FGS decoder based on quality estimated at the decoder

• US 20040001635A1
• Filed: 06/27/2002
• Published: 01/01/2004
• Est. Priority Date: 06/27/2002
• Status: Active Grant

• Current Assignee: Funai Electric Co., Ltd.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Van Der Schaar, Mihaela
• Granted Patent: US 7,136,532 B2
• Time in Patent Office: Days
• US Class Current: 382/233
• CPC Class Codes: H04N 19/29 involving scalability at the object level, e.g. video object layer [VOL]
• CPC Class Codes: H04N 19/34 Scalability techniques involving progressive bit-plane based encoding of the enhancement layer, e.g. fine granular scalability [FGS]
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/25808 Management of client data terminal profiles in network data switching protocols H04L67/303
• 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 21/440227 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/4621 Controlling the complexity of the content stream or additional data, e.g. lowering the resolution or bit-rate of the video stream for a mobile client with a small screen arrangements for using the results of monitoring on user's side in broadcast systems H04H60/65; flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/6373 for rate control , e.g. request to the server to modify its transmission rate flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/6377 directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613
• CPC Class Codes: H04N 21/658 Transmission by the client directed to the server

Abstract

A method for decoding a stream of data includes the steps of: identifying a relationship (100) between quality of a decoded image and a bit rate for decoding the image; selecting a desired quality (110) of images to be decoded from the stream of data; determining a bit rate (112) corresponding to the desired quality using the relationship; and decoding a minimum number of bit-planes corresponding to the determined bit rate from the stream of data.

Claims

1. A method for decoding a stream of data, comprising the steps of:

(a) identifying a relationship (100) between quality of a decoded image and a bit rate for decoding the image;

(b) selecting a desired quality (10) of images to be decoded from the stream of data;

(c) determining a bit rate (112) corresponding to the desired quality using the relationship; and

(d) decoding a minimum number of bit-planes (116) corresponding to the determined bit rate from the stream of data.

2. The method of claim 1, wherein the relationship is defined by the equation:

Q(R)=QBL+(R−

RBL)/c,

where Q(R) is the quality of the image at a bit rate R, QBL is a quality measure of a base layer of the data stream, RBL is a bit rate corresponding to transmission of the base layer, and c is a constant.

3. The method of claim 1, further comprising the steps of:

(e) identifying a change in the relationship (202); and

(f) dynamically adjusting the number of bit-planes (206, 207) decoded to correspond to the desired quality and the changed relationship.

4. The method of claim 3, wherein step (f) includes using a relatively low bit rate (209) for an image sequence having low detail.

5. The method of claim 3, wherein steps (e) and (f) are performed when a scene change is detected (200).

6. The method of claim 1, comprising displaying at least two values of image quality (304) and a respective measure of a resource required to decode the image for each of the at least two values of image quality, before step (b).

7. The method of claim 1, further comprising transmitting the determined bit rate to a source of the stream of data (308), wherein the source of the stream of data is requested to only transmit future streams of data at the determined bit rate.

8. A computer readable medium (400) having computer program code encoded thereon, wherein, when the computer program code is executed by a processor, the processor executes a method for decoding a stream of data, comprising the steps of:

(a) identifying a relationship (100) between quality of a decoded image and a bit rate for decoding the image;

(b) selecting a desired quality (10) of images to be decoded from the stream of data;

(c) determining a bit rate (112) corresponding to the desired quality using the relationship; and

(d) decoding a minimum number of bit-planes (116) corresponding to the determined bit rate from the stream of data.

9. The computer readable medium of claim 8, wherein the relationship is defined by the equation:

Q(R)=QBL+(R−

RBL)/c,

where Q(R) is the quality of the image at a bit rate R, QBL is a quality measure of a base layer of the data stream, RBL is a bit rate corresponding to transmission of the base layer, and c is a constant.

10. The computer readable medium of claim 9, wherein c is approximately equal to RBL.

11. The computer readable medium of claim 9, further comprising receiving a value of QBL (104) from a source of the data stream.

12. The computer readable medium of claim 9, further comprising computing QBL based on one or more of the group consisting of quantization steps, motion-vectors, and macroblock prediction types.

13. The computer readable medium of claim 8, wherein the minimum number of bit-planes is one of the group consisting of a real number corresponding to the bit rate determined in step (c) and a smallest integer greater than or equal to the bit rate determined in step (c).

14. The computer readable medium of claim 8, further comprising the steps of:

(e) identifying a change in the relationship (202); and

(f) dynamically adjusting the number of bit-planes (206, 207) decoded to correspond to the desired quality and the changed relationship.

15. The computer readable medium of claim 14, wherein step (f) includes using a relatively high bit rate (208) for an image sequence having high detail and low motion.

16. The computer readable medium of claim 14, wherein step (f) includes using a relatively low bit rate (209) for an image sequence having relatively low detail.

17. The computer readable medium of claim 14, wherein steps (e) and (f) are performed when a scene change is detected (200).

18. The computer readable medium of claim 8, wherein the method includes displaying at least two values of image quality (304) and a respective measure of a resource required to decode the image for each of the at least two values of image quality, before step (b).

19. The computer readable medium of claim 18, wherein the measure of the resource (302) is one of the group consisting of a time to decode the stream of data with the respective image quality, a fraction of battery charge used to decode the stream of data at the respective image quality, and a bit rate used to decode the stream of data at the respective image quality.

20. The computer readable medium of claim 8, wherein the method further comprises transmitting the determined bit rate to a source of the stream of data (308), and the source of the stream of data is requested to only transmit future streams of data at the determined bit rate.

21. A decoder (400) for decoding a stream of data, comprising:

means (110) for receiving a selection of a desired quality of images to be decoded from the stream of data;

means (112) for determining a bit rate for decoding the image based on a quality of a decoded image, the determining means providing a desired bit rate corresponding to the desired quality; and

means (460) for controlling a number of bit-planes to be decoded, so that a minimum number of bit-planes are decoded to form one or more images, corresponding to the desired bit rate from the stream of data.

22. The decoder of claim 21, further comprising:

means (202) for identifying a change in a relationship between the bit rate and the quality of the decoded image; and

means (206, 207) for dynamically adjusting the number of bit-planes decoded to correspond to the desired quality and the changed relationship.

23. The decoder of claim 22, wherein the adjusting means uses a relatively low bit rate (209) for an image sequence having relatively low detail.

24. The decoder of claim 22, wherein the change identifying means identifies a change in the relationship when a scene change is detected (200).

25. The decoder of claim 21, wherein the decoder is included in a mobile device that displays at least two values of image quality and a respective measure of a resource required to decode the image for each of the at least two values of image quality.

26. The decoder of claim 25, wherein the measure of the resource (302) is one of the group consisting of a time to decode the stream of data with the respective image quality, a fraction of battery charge used to decode the stream of data at the respective image quality, and a bit rate used to decode the stream of data at the respective image quality.

27. The decoder of claim 21, wherein the decoder is included in a mobile device that transmits the determined bit rate to a source of the stream of data, so as to request that the source of the stream of data only transmit future streams of data at the determined bit rate.