Low power scheduling for multimedia systems

• US 20030028659A1
• Filed: 06/29/2001
• Published: 02/06/2003
• Est. Priority Date: 06/29/2001
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Turner, Yoshio Frank, Mesarina, Malena Rosa
• Granted Patent: US 7,043,557 B2
• Time in Patent Office: Days
• US Class Current: 709/231
• CPC Class Codes: H04B 1/66 for reducing bandwidth of signals; for improving efficiency of transmission H04B1/68 takes precedence
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/25808 Management of client data terminal profiles in network data switching protocols H04L67/303
• CPC Class Codes: H04N 21/25833 involving client hardware characteristics, e.g. manufacturer, processing or storage capabilities allocation of resources considering hardware capabilities in multiprogramming arrangements G06F9/5044; allocation of resources considering software capabilities in multiprogramming arrangements G06F9/5055
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/435 Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer

Abstract

A method and system thereof for reducing the energy consumed when decoding an encoded and synchronized multimedia data stream, wherein the data stream is non-preemptable and subject to precedence constraints. In a client-server environment, the server delivers to the client the stream for decoding. The client has a processor operating on a discrete variable-voltage power supply. Prior to transmitting the stream to the client, the server produces an execution schedule according to the precedence constraints. The server also assigns a voltage setting for each task in the schedule, wherein each task decodes a frame in the stream without preemption. The server transmits the execution schedule and voltage settings to the client with the encoded data stream. The schedule and voltage settings reduce energy consumption by the client while satisfying multimedia timing constraints.

Claims

1. In a server device, a method for processing an encoded data stream wherein said encoded data stream is non-preemptable and subject to precedence constraints, said method comprising the steps of:

a) assigning a processor setting to a task in a plurality of tasks, wherein said processor setting corresponds to a setting used by a processor of a client device to execute said task and wherein said task decodes without preemption a frame of said encoded data stream;

b) generating an execution schedule for decoding said encoded data stream, wherein said execution schedule comprises a sequence for executing at said client device said plurality of tasks according to said precedence constraints; and

c) transmitting to said client device said execution schedule and said processor setting.

2. The method as recited in claim 1 wherein said processor setting comprises a voltage amount used by said processor to execute said task.

3. The method as recited in claim 1 wherein said processor setting comprises a processor clock speed at which said processor executes said task.

4. The method as recited in claim 1 wherein said processor of said client device operates using a discrete variable-voltage power supply.

5. The method as recited in claim 1 wherein said encoded data stream comprises an audio portion and a video portion.

6. The method as recited in claim 1 comprising the steps of:

assigning a processor setting to each task in said plurality of tasks; and

transmitting said processor setting for said each task to said client device.

7. The method as recited in claim 1 wherein said step of generating said execution schedule is independent of client device type.

8. The method as recited in claim 1 wherein said step of generating said execution schedule comprises the steps of:

generating different sequences for executing a subset of said plurality of tasks; and

selecting a sequence that results in minimum energy use by said processor of said client device.

9. The method as recited in claim 1 comprising the step of:

transmitting said encoded data stream to said client device with said execution schedule and said processor setting.

10. A computer system comprising:

a bus;

a memory unit coupled to said bus;

a communication interface coupled to bus and operable to establish a communication link with a client device; and

a processor coupled to said bus, said processor for executing a method for processing an encoded data stream wherein said encoded data stream is non-preemptable and subject to precedence constraints, said method comprising the steps of;

a) assigning a processor setting to a task in a plurality of tasks, wherein said processor setting corresponds to a setting used by a processor of said client device to execute said task and wherein said task decodes without preemption a frame of said encoded data stream;

b) generating an execution schedule for decoding said encoded data stream, wherein said execution schedule comprises a sequence for executing at said client device said plurality of tasks according to said precedence constraints; and

c) transmitting to said client device said execution schedule and said processor setting.

11. The computer system of claim 10 wherein said processor setting comprises a voltage amount used by said processor of said client device to execute said task.

12. The computer system of claim 10 wherein said processor setting comprises a processor clock speed at which said processor of said client device executes said task.

13. The computer system of claim 10 wherein said processor of said client device operates using a discrete variable-voltage power supply.

14. The computer system of claim 10 wherein said encoded data stream comprises an audio portion and a video portion.

15. The computer system of claim 10 wherein said method comprises the steps of:

assigning a processor setting to each task in said plurality of tasks; and

transmitting said processor setting for said each task to said client device.

16. The computer system of claim 10 wherein said step of generating said execution schedule is independent of client device type.

17. The computer system of claim 10 wherein said step b) of said method comprises the steps of:

generating different sequences for executing a subset of said plurality of tasks; and

selecting a sequence that results in minimum energy use by said processor of said client device.

18. The computer system of claim 10 wherein said method comprises the step of:

transmitting said encoded data stream to said client device with said execution schedule and said processor setting.

19. A computer-usable medium having computer-readable program code embodied therein for causing a computer system to perform the steps of:

a) assigning a processor setting to a task in a plurality of tasks, wherein said processor setting corresponds to a setting used by a processor of a client device to execute said task and wherein said task decodes without preemption a frame of said encoded data stream;

b) generating an execution schedule for decoding said encoded data stream, wherein said execution schedule comprises a sequence for executing at said client device said plurality of tasks according to said precedence constraints; and

c) transmitting to said client device said execution schedule and said processor setting.

20. The computer-usable medium of claim 19 wherein said processor setting comprises a voltage amount used by said processor to execute said task.

21. The computer-usable medium of claim 19 wherein said processor setting comprises a processor clock speed at which said processor executes said task.

22. The computer-usable medium of claim 19 wherein said processor of said client device operates using a discrete variable-voltage power supply.

23. The computer-usable medium of claim 19 wherein said encoded data stream comprises an audio portion and a video portion.

24. The computer-usable medium of claim 19 wherein said computer-readable program code embodied therein causes a computer system to perform the steps of:

assigning a processor setting to each task in said plurality of tasks; and

transmitting said processor setting for said each task to said client device.

25. The computer-usable medium of claim 19 wherein said step of generating said execution schedule is independent of client device type.

26. The computer-usable medium of claim 19 wherein said computer-readable program code embodied therein causes a computer system to perform the steps of:

generating different sequences for executing a subset of said plurality of tasks; and

selecting a sequence that results in minimum energy use by said processor of said client device.

27. The computer-usable medium of claim 19 wherein said computer-readable program code embodied therein causes a computer system to perform the step of:

transmitting said encoded data stream to said client device with said execution schedule and said processor setting.

28. In a client device, a method for decoding an encoded data stream, said method comprising the steps of:

a) receiving said encoded data stream, wherein said encoded data stream is non-preemptable and subject to precedence constraints;

b) receiving an execution schedule for decoding said encoded data stream, wherein said execution schedule comprises a sequence for executing a plurality of tasks according to said precedence constraints, wherein a task decodes without preemption a frame of said encoded data stream; and

c) receiving a processor setting for each task in said plurality of tasks, wherein said processor setting specifies a setting used by a processor of said client device to execute a respective task.

29. The method as recited in claim 28 wherein said processor setting comprises a voltage amount used by said processor of said client device to execute said task.

30. The method as recited in claim 28 wherein said processor setting comprises a processor clock speed at which said processor of said client device executes said task.

31. The method as recited in claim 28 wherein said processor of said client device operates using a discrete variable-voltage power supply.

32. The method as recited in claim 28 wherein said encoded data stream comprises an audio portion and a video portion.