JP2001319407A - Device and method for reproducing music, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen the battery drive time. SOLUTION: A microphone 22 detects an ambient noise level, and a comparison circuit 26 compares the output of the microphone 22 with a set value. An operation mode control device 32 decides a normal mode or a low power consumption mode according to the output of the comparison circuit 26 and a battery remaining capacity notifying signal from a power source device 30. Plural data files in which the same music is compressed at different compression ratios are stored in a hard disk 20. A RAM 12b can select use or non-use. In the normal mode, a data file of a low compression ratio is loaded into a RAM 12 from the hard disk 20, expanded, and applied to a headphone 18 from a D-A converter 16. In the low power consumption mode, a data file of a high compression ratio is loaded into a RAM 12a from the hard disk 20, expanded, and applied to the headphone 18 from the A-D converter 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a music reproducing apparatus, method, and storage medium, and more particularly, to a music reproducing apparatus, method, and storage medium for reproducing compressed audio data.

[0002]

2. Description of the Related Art A conventional music reproducing apparatus for reproducing compressed audio data decodes a selected audio data file in a storage device built in the device, and then converts the decoded audio data file into an analog signal. By supplying the sound to a speaker, the sound is reproduced. If it has a communication function, an audio data file may be imported from outside. Portable music playback devices
In general, a battery operates as a power source, and a user can enjoy reproduced music by wearing headphones.

[0003]

In the prior art, while listening to music, a CPU or a decoding device of a device must execute an arithmetic process for decompressing compressed audio data. There is less room to reduce power consumption. However, in the case of a battery-powered portable device, reducing power consumption is an important issue, and if the operating time can be increased, the convenience of the user will be significantly improved.

[0004] It is an object of the present invention to provide a music reproducing apparatus and method and a storage medium for reducing power consumption during sound reproduction.

[0005]

A music reproducing apparatus according to the present invention is a music reproducing apparatus having a plurality of operation modes corresponding to power consumption, and comprises a plurality of music data files obtained by compressing the same music at different compression ratios. , A decompression means for decompressing the compressed music data, an operation mode determination means for determining an operation mode to be applied, and the operation mode determination among the plurality of music data files on the storage medium Data transfer means for reading out a music data file having a compression rate corresponding to the operation mode determined by the means and supplying the music data file to the decompression means; and output means for outputting music information decompressed by the decompression means. Features.

The music reproducing apparatus according to the present invention further comprises a first music data file obtained by compressing the same music at a first compression rate, and a second music data file obtained by compressing the same music at a second compression rate higher than the first compression rate. Storage medium for storing the music data file, expansion means for expanding the compressed music data, noise detection means for detecting the surrounding noise level, and a noise level detected by the noise detection means being less than a predetermined value. In this case, the first music data file is read from the storage medium and supplied to the decompression means. If the value is equal to or greater than a predetermined value, the second music data file is read from the storage medium and supplied to the decompression means. It is characterized by comprising a data transfer means and an output means for outputting the music information expanded by the expansion means.

The music reproducing apparatus according to the present invention also has a plurality of operation modes according to power consumption, a first music data file obtained by compressing the same music at a first compression ratio, and a first compression ratio. A music playback device capable of playing back a second music data file compressed at a higher second compression ratio,
Data receiving means, expanding means for expanding compressed music data, operating mode determining means for determining an operation mode to be applied, and music data having a compression ratio corresponding to the operating mode determined by the operating mode determining means Data receiving means for receiving the file by the receiving means and supplying it to the decompressing means, and output means for outputting the music information decompressed by the decompressing means.

The music reproducing apparatus according to the present invention also includes a first music data file obtained by compressing the same music at a first compression rate and a second music data file obtained by compressing the same music at a second compression rate higher than the first compression rate. Music playback device capable of playing back music data files, a data receiving means, a decompression means for decompressing compressed music data, a noise detection means for detecting a surrounding noise level, and a noise detection means for detecting the noise level. When the received noise level is less than the predetermined value, the receiving means receives the first music data file and supplies it to the decompressing means. When the noise level is equal to or more than the predetermined value, the receiving means outputs the second music data file. It is characterized by comprising data transfer means for receiving a file and supplying it to the decompression means, and output means for outputting music information decompressed by the decompression means.

A music reproducing method according to the present invention includes an operation mode determining step of determining an operation mode to be applied among a plurality of operation modes according to power consumption, and a plurality of music files obtained by compressing the same music at different compression ratios. A reading step of reading a music data file corresponding to the operation mode determined by the operation mode determining means from a storage medium storing the data file; an expanding step of expanding the data file read in the reading step; Outputting the music information decompressed in the decompression step.

The music reproducing method according to the present invention further includes a noise detecting step of detecting a surrounding noise level, a first data file obtained by compressing the same music at a first compression rate, and a first data file obtained by compressing the first music file. When the noise level detected in the noise detection step is less than a predetermined value, the first data file is read from a storage medium storing the second data file compressed at a high second compression ratio, and In the above case, there are provided a reading step of reading the second data file, a decompression step of decompressing the data file read in the reading step, and an output step of outputting the music information decompressed in the decompression step. It is characterized by doing.

The music reproducing method according to the present invention also includes an operation mode determining step of determining an operation mode to be applied among a plurality of operation modes according to power consumption, and an operation mode determined by the operation mode determining means. And a decompression step of decompressing the music data file fetched in the fetching step, and an output step of outputting the music information decompressed in the decompression step. It is characterized by the following.

The music reproducing method according to the present invention also includes a noise detecting step of detecting a surrounding noise level, a first music data file obtained by compressing the same music at a first compression ratio, and the first music data file. If the noise level detected in the noise detection step is less than a predetermined value from the storage medium that stores the second data file compressed at the second compression ratio that is high, the first music data file is fetched. A capturing step of capturing a second music data file compressed at a second compression rate higher than the first compression rate when the value is equal to or greater than a predetermined value; and an expanding step of expanding the music data file captured in the capturing step. And an output step of outputting the music information decompressed in the decompression step.

The storage medium according to the present invention stores program software for executing the above-described music reproducing method.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic block diagram of a first embodiment of the present invention. 10 is an RO for storing programs, etc.
M and 12 are RAMs (Random Access Me)
memory). The RM 12 operates as primary data storage means. In this embodiment, the RAM 12 is divided into two blocks 12a and 12b. The RAM 12a of one block is a block that is always used, and the RAM 12b of the other block operates in the low power consumption operation mode of the RAM element when not used in the low power consumption operation mode. The low power consumption operation mode of the RAM element is, for example, a self-refresh mode for a DRAM having a self-refresh mode.

Reference numeral 14 denotes a CPU / memory control device which is in charge of calculation of a program, memory control, and the like.

Reference numeral 16 denotes a D / A converter for converting audio data into an analog signal, and reference numeral 18 denotes a headphone for outputting an audio signal from the D / A converter 16 as sound. The user listens to the reproduced music using the headphones 18.

Reference numeral 20 denotes a hard disk for storing compressed audio data. A rewritable nonvolatile memory element such as a flash memory may be used.

Reference numeral 22 denotes a microphone for detecting a noise level around the device, and specifically includes an amplifier for amplifying the detected sound signal. Reference numeral 24 denotes a setting value holding device for holding the set value of the surrounding noise level, and reference numeral 26 denotes a comparison circuit for comparing the output level of the microphone 22 with the set value output from the set value holding device 24. The comparison circuit 26 sets the output to high when the output level of the microphone 22 is higher than the set value. The set value holding device 24 is specifically composed of a semi-fixed resistor connected between the power supply inside the device and the ground level of the device, and the user can set the set value according to the set position of the semi-fixed resistor. Can be changed. In addition to the EE,
A configuration in which the set value is held in a memory device such as a PROM may be employed.

Reference numeral 28 denotes a battery serving as a power supply, and 30 denotes a battery 28.
A power supply device that operates according to and supplies necessary power to each part,
Reference numeral 32 denotes an operation mode control device that makes a transition to one of a normal operation mode and a low power consumption operation mode as an operation mode according to the ambient noise level and the remaining capacity of the power supply battery for device operation. In FIG. 1, power supply lines are omitted. The power supply device 30 monitors and detects the remaining capacity of the battery 28, and notifies the operation mode control device 32 when the remaining battery capacity becomes lower than a certain value. Operation mode control device 32
Instructs the CPU / memory control device 14 to transition to the low power consumption operation mode when the remaining battery power is low. Specifically, in the low power consumption operation mode, the operation mode control device 32 outputs the STP_REQ signal requesting the stop of the internal clock of the CPU to the CPU / memory control device 1.
4 is output. The operation mode control device 32 operates the STP_RE by manipulating the bits of the internal control register.
The output of the Q signal and its stop can be controlled. STP_RE
The Q signal will be described later. The operation mode control device 32 also detects a change in the output of the comparison circuit 26, and
When the battery remaining capacity notification signal is received from the power supply device 30, the CPU / memory control device 14 is interrupted.

Reference numeral 34 denotes an operation panel on which a user inputs an operation instruction of the device. The operation panel 34 is, specifically,
An input from a button or a key is detected and notified to the CPU / memory control device 14.

FIG. 2 shows an example of music data stored in the hard disk 20. FIG. 2A shows music data having a name “ABC”, and FIG. 2B shows music data having a name “DEF”. In this embodiment, a plurality of (three in FIG. 2) files having different compression ratios are prepared for one music.

Reference numerals 40H, 40M, and 40L denote music data files of "ABC". The file 40H has the lowest compression ratio, the file 40L has the highest compression ratio, and the file 40M is intermediate. Accordingly, the file size decreases in the order of the files 40H, 40M, and 40L, and the sound quality decreases in the order of the files 40H, 40M, and 40L.

Similarly, 42H, 42M and 42L correspond to "D
EF "music data file. The file 42H has the lowest compression rate, the file 42L has the highest compression rate, and the file 42M is intermediate. Therefore, the file size decreases in the order of the files 42H, 42M, and 42L, and the sound quality is reduced to the files 42H, 42M, and 42L.
In order.

It goes without saying that more music data may be stored on the hard disk 20.

In this embodiment, when the ambient noise level is higher than the set value, high sound quality data is used for reproduction, and when the ambient noise level is lower than the set value, low sound quality data is used for reproduction. I do. To determine the ambient noise level more finely, more files with different sound qualities may be prepared. In the example shown in FIG. 2, three files having different compression ratios are prepared. By providing two setting values for the ambient noise level, low sound quality data, intermediate sound quality data, High quality sound data can be used properly.

CPU 14 of CPU / memory controller 14
a includes a clock signal CPU_CL as shown in FIG.
K and an external signal STP_REQ requesting that the internal operation of the CPU 14a be stopped. The CPU 14a operates using the clock signal CPU_CLK as a basic clock, but when the signal STP_REQ goes to the H (high) level,
The clock signal supplied to the PU internal block is stopped, and the internal operation is stopped. While the internal operation is stopped, the clock signal supplied to the internal blocks of the CPU 14a is stopped, so that the power consumption of the CPU 14a is significantly reduced. When the signal STP_REQ returns to the L (low) level, the CPU 14a resumes the supply of the clock signal to the internal block, and returns to the normal operation mode. In this normal operation mode, the power consumption of the CPU 14a increases again.

FIG. 4 shows an example of a timing chart of the operation of the CPU 14a with respect to the clock signal CPU_CLK and the external signal STP_REQ. The CPU 14a sets the period t
Normal operation is performed at 1, t3 and t5. When the signal STP_REQ changes from L to H, the supply of the internal clock of the CPU 14a stops, and the internal operation stops. Therefore, the periods t2 and t4
During the operation, the internal operation of the CPU 14a is stopped and the CPU 14a is stopped.
The power consumption consumed by a is reduced. Signal STP_RE
When Q returns from H to L, the clock supply inside the CPU 14a is restarted, and the CPU 14a returns to the normal operation mode.

The clock signal CPU_CLK is generated by a clock oscillation circuit (not shown) and supplied to the CPU / memory control device 14. The signal STP_REQ is generated by the operation mode control device 32 and supplied to the CPU / memory control device 14. The signal STP_REQ is a clock signal having a duty ratio longer than the clock CPU_CLK, as shown in FIG. When the STP_REQ signal is enabled in the control register in the operation mode control device 32 in the low power consumption operation mode, the operation mode control device 32 is enabled during the enabled period.
Keeps outputting the signal STP_REQ as a clock signal having a certain duty ratio. When the device is reset to the normal operation mode and the STP_REQ signal is disabled in the control register in the operation mode control device 32, the signal STP_REQ immediately goes to the L level and the CP
The U / memory controller 14 shifts to a normal operation.

The duty ratio of the signal STP_REQ is C
The value is set to a value that allows the PU 14a to maintain a calculation performance that allows the PU 14a to reproduce the high-compression digital audio data without interruption.

FIG. 5 shows the CPU / memory controller 14 and the R
FIG. 3 is a block diagram showing signal connections between AMs 12a and 12b. An address bus 50 has a width of 13 bits in this example. Reference numeral 52 denotes a data bus.
It is 6 bits wide. Address bus 50 and data bus 52
Is common to both the RAMs 12a and 12b. 54
Is a control signal line for transmitting various control signals for memory control, and includes a write signal line, a read signal line, and the like.
56a is a chip select signal for selecting the RAM 12a, and 56b is a chip select signal for selecting the RAM 12b.

In the normal operation mode, the RAMs 12a and 12a
b is used, but in the low power consumption operation mode, the RAM 12b is not used. In the low power consumption operation mode, the chip select signal 56a becomes inactive (inactive), and the RAM 12b is not selected.
When the RAM 12b is enabled by a control register for the RAM 12b in the CPU / memory control device 14, the chip select signal 56b becomes active, and R
AM 12b becomes usable. When the control register for the RAM 12b disables the RAM 12b, the chip select signal CS1 becomes inactive and the RAM 12b cannot be used.

In this embodiment, the RAM 12b not used in the low power consumption operation mode is set to the low power consumption operation state by inactivating the chip select signal 56b. However, the DRAM requiring the refresh operation is replaced with the RAM 12a, 12b
, A slow refresh mode or a self-refresh mode, which is a power saving mode of the DRAM itself, may be used. In this case, a signal line required for refresh control is wired to the RAM 12b separately from the RAM 12a and its operation mode is individually controlled, so that the RAM 12a is kept operating in the normal operation mode during the low power consumption operation mode of the device. The RAM 12b can be shifted to the power saving mode of the DRAM itself.

FIG. 6 shows an example of the memory map of this embodiment. The RAM 12a stores the lower address of the memory map,
The RAM 12b is assigned to an upper address. RA
M12b is allocated to the area of addresses A3 to A4. FIG. 6A shows a memory map in the normal operation mode, and FIG. 6B shows a memory map in the low power consumption operation mode.

The range from the address A0 to the address A1 is a system area used in the system. The range from address A1 to address A2 is the work area. The work area is used during the process of decompressing the compressed audio data, and the decompressed data is stored in the D / D.
This is an area where data is temporarily stored until output to the A converter 16. These are the same in the normal operation mode and the low power consumption operation mode.

In the normal operation mode, the address A2 and higher,
Low-compression data (high-quality data) stored in the hard disk 20 is read into the range up to the address A4.

In the low power consumption operation mode, the address A2
As described above, the high-compression data (low-sound-quality data) stored in the hard disk 20 is read in a range below the address A3, that is, in a portion excluding the system area and the work area of the RAM 12a. The range above the address A3, that is, the RAM 12b is a standby area.

In the normal operation mode, the CPU 14a reads the low-compression data file into the data area (addresses A2 to A4) in block units, which are a part of the low-compression data file. Output to the converter 16.

In the low power consumption operation mode, the CPU 14a
Reads the high-compression data file into the data area (addresses A2 to A3) in block units as a part thereof,
Decompression operation is performed sequentially while reading out to the work area,
Output to the D / A converter 16. The high-compression data read in the low-power-consumption operation mode has a smaller data amount than the low-compression data.
A3) is not insufficient. In the example shown in FIG. 5, during the low power consumption operation mode, the chip select signal for the RAM 12b is deactivated.

The operation of the present embodiment will be described in detail with reference to FIGS.

FIG. 7 is a flowchart of the compressed data reproducing process. In accordance with the data reproduction instruction, the flow shown in FIG. 7 starts. An operation mode flag indicating the current operation mode is read (S1). The operation mode flag has, for example, 1-bit data secured in the system area, and is “0” in the low power consumption operation mode and “1” in the normal operation mode.

Based on the read operation mode flag, it is determined whether the operation mode is the normal operation mode or the low power consumption operation mode (S
2). In the case of the normal operation mode (S2), the STP_REQ signal is disabled in a register in the operation mode control device 32, and the ST / REQ signal to the CPU / memory control device 14 is set.
The P_REQ signal is set to L (S3). Further, a RAM control register in the CPU / memory control device 14
b is enabled and the chip select signal 56b is activated to make the RAM 12b usable.

A high-quality (low-compression) file is stored in the RAM 12
a and 12b (S4), decompress and reproduce (S4).
5). In this embodiment, instead of reading the entire audio file for one file into the RAMs 12a and 12b and then decompressing and reproducing it, a part of the file is stored in the RAM 12a and 12b.
a, 12b, and while performing decompression / reproduction processing, data to be reproduced next is stored in the RAM 12a,
12b. That is, processing is performed in the background so as not to interrupt the reproduced sound. Therefore, in this step S5, the data of the unit block necessary for reproduction is read into the data area. Information indicating how much of the target data file has been read into the data area of the RAMs 12a and 12b and information indicating how much of the data block in the data area has been expanded and reproduced are stored in the system area. It is checked whether or not the target data file has been reproduced to the end (S9). If there is any remaining data file, S1 and the subsequent steps are repeated.

In the case of the low power consumption operation mode (S2), the STP_REQ signal is enabled by a register in the operation mode control device 32, and the CPU / memory control device 14
STP_REQ signal to H (S6). Further, C
In the memory control register in the PU / memory controller 14, R
The AM 12b is set to be disabled, the chip select signal 56b is made inactive, and the RAM 12b is not used.

The low sound quality (high compression) file is stored in the RAM 12
a and 12b (S7), decompress and reproduce (S7).
8). Except for reading low-quality files instead of high-quality files, and except for the small data area,
4 and S5. It is checked whether or not the target data file has been reproduced to the end (S9). If there is any remaining data file, S1 and the subsequent steps are repeated.

If the user instructs the stop of the reproduction by the operation panel 34 before the end of the reproduction processing, the reproduction processing is stopped by the interruption processing.

FIG. 8 shows a flowchart of an interrupt process for setting an operation mode flag. There are three interrupt sources for starting the interrupt processing shown in FIG. The noise level around the device becomes higher than the set value, the noise level around the device becomes lower than the set value, and the remaining capacity of the battery 28 becomes lower than the set value. A change in the output of the comparison circuit 26 indicates a change in the noise level. The power supply device 30 monitors the remaining capacity of the battery 28, and outputs a warning signal to the operation mode control device 32 when the remaining capacity is less than the set remaining capacity. The operation mode control device 32 outputs an interrupt processing request to the CPU / memory control device 14 according to the output change of the comparison circuit 26 and the warning from the power supply device 30. The operation mode control device 32 simultaneously stores which interrupt has occurred in the status register.

The operation mode flag is read from the system area of the RAM 12 (S11). Operation mode control device 3
2 is read (S12), and it is determined whether or not the request is for shifting to the low power consumption operation mode (S13). For example,
When the ambient noise level is lower than the set value and the remaining battery level is large, the operation mode is not the low power consumption operation mode shift request, and the normal operation mode is set. When the ambient noise level becomes larger than the set value or the remaining battery capacity becomes smaller, a request to shift to the low power consumption operation mode is issued.

When it is necessary to shift to the normal operation mode (S1
3) The necessity of mode transition is determined by checking whether the operation mode (current mode) indicated by the operation mode flag read in S11 is the normal operation mode (S1).
4), if the current mode is not the normal operation mode (S1)
4) The operation mode flag in the system area is set to "1", that is, the normal operation mode is set (S15).

When the mode should be shifted to the low power consumption operation mode (S13), it is determined whether or not the operation mode (current mode) indicated by the operation mode flag read in S11 is the low power consumption operation mode. The necessity is determined (S14), and if the current mode is not the low power consumption operation mode (S14), the operation mode flag in the system area is set to '0', that is, set to the low power consumption operation mode (S17). ).

FIG. 9 shows a state transition diagram of this embodiment. S
31 is a power off state, S32 is an idle state, S33 is a normal operation state, and S34 is a low power consumption operation state.

When there is a power-on instruction in the power-off state S31, the state transits to the idle state S32.

The idle state S32 is a state of waiting for an operation instruction from the user. When an instruction to turn off the power is given or when the remaining battery capacity is exhausted, the state transits to the power-off state S31. If there is a music playback instruction and the ambient noise is smaller than the set value and the remaining battery charge is larger than the set value, the process transits to the normal operation state S33. Even if there is a music playback instruction, if the ambient noise is larger than the set value, or if the remaining battery charge is smaller than the set value, the process transits to the low power consumption operation state S34.

In the normal operation state S33, the audio data instructed to be reproduced is transferred from the hard disk 20 to the RAM.
After the data is read by the D / A converter 12, the data is converted into an analog signal by the D / A converter 16 and output from the headphones 18. The audio data to be reproduced here has a lower compression rate and higher sound quality than data to be reproduced in a low power consumption state, which will be described later.
4a increases the amount of calculation processing. If you are instructed to stop playing music, or if the music being played ends,
Transit to the idle state S32. If it is previously instructed to play back multiple audio data consecutively,
When the reproduction of all the specified files is completed, the state transits to the idle state S32. If there is an instruction to turn off the power, the state transits to the power off state S31. When the ambient noise level becomes higher than the set value or when the remaining battery capacity becomes lower than the set value, the low power consumption operation state S
It changes to 34.

In the low power consumption operation state S34, audio data having a high compression rate is selected and reproduced, and the RAM 1
2 is a state where low power consumption operation is performed. If the ambient noise level is lower than the set value and the remaining battery charge is higher than the set value, the process transits to the normal operation state S33. When there is an instruction to stop music reproduction, or when the music being reproduced ends, the state transits to the idle state S32. If it is instructed to reproduce a plurality of audio data successively in advance, when the reproduction of all the specified files is completed, the state transits to the idle state S32. If there is an instruction to turn off the power, the state transits to the power off state S31.

The processes described with reference to FIGS. 7 and 8 are performed on the ambient noise and the remaining battery level among the events that trigger the state transition. Power on / off,
Regarding each instruction of reproduction and stop, corresponding processing is executed by interruption by an instruction input by the user through the operation panel 34.

In this embodiment, the situation where the surrounding noise is loud,
That is, in a situation where it is difficult to understand the difference between the high-quality music and the low-quality music, it is possible to automatically select and reproduce the low-quality data and reduce the power consumption of the device. Therefore, the battery operation time can be lengthened without any special consideration.

In the embodiment shown in FIG. 1, audio data is stored on the local hard disk 20.
The present invention can be applied to a case where compressed audio data stored in a remote hard disk or a file server is read and expanded and reproduced.

FIG. 10 is a schematic block diagram showing an embodiment for reading and reproducing compressed audio data from a remote place via a communication line. Local hard disk 20
Instead, a communication device 60 is provided. Of course, the communication device 60 may be added without changing the hard disk 20. The communication medium of the communication device 60 may be wireless or wired.
As with the hard disk 20, the server that provides compressed audio data stores a plurality of files of the same music with different compression ratios, and uses audio data with a compression ratio in response to an external request as a request source. provide. In the case of a wireless line, the communication device 60 includes an antenna and a modem required for wireless communication.

The difference from the embodiment shown in FIG. 1 lies in whether audio data is read from the local hard disk 20 or from a remote server, and the other operations are the same. Detailed description of the operation of the example is omitted.

In the embodiment shown in FIG. 10, as compared with the operation and effect of the embodiment shown in FIG. 1, during operation with low power consumption, high compression data (low quality data) having a small data amount is used. The communication time is reduced as compared with the normal operation for reproducing (high quality data). As a result, the power required for communication is reduced, which also contributes to extending the battery operating time.

[0062]

As can be easily understood from the above description, according to the present invention, audio data having a different compression ratio is selected according to the ambient noise level, so that the load on the reproduction processing can be reduced and the battery operation can be reduced. You can extend the time. When the ambient noise level is high, by operating a part of the memory used for the reproduction process with low power consumption, the power consumption can be further reduced and the battery operating time can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a first embodiment of the present invention.

FIG. 2 is an example of music data stored on a hard disk 20.

FIG. 3 shows a CPU 14a of the CPU / memory control device 14.
5 is an example of an input signal to the control unit.

FIG. 4 shows a clock signal CPU_CLK and an external signal S.
5 is a timing chart example of the operation of the CPU 14a with respect to TP_REQ.

FIG. 5 shows a CPU / memory controller 14 and a RAM 12.
It is a block diagram which shows the signal connection between a and 12b.

FIG. 6 is an example of a memory map according to the first embodiment;

FIG. 7 is a flowchart of a compressed data reproduction process according to the first embodiment.

FIG. 8 is a flowchart of an interrupt process for setting an operation mode flag.

FIG. 9 is a state transition diagram of the first embodiment.

FIG. 10 is a schematic configuration block diagram of a second embodiment of the present invention.

[Explanation of symbols]

10: ROM 12, 12a, 12b: RAM 14: CPU / memory control device 14a: CPU 16: D / A converter 18: Headphones 20: Hard disk 22: Microphone 24: Setting value holding device 26: Comparison circuit 28: Battery 30 : Power supply device 32: Operation mode control device 34: Operation panel 40 H, 40 M, 40 L: Music data file of “ABC” 42 H, 42 M, 42 L: Music data file of “DEF” 50: Address bus 52: Data bus 54: Control Signal lines 56a, 56b: chip select signal 60: communication device

Claims (25)

[Claims] 1. A music reproducing apparatus having a plurality of operation modes according to power consumption, comprising: a storage medium for storing a plurality of music data files obtained by compressing the same music at different compression ratios; Decompression means for decompressing, operation mode determination means for determining an operation mode to be applied, and a compression ratio of the plurality of music data files of the storage medium according to the operation mode determined by the operation mode determination means. A music reproducing apparatus comprising: a data transfer unit that reads out a music data file and supplies the music data file to the decompression unit; and an output unit that outputs music information decompressed by the decompression unit. And a noise detection unit for detecting an ambient noise level, wherein the operation mode determination unit determines an operation mode with low power consumption according to the noise level detected by the noise detection unit. The music playback device according to claim 1. 3. The decompression means includes a RAM composed of a plurality of blocks including at least one block whose power consumption can be controlled, and performs decompression processing in accordance with the operation mode determined by the operation mode determination means. The music reproducing device according to claim 1, wherein the number of blocks used is increased or decreased. 4. A battery as a power source, and a remaining capacity monitoring means for monitoring a remaining capacity of the battery, wherein the operation mode determining means consumes power when the remaining capacity of the battery becomes less than a predetermined value. The music playback device according to claim 1, wherein an operation mode with low power is determined. 5. A first compressed same music at a first compression ratio.
A storage medium for storing a music data file and a second music data file compressed at a second compression rate higher than the first compression rate; a decompression means for decompressing the compressed music data; Noise detection means for detecting the level; reading the first music data file from the storage medium and supplying the read data to the decompression means when the noise level detected by the noise detection means is less than a predetermined value; In the above case, there is provided a data transfer means for reading out the second music data file from the storage medium and supplying it to the decompression means, and an output means for outputting music information decompressed by the decompression means. Music playback device. 6. The decompression means includes a RAM composed of a plurality of blocks including at least one block whose power consumption is controllable, and is used for decompression processing in accordance with a noise level detected by the noise detection means. The music playback device according to claim 5, wherein the number of blocks to be played is increased or decreased. 7. A first music data file having a plurality of operation modes according to power consumption and compressing the same music at a first compression rate, and a second compression rate higher than the first compression rate. A music reproducing apparatus capable of reproducing the second music data file compressed in step (a), data receiving means, decompressing means for decompressing the compressed music data, and operation mode determining means for determining an operation mode to be applied. A data transfer unit that receives a music data file having a compression rate according to the operation mode determined by the operation mode determination unit by the reception unit and supplies the music data file to the expansion unit; A music playback device comprising: an output unit for outputting. 8. The apparatus further comprises noise detection means for detecting a surrounding noise level, wherein the operation mode determination means determines an operation mode with low power consumption according to the noise level detected by the noise detection means. The music playback device according to claim 7. 9. The decompression means includes a RAM composed of a plurality of blocks including at least one block whose power consumption can be controlled, and performs decompression processing in accordance with the operation mode determined by the operation mode determination means. The music playback device according to claim 7, wherein the number of blocks used is increased or decreased. 10. A battery as a power source, and a remaining capacity monitoring means for monitoring the remaining capacity of the battery, wherein the operation mode determining means consumes power when the remaining capacity of the battery becomes less than a predetermined value. 8. An operation mode with low power is determined.
A music playback device according to claim 1. 11. A first music data file obtained by compressing the same music at a first compression rate and a second music data file compressed at a second compression rate higher than the first compression rate can be reproduced. A music reproducing apparatus, comprising: a data receiving unit; an expanding unit that expands compressed music data; a noise detecting unit that detects a surrounding noise level; and a noise level detected by the noise detecting unit is less than a predetermined value. In this case, the first music data file is received by the receiving means and supplied to the decompressing means. If the value is equal to or greater than a predetermined value, the receiving means receives the second music data file and the decompressing means A music reproducing device comprising: a data transfer unit that supplies the music information to the music data; and an output unit that outputs the music information expanded by the expansion unit. 12. The decompression means includes a RAM composed of a plurality of blocks including at least one block whose power consumption can be controlled, and is used for decompression processing according to a noise level detected by the noise detection means. The music playback device according to claim 11, wherein the number of blocks to be played is increased or decreased. 13. An operation mode determining step of determining an operation mode to be applied among a plurality of operation modes according to power consumption, and a storage medium for storing a plurality of music data files obtained by compressing the same music at different compression ratios. A reading step of reading a music data file corresponding to the operation mode determined by the operation mode determining means, a decompression step of decompressing the data file read in the reading step, and a music decompressed in the decompression step. An output step of outputting information. 14. A noise detection step for detecting a surrounding noise level, wherein the operation mode determination step determines an operation mode with low power consumption according to the noise level detected by the noise detection step. The music reproduction method according to claim 13. 15. The expansion step can use a RAM composed of a plurality of blocks including at least one block whose power consumption is controllable, and expands the RAM according to the operation mode determined in the operation mode determination step. 14. The music reproducing method according to claim 13, wherein the number of blocks used for processing is increased or decreased. 16. The apparatus further comprises a remaining capacity monitoring step of monitoring a remaining capacity of a battery serving as a power supply, wherein the operation mode determining step includes the step of: when the remaining capacity of the battery becomes less than a predetermined value.
14. The music reproducing method according to claim 13, wherein an operation mode with low power consumption is determined. 17. A noise detecting step for detecting a surrounding noise level, a first data file obtained by compressing the same music at a first compression ratio, and a first data file compressed at a second compression ratio higher than the first compression ratio. If the noise level detected in the noise detection step is less than a predetermined value, the first data file is read from the storage medium storing the second data file, and if the noise level is equal to or more than the predetermined value, the second data file is read. A music playback comprising: a reading step of reading a data file; a decompression step of decompressing the data file read in the reading step; and an output step of outputting music information decompressed in the decompression step. Method. 18. The expansion step can use a RAM composed of a plurality of blocks including at least one block whose power consumption is controllable, and expands the RAM in accordance with the operation mode determined in the operation mode determination step. The music reproducing method according to claim 17, wherein the number of blocks used for the processing is increased or decreased. 19. An operation mode determining step of determining an operation mode to be applied among a plurality of operation modes according to power consumption, and music data having a compression ratio according to the operation mode determined by the operation mode determining means. A music reproducing method comprising: a capturing step of capturing a file; a decompression step of decompressing the music data file captured by the capturing step; and an output step of outputting music information decompressed by the decompression step. . 20. A noise detecting step for detecting a surrounding noise level, wherein the operating mode determining step determines an operating mode with low power consumption according to the noise level detected by the noise detecting step. The music reproducing method according to claim 19. 21. The expansion step can use a RAM composed of a plurality of blocks including at least one block whose power consumption is controllable, and expands the RAM according to the operation mode determined in the operation mode determination step. The music reproducing method according to claim 19, wherein the number of blocks used for the processing is increased or decreased. 22. The method according to claim 22, further comprising: a remaining capacity monitoring step of monitoring a remaining capacity of a battery serving as a power supply, wherein the operation mode determining step includes a step of:
The music reproducing method according to claim 19, wherein an operation mode with low power consumption is determined. 23. A noise detecting step of detecting a surrounding noise level, a first music data file obtained by compressing the same music at a first compression rate, and a second compression rate higher than the first compression rate. If the noise level detected in the noise detection step is less than a predetermined value, the first music data file is fetched from a storage medium that stores the compressed second data file. A capturing step of capturing a second music data file compressed at a second compression rate higher than 1; a decompression step of expanding the music data file captured in the capturing step; An output step of outputting the music information. 24. The expansion step includes using a RAM composed of a plurality of blocks including at least one block whose power consumption is controllable, and expanding the RAM in accordance with the operation mode determined in the operation mode determination step. The music reproducing method according to claim 23, wherein the number of blocks used for the processing is increased or decreased. 25. A music reproducing method storing program software for executing the music reproducing method according to claim 13. Description: