JPH11234624A - Image recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance image quality of a still image by outputting still image data based on compressed still image data in the case of reproducing a still image by generating compressed still image data in addition to compressed moving image data and recording composited data compositing both onto a recording medium. SOLUTION: Received moving image data are compressed by a moving picture experts group MPEG system CODEC 12 and compressed moving image data of 1.5 Mbps are generated. Furthermore, the same moving image data are compressed every 9 frames by a JPEG CODEC 14 so that compressed still image data are generated every 9 frames. The compressed moving image data and the compressed still image data are subject to time division multiplex by a data multiplexer/demultiplexer circuit 16 and the composited data obtained thereby are recorded on an optical disk 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording and reproducing apparatus, and more particularly to, for example, compressing input image data and recording the compressed image data on a recording medium, and expanding and outputting compressed image data reproduced from the recording medium. The present invention relates to an image recording / reproducing device.

[0002]

2. Description of the Related Art As a conventional image recording / reproducing apparatus of this type, there is an apparatus which compresses input moving image data according to an MPEG format and records the compressed moving image data on a recording medium such as an optical disk.

[0003]

However, if the compression ratio is increased in order to lengthen the time that can be recorded on the recording medium, the image quality of the reproduced image, that is, the decompressed image is degraded. vice versa,
If the compression ratio is reduced, the image quality is improved, but the recordable time is shortened. Assuming that an optical disk having a memory capacity of 1 gigabyte is used as a recording medium, if data is compressed to about 1.5 Mbps, a recordable time of 90 minutes can be secured, but the image quality at the time of reproduction deteriorates. That is, even if a sufficient image quality is obtained in the normal reproduction mode for reproducing a moving image, the image quality of a still image reproduced in the still reproduction mode is insufficient. On the other hand, if the data is compressed to about 6 Mbps, sufficient image quality can be obtained in both the normal playback mode and the still playback mode. However, the recordable time can be secured only about 20 minutes.

[0004] Therefore, a main object of the present invention is to provide an image recording / reproducing apparatus capable of extending the recordable time and improving the image quality of a reproduced still image.

[0005]

SUMMARY OF THE INVENTION The present invention provides first compression means for compressing input moving image data by a first method to generate compressed moving image data, and intermittently moving image data to a second method. A second compression means for generating compressed still image data by compressing the compressed data, a synthesizing means for synthesizing the compressed moving image data and the compressed still image data by a predetermined method, and recording the synthesized data output from the synthesizing means on a recording medium. An image recording / reproducing apparatus including a recording unit.

[0006]

The input moving image data is compressed by the MPEG method, and 1.5 Mbps compressed moving image data is generated. Also, the same moving image data is compressed by the JPEG method every nine frames, whereby compressed still image data is generated every nine frames. Each of the compressed moving image data and the compressed still image data is written to the corresponding FIFO memory at a reference clock rate, and thereafter read at a high speed clock rate twice the reference clock rate. In this way, the transmission rate of each data is converted. The compressed moving image data and the compressed still image data read at a high clock rate are thereafter time-division multiplexed, and the resulting composite data is recorded on an optical disk.

The composite data reproduced from the optical disk is
Separated into compressed moving image data and compressed still image data,
Further, the respective transmission rates are restored using the FIFO memory. That is, the high-speed clock rate is converted to the reference clock rate. Then, the compressed moving image data and the compressed still image data are expanded by the MPEG system and the JPEG system, respectively. A switch connected to the output terminal selects decompressed moving image data in the normal reproduction mode. On the other hand, when the still playback mode is set, this switch selects the expanded still image data. In the still reproduction mode, the decompression process in the JPEG format is further stopped, and the decompressed still image data decompressed immediately before the stop of the decompression process is continuously output from the output terminal.

[0008]

According to the present invention, in addition to the compressed moving image data, the compressed still image data is also generated, and the combined data obtained by combining the two is recorded on the recording medium. By outputting still image data based on the image data, the image quality of the still image can be improved. For this reason, the compression ratio of the first method can be set low, and the recordable time becomes long.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0010]

Referring to FIG. 1, an image recording / reproducing apparatus 10 of this embodiment includes an input terminal S1 for inputting moving image data. This moving image data is directly transmitted to the MPEG codec 12
And is subjected to a compression process according to the MPEG system.
As a result, 1.5 Mbps from the MPEG codec 12
Is output.

The moving image data input from the input terminal S1 is also supplied to the JPEG codec 1 via the switch SW2.
4 is input. The timing generator 28 is shown in FIG.
As shown in (A), a frame pulse whose level is switched every half frame is output, and the frequency divider 26 divides this frame pulse into one tenth. Therefore, a frequency-divided pulse which becomes a high level only for one frame out of every ten frames as shown in FIG. By such a frequency division pulse, the switch SW
2 is turned on / off, and the moving image data is input to the JPEG codec 14 every other frame, that is, every nine frames. JPEG codec 14 is JPE
The compression process is performed by the G method, and the compressed still image data is output every nine frames.

When the operator sets the recording mode by operating the recording button 32, the system controller 30 gives a compression processing command to the MPEG codec 12 and the JPEG codec 14, and activates the timing generator 28. From the MPEG codec 12, as shown in FIG.
Data, B data and P data are output. Also,
The JPEG codec 14 outputs compressed still image data (J data) as shown in FIG. I,
The numbers written in each of B, P, and J mean frame numbers. In addition, I data, B data, P data and J data are different depending on their compression ratios.
Has different data length. Such compressed moving image data and compressed still image data are transmitted to the data synthesizing / separating circuit 1.
6 is input.

The data synthesizing / separating circuit 16 is configured as shown in FIG. The compressed moving image data is input from the input terminal S3 to the FIFO-RAM 16a, and is temporarily written according to the memory control data output from the CPU 24. At this time, the compressed moving image data is written at the reference clock rate and for each frame. The written compressed moving image data is thereafter read at a predetermined timing and at a high-speed clock rate twice as high as the reference clock rate. That is, from the FIFO-RAM 16a, FIG.
As shown in (B), I data, B data and P data are output.

On the other hand, the compressed still image data output every nine frames from the JPEG codec 14 is input from the input terminal S4 to the FIFO-RAM 16b. Then, the data is temporarily written in accordance with the memory control data from the CPU 24, and thereafter read at a predetermined timing. At this time, writing is performed at the reference clock rate, and reading is performed at the high clock rate. Therefore, from the FIFO-RAM 16b, FIG.
The compressed still image data is output as shown in FIG.

Since the transmission rates of the compressed moving image data and the compressed still image data are converted by the FIFO-RAMs 16a and 16b, FIGS.
As can be seen from (D), the data lengths of the I data, B data, P data, and J data are reduced to half. The switch SW4 selects compressed moving image data or compressed still image data according to the switching data from the CPU 24, whereby each image data is time-division multiplexed. The CPU 24 also outputs header data related to each of the I data, B data, P data, and J data, and outputs the I data, B data, P data.
The switch SW4 is controlled so that the header data is added to the head of the data and the J data. As a result, as shown in FIG. 3E, synthesized data obtained by time-division multiplexing of I data, B data, P data, J data, and header data is output from the output terminal S7.

Referring to FIG. 5, the header data has a data length of 64 bits, and synchronization data is written in the first 32 bits. Frame synchronization is achieved by the synchronization data. Following the synchronization data, an MPEG / JPEG identification flag and I / B /
The P identification flag is written. The MPEG / JPEG identification flag identifies whether the image data to which the header data is added is MPEG data or JPEG data. The I / B / P identification flag indicates whether the image data to which the header data is added is Indicates whether the data is I data, B data, or P data. The next two bits of the I / B / P identification flag are used as a reserved area, and the use of the reserved area is not particularly determined. The frame number is written in the first 10 bits of the remaining 26 bits, and the last 10 bits are written.
The data length of the data to which the header data is added is written in the bit. Six bits between 10 bits for recording the frame number and 10 bits for recording the data length are also reserved areas, and their uses are not determined.

The combined data output from the output terminal S7 is provided to the disk drive 20 via the interface circuit 18, and is recorded on the optical disk 22 by the disk drive 20. The operator presses the play button 34
By operating, the normal playback mode is set. At this time, the disk drive 20 reproduces the combined data recorded on the optical disk 22 and supplies the combined data to the data combining / separating circuit 16 via the interface circuit 18. The synthesized data is input from the input terminal S8 shown in FIG.
It is separated into compressed moving image data and compressed still image data by W5. That is, the combined data is also given to the CPU 24, and the CPU 24 detects the header data included in the combined data, and detects the MPEG / JPE included in the header data.
The switch SW5 is switched with reference to the G identification flag. The compressed moving image data and the compressed still image data individually taken out in this way are respectively FIFO-R
The data is input to the AM 16c and the FIFO-RAM 16d.

The CPU 24 also has a FIFO-RAM 16
Write / read processing is performed on c and 16d. As with recording, writing compressed moving image data
The reading is performed every frame and at a high clock rate, and the reading is performed at a reference clock rate. Therefore, the compressed moving image data as shown in FIG. 3A is obtained from the compressed moving image data as shown in FIG. 3B separated by the switch SW5. Then, the compressed moving image data shown in FIG. 3A is output from the output terminal S5. FIF
The CPU 24 also writes to the O-RAM 16d at a high clock rate and reads at a reference clock rate. Therefore, the compressed still image data shown in FIG. 3C is obtained based on the compressed still image data shown in FIG. 3D separated by the switch SW5, and is output from the output terminal S6.

Returning to FIG. 1, the data synthesizing / separating circuit 16
The compressed moving image data and the compressed still image data output from the
It is input to the G codec 14. In the normal reproduction mode, the CPU 24 keeps the switch SW3 on, and the compressed still image data is input to the JPEG codec 14 every nine frames. MPEG codec 12
Expands the input compressed moving image data by the MPEG method to generate expanded moving image data. Further, the JPEG codec 14 converts the input compressed still image data into a JPE codec.
The image data is decompressed by the G method to generate decompressed still image data. In the normal playback mode, the CPU 24 sets the switch SW1 to MPE
Connect to G codec 12 side. Therefore, the output terminal S
2 outputs the decompressed moving image data generated by the MPEG codec. That is, a moving image is reproduced.

When the operator operates the still button 36 during reproduction of a moving image, the mode is switched to the still reproduction mode. At this time, the system controller 30
A still reproduction command is given to the PU 24. Therefore, the CPU 24 switches the switch SW1 to the JPEG codec 14, and turns off the switch SW3 at a predetermined timing. In the JPEG codec 14,
First, the compressed still image data is expanded, and the expanded still image data is temporarily stored in the memory 14a. And memory 1
The expanded still image data is read from 4a and output. When the next compressed still image data is input, the decompression process is executed again, and the memory 14a is updated with the new decompressed still image data. When the switch SW3 is turned off, the decompression process and the writing to the memory 14a are stopped, and immediately before the switch SW3 is turned off, the memory 14 is turned off.
The decompressed still image data stored in a is continuously read. As a result, the same still image is continuously reproduced.

As described above, the compressed still image data is input to the JPEG codec 14 every nine frames. That is, the compressed still image data is not necessarily stored in the still button 3
6 is not input to the JPEG codec 14 at the operation timing, and in most cases, a slight shift occurs between the actually displayed still image and the still image desired by the operator. In order to minimize such a shift, the CPU 24 determines the timing of turning off the switch SW3 based on the frame number recorded in the header data and the input timing of the still playback command.
More specifically, as can be seen from FIG. 3E, the header data is input to the CPU 24 at a predetermined timing. Therefore, the CPU 24 determines at which timing the still button 36 has been pressed based on the frame numbers written in the respective header data. If the operation timing of the still button 36 is close to the input timing of the current compressed still image data, the CPU 24 immediately turns off the switch SW3. On the other hand, if the operation timing of the still button 36 is close to the input timing of the next compressed still image data, the CPU 24 turns off the switch SW3 after completing the input of the next compressed still image data.

In this embodiment, since three frames of still image data are input to the JPEG codec 14 per second, the data amount of the compressed still image data of each frame is reduced by four.
Assuming 0 kilobytes, the data amount per second is 1.0 Mbps. At such a compression ratio, the image quality of a still image obtained at the time of reproduction is almost equal to the image quality of a moving image obtained by expanding compressed moving image data of 1.5 Mbps. In order to create still images of the same image quality from decompressed moving image data, it is necessary to limit the moving image data to a compression rate of about 5 to 7 Mbps. In this embodiment, however, the total amount of each compressed data is 2. Since the data rate is 5 Mbps, the data amount can be suppressed to about 1/2 to 1/3. In other words, the time that can be recorded on the optical disk 22 can be extended two to three times.

[Brief description of the drawings]

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

FIG. 2 is a timing chart showing a part of the operation of the embodiment in FIG. 1;

FIG. 3 is a timing chart showing another part of the operation in the example of FIG. 1;

FIG. 4 is a block diagram illustrating a data synthesis / separation circuit.

FIG. 5 is an illustrative view showing one portion of a configuration of header data;

[Explanation of symbols]

 Reference Signs List 10 image recording / reproducing device 12 MPEG codec 14 JPEG codec 16 data synthesizing / separating circuit 24 CPU 20 disk drive

Claims (9)

[Claims] A first compression means for compressing input moving image data by a first method to generate compressed moving image data; intermittently compressing the moving image data by a second method to compress and compress the moving image data; A second compression unit that generates image data, a combination unit that combines the compressed moving image data and the compressed still image data in a predetermined format, and a recording unit that records the combined data output from the combination unit on a recording medium. An image recording / reproducing device provided. 2. The image processing apparatus according to claim 1, wherein said synthesizing means includes a first converting means for converting a transmission rate of the compressed moving image data, a second converting means for converting the transmission rate of the compressed still image data, and a first converting means. 3. A multiplexing means for time-division multiplexing an output and an output of said second conversion means.
The image recording / reproducing apparatus according to the above. 3. The image recording / reproducing apparatus according to claim 3, wherein said synthesizing means further includes an adding means for adding an identifier to each of the output of said first converting means and the output of said second converting means. 4. A reproducing means for reproducing the synthesized data from the recording medium; an extracting means for individually extracting the compressed moving image data and the compressed still image data from the synthesized data; First decompression means for decompressing the compressed still image data by a second method to generate decompressed still image data, and second decompression means for generating decompressed still image data by the second method. 5. The image recording / reproducing apparatus according to claim 1, further comprising a selection unit that selects one of the expanded still image data. 5. The second decompression means includes a memory, decompression processing means for performing decompression processing, writing means for writing the decompressed still image data decompressed by the decompression processing means to the memory, and the decompression from the memory. 5. The image recording / reproducing apparatus according to claim 4, further comprising a reading unit that continuously reads out still image data. 6. A setting means for setting a reproduction mode, a selection control means for controlling the selection means according to the reproduction mode, and an inability to disable the decompression processing means and the writing means according to the reproduction mode. 6. The image recording / reproducing apparatus according to claim 5, further comprising a conversion unit. 7. The selection control means causes the selection means to select the decompressed still image data in the still reproduction mode, and the disabling means disables the decompression processing means and the writing means in the still reproduction mode. , Claim 6
The image recording / reproducing apparatus according to the above. 8. The image recording / reproducing apparatus according to claim 7, wherein said disabling means determines a disabling timing based on a timing at which said still reproduction mode is set. 9. The method according to claim 1, wherein said first method is an MPEG method, and said second method is a JPEG method.
An image recording / reproducing apparatus according to any one of the above.