraframe compression processing. Like this
Intra-frame coded and inter-frame coded data is the amount of information
Since these are different, these digital data need to be transferred
The rate changes momentarily in the range from the minimum value Rmin to the maximum value Rmax.
Variable-rate coding
It

In normal reproduction, reproduced digital data A
As a result of decoding B, B is obtained as a decoded output signal. That is, B
Then, each frame time is fixed at 1/30 seconds.

[0010] Here, although the output time of the 0th frame shown in FIG. 1 (B) is a delay of several frames as compared with FIG. (A), the delay time is to occur during decoding. For example, in the case of an encoding method that requires the information of the sixth frame for decoding the first frame, the reproduction signal of the first frame is calculated and decoded after the data of the sixth frame is reproduced. Become.

In this case, the delay amount becomes larger than that in FIG. 1 (B), but the present invention is not related to this delay time (FIG. 1 (B)), but the delay amount is one example. Is only shown.

Next, consider the case of high speed reproduction. Consider the case of playing only the frames for in-frame processing during cue (fast forward) playback. That is, immediately after the data of the frame 0 is reproduced, the frame 6 is reproduced by jumping to the track in which the data of the frame 6 is recorded. This (Fig. 1
(C)).

The output signal at this time is, for example, as shown in FIG.
(D)) and intermittent reproduction is unavoidable. This is because the reproduction time of the data of one frame is longer than the output time after decoding.

Therefore, as a first embodiment of the present invention, the intermittent output reproduction is stopped and the same frame information is repeatedly displayed (FIG. 1 (E)). This
For example, it is possible to obtain a reproduced image that is significantly better than the intermittent output reproduction of D. However, displaying the same information for four frames means that the queue speed is only 6/4 = 1.5, that is, 1.5 times speed.

To increase the speed, it is possible to increase the access frame interval such as accessing 12 frames after 0 frame. However, in this case, the image becomes rough in time, and smooth high-speed reproduction cannot be obtained.

Therefore, in the second embodiment of the present invention, the disk rotation speed is increased and the transfer rate is increased during high speed reproduction.

(FIG. 1 (F) (G))
The transfer rate is increased to about 4 times the above Rmax.
ing. The data reproduction time of a frame coded in the field or in the frame is ¼ the conventional time. Within 1/30 seconds including the access time, it becomes possible to update the decoded signal frame by frame (Fig. 1 (G)).
Is output. In this case, 6 times speed is realized.

Of course, the increase in the number of rotations, that is, the transfer rate is not limited to the above-mentioned 4 times, but may be about 2 times or 10 times. Further, in that case, it is necessary to raise the frequency of the reproduction signal processing clock accordingly and cope with the increase of the transfer rate.

The number of times the same frame is displayed is not limited to one as described above, and the transfer rate is increased and the number of times of display is switched to 1 or 2 or 3 when the reproduction data is stored. Is also good.

In addition,In this embodiment,During high speed playback,
Play only intra-coded framesShowed an example
However, if the playback speed is 2 to 3 times, the transfer
Processing by interframe coding
It is possible to play back some of the frames that have been created.
This allows for smoother queues and reviews.
Wear.

Further, in the above-mentioned embodiment, the intra-frame or inter-frame coding process is described, but the same applies to the intra-field or inter-field coding process.

[0022]

As described above, according to the present invention ,
Or intra-frame processing and inter-field or inter-frame processing
Optical to reproduce digital image data encoded using
In the disk device, the image data is required to be transferred.
The rate is constantly changing with time in the range of Rmin to Rmax.
Digitally compressed with variable rate coding that varies with
Digital image data, optical disc during normal playback
The transfer rate from is approximately Rmax, and the queue and review
During high speed playback, set the transfer rate from the optical disc to Rmax.
Higher Rhigh, in-field or in-frame processing
The encoded data of the field or frame compressed by
Playback and decrypt only the same
Displaying the fields or the same frame one or more times
As a result, it is possible to prevent the reproduction output image from being lost and to realize high-speed reproduction (cue, review) with smooth movement, which is very effective in variable speed reproduction of the disc.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a reproduction signal pattern in an embodiment of the present invention.

Claims (2)

(57) [Claims] 1. A disc apparatus for reproducing a digital <br/> barrel image data coded using the intra-field or inter-frame processing and field or inter-frame processing, pre
The required transfer rate of image data is from minimum Rmin to maximum
Variable rate code that changes with time in the range of Rmax
Digital image data that has been digitally compressed by encoding
Ri, queue, review high-speed reproduction at the time of rolling from the optical disk
Simultaneously with reproducing the transmission rate at Rhigh higher than Rmax and reproducing and decoding only the encoded data of the field or frame compressed by the in-field or intra-frame processing.
To the same field or the same decoded frame
An optical disk device characterized by displaying a plurality of times . 2. A disc apparatus for reproducing a digital <br/> barrel image data coded using the intra-field or inter-frame processing and field or inter-frame processing, pre
The required transfer rate of image data is from minimum Rmin to maximum
Variable rate code that changes with time in the range of Rmax
Digital image data that has been digitally compressed by encoding
Therefore, during normal playback, the transfer rate from the optical disk should be approximately Rmax.
And then, queue, review high-speed reproduction at the time of, or optical disk
The transfer rate is increased to Rhigh which is higher than Rmax, and only the encoded data of the field or frame compressed by the intrafield or intraframe processing is reproduced and decoded.
Sometimes, the same field or frame that has been decoded
Is an optical disk device characterized by displaying multiple times .