EP0598499A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
System and method for synchronization of multimedia streams
Assignee: International Business Machines Corp
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Filing: 1993-10-25
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Granted: —
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Expires: 2013-10-25
Abstract
Abstract A computer-based multimedia presentation system is provided with a synchronization scheme for recording and playing independent media. The disclosed system and method allows media processes and single medium processes to achieve and maintain synchronization with each other without process interdependence and without interprocess communication. This capability is provided by assigning a common clock for all processes, requiring all participating media processes to reference the common clock, informing each process of a synchronization basepoint called a "zero-time", and then allowing each process to independently synchronize itself to the common clock. The common clock itself does not provide any stimulus to a media process; it is a passive component in the synchronization. The media process is the active component, referring to the common clock as required to maintain synchronization for the particular media it is handling.
Inventors
- 👤 Michael Jon Dockter
- 👤 Charles Leslie Haug
- 👤 Kevin Darrell Seppi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 14:58
CPC Classifications
G; G06; G06F; G06F8/00; G06F8/40; G06F8/41; G06F8/45; G06F8/458; G06F16/00; G06F16/40; G11; G11B; G11B27/00; G11B27/10
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
85 words
A method for synchronizing initiation of media operations in a multimedia recording and playback system, comprising the steps of: in a starter process, receiving the current time from a clock means, assigning the received current time as an initialization-time value, determining a zero-time value by adding a process preparation time to the initialization-time value, broadcasting the zero-time value to at least one media process; and in the media process, receiving the zero-time value, upon the current time reaching the zero-time value, initiating the media operation.
Claim 2
Dependent Claim
16 words
A method as recited in claim 1, wherein the clock means is a system real-time clock.
Claim 3
Dependent Claim
20 words
A method as recited in claim 1, wherein the media process initiates its media operation independently of other media processes.
Claim 4
Dependent Claim
36 words
A method as recited in claim 3, wherein media process receives exactly one zero-time value transmission, and wherein the zero-time value transmission constitutes the only synchronization transmission initiated from the starter process to the media process.
Claim 5
Independent Claim
61 words
A method comprising the steps of: in the media process, upon the current time reaching the zero-time value, repeating for each media event the sub-steps of obtaining the current time from the clock means, determining an event offset based on the zero-time value and the current time, logging the event offset in association with the media event, recording the media event.
Claim 6
Dependent Claim
34 words
A method as recited in claim 5, wherein the step of repeating for each media event further comprises the sub-step of, after recording the media event, waiting for arrival of the next media event.
Claim 7
Dependent Claim
24 words
A method as recited in claim 5, wherein a media event includes any of a single presentation object and a set of presentation objects.
Claim 8
Dependent Claim
23 words
A method as recited in claim 5, wherein the logging step logs the event offset into the data rate of the recorded data.
Claim 9
Dependent Claim
26 words
A method for synchronizing media recording as recited in claim 5, wherein the event offset is determined by subtracting the zero-time value from the current time.
Claim 10
Dependent Claim
28 words
A method as recited in claim 5, wherein the media process determines the granularity and number of media events independently of the starter process and other media processes.
Claim 11
Independent Claim
61 words
A method as claimed in any of claims 1 to 4, comprising the steps of: in the media process, accessing a log of event offset times associated with a plurality of media events, for each logged event offset time, performing the sub-steps of readying the associated media event for playing, and when the event offset time arrives, playing the media event.
Claim 12
Dependent Claim
33 words
A method as recited in claim 11, wherein the event offset time arrival is determined by comparing the current time with the sum of the zero-time value and the logged event offset time.
Claim 13
Dependent Claim
24 words
A method as recited in claim 11, wherein the log of event offset times is provided in the data rate of the recorded data.
Claim 14
Dependent Claim
22 words
A method as recited in claim 11, wherein the log of event offset times is created by any of recording and authorship.
Claim 15
Dependent Claim
47 words
A method as recited in claim 11, wherein the step of performing sub-steps further comprises the sub-steps of determining a correction time based on the event offset time, the current time, and zero-time, for a non-zero correction time, performing a resynchronization action on the next media event.
Claim 16
Dependent Claim
28 words
A method as recited in claim 11, wherein the correction time is determined by subtracting the current time from the sum of zero-time and the event offset time.
Claim 17
Dependent Claim
23 words
A method as recited in claim 11, wherein for a negative correction time the resynchronization action includes any of compression, truncation, and deletion.
Claim 18
Dependent Claim
22 words
A method as recited in claim 11, wherein for a positive correction time the resynchronization action includes any of waiting and elongation.
Claim 19
Dependent Claim
29 words
A method as recited in claim 5 or claim 11, wherein the step of determining a zero-time value further includes coding the zero-time value by computing its two's complement.
Claim 20
Dependent Claim
19 words
A method as recited in claim 11, wherein the media process terminates itself upon playing its final media event.
References Cited (Backward Citations)
No citation records indexed.
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