JP3133113B2 - Compressed video data expansion / reproduction system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for expanding and reproducing compressed moving image data which can execute another application program when expanding and reproducing moving image data compressed on the same system and display the same on the same display.

[0002]

2. Description of the Related Art Conventionally, as a system for expanding and reproducing compressed moving image data, for example, "NIKKEI B
YTE / AUGUST Nikkei BP 1989 3
There is an apparatus described on pages 09 to 321.

The above prior art will be described with reference to FIGS. 2, 4 and 6. FIG. 2 is a diagram illustrating a conventional system configuration, FIG. 4 is a diagram illustrating a CPU (Central Processing Unit) load state of the conventional system, and FIG. 6 is a diagram illustrating a CPU load state by processing.

In FIG. 2, a system bus 1 is a common bus, and is connected to a CPU 2, a display control circuit 3, a moving image decompression / reproduction unit 4, a moving image file 5, an input / output interface 6, a memory 7, and a program data file 8. I have. The input / output interface 6 is connected to a keyboard 20 and a mouse 19 of an input device, and receives an input instruction for reproducing a moving image or the like and outputs it to a system bus. The moving image file 5 stores compressed moving image data. The expanded moving image data and the microprogram of the program data file 8 are expanded and temporarily stored in the memory 7. The program data file 8 stores a control program for compression / decompression of a moving image, and a microprogram of an application program (application program) such as a spreadsheet, a graph display, and a statistical process. The moving picture decompression / reproduction unit 4 decompresses and reproduces the moving picture data of the moving picture file 5 in accordance with the program of the program data file 8, and outputs a moving picture output 10 and an audio signal 14. Here, the normal decompression reproduction method is referred to as method 1. The display control circuit 3 outputs a display output 9 by instructing layout when outputting to the display 13, displaying other icons, and controlling display of graphs and tables after application processing. A display output 9 output from the display control circuit 3 and a video output 10 output from the video decompression / reproduction unit 4
Is input to the display superposition circuit (MIX) 11.
The display signal 12 output from the display superposition circuit 11 is input to the display 13. The audio signal 14 output from the video decompression / reproduction unit 4 is input to a speaker 15. In the CPU 2, a start instruction in the moving image decompression / reproduction unit 4 is provided.
It accesses memory, loads control programs, sets registers, controls display, and processes application programs such as graphs and tables.

For the sake of convenience, in order to make the load state of the CPU easy to understand, as shown in FIG.
Assume a load of In order to actually know the load state of the CPU, an interrupt signal is counted or data on the system bus is monitored. In FIG. 6, when the system of FIG. 2 is in the operating state and the moving image playback or other application is not executed, the steady state is set.
Assume a PU load of 20% ± 5%. It is assumed that the CPU load when the moving image is expanded and reproduced is 60% ± 5% (in the case of the method 1). Assume that the CPU load during execution of another application is 30% ± 5%.

FIG. 4 shows a load state of the CPU when the system shown in FIG. 2 starts reproduction of a moving image from a steady state and starts another application during reproduction of the moving image. In FIG. 4, the load on the CPU is shown as an addition of the load for each process currently performed by the CPU. In a steady state, a load of 15 to 25% is applied to the CPU. In the system shown in FIG. 2, when the reproduction of a moving image is started from the input device, the CPU 2 reads out the compressed moving image data from the moving image compression file 5 and inputs it to the moving image decompression / reproduction unit 4. In the video decompression / playback unit 4,
The data is expanded and reproduced according to the method 1, and the moving image output 10 and the audio signal 14 are output. The video output 10 and the display output 9 from the display control circuit 3 are combined with a display superposition circuit 11
Are superimposed to form a display signal 12, and a moving image is displayed on the display 13. The audio signal 14 is input to a speaker 15, and the speaker 15 outputs a sound. 60% ± 5% CPU during video expansion and playback (method 1)
Since the load is further increased, as shown in FIG.
The CPU load becomes about 90%. Next, another application is started. In FIG. 2, the keyboard 20
Alternatively, an input device such as the mouse 19 receives an instruction to start another application, and the CPU 2 starts another application. The CPU 2 reads out the program data from the program data file 8 and expands the program in the memory 7. Processing is performed by the CPU 2 according to the program, display is performed by the display control circuit 3, and the display is displayed on the display 13. At this time, a load of 25 to 30% is further applied to the CPU 2, so that as shown in FIG.
The load becomes 95 to 125% as a whole, and the load state of the CPU exceeds 100% (shown by hatching in FIG. 4). At this point, the processing is not performed normally.
Conventionally, since the load state is not detected, the load state becomes 1
If it exceeds 00%, the playback frame rate of the moving image will decrease, the entire system will stop, and the processing of other application programs will stop.

[0007]

According to the above prior art, when decompressing and reproducing certain moving image data, the processing load of the CPU during reproduction of the moving image and the processing load of the CPU during the execution processing of another application program are reduced. If the processing load overlaps and a processing load of a certain level or more is applied to the CPU, the processing capacity of the CPU is exceeded. For this reason, for example, if another application program such as a spreadsheet, a graph display, and a statistical process is simultaneously executed and displayed on the same display screen at the same time,
A moving image is not normally reproduced, and a problem such as a decrease in the reproduction frame rate of the moving image, a stop of the entire system, or a stop of other application program processing may occur.

[0008] In order to solve the above problems, the present invention provides a C
In order to prevent the processing load of the PU from being detected and to stop the entire system from being stopped, the CPU used in the conventional system is not changed to a CPU having a high processing capacity, and the CPU is used.
An object of the present invention is to provide a compressed moving image data decompression / reproduction system capable of decompressing and reproducing compressed moving image data while simultaneously executing another application program and displaying the same on the same screen while suppressing the processing load of U.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a decompression / reproduction unit for decompressing / reproducing data-compressed moving image data, and an instruction for processing other applications and for starting decompression / reproduction. In a system for displaying a moving image on a display screen having a CPU, the decompressing / reproducing unit decompresses / reproduces the data-compressed moving image data and has a relatively large processing load. A detection means for detecting a load state of the CPU; a detection means for detecting at least two of the reproduction method and a second reproduction method for performing decompression / reproduction by reducing the processing load of the CPU; And a switching unit for switching the method of the decompression / reproduction unit according to the load state of

[0010] The switching unit includes a CPU from the detecting means.
If the load state of the CPU is overloaded not less than the threshold value by comparing the load state of the CPU with a preset threshold value, the processing is switched to the second reproduction method of expanding and reproducing while suppressing the processing load of the CPU. Otherwise, there is provided a means for instructing the decompression / reproduction unit to reproduce in the first reproduction method.

The threshold value of the switching unit has a hysteresis characteristic having two threshold values, and switches to the second reproduction method when an overload equal to or more than one threshold value is set, and thereafter, the threshold value is reduced to two or less. When this happens, it is possible to switch to the first reproduction method.

The switching section may store a threshold value and have a threshold value table which can be set and changed.

[0013]

When the load of the CPU exceeds a threshold value, for example, when the load state of the CPU is constantly detected by the detecting means, and the moving image is expanded and reproduced and another application program is started, the load is increased.
The method of expanding / reproducing moving images by switching means
Switching to the second reproduction method in which the processing of U is reduced. Further, by providing a hysteresis characteristic having two thresholds of the switching means, the system switches to the second reproduction method when an overload equal to or more than 1 threshold is performed, and thereafter, when the load becomes equal to or less than 2 thresholds. Switch to the first playback method.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a system configuration diagram of the present embodiment. In FIG. 1, a system bus 1 is a common bus to which a CPU 2, a display control circuit 3, a moving image decompression / reproduction unit 4a, a moving image file 5, an input / output interface 6, a memory 7, and a program data file 8 are connected. The input / output interface 6 includes a keyboard 20 and a mouse 19 of an input device.
Is connected, and receives an input instruction such as moving image reproduction and outputs it to the system bus. The moving image file 5 stores compressed moving image data. The moving image data can be input from outside. The expanded moving image data and the microprogram of the program data file 8 are expanded and temporarily stored in the memory 7. The program data file 8 stores a control program for compression / decompression of a moving image and microprograms for application programs such as spreadsheets, graph displays, and statistical processing. The moving image decompression / reproduction unit 4a decompresses and reproduces the moving image data of the moving image file 5 according to the program of the program data file 8, and outputs a moving image output 10 and an audio signal 14. Here, the decompression reproduction method in which the processing load on the CPU is reduced is referred to as method 2. Method 2 may be any method that reduces the processing load on the CPU compared to method 1, and is set in advance. Method 2 is, for example, a method of reducing the amount of data by dropping frames, reducing the frame rate, reducing the display resolution, or displaying only the reference. Method 1 and method 2 of the normal expansion / reproduction method are set in advance in the moving image expansion / reproduction unit 4a. Alternatively, the program of the method 1 and the program of the method 2 may be stored in the program data file 8. The display control circuit 3 outputs a display output 9 by instructing layout when outputting to the display 13, displaying other icons, and controlling display of graphs and tables after application processing. The display output 9 output from the display control circuit 3 and the video output 10 output from the video decompression / reproduction unit 4a are input to a display superimposition circuit (MIX) 11. The display signal 12 output from the display superposition circuit 11 is input to the display 13. The audio signal 14 output from the video decompression / reproduction unit 4a is input to a speaker 15. CPU
In 2, a start instruction in the moving image decompression / reproduction unit 4a, loading of a control program, register setting, display control, and processing of application programs such as graphs and tables are performed. In addition, the CPU 2 outputs a detection signal 16 for indicating the load state of the CPU. The detection signal 16 output from the CPU 2 is input to the load detection unit 17. Detection signal 1
Reference numeral 6 includes, for example, an interrupt request signal, input / output information on the system bus 1 from the CPU 2, and a write / read signal to / from the memory 7. The detection signal 16 can detect any one of the above signals or a signal obtained by combining them. The load detecting means 17 monitors the signal as described above, counts how many times the signal has occurred in a certain period, and detects the load state based on a predetermined condition. For example, the load state is determined by the frequency of use on the system bus 1 and the frequency of writing and reading to and from the memory 7. The detected load state is output to the switching unit 18 as a percentage (%) of the CPU load. When the ratio is output, a table indicating the correspondence between the setting condition and the ratio of the CPU load may be provided in advance. The correspondence table can receive an instruction from the keyboard 20 or the mouse 19 of the input device. By referring to the correspondence table, the detection signal 16
When a predetermined condition is determined by counting the signals from the CPU, the corresponding CPU load ratio is output. Further, instead of the correspondence table, the ratio may be calculated from the count number of the number of occurrences in a certain period. Further, the load detecting means 17 can detect the load by monitoring data on the system bus 1 instead of the detection signal 16 output from the CPU 2. The output of the load detecting means 17 is input to the switching unit 18 and the switching unit 1
8 compares the CPU load state with a predetermined threshold value, and when the CPU load state is overloaded beyond the threshold value, switches the video decompression / reproduction unit 4a to switch between the method 1 and the method 2. Instructions can be output. The switching unit 18 has a threshold table for setting a threshold for system switching, and a keyboard 20 of the input device.
And an instruction from the mouse 19 can be received. The switching threshold will be described later with reference to FIG.

Next, the operation of this embodiment will be described with reference to FIGS. 1, 3 and 5. FIG. 3 is a characteristic diagram of the switching unit,
FIG. 5 is a diagram illustrating a CPU load state according to the present embodiment.

In FIG. 1, the moving image decompression / reproduction unit 4a
In addition to the moving image decompression reproduction (method 1), it has a moving image decompression reproduction (method 2). When the output of the switching unit 18 is 0, method 1 is selected, and when the output of the switching unit 18 is 1, method 2 is selected. The two methods are switched. It is assumed that the CPU load state of the moving image decompression reproduction (method 2) is 30% ± 5% as shown in FIG. 6 (１ ／ of method 1). The operation of the load detection means 17 shown in FIG. 1 uses the detection signal 16 input from the CPU 2 and
The CPU 2 outputs a load state (%) of the CPU 2 by measuring a change in the load. Depending on the load state of the CPU 2 input to the switching unit 18, the output of the switching unit 18 becomes 0 or 1 with characteristics as shown in FIG. In the example of FIG. 3, when the load exceeds 95%, the switching output changes from 0 to 1.
, And when the load falls below 60%, the switching output changes from 1 to 0. As described above, the threshold value table is set with the two threshold values having hysteresis depending on the load state of the CPU 2. These two thresholds are indicated by broken lines as shown in FIG. In FIG. 5, when the system of this embodiment is in a steady state, the load state of the CPU is 15 to 25%. When the reproduction of the moving image is started from this state, in the system shown in FIG. 1, the CPU 2 reads out the compressed moving image data from the moving image compression file 5 and inputs it to the moving image decompression / reproduction unit 4a. Since the output of the switching unit 18 input to the moving image decompression / reproduction unit 4a is initially 0,
The reproducing unit 4a expands and reproduces the data according to the method 1, and outputs a moving image output 10 and an audio signal 14. The video output 10 and the display output 9 from the display control circuit 3 are superimposed by a display superimposition circuit 11 to form a display signal 12,
It is displayed on the display 13. The audio signal 14 is input to the speaker 15, and the audio is output from the speaker 15. 60% at the time of video expansion / reproduction (method 1)
Since a CPU load of ± 5% is applied, the CPU load is 70 to 90% as shown in FIG. Next, another application is started. In FIG. 1, an input device such as a keyboard 20 or a mouse 19 receives an instruction to activate another application, and the CPU activates the other application. The CPU reads out the program data from the program data file 8 and expands the program in the memory 7. The CPU 2 performs processing according to a program, performs display control by the display control circuit 3, and displays an image, processing data of an application, and the like on the display 13. As shown in FIG. 5, at this time, a load of 25 to 30% is further applied to the CPU 2, so that shortly after the start of the other application, the load detecting unit 17 is started.
, It is detected that the CPU load has exceeded the threshold value of 95%. The switching unit 18 detects that the CPU load has exceeded the threshold of 95%, and changes the output of the switching unit 18 from 0 to 1
To As a result, the method of the moving image decompression / reproduction unit 4a is switched from method 1 to method 2. Therefore, after that, the moving image decompression / reproduction unit 4a decompresses / reproduces the data according to the method 2, which is 30% less than that of the CPU load method 1.
Since it is reduced, the total is 65 to 95% even when combined with the CPU load of another application, and the CPU load is 1%.
Since it does not exceed 00%, CPU processing can continue normally. Then, shortly after finishing the processing of the other application, the processing load of the entire CPU falls below the threshold of 60%,
The output of the switching unit 18 changes from 1 to 0,
The method of decompressing / reproducing moving image data in the reproducing unit 4a changes from method 2 to method 1, and decompresses / decompresses data according to method 1.
Reproduce. At this time, the load state of the entire CPU becomes 70 to 90% as before starting other applications, and the processing of the CPU continues normally.

According to this embodiment, when a certain CPU load is applied at the time of reproducing a moving image, even if another application is started, even if another application is started, the load detecting means 17 detects the C value.
Since the moving image decompression / reproduction method is switched by the switching means 18 so that the load state of the PU 2 is detected and the load of the CPU 2 does not exceed 95%, the system may not operate normally due to the activation of another application, or the system may not operate normally. Will not stop.

In this embodiment, the CPU load state for each process is assumed as shown in FIG.
The description has been made assuming that the loads on the respective processes performed by the PU are added. However, in practice, this does not always match this example. In this case, the threshold of the threshold table in the characteristics of the switching unit 18 is changed from the input device. By doing so, it is possible to deal with the actual CPU load state. In addition, a countermeasure is taken by adjusting the time of a certain period for measuring the change of the detection signal 16 from the CPU 2 in the load detecting means 17. By shortening this fixed period, C
An instantaneous change in the load fluctuation of the PU 2 can be detected, and an average load state of the CPU 2 can be detected when the certain period is extended.

Further, by providing the threshold value with hysteresis, even when the load condition slightly changes, the method 1
And Method 2 are not switched in a short period of time. As a result, there is no instantaneous switching between the reproduction screens of the method 1 and the method 2.

[0020]

According to the present invention, in order to detect the load state of the CPU, the system for expanding / reproducing moving images is switched to a system in which the processing of the CPU is reduced when the load exceeds a certain value and becomes overloaded. Thus, the load on the entire CPU can be reduced. That is, the CP used in the system
Decompress and reproduce compressed video data without changing U to one with high processing capacity, and execute video and video on the same screen without stopping the system even if other application programs are executed. The processing result of the program can be displayed.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an embodiment.

FIG. 2 is a configuration diagram of a conventional system.

FIG. 3 is a characteristic diagram of a switching unit.

FIG. 4 is an explanatory diagram showing a CPU load state of a conventional system.

FIG. 5 is an explanatory diagram illustrating a CPU load state according to the embodiment;

FIG. 6 is an explanatory diagram showing a CPU load state for each process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... System bus, 2 ... CPU, 3 ... Display control circuit, 4
... moving image decompression / playback unit, 5 ... moving image compression file, 9 ... display output, 10 ... moving image output, 11 ... display superimposing circuit, 1
2 ... display signal, 13 ... display, 14 ... audio signal,
15 speaker, 16 detection signal, 17 load detection means, 18 switching unit.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomohisa Kohiyama 292 Yoshidacho, Totsuka-ku, Yokohama-shi, Yokohama, Japan Inside Microelectronics Devices Development Laboratory, Hitachi, Ltd. (72) Inventor Masataka Musha Yoshidacho, Totsuka-ku, Yokohama-shi, Kanagawa 292 Hitachi Electronics, Ltd.Microelectronics Device Development Laboratory (72) Inventor Junji Nakata 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd.Microelectronics Device Development Laboratory (72) Inventor Masami Yamagishi Kanagawa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Hitachi Microelectronics Equipment Development Laboratory Co., Ltd. (72) Inventor Yuji Kimura 292 Yoshida-cho, Toda-ku, Yokohama-shi, Kanagawa, Japan Microelectronics, Inc. (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N ^7/ 24-7/68

Claims (4)

(57) [Claims] 1. A system for displaying a moving image on a display screen having a decompression / reproduction unit for decompressing / reproducing data-compressed moving image data and a CPU for instructing activation of decompression / reproduction and processing of another application. The decompression / reproduction unit decompresses / reproduces the compressed video data and performs the first reproduction method having a relatively large processing load and the second reproduction which performs decompression / reproduction by reducing the processing load on the CPU. It has at least two or more of the methods, and has a detecting means for detecting the load state of the CPU, and a switching section for switching the method of the decompression / reproduction section according to the load state of the CPU from the detecting means. Characterized compressed video data expansion / reproduction system. 2. The switching unit according to claim 1, wherein the switching unit compares a load state of the CPU from the detection unit with a preset threshold value, and when the load state of the CPU is equal to or more than the threshold value,
A means for instructing the decompression / reproduction unit to switch to the second reproduction method for decompressing / reproducing while suppressing the processing load of the CPU, and otherwise to reproduce in the first reproduction method. Characterized compressed video data expansion / reproduction system. 3. The switching device according to claim 2, wherein:
It has a hysteresis characteristic having two thresholds, and switches to the second reproduction mode when the overload exceeds 1 threshold, and then switches to the first reproduction mode when the load becomes 2 thresholds or less. A compressed moving picture data expansion / reproduction system characterized by switching. 4. A compressed moving picture data decompression / reproduction system according to claim 2, wherein said switching section stores a threshold value and has a threshold value table which can be set and changed.