British Telecommunications Public Limited Company

Yousif Humeida

Michael Erling Nilsson

Stephen Clifford Appleby

Richard Gedge

Ian Christopher Kegel

Nicola Bull

Methods and apparatus are disclosed for selecting an encoding specification for encoding audio and/or video data to be streamed between a user-device () and a remote device (), where the user-device is operable to communicate with the remote device via a digital subscriber line (DSL,) for a portion of a path () between the user-device and the remote device, the DSL portion () extending between a user-side DSL modem device () and a DSL aggregation transceiver device (). The method comprises: at the user-side DSL modem device () and/or the DSL aggregation transceiver device (), collecting performance data in respect of data communications on the DSL portion (); in dependence on the performance data collected, determining one or more data communication characteristics in respect of data communications on the DSL portion (); and selecting an encoding specification for encoding the data to be streamed, the selection being made in dependence on the determined data communication characteristics.

Methods and apparatus for the encoding of audio and/or video data

In examples of the present invention, during delivery of content, the round trip times for each delivered data packet are measured and the congestion window used for delivery is adjusted accordingly. The congestion window is set to a relatively high value when the round trip times are relatively low, and set to a relatively low value when the round trip times are relatively high.

Congestion response

Methods and apparatus are disclosed for selecting encoding specifications for encoding audio and/or video data to be streamed from a sender to a receiver via a network. Methods and apparatus for encoding data using a selected encoding specification, and for streaming data which has been encoded using a selected encoding specification from a sender to a receiver via a network are also disclosed. The selecting method comprises selecting an encoding specification (s) in dependence on performance measures () previously obtained using a plurality of different encoding specifications in respect of a monitored network when in each of a plurality of different network conditions (), respective network conditions being characterised by different combinations of data-transmission characteristics.

A method of determining the bandwidth of a link carrying a plurality of data streams between a plurality of sources and a plurality of destinations in a network, the method including sending data packets from a first data stream over the link from one source to one destination at a first transmission rate, and measuring an associated first packet loss rate; sending further data packets from the first data stream over the link from the one source to the one destination at a second transmission rate, and measuring an associated second packet loss rate; and determining the bandwidth of the link in dependence on the first and second packet loss rates and the first and second transmission rates.

Determining the bandwidth of a communication link

A method of delivering media content over a network, the media content including a plurality of temporal segments, wherein each temporal segment comprises a plurality of data packets, the method including: selecting an initial size of a first congestion window; delivering the plurality of data packets of a first segment using the first congestion window, the initial size of the first congestion window being used to control the size of the first congestion window for the duration of the first segment delivery; measuring the packet loss during the delivery of the first segment; determining an initial size of a second congestion window in dependence on the measured packet loss for the first segment; and delivering a second segment using the second congestion window, the initial size of the second congestion window being used to control the size of the second congestion window for the duration of the second segment delivery.

Managing congestion response during content delivery

In examples of the present invention, delivery of a segment of content is done using an initial congestion window, preferably chosen to give a delivery rate that ensures timely delivery of that segment. However, under high levels of packet loss, the delivery rate may not be sufficient. Hence, at any stage during delivery of a segment, the actual delivery rate is measured, and used, together with the previous congestion window size, the amount of content segment data still to be delivered, and the time left for delivery, to calculate an updated congestion window. The remainder of the segment is then delivered using this revised congestion window.

Growing community of inventors

London, United Kingdom

Yousif Humeida