Electrical computers and digital processing systems: multicomput – Multicomputer synchronizing
Reexamination Certificate
1999-05-25
2002-11-12
Barot, Bharat (Department: 2154)
Electrical computers and digital processing systems: multicomput
Multicomputer synchronizing
C709S200000, C709S231000, C709S236000, C348S500000, C348S512000, C348S513000, C348S515000, C348S423100
Reexamination Certificate
active
06480902
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates to a system for multimedia communication, specially to an intermedia synchronization system with bounded skew guarantee to transmit multimedia data streams according to sequential marks.
B. Description of the Prior Art
Recent development in high-speed communication technology allows the multimedia communication to grow rapidly. Multimedia information including text, graphics, images, voice, animation, and full-motion video now can be accessed in a relatively fast speed.
Conventional multimedia transmission uses only one network connection for transmitting multimedia data streams regardless of the differences in data types. It is known that video frames are usually much more larger than audio frames. To establish a smooth connection, video frames require about 3 mega bps (bits per second) for transmission while audio frames only 64 K bps. Thus, if we want to use a network connection to transmit video and audio signals simultaneously with a guaranteed quality, we will need a bandwidth of about 3M plus 64 k bps, that is, 3.5 M bps. Such a large bandwidth can only be provided by a dedicated high speed network which is very expensive.
To save the cost and utilize the bandwidth of the networks more efficiently, clients may rent different dedicated network connections with acceptable bandwidths and prices for transmitting audio frames and video frames separately. However, when two or more correlated media are distinctively transported over the networks, the intermedia synchronization problems may occur. That is, the arrival time for the correlated media at the receiving site may be different due to several factors, such as, current network condition, the speed of transmission, and data size.
The three most popular approaches for solving intermedia synchronization problem include: feedback-based, time-stamped-based, and sequence-marking-based approaches. Feedback-based approach performs intermedia synchronization based on feedback packets that are periodically sent back to the sending site so that the number of retrieval times and compensation for the network jitter can be calculated. The time-stamped-based approach utilizes the time stamp recorded in each frame to rearrange its sequence before it is played out. In general, the disadvantage for the feedback-based approach is that it is not fast enough for real-time transmission. On the other hand, the time-stamped-based approach requires drastic computation and very often results in frame overhead.
In contrast, the sequence-marking-based approach employs rather streamlined time stamps referred to as sequential marks. This approach is simple for implementation and practical in application. However, the determination on marking frequency has been a compromise issue between skew assurance and computing overhead.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an intermedia synchronization system with bounded skew guarantee which can transmit multimedia data streams over different network connections with minimum overhead.
It is a further object of the present invention to provide an intermedia synchronization system which allows users to rent network connections of suitable bandwidths and prices without suffering from the quality of service on networks.
Accordingly, the system of the invention mainly includes: a synchronization marker at a transmitting site and a synchronization forcer at a receiving site connecting to each other via computer networks. The synchronization marker performs the sequential marking of frames per every marking interval. The synchronization forcer regulates the play time of the audio signals and their corresponding video signals according to their sequential marks. The inventive system can determine precisely about the minimum marking interval yielding a bounded skew requirement. The skew is first formulated as a function of scene pause (video frame lack) and scene leap (video frame loss), which are in turn derived by means of an Markov Batch Bernoulli arrival process D/K/1 (hereinafter referred to as MBBP/D/K/1) queuing model assuming the Markov Batch Bernoulli arrival process (hereinafter referred to as MBBP). Analytical results have shown that skew increases when the buffer size and the burst of the arrival traffic increase and vice versa. Consequently, the invention satisfies any given skew requirement under various buffer size and traffic arrivals while imposing minimal overhead.
REFERENCES:
patent: 5642171 (1997-06-01), Baumgartner et al.
patent: 5737531 (1998-04-01), Ehley
patent: 5768535 (1998-06-01), Chaddha et al.
patent: 5959684 (1999-09-01), Tan et al.
patent: 6016166 (2000-01-01), Huang et al.
patent: 6141693 (2000-10-01), Perlman et al.
patent: 6148135 (2000-11-01), Suzuki
patent: 6154771 (2000-11-01), Rangan et al.
patent: 6262776 (2001-07-01), Griffits
patent: 6262777 (2001-07-01), Brewer et al.
patent: 6415326 (2002-07-01), Gupta et al.
Chen Yu-Guo
Tien Po-Lung
Yuang Maria C.
Barot Bharat
Berkowitz Marvin C.
Institute for Information Industry
Nath & Associates PLLC
Novick Harold L.
LandOfFree
Intermedia synchronization system for communicating... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Intermedia synchronization system for communicating..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Intermedia synchronization system for communicating... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2969365