Method of and apparatus for digital data storage

• US 6,828,967 B1
• Filed: 03/16/2001
• Issued: 12/07/2004
• Est. Priority Date: 07/20/1999
• Status: Expired due to Fees

• Current Assignee: Internet Pro Video Limited
• Original Assignee: Internet Pro Video Limited
• Inventors: Cole, David John, King, Tony Richard
• Primary Examiner(s): Nguyen, Phu K.
• Application Number:
  US09/787,230
• Time in Patent Office: 1,362 Days
• Field of Search: 707/102, 707/104.1, 711/117, 711/1, 341/51, 341/79, 709/104, 705/52, 382/167, 348/391.1, 345/419, 345/428, 345/619
• US Class Current: 345/428
• CPC Class Codes: G06T 9/007 Transform coding, e.g. discrete cosine transform

Abstract

Digital data storage conventionally requires an election to be made between retaining data on-line, which consumes expensive media, or moving it to a far cheaper archive medium, which is relatively inacessible. This specification discloses a hybrid arrangement in which all material is retained on-line, but is progressively degraded as it becomes less useful, with off-line storage of the source material. On-line browsing of an entire library remains possible, but without incurring the expense of maintaining the entire library at source quality on-line.

Claims

1. A method of storing digital data comprising the steps of:

(a) providing a media object at a given quality level;

(b) providing a reversible function, the reversible function comprising a splitting function capable of iterative application, and an inverse splitting function capable of iterative application;

(c) manipulating the media object, using the splitting function of the reversible function, into a first data part, from which a first quality version of the media object can be re-generated, the first data part being stored on a first storage medium which is accessible on-line,

and a second data part, the second data part being re-combinable with the first data part using the inverse splitting function of the reversible function to enable a version of the media object to be regenerated which is of higher quality than the quality of the version of the media object which could be re-generated using only the first data part;

(d) transferring the second data part to a second storage medium which is near on-line accessible and which is physically separate from the first storage medium; and

(e) storing the reversible function on the second storage medium.

2. The method of claim 1 where:

the media object is a layered file with the property that it can be reconstructed to meet specified quality criteria, this property being independent of the choice of original compression format;

the layers sit in a dependency hierarchy and groups of these layers are related by dependency;

the layers are identified by unique labels such that all layers have a numerically lower label value than those that depend on them; and

,

the quality criteria include one or more of the following;

scale, fidelity, color, temporal blur.

3. The method of claim 1 in which the reversible function can generate the first and second data parts in dependence on one or more criteria.

4. The method of claim 3 in which the criteria include the following:

(i) the time elapsed since the creation of the media object or the first data part;

(ii) metadata associated with an original from which the media object is derived;

(iii) usage patterns;

(iv) the availability of either on-line and/or lower cost storage;

(v) flags set by a user to denote content of interest.

5. The method of claim 1 in which the second storage medium is an archival medium.

6. The method of claim 1 in which the second storage medium can be accessed in order to transfer back to a processing unit the second data part to enable the re-generation of a version of the media object of quality higher than that obtainable from the first part.

7. The method of claim 6 in which the transfer back occurs automatically on the request of a user.

8. The method of claim 1 in which the reversible function can address different aspects of quality, including bit depth, size and frame rate.

9. The method of claim 1 in which the first quality version is of a lower quality than the second quality version.

10. The method of claim 9 in which a user can preview the first, lower quality version associated with the first data part before accepting that manipulation.

11. The method of claim 1 in which the media object is in a format which allows the step of manipulation to occur without additional processing to alter the file format of the media object.

12. The method of claim 11 in which the media object is generated using layered labeling.

13. The method of claim 12 in which the second data part is refinement layer information which, when combined with the first data part, allows the original media object to be regenerated.

14. A method of recovering a media object which has been stored using the method of claim 1, comprising the step of re-combining the first data part and the second data part using the reverse of the function.

15. Digital data stored using the storage method of claim 1.

16. A computer program which, when running on a client, enables the client to receive and playback a media object previously stored using the method of claim 1.

17. A computer program which when running on a computer enables the computer to perform the method of claim 1.

18. A computer programmed to perform the method of claim 1.

19. A computer network comprising several computers, at least one of which performs the data storage method of claim 1 and enables users to access the different versions of the media object.