Patent ID: 8996713
Filing Date: 2015-03-31
Classification: H04L,H04N

Abstract:
1. A method of transmitting a video sequence from a server to a receiver over a transmission link in a network, comprising: (a) generating a plurality of video streams by encoding a video sequence at a respective plurality of quality levels; (b) determining for each video stream a set of pre-calculated data comprising, for each of a plurality of temporal positions in the video stream, i) for each of a plurality of transmission rates, the minimum preload required at the receiver for timely delivery of the video stream from said temporal position to the end of the video stream, and ii) the transmission rate required for timely delivery of the video stream from said temporal position to the end of the video stream where no preload is present at the receiver, wherein the preload is the playout duration of the data buffered at the receiver, and timely delivery is such that no buffer underflow occurs at the receiver; (c) transmitting one of the video streams to the receiver; and during transmission, (d) determining the current preload at the receiver, and for a video stream encoded at one of the plurality of quality levels; after an elapsed time following step (d), (e) calculating a sufficient delivery rate as equal to the difference between the number of bits delivered by the intersection time and the actual number of bits delivered during the elapsed time divided by the sum of the current preload and intersection time minus the elapsed time; and calculating a new acceptable delivery rate by repeating step (d); and (f) determining the minimum required delivery rate to ensure timely delivery of the remainder of the stream as the minimum of the new acceptable delivery rate and the sufficient delivery rate.