JP2003319390A - Image reproducing terminal apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reproducing terminal apparatus capable of reproducing an image with suppressed power consumption. <P>SOLUTION: The image reproducing terminal apparatus sets an optimum operation clock rate for a CPU depending on the types of a moving picture (screen size, presence/absence of sound, presence/absence of a telop, and a frame rate or the like) and controls the operation at the irreducible minimum clock rate according to the setting. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable terminal device having a function of reproducing images, and more particularly to a portable terminal device suitable for reproducing moving images.

[0002]

2. Description of the Related Art A portable terminal device represented by a mobile phone or an electronic organizer is small in size and is intended to be carried around.
It is necessary to design for lightweight and power saving. For example, in order to extend the continuous standby time and continuous talk time on a mobile phone, use a low power consumption CPU and peripheral circuits,
Furthermore, it is necessary to perform detailed power control such as stopping the CPU when not in use.

[0003]

When an image, particularly a moving image, is to be continuously reproduced on such a portable terminal device, the moving image compressed by a compression method such as MPEG4 (Moving Picture Experts Group phase 4) is used. In order to decode the file, it is conceivable that a LSI dedicated for image reproduction is separately mounted, or a second CPU that can be used for multiple purposes is mounted and the moving image is decoded and reproduced by software. In particular, by installing a second CPU, not only the moving image playback function, but also the thumbnail display of images can be displayed at high speed, and applications using the Java language (“Java” is a registered trademark of Sun Microsystems, Inc.) You can expect big advantages such as moving at high speed. In this case, by using a system LSI that combines a CPU and DSP (Digital Signal Processor)
And DSP can be shared efficiently. However, it requires a large amount of power consumption to reproduce moving images using a CPU, and the continuous operation time is reduced, which is a great obstacle to the way to carry and carry around. Therefore, an object of the present invention is to provide an image reproduction terminal device capable of reproducing an image while suppressing power consumption.

[0004]

In order to solve the above problems, a moving image reproducing terminal device according to the present invention determines an optimum CPU operation clock rate according to the type of moving image, and according to this operation clock rate. Control to work.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION An image reproducing terminal device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the system configuration of the image reproduction terminal device according to the present embodiment. Antenna 1001 is a switch (SW) 10
00, GPS (Global Position
ing System) Amp 1002, cd for receiving telephone and communication functions
maAmp1003, cdma (Code Division Multipl
e Access) Connect with Amp1004. Communication processor 1010
Controls each GPS amplifier to calculate location information and perform communication / call processing. The communication processor 1010 includes keys 1014 for inputting a telephone number or email, operating the device, a microphone 1012 for making a voice call, and an ear speaker.
1013 is connected.

The image reproducing terminal device according to the present embodiment is
An application processor 1020 is installed as a second CPU that can be used for multiple purposes. Communication processor 10
10 and the application processor 1020 are connected by a dedicated bus 1015, and are equipped with a memory 1011 that can be shared and used.

An external memory 1021, an LCD (Liquid Crystal Display) 1022, and a sub LCD 1023 are connected to the application processor 1020. Especially, decoding of moving images and reproduction of games moving at high speed are performed by the application processor 1020.
I am trying to make full use of the ability of 1020. In addition, the application processor 1020
Camera 1024, speaker 1025, R-UIM (Removable User I
The dentification module) 1026 is installed, and it can also have a multimedia function and an electronic commerce authentication function.

The image reproducing terminal device operates by itself by a battery (not shown) without requiring an external power source. In addition, the battery can be charged and reused if necessary.

FIG. 2 is an image diagram of an image reproduced by the image reproducing terminal device according to the present embodiment. There are roughly two types of image sizes as shown in FIGS. 2 (a) and 2 (b), and FIG. 2 (a) shows QCIF (Quarter Common Intermediate Form).
at 176 × 144 pixels), Figure 2 (b) shows sub QCIF (S-QCIF 128 ×
96 pixels). Further, as shown in FIGS. 2 (c) and 2 (d), a telop portion for displaying characters or symbols may be provided below each image. For example, the dialogue of karaoke can be displayed, and a comment can be added to each scene of the moving image. In addition, since the processing load increases when a voice is attached, the types are also distinguished by the presence or absence of voice.

FIG. 3 is a diagram showing the CPU operating rate of the application processor of the image reproducing terminal device according to the present embodiment. The horizontal axis represents time, and the vertical axis represents whether or not the moving image reproducing application is operating. In this embodiment, the operating clock of the processor can be switched from 120 MHz to 40 MHz in four steps. When the application processor is running at the maximum speed of 120 MHz, the busy rate due to moving image playback is low, but the busy rate increases as the operating clock decreases, and at 40 MHz, for example, other processing can hardly be performed, resulting in video It cannot be used because it causes a problem such as frame dropping in image reproduction. Here, the power consumption of the application processor depends on the operating clock rate, and the higher the speed, the higher the power consumption.

FIG. 4 is an explanatory diagram showing a data format of a moving image reproduced by the image reproducing terminal device according to the present embodiment. FIG. 4 (a) shows an example of the entire moving image data, including a header, moving image attribute data, contents (moving image data body), a symbol indicating the end of the file, and EO.
It consists of F (End Of File). Further, FIG. 4B shows the details of the attributes. For example, the image size of the moving image shown in FIG. 2, the total playback time of the moving image, the presence / absence of audio, the presence / absence of a telop, and the presence of a telop. The telop data of is included. The telop data may be included in the content shown in FIG. 4A depending on the type of moving image format.

FIG. 5 is a data table showing the relationship between the type of reproduced image of the image reproducing terminal device according to this embodiment and the clock of the application processor. In this embodiment, there are two types of image sizes, QCIF and S-QCIF, and a total of eight types of patterns depending on the presence or absence of voice and the presence or absence of telop. When the image size is large, the work required for the reproduction process increases, and the CPU operating clock needs to be faster. The presence or absence of voice and the presence or absence of telop are the same, and it is possible to play back moving images without failure under these conditions.
The lower limit clock (clock as slow as possible) is set as the operation clock. This data table is
The data table referred to by the program in the application processor is stored in the mobile terminal device in the program or as a data file.

As described above, by setting the required clock rate before the reproduction by the attribute of the moving picture data shown in FIG. 4, the moving picture is reproduced at the minimum necessary clock rate to reduce the power consumption. It can be reduced.

The operating clock rate is not limited to the example shown in FIG. 5, and the clock rate may be set in consideration of the frame rate of moving images (the number of playback frames per second). good. Since the frame rate greatly affects the power consumption, it is possible to reduce the power consumption by setting the clock accordingly.

FIG. 6 is a flowchart showing a method in which the application processor sets an operation clock when reproducing a moving image. First, data analysis 6000 is performed to analyze the attributes of the moving image data shown in FIG. Based on the analysis result, the image size is first determined (6010), and if it is QCIF, the next telop presence / absence is determined (6020). If there is a telop, set the maximum speed of 120MHz to the operation clock (6
040). If the image size is S-QCIF, it is next determined whether or not there is a telop (6030), and if there is no telop, the operation clock is set to the lowest 60 MHz (6060). When the image size is QCIF and no telop, or when the image size is S-QCIF and telop is set, set the operation clock to 80MHz, and after setting the operation clock respectively, start playback (6
070).

In the present embodiment, the operating capacity and power consumption of the application processor are changed by changing the operating clock of the application processor. This is because the master clock input to the application processor is divided inside the processor. Determined by the dividing circuit that performs the circuit. For example, when the master clock is 20 MHz, the frequency is divided by 40, 60, 80 MH by the frequency dividing circuit.
The clock is increased by multiplying it by N such as z.

FIG. 7 is a diagram for explaining the software structure of the image reproducing terminal device according to the present embodiment, which shows a method for saving power by switching the operation mode of the CPU.
In this embodiment, the software is a multitasking OS
It operates by managing, and multiple types of tasks operate in a time-sharing manner. Specifically, for example, if you receive a call while editing an email, leave the task of editing the email as it is and activate the task of processing the call.
Perform call processing. This operation is possible by assigning a priority of 7000 to each task, and a task that operates according to the priority is selected. In the above example, the incoming call is the highest priority task, so when a call comes in, the task with lower priority, specifically the mail composition task, suspends the temporary operation and processes the call. To perform the task. At this time, the multi-task OS
Can stop the mail processing task without closing it, including its work area, and when the execution right comes back to the mail processing task, the operation before the stop can be continued. .

In FIG. 7, task 1 (7020) is performing processing 7021. When the processing is completed, task 1 enters the idle state (7022). This is managed by the task manager, and the state transitions to the working state of task 2 (7030) having a low priority (7023). When the task 2 enters the idle state, the state transitions to a task with a lower priority in sequence, and finally to the idle task 7050, and this processor enters an idle state in which no processing is performed. At this time, nothing is processed in the idle state of the idle task (NO
P (No Operation) instructions are being executed in an infinite loop, resulting in wasted power consumption. The power consumption at this time depends on the operating clock, and the more operating clocks, the more wasteful power consumption.

In this embodiment, when the idle task enters the idle state, the CPU is transited to the sleep state (7052). The sleep state is a state in which the core part of the CPU has stopped operating, regardless of the operating clock.
The state can be maintained with the minimum power consumption, and the power consumption of the CPU can be minimized.

The return from the sleep state is automatically performed when an external access to a register or memory or an interrupt occurs. Specifically, for example, after moving image data is decoded and sent to the LCD, automatic restoration is performed when the next data is requested from the LCD.

FIG. 8 is a block diagram showing the core portion of the application processor of the image reproduction terminal device according to this embodiment.

The application processor is the CPU
CPU 8001 and internal memory 8002 are placed in the core part 8000,
It is connected by a high-speed internal bus 8004 that closes only inside the core. The connection with the communication processor in FIG.
The external bus 8010 has a bus I / F 8003 for converting signals between buses having different speeds. In FIG. 7, when an idle task is in an idle state and an instruction such as NOP is executed in an endless loop, signals are exchanged at high speed only between the CPU 8001 and the internal memory 8002, or the program (for example, NOP instruction) is in the CPU 8001. It is in the cache of, and the state where the cache exchanges signals at high speed with the accumulator inside the CPU (not shown). In this state, the operating current of the CPU is not completely low and the memory access is activated, so that unnecessary current consumption is flowing. The current fluctuates according to the operation clock, and the higher the clock speed, the larger the current consumption. In the present embodiment, the power consumption can be suppressed by setting the CPU in the sleep state as described above.

FIG. 9 is a graph showing the current consumption in the reproduction of a moving image by the image reproduction terminal device according to the present embodiment. The top of the graph shows memory access and the second shows write access to the LCD. After accessing the LCD to output the decoded image (9021), the next image data is read from the memory (9011) and decoded. The decoding at this time consumes a current of 9031, which is the power required for decoding the moving image, and is an area that cannot be reduced. The decoded moving image is output to the LCD, and the operation of reading the next image data from the memory is repeated. When accessing the memory or LCD, the CPU is in a wait state as hardware, and the current consumption at that time is as indicated by reference numeral 9033 in the figure.

In normal operation (when the idle state shown in FIG. 7 is composed of an infinite loop of NOPs),
The current consumption is 9032 until the moving image is decoded and output to the LCD and from the output to the LCD until the next image data is read from the memory. CPU is w
Since the program is running instead of ait, the entire CPU is not activated like decoding, so the current consumption is low, but some current consumption depends on the operating clock.

In this embodiment, when the idle state is set, s
By changing to the sleep state, it is possible to reduce current consumption (9042) and save power. As a specific example, the idle current has been reduced from 45mA to 25mA,
The average current can be reduced by 60% in moving image decoding.

The present embodiment shows an example in which the decoding of a moving image is performed by using a CPU whose clock change control is possible and whose current consumption changes due to the clock change, but this is only for moving image reproduction. The DSP can also control the clock change for decoding the moving image, and the same effect can be obtained as long as the current consumption changes due to the clock change.

As described above, in the present embodiment, the optimum CPU operation clock rate is set according to the type of moving image, and the operation is performed at the minimum necessary clock rate according to the operation clock rate, thereby operating with battery. It is possible to reduce the power consumption of the portable terminal device, extend the actual usage time, and use the portable terminal device without worrying about frequent charging and battery replacement. In particular, a mobile phone can prevent a decrease in continuous standby time, and can be expected to have a great effect in preventing the basic problem that the battery runs out and the phone cannot be used when it is essential.

[0028]

According to the present invention, the power consumption is suppressed,
An image reproduction terminal device capable of reproducing an image can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of an image reproduction terminal device.

FIG. 2 is an image diagram of an image reproduced by the image reproduction terminal device.

FIG. 3 is a diagram showing a CPU operating rate of an application processor of an image reproduction terminal device.

FIG. 4 is an explanatory diagram showing a data format of a moving image reproduced by the image reproducing terminal device.

FIG. 5 is a data table showing the relationship between the type of reproduced image of the image reproducing terminal device and the clock of the application processor.

FIG. 6 is a flowchart showing a method in which the application processor of the image reproduction terminal device actually sets its own operation clock when reproducing a moving image.

FIG. 7 is an explanatory diagram of a software structure showing a method of saving power by switching the operation mode of the CPU of the image reproduction terminal device.

FIG. 8 is a block diagram showing a core portion of an application processor of the image reproduction terminal device.

FIG. 9 is a graph of current consumption of the image reproduction terminal device in reproducing a moving image.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshio Uemura             292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Ceremony Hitachi Digital Media Development Book             Department (72) Inventor Kozo Masuda             1410 Inada Stock Company, Hitachinaka City, Ibaraki Prefecture             Hitachi Mobile Device Division F term (reference) 5B079 AA04 BA01 BB10 BC01 DD03                 5C059 KK49 MA00 PP04 PP20 RA04                       RC32 RC34 SS10 TA00 TC24                       TC25 UA05 UA09 UA38                 5C064 AA01 AB04 AC11 AC17 AD01                       AD13 AD14                 5K027 AA11 BB17 FF01 FF22

Claims (9)

[Claims] 1. An image reproduction terminal device capable of reproducing a moving image, comprising: a decoding means having a plurality of decoding processes for decoding moving image data; a moving image type; and a moving image type. And a storage unit that stores the corresponding decoding process according to the type of the moving image stored in the storage unit when decoding the moving image data. An image reproduction terminal device, comprising: a control unit that controls to decode the moving image data. 2. An image reproducing terminal device having a display device capable of reproducing images driven by a battery, wherein the image reproducing terminal device is capable of reproducing moving images, and the moving images are in a compressed form. Has a processing circuit for decoding the moving image data supplied thereto, and the processing circuit is capable of switching the processing capability. The processing capability is automatically switched according to the data format of the moving image to decode the moving image. And an image reproduction terminal device having a function of performing reproduction. 3. The image reproducing terminal device according to claim 2, wherein the image reproducing terminal device has a data table that pairs types of moving images and processing capacity switching parameters of a processing circuit. 4. The image reproducing terminal device according to claim 2 or 3, wherein the type of moving image is determined by a combination of at least one of image size, presence / absence of sound, presence / absence of telop. Playback terminal device. 5. The image reproducing terminal device according to claim 4, wherein the type of the moving image is described in an area in the image data different from the moving image content, and the moving image is read prior to reading the moving image content. The image reproducing terminal device is characterized in that the processing capability of the processing circuit is automatically switched by reading the type of the. 6. The image reproducing terminal device according to claim 2, wherein the processing capability of the processing circuit is an operation clock of the processing circuit. 7. The image reproduction terminal device according to claim 6, wherein the operation clock of the processing circuit is determined by setting of a frequency dividing circuit that divides the master clock input to the processing circuit inside the processing circuit. An image reproducing terminal device characterized by. 8. An image reproducing terminal device having a display device capable of reproducing images driven by a battery, wherein the image reproducing terminal device is controlled by software operating under the control of a multitasking OS. When all the internal operations of the playback terminal device become idle,
An image reproducing terminal device characterized by causing an internal operation to transit to a sleep state. 9. The image reproducing terminal device according to claim 8, wherein the transition to the sleep state is performed within a program managed by a multitasking OS and transiting to an idle state.