Method and system for synchronizing audio and video streams in media relay conferencing
First Claim
Patent Images
1. A method, comprising:
- receiving, at an intermediate device that is communicatively coupled between a plurality of media relay endpoints, a plurality of input streams from the plurality of media relay endpoints, wherein each stream comprises input data chunks;
parsing the input data chunks;
converting a timestamp field of each input data chunk into a manipulated timestamp, reflecting a single time domain; and
calculating a parameter corresponding to each input stream for converting the timestamp field of the input data chunks into the single time domain, comprising;
estimating a difference between a clock of a transmitting media relay endpoint of the input stream and a clock of the intermediate device; and
determining the parameter as a function of the estimated difference, a timestamp clock rate associated with the input stream, a clock field and a timestamp field in a sender report corresponding to the input stream, a clock value of the intermediate device, and a timestamp value of the intermediate device,wherein the clock value of the intermediate device and the timestamp value of the intermediate device are obtained at a same time.
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Abstract
A novel technique allows synchronizing a plurality of audio and video streams received at a receiving media relay endpoint via an intermediate node, such as a media relay multipoint control unit. The received streams were generated by a plurality of transmitting media relay endpoints and been relayed to the plurality of receiving media relay endpoints via the intermediate node, but are seen as being using a single time domain, in terms of wall clock and manipulated timestamps, while preserving the correct capture time.
10 Citations
27 Claims
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1. A method, comprising:
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receiving, at an intermediate device that is communicatively coupled between a plurality of media relay endpoints, a plurality of input streams from the plurality of media relay endpoints, wherein each stream comprises input data chunks; parsing the input data chunks; converting a timestamp field of each input data chunk into a manipulated timestamp, reflecting a single time domain; and calculating a parameter corresponding to each input stream for converting the timestamp field of the input data chunks into the single time domain, comprising; estimating a difference between a clock of a transmitting media relay endpoint of the input stream and a clock of the intermediate device; and determining the parameter as a function of the estimated difference, a timestamp clock rate associated with the input stream, a clock field and a timestamp field in a sender report corresponding to the input stream, a clock value of the intermediate device, and a timestamp value of the intermediate device, wherein the clock value of the intermediate device and the timestamp value of the intermediate device are obtained at a same time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A media relay multipoint controller comprising:
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a signaling and control module configured to select one or more transmitting media relay endpoints of a plurality of transmitting media relay endpoints; and a compressed media processor controlled by the signaling and control module, configured to; parse input data chunks corresponding to a plurality of input streams; convert a timestamp field of the input data chunks from a received timestamp value to a manipulated timestamp value reflecting a single time domain; and calculate a parameter for each input stream of the plurality of input streams for use in converting the timestamp fields of each input data chunk contained in the input stream, comprising configuring the compressed media processor to; estimate a difference between a wall clock of each transmitting media relay endpoint and a wall clock of the media relay multipoint controller; and determine the parameter as a function of the estimated difference, a timestamp clock rate used for the input stream, a value of a wall clock field and a timestamp field in a sender report corresponding to the input stream, and the wall clock value and a timestamp value of a relevant media clock of the media relay multipoint controller, wherein the wall clock value and the timestamp value of relevant media clock of the media relay multipoint controller are obtained at a same time. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification