Sound link translation

1. A method of accessing a content site comprising the steps of:

(a) receiving a sound passage at a first system, the sound passage being associated with a content site;

(b) sending the sound passage, or a representation of it, from the first system to a service system;

(c) at the service system, comparing a representation of the sound passage sent from the first system with stored representations of sound passages that each have an associated URI; the service system on finding a match, sending back to the first system the URI associated with the matched stored sound-passage representation; and

(d) at the first system, receiving the URI sent by the service system and using it to access the content site.

2. A method according to claim 1 , wherein the sound passage is received in step (a) through a microphone and converted to an audio file format for sending to the service system in step (b).

3. A method according to claim 1 , wherein the sound passage is received in step (a) as an analogue electrical signal and is converted to an audio file format for sending to the service system in step (b).

4. A method according to claim 1 , wherein the sound passage is received in step (a) in digital form and is sent in an audio file format to the service system in step (b).

5. A method according to claim 1 , wherein the search space for the comparison search effected in step (c) is reduced by forming a frequency/power spectrum for the received sound passage representation, the stored sound passage representations being classified into groups by frequency/power spectrum and the service system limiting its comparison search to the group of stored representations that have a frequency/power spectrum covering that of the received sound-passage representation.

6. A method according to claim 1 , wherein the stored sound passage representations are representations of full length musical works, the sound passage received by the service system being matched against these representations by successive comparisons along the length of the works where the duration of the received sound passage is less than that of the works represented by the stored representations.

7. A method according to claim 1 , wherein in step (c) the service system extracts features from the received sound passage with the extracted feature set then being used to carry out the comparison searching, said stored representations being similar feature sets of their corresponding sound passages.

8. A method according to claim 7 , wherein the extracted features are the notes of a basic tune presented by the sound passage.

9. A method according to claim 1 , wherein the said first system is a voice browser.

10. A method according to claim 1 , wherein said URI is a URL.

11. A service system for translating sound passages to URIs, the apparatus comprising:

means for receiving a representation of a sound passage from a client entity;

a database subsystem holding stored representations of sound passages that each have an associated URL,

comparison means for comparing the received sound-passage representation with the stored sound-passage representations and, on finding a match, retrieving the URI associated with the matched stored representation; and

means for returning the retrieved URI to the client entity.

12. A service system according to claim 11 , wherein the received sound-passage representation is an encoding of the sound passage in a standard audio file format.

13. A service system according to claim 11 , wherein the stored sound-passage representations are classified into groups by frequency/power spectrum, the comparison means includes means for forming a frequency/power spectrum for the received sound-passage representation, and the comparison means being operative to limit its comparison search to the group of stored representations that have a frequency/power spectrum covering that of the received sound-passage representation.

14. A service system according to claim 11 , wherein the stored sound-passage representations are representations of full length musical works, the comparison means being operative to match the received sound-passage representations against the stored representations by successive comparisons along the length of the works where the duration of the received sound passage is less than that of the works represented by the stored representations.

15. A service system according to claim 11 , wherein each stored sound-passage representations take the form of a set of features extracted from the sound passage represented, the comparison means including means for extracting features from the sound passage represented by the received representation , and means for comparing the set of features so extracted with the features sets forming the stored representations.

16. A service system according to claim 15 , wherein the extracted features are the notes of a basic tune presented by the sound passage.

17. A service system according to claim 11 , wherein said URI is a URL.