WO2007112781A1

WO2007112781A1 - Electronic apparatus and method of conserving energy

Info

Publication number: WO2007112781A1
Application number: PCT/EP2006/061300
Authority: WO
Inventors: Andy Barth
Original assignee: Freescale Semiconductor, Inc.
Priority date: 2006-04-04
Filing date: 2006-04-04
Publication date: 2007-10-11

Abstract

A battery-powered electronic apparatus (106) for playing media comprises a hardware element (204) and an application for processing a media file. The application is supported at least in part by the hardware element (106) and arranged to process a data file for representing user-discernable content. In order to conserve energy, a energy-conserving module (300) is arranged to determine performance required of the hardware element (106) in order to process the data file, but that does not expend energy unnecessarily and hence wastefully. The performance level needed is then recorded as characterisation data and the characterisation data is associated with the data file. The energy-conserving module (300) can therefore use the stored characterisation data to impose the same power management settings for subsequent instances of processing the data file by the application.

Description

ELECTRONIC APPARATUS AND METHOD OF CONSERVING ENERGY

Field of the Invention

This invention relates to an electronic apparatus of the type, for example, that processes a data file, such as a media file on repeated occasions. This invention also relates to a method of conserving energy used by a hardware element .

Background of the Invention

In the field of portable electronic devices, it is known to download files to a portable device, for example, a media file for enjoyment of content represented by the media file. The content can be audio in nature, for example music, visual in nature, for example moving images, or a combination of the two.

In order to play the media file downloaded, hardware of the portable device supports a so-called media player application, for example an MP3 player. Additionally, the hardware of the portable media player also supports other applications to provide device functionality such as a Graphical User Interface (GUI) application, a file server application and other system software.

Typically, the portable device is battery-powered and so an important consideration in relation to the portable device is power consumption as this impacts upon how quickly the energy of the battery is depleted and hence the amount of time for which the portable device can be used.

Despite gradual improvements in recent decades, battery technology has not kept pace with the power consumption demands of the latest portable electronic devices, like multimedia players and the third generation (3G) mobile phones. Hardware designers are using advanced power- saving techniques to help minimize Integrated Circuit (IC) and system power consumption. However, most of these techniques do not yield significant energy conservation, i.e. better battery life, unless intelligent software is used to exploit them effectively.

In this respect, new generations of applications processor, baseband processor, audio processor and other platform components now include enhanced power management hardware mechanisms, for example Dynamic Frequency Scaling (DFS) , Dynamic Voltage Scaling (DVS) , and multiple idle modes such as Wait, Deep Sleep and/or Hibernate. Power reduction and energy conservation is achieved by placing hardware blocks into lower power states, where performance is also lower or non-existent. To do this dynamically while programs are running requires an accurate knowledge of ever-changing workload that software being executed requires of the various blocks of hardware making up the portable device, for example the processor and/or peripherals.

In relation to the processor, Performance-Power (PP) states, for example operating clock frequency and operating voltage of the processor ideally should be set just high enough to ensure that application programs and other critical software execute fast enough to meet real- time processing deadlines, but not higher than necessary, thereby avoiding wastage of power. Further, the PP states need to be set as the software is being executed.

Statement of Invention

According to the present invention, there is provided an electronic apparatus and a method of conserving energy as set forth in the appended claims.

Brief Description of the Drawings

At least one embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a download system for downloading content from a network to a portable electronic apparatus, the electronic constituting an embodiment of the invention;

FIG. 2 is a schematic diagram of the electronic apparatus of FIG. 1 in greater detail;

FIG. 3 is a schematic diagram of an energy-conserving module interfacing with hardware of the FIGs. 1 and 2; and

FIG. 4 is a flow diagram of a method of conserving energy employed by the energy-conserving module of FIG. 3. Description of Preferred Embodiments

Throughout the following description identical reference numerals will be used to identify like parts.

Referring to FIG. 1, a content download system 100, for example a media download system such as an audio file download system, comprises a general purpose computing apparatus, for example a Personal Computer (PC) 102 coupled to a communications network, for example an Internet 104. The PC 102 supports one or more software application for downloading data files from a remote server (not shown) via the Internet 104. Such software is known in the art, for example the iTunes application available from Apple^® Computers, Inc., and so is not described herein. The PC 102 also supports a synchronisation application (not shown) in order to transfer the data files from the PC 102 to a portable electronic device, for example a media player device 106, such as an iPod music or video player also from Apple^® Computers, Inc. The media player 106 is powered, in this example, by a replenished power source, such as a battery or a fuel cell. The media player 106 is coupled to the PC 102 via, in this example, a Universal Serial Bus (USB) cable 108 coupled to a first USB port 110 of the PC 102 and a second USB port 112 of the media player 106.

Turning to FIG. 2, the portable electronic apparatus 106 comprises a processing resource, for example a microprocessor 200, coupled to a communications bus 202. A video processor 206 is coupled to the communications bus 202 and a display device 208, for example a liquid crystal display panel. A volatile storage unit, for example a Random Access Memory (RAM) 210 and a non^¬ volatile storage unit, for example a Read Only Memory (ROM) 211 are coupled to the communications bus 202, an audio processor 212 being coupled to the communications bus 202 as well. In this example, the audio processor 212 has an audio interface 214, for example a headphone jack socket. At least one storage device 215, for example a hard disc drive, is additionally coupled to the bus 202. Buttons 216, to communicate inputs from a user, are coupled to the processor 200.

The processor 200, the video processor 206, the display device 208, the RAM 210, the audio processor 212 and the at least one storage device 215 constitute, in this example, Power Managed Components (PMCs) 204.

Each of the plurality of PMCs 204 comprise at least one power saving mechanism (not shown) in order to minimise power usage by the PMCs 204 whilst maintaining a minimum level of performance required of each PMC to process data within real-time output constraints. Examples of power saving mechanisms include Dynamic Voltage Scaling, Dynamic Frequency Scaling, and/or one or more low-power idle modes.

In relation to FIG. 3, an energy-conserving module 300 is supported by and works closely with an operating system, for example Linux, running on the processor 200. The energy-conserving module 300 comprises a performance estimation module 302 capable of communicating with a performance setting module 304, the performance setting module 304 comprising a characterisation engine 306 and is also capable of communicating with the PMCs 204 in order to set one or more of the PMCs 204 into and/or out of two or more power saving states each.

A media data file once downloaded to the media player 106 is typically processed a number of times in a substantially identical manner. In this example, the data file comprises a plurality of successive blocks or frames of data. The successive blocks or frames of data correspond to respective successive time intervals of user-discernable content, when translated into content through processing by the media player 106.

In contrast with a general purpose computing device, electronic apparatus of a dedicated nature, such as the media player 106 where a relatively limited (and small) number of applications (for example an audio and/or a video player application, a Graphical User Interface

(GUI), and a file server application) are running concurrently, process the data file representing user discernable content, for example a media file, in substantially deterministic way. In this respect, performance requirements of a multimedia application

(program) are highly dependent on the type of the multimedia application, for example video, audio, or photographic, and the specific content to be processed by the multimedia application, for example an audio data file; the performance requirements are less upon other system software the portable electronic apparatus 106.

Due to these constraints relating to the media player 106 and the repeated processing of the data file, it is possible to take advantage of the repeated processing aspect to conserve energy by the PMCs whilst providing a level of performance sufficient to meet real-time processing deadlines associated with processing of the data file into another form, for example an audio signal, without the level of performance exceeding a minimum level of performance necessary to meet the real-time processing deadlines.

In operation (FIG. 4), the data file representing the user-discernable content is transferred to the media player 106 for enjoyment by a user thereof. When the user wishes to play the media file, i.e. initiate processing of the data file by the media player 106, the user initially powers up the media player 106 and selects a menu option (not shown) to initiate launch of a media player application supported by the media player 106. The energy-conserving module 300 detects (Step 400) launch of the media player application. The user then selects the media file to be played, i.e. selects the data file transferred from the PC 102, and the energy- conserving module 300 detects (Step 402) the accessing of the data file by the media player application. The energy-conserving module 300 then determines (Step 404) whether the data file has been previously processed, in this example played. In this example, the data file is to be processed for the first time and so the energy- conserving module 300 instructs the performance setting module 304 not to employ any power conserving measures in relation to the PMCs 204 by setting the Performance-Power settings for each of the PMCs to maximum performance settings (Step 406) . For each block or frame to which data in the data file corresponds, the performance estimation module 302 generates power performance settings that are appropriate for each block or frame processed as the processing of the data file takes place. In this respect, the performance estimation module 302 measures (Step 408) idle time for each block or frame for each of the PMCs 204, for example the processor 200. After each measurement, the performance setting module 304 then calculates (Step 410) Performance-Power settings to enable any relevant PMC 204, for example the processor 200, to meet a real-time processing deadline for the block or frame being processed by the PMC 204 whilst minimising power usage. The characterisation engine 306 collects the Performance-Power settings generated by the performance setting module 304 and creates (Step 412) a performance characterisation file. As Performance-Power settings are calculated for each block or frame, they are added to the characterisation file by the characterisation engine 306 once they are generated. Once the data file has been fully processed, the data file is tagged with the identity of the characterisation file so that the characterisation file can be identified and used for subsequent instances of processing of the data file. When the user decides to re-play the content, the data file is accessed once again and the energy- conserving module 300 again detects (Step 402) access of the data file. In this example, it is assumed that the media player 106 is still in the launched state. Thereafter, the energy-conserving module 300 determines (Step 404) whether the media file has been previously played by determining whether or not the data file is tagged with the identity of any characterisation file. In this example, the data file is tagged with the identity of the characterisation file, the creation of which has been described above. Consequently, the performance setting module 304 uses the Performance-Power settings contained in the characterisation file in order to set performance levels of one or more of the PMCs 204 when processing the data file, i.e. playing the media file.

During processing of the data file, the energy-conserving module 300 verifies (Step 416) , before processing a block or frame of data from the data file, whether the end of the data file has been reached. If the end of the data file has not been reached, the performance estimation module 302 determines (Step 418) whether processing of the block or frame just processed meets a desired quality of service, i.e. performance, level required in order to meet real-time performance deadlines. If the real-time performance deadlines are met, no action is taken. However, if the performance level falls below an acceptable level, i.e. the real-time processing deadline is not met, the performance estimation module 302 recalculates (Step 420) the performance requirements of the one or more PMC 204 responsible for failing to meet the real-time processing deadline and instructs the performance setting module 304 to set new power performance settings. In this respect, the characterisation engine 306 updates the characterisation file with the newly created power performance settings in respect of the block or frame concerned. Once processing of the data file has finished, the electronic apparatus 106 awaits further instructions from the user.

Alternative embodiments of the invention can be implemented as a computer program product for use with a computer system, the computer program product being, for example, a series of computer instructions stored on a tangible data recording medium, such as a diskette, CD- ROM, ROM, or fixed disk, or embodied in a computer data signal, the signal being transmitted over a tangible medium or a wireless medium, for example, microwave or infrared. The series of computer instructions can constitute all or part of the functionality described above, and can also be stored in any memory device, volatile or non-volatile, such as semiconductor, magnetic, optical or other memory device.

It is thus possible to provide an electronic apparatus and method of conserving energy that results in a greater battery lifetime and hence longer usage of the electronic apparatus. Of course, the above advantages are exemplary, and these or other advantages may be achieved by the invention. Further, the skilled person will appreciate that not all advantages stated above are necessarily achieved by embodiments described herein.

Claims

Claims (EP )

1. An electronic apparatus for playing media file, the apparatus comprising: a hardware element having at least two power usage modes respectively corresponding to at least two levels of performance; an application for processing a media file, the application being supported at least in part by the hardware element and arranged to process, when in use, a data file for representing user-discernable content; characterised by: an energy-conserving module arranged to determine, when in use, performance required of the hardware element to process at least part of the data file whilst conserving energy consumed by the hardware element, and record the determined performance required whilst conserving energy as characterisation data; and the characterisation data being associated with the data file for use by the energy-conserving module during a subsequent instance of processing of the at least part of the data file by the application .

2. An apparatus as claimed in Claim 1, wherein the energy-conserving module is arranged to control use of the at least two power usage modes in response to the characterisation data.

3. An apparatus as claimed in Claim 1 or Claim 2, wherein the energy-conserving module determines performance required of the hardware element whilst conserving energy by identifying one of the at least two power usage modes to be used by the hardware element that provide the performance required of the hardware element whilst conserving energy thereof.

4. An apparatus as claimed in any one of the preceding claims, wherein the data file represents real-time media .

5. An apparatus as claimed in Claim 4, wherein the media is non-streamed media.

6. An apparatus as claimed in any one of the preceding claims, wherein the application for processing a media file is a media player application.

7. An apparatus as claimed in Claim 6, wherein the media player application is a non-streamed media player application.

8. An apparatus as claimed in any one of the preceding claims, wherein the application for processing a media file is arranged to play an audio media file and/or a video media file.

9. An apparatus as claimed in any one of the preceding claims, wherein the data file comprises successive blocks of data, the successive blocks of data comprising the part of the data file.

10. An apparatus as claimed in Claim 9, wherein the successive blocks of data correspond to successive time intervals.

11. An apparatus as claimed in any one of the preceding claims, wherein the association between the characterisation data and the data file is recorded.

12. An apparatus as claimed in any one of the preceding claims, wherein the data file is tagged with information identifying the characterisation data.

13. An apparatus as claimed in any one of the preceding claims, wherein the characterisation data is stored in a characterisation file.

14. An apparatus as claimed in any one if the preceding claims, wherein the energy-conserving module is arranged to determine the performance required whist conserving energy during an initial instance of processing of the data file.

15. An apparatus as claimed in Claim 14, wherein the energy-conserving module does not invoke any power conservation measures during the initial instance of processing of the data file.

16. An apparatus as claimed in any one of the preceding claims, wherein the energy-conserving module is arranged to detect, when in use, violation of a real-time deadline associated with processing the part of the data file.

17. An apparatus as claimed in Claim 16, wherein the energy-conserving module is arranged to monitor critical system events to identify the violation of the real-time deadline.

18. An apparatus as claimed in Claim 16 or Claim 17, wherein the energy-conserving module is arranged to repeat determination of the performance required of the hardware element to process the at least part of the data file whilst conserving energy in response to the detection of the violation of the real-time deadline .

19. An apparatus as claimed in any one of the preceding claims, wherein the hardware element is a power managed component .

20. An apparatus as claimed in any one of the preceding claims, wherein the hardware element is a processor.

21. A portable media player comprising the battery- powered electronic apparatus as claimed in any one of the preceding claims.

22. A method of conserving energy used by a hardware element in an apparatus, the method comprising the steps of: processing a data file for representing user- discernable content; characterised by: determining performance required of the hardware element to process at least part of the data file whilst conserving energy consumed by the hardware element; recording the determined performance required whilst conserving energy as characterisation data; and associating the characterisation data with the data file for use during a subsequent instance of processing of the at least part of the data file.

23. A method as claimed in Claim 22, further comprising the step of: using the characterisation file to conserve energy consumed by the hardware element during the subsequent instance of processing of the at least part of the data file, the hardware element providing a level of performance required to process the at least part of the data file.

24. A computer program element comprising computer program code means to make a computer execute the method as claimed in Claim 22 or Claim 23.

25. A computer program element as claimed in Claim 24, embodied on a computer readable medium.