Vantrix Corporation

Sebastien Cote

Yves Lefebvre

Francis Roger Labonte

Jean Mayrand

Marc Courtemanche

Robert Buchnajzer

Louis Benoit

Jean-Noël Krause

Audio and video streams of a media file are transcoded just-in-time by keeping the transcoding process synchronized to a wall clock. The transcoding is initially configured slightly faster than real-time. The transcoded frames are pushed from the transcoder through a variable bandwidth connection as soon as they are transcoded. Transcoding is then monitored periodically to assess the bandwidth that was available during the transmission of a transcoded buffer. Two time intervals are measured: a buffer interval which is the difference in the transcoded buffer timestamps of the previous two transmissions, and a clock interval corresponding to the real time transmission time of the last transcoded buffer. If a significant difference is observed, the transcoder bit rate is adjusted by a factor that is derived from that difference.

Dynamic bit rate adaptation over bandwidth varying connection

A method and system to trigger ingestion of remote content or playlists by a streaming server using URL folder mapping is disclosed. The streaming server maintains a URL Map having entries that map a URL folder referenced in the streaming URL to a content server folder located on the content server. This folder level mapping enables maintaining a many-to-many relationship between multiple content identified at the streaming server and their corresponding content located at the content server.

Method and system for triggering ingestion of remote content by a streaming server using uniform resource locator folder mapping

Web objects, such as media files are sent through an adaptation server which includes a transcoder for adapting forwarded objects according to profiles of the receiving destinations, and a cache memory for caching frequently requested objects, including their adapted versions. The probability of additional requests for the same object before the object expires, is assessed by tracking hits. Only objects having experienced hits in excess of a hit threshold are cached, the hit threshold being adaptively adjusted based on the capacity of the cache, and the space required to store cached media files. Expired objects are collected in a list, and may be periodically ejected from the cache, or when the cache is nearly full.

Method and system for self-tuning cache management

A system and methods for adapting streaming data for transmission over a connection of time-varying capacity are disclosed. A streaming server individually adapts transmission rates of signals directed to subtending clients according to measurements characterizing connections from the streaming server to the clients. The measurements may relate to characteristics such as transfer delay, data-loss fraction, and occupancy level of a buffer at a client's receiver. A flow controller associated with the streaming server derives metrics from measurements taken over selected time windows to determine a permissible transmission rate from the server to each active client. Metrics related to a specific characteristic may include a mean value over a moving window as well as short and long term tendencies of respective measurements. An adaptable encoder at the streaming server encodes signals to meet permissible transmission rates.

Flow-rate adaptation for a connection of time-varying capacity

A method of data streaming from an encoder to a decoder through a time-varying connection, is disclosed. The method includes associating an encoding coefficient with said time-varying connection, the encoding coefficient determining a flow rate at an output of said encoder; defining a performance metric of the time-varying connection; defining an acceptance interval of the performance metric having a lower bound and an upper bound; acquiring a set of performance measurements of the time-varying connection over a time window at a current encoding coefficient; determining a current value of the metric of the time-varying connection according to the set of measurements; determining a preferred encoding coefficient according to the current value of the metric; and modifying the current encoding coefficient based on the current value of the metric and the acceptance interval to attain the preferred encoding coefficient. A corresponding streaming server and system for data streaming are also provided.

Data streaming through time-varying transport media

Methods of data streaming from an encoder to a decoder through a connection subjected to time-varying conditions are disclosed. The connection is assigned a nominal flow rate and an encoding coefficient associated with the connection modifies the nominal flow rate to determine a permissible flow rate compatible with a time-varying state of the connection. Multiple performance characteristics are associated with the connection and corresponding sets of performance measurements taken over adaptively selected time windows are acquired. Performance metrics having one-to-one correspondence to the performance characteristics are determined and compared with lower bounds and upper bounds of respective predefined acceptance intervals. A current encoding coefficient is computed as a function of the performance metrics and used to determine the permissible flow rate. The encoder's configuration is adapted to produce an encoded signal which maximizes signal fidelity under the constraint of the permissible flow rate.

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Montreal, Canada

Sebastien Cote