File reproducing apparatus and file reproducing method

• US 20030225952A1
• Filed: 02/13/2003
• Published: 12/04/2003
• Est. Priority Date: 02/18/2002
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Murakami, Yuzo
• Granted Patent: US 7,359,623 B2
• Time in Patent Office: Days
• US Class Current: 710/200
• CPC Class Codes: G11B 20/1251 for continuous data, e.g. digitised analog information signals, pulse code modulated [PCM] data
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 27/329 on a disc [VTOC]
• CPC Class Codes: Y10S 707/99931 Database or file accessing

Abstract

The file reproducing apparatus for reproducing files recorded on a recording medium by using a FAT (File Allocation Table) file system, has a cluster table which associates offset positions indicating the distances from the head of the file set at the predetermined offset intervals with cluster numbers indicating locations of the files recorded on the recording medium in which the data at the corresponding offset positions are stored. During a reproduction operation in a reverse direction which proceeds from the end of the file toward the head, the location of the data to be read is determined with reference to the cluster table.

Claims

1. A file reproducing apparatus for reproducing files recorded on a recording medium by using a FAT file system, comprising:

a reading section that reads data of a file from the recording medium;

a reproduction processor that applies a predetermined reproduction process to the data read by the reading section;

a data storage device; and

a controller that controls the reading section, the reproduction processor, and the data storage section,

wherein the data storage device stores a cluster table which associates an offset position indicating a position from the head of a file and set at a predetermined offset interval with a cluster number indicating a location on the recording medium on which data at the corresponding offset position is stored, and the controller determines a location on the recording medium at which the data to be read is located with reference to the cluster table during a reproducing operation in a reverse direction which proceeds from the end of the file toward the head thereof.

2. The file reproducing apparatus according to claim 1, wherein the file to be reproduced contains motion picture data comprising a plurality of video frames.

3. The file reproducing apparatus according to claim 2, wherein when the entire motion picture data is divided into substantially equally into N (N is a natural number) parts, the offset interval is equal to a data length of one part.

4. The file reproducing apparatus according to claim 2, wherein the offset interval is equal to a data length of N (N is a natural number) video frames.

5. The file reproducing apparatus according to claim 4, wherein the number N of video frames is changed according to a securable vacant capacity of the data storage device.

6. The file reproducing apparatus according to claim 2, wherein the controller generates the cluster table on the data storage device when the motion picture data reproduced in a forward direction.

7. The file reproducing apparatus according to claim 6, wherein in the case where the cluster number of a video frame is already recorded in the cluster table, the controller does not generate a cluster table related to the video frame when the video frame is going to be reproduced again in the forward direction.

8. The file reproducing apparatus according to claim 1, wherein when a new cluster table is generated in the presence of the formerly generated cluster table, the controller overwrites a region of the storage device on which the formerly generated cluster table is stored to generate the new cluster table.

9. A file reproducing method for reproducing files recorded on a recording medium by using a FAT file system, comprising:

generating a duster table which associates an offset position indicating a position from the head of a file and set at a predetermined offset interval with a cluster number indicating a location on the recording medium on which data at the corresponding offset position is stored; and

determining a location on the recording medium at which the data to be read is located with reference to the cluster table during a reproducing operation in a reverse direction which proceeds from the end of the file toward the head thereof.

10. The file reproducing method according to claim 9, wherein the file to be reproduced contains motion picture data comprising a plurality of video frames.

11. The file reproducing method according to claim 10, wherein when the entire motion picture data is divided into substantially equally into N (N is a natural number) parts, the offset interval is equal to a data length of one part.

12. The file reproducing method according to claim 10, wherein the offset interval is equal to a data length of N (N is a natural number) video frames.

13. The file reproducing method according to claim 12, wherein the number N of video frames is changed according to a securable vacant capacity of a data storage device in which the cluster table is stored.

14. The file reproducing method according to claim 10, further comprising generating the cluster table when the motion picture data reproduced in a forward direction.

15. The file reproducing method according to claim 14, wherein in the case where the cluster number of a video frame is already recorded in the cluster table, a cluster table related to the video frame is not generated when the video frame is going to be reproduced again in the forward direction.

16. The file reproducing method according to claim 9, further comprising, when a new cluster table is generated in the presence of the formerly generated cluster table, overwriting a region of a storage device on which the formerly generated cluster table is stored to generate the new cluster table.