Virtual format for the storage of streaming data

• US 7,925,773 B2
• Filed: 06/22/2007
• Issued: 04/12/2011
• Est. Priority Date: 06/22/2007
• Status: Expired due to Fees

• Current Assignee: ServiceNow Incorporated
• Original Assignee: Microsoft Corporation
• Inventors: Reneris, Ken, Gates, Matthijs, Sather, Dale
• Primary Examiner(s): Chankong; Dohm
• Assistant Examiner(s): Hussain; Tauqir
• Application Number:
  US11/767,370
• Publication Number:
  US 20080320157A1
• Time in Patent Office: 1,390 Days
• Field of Search: 709/231
• US Class Current: 709/231
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/322 used signal is digitally coded
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 5/765 Interface circuits between an apparatus for recording and another apparatus
• CPC Class Codes: H04N 9/8205 involving the multiplexing of an additional signal and the colour video signal

Abstract

Systems and methods for storing streaming data are provided. A system is disclosed that includes a computer program which, when executed on a computing device, is configured to store a data stream in memory of the computing device in a virtual file format. The virtual file format may include a timeline of events. The events in the timeline may include a plurality of spanning events. Each spanning event may contain respective state information representing a state of the data stream across an interval in the timeline, and may be linked to at least one other spanning event.

Claims

1. A computer-readable storage device, comprising:

a computer program that, when executed on a computing device, is configured to store a data stream in memory of the computing device in a virtual file format, the virtual file format including a timeline of events, wherein the event type is selected from the group consisting of media sample, seekpoint, and state table, and wherein events of the seekpoint and state table type are spanning events, the events in the timeline including a plurality of spanning events, each spanning event containing respective state information representing a state of the data stream across an interval in the timeline, and being linked to at least one other spanning event;

wherein each of the spanning events is configured to contain a pointer that refers to a byte offset of a previous spanning event in the timeline, if present;

wherein the computer program is configured to recover an attribute of a state of the data stream at a target position within the data stream, by accessing a spanning event with current state information for the attribute, and reading the state information from the spanning event; and

wherein the computer program is configured to access a spanning event with current state information for the attribute by identifying a seekpoint spanning event associated with the target position, identifying a pointer in the seekpoint spanning event to a previous spanning event in the timeline, accessing the previous spanning event via the pointer, and reading state information from the previous event.

2. The computer-readable storage device of claim 1, wherein events are ordered according to a byte offset in the timeline, and wherein each event has a position that is independent of the byte offset of the event.

3. The computer-readable storage device of claim 2, wherein the timeline is a first timeline, wherein the virtual file format further includes a second timeline.

4. The computer-readable storage device of claim 3, wherein a plurality of events from the first timeline and/or the second timeline that have the same position are concurrent in the data stream.

5. The computer-readable storage device of claim 1, wherein each event is configured to include a type, size, context, and/or payload.

6. The computer-readable storage device of claim 5, wherein an event with no payload acts to signal the end of a state in the timeline.

7. The computer-readable storage device of claim 1, wherein each state table includes consolidated state information from a plurality of spanning events that affect at least one attribute of the state of the data stream at a position.

8. The computer-readable storage device of claim 7, wherein the state table is a variable-length entries table, including a header, a redirector, and entries of variable length, wherein the redirector is configured to reference a start of each variable-length entry in the table.

9. The computer-readable storage device of claim 1, wherein the previous spanning event is a state table.

10. A computing device, comprising:

a processor;

memory; and

a mass storage device containing programming stored thereon that is executable by the processor to perform a method for storing streaming data, the method comprising,

accessing a virtual file format for a data stream stored in the memory of the computing device, the virtual file format including a timeline of events, to recover an attribute of a state of the data stream at a target position within the data stream, wherein the event type is selected from the group consisting of media sample, seekpoint, and state table, and wherein events of the seekpoint and state table type are spanning events,

accessing a spanning event with current state information for the attribute, the spanning event being linked to at least one other spanning event; and

reading state information from the spanning event;

wherein accessing a spanning event with current state information for the attribute includes;

identifying a seekpoint spanning event associated with the target position;

identifying a pointer to a previous spanning event in the timeline, within the seekpoint spanning event;

accessing the previous spanning event via the pointer; and

if the previous spanning event is a state table, reading state information from the state table, and if the previous spanning event is not a state table, backwardly traversing one or more spanning events in the timeline via respective spanning event pointers contained in the one or more spanning events, until a state table spanning event is reached.

11. The computing device of claim 10, wherein the method further comprises:

determining that there is another timeline in the virtual file format; and

accessing an additional state table in the other timeline with state information for the target position that is based on one or more events in the other timeline.

12. The computing device of claim 10, wherein the data stream contains audio and/or video data.

13. A computing device, comprising:

a processor;

memory; and

a mass storage device containing a computer program thereon that when executed on the computing device is configured to store a data stream in the memory of the computing device in a virtual file format;

wherein the virtual file format includes a timeline of events, wherein the event type is selected from the group consisting of media sample, seekpoint, and state table, and wherein events of the seekpoint and state table type are spanning events;

wherein the timeline further includes a plurality of spanning events containing respective state information about the data stream;

wherein each spanning event is configured to reference a previous spanning event in the timeline, if present, by inclusion within each spanning event of a byte offset in the timeline of the respective previous spanning event;

wherein the computer program is configured to recover an attribute of a state of the data stream at a target position within the data stream, by accessing a spanning event with current state information for the attribute, and reading the state information from the spanning event; and

wherein the computer program is configured to access a spanning event with current state information for the attribute by identifying a seekpoint spanning event associated with the target position, identifying a pointer in the seekpoint spanning event to a previous spanning event in the timeline, accessing the previous spanning event via the pointer, and reading state information from the previous event.

14. The computing device of claim 13, wherein the timeline further includes a state table having state information that has been consolidated from a plurality of spanning events.