Data streaming system and method

• US 20090116551A1
• Filed: 08/29/2008
• Published: 05/07/2009
• Est. Priority Date: 03/27/2002
• Status: Active Grant

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Jebb, Timothy R., Nilsson, Michael E.
• Granted Patent: US 8,386,631 B2
• Time in Patent Office: Days
• US Class Current: 375/240.30
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/752 adapting media to network capabilities
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/503 involving temporal prediction adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/23439 for generating different versions
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/44016 involving splicing one content stream with another content stream, e.g. for substituting a video clip
• CPC Class Codes: H04N 21/8455 involving pointers to the content, e.g. pointers to the I-frames of the video stream

Abstract

A data streaming system and method typically use a server arranged to stream one of a plurality of encoded data streams to a client. Each of the plurality of data streams may be an independent representation of a common data source encoded at a different resolution to the other of the plurality of data streams. The server can include a transmitter and a first buffer. The transmitter can be arranged to transmit data packets of the encoded data stream to the client via the first buffer. The transmitter can be arranged to monitor the content of the first buffer and switch to transmit another of the plurality of data streams in the event that predetermined criteria are detected from the first buffer.

Claims

1. A method of streaming a first and a second encoded video stream, each of the streams being an independent representation of a common source encoded at a different resolution from the other stream, and wherein each stream is encoded as a series of pictures predictively encoded in dependence on the previous pictures in the stream, the method including:

generating linking pictures of the second stream predictively encoded in dependence on previous pictures in the first stream, whereby a receiver receiving the first stream may then receive a linking picture followed by pictures of the second stream,

each linking picture being coded by

(a) quantizing the picture that is to be coded;

(b) quantizing the picture that is to be used as prediction;

(c) subtracting the quantized prediction from the quantized picture to be coded to obtain a prediction error signal that is transmitted without further quantization;

wherein pictures interspersed at predetermined points in the second data stream contemporary with the linking pictures are access pictures to which are applied a quantization that matches that applied to the corresponding linking picture, such that a receiver can reconstruct a linking picture identically to the simultaneous access picture; and

testing an access picture to identify any area of the picture for which the prediction is a good representation such that no data needs to be transmitted and, in respect of such area, setting said quantizations in the access picture and in the associated linking picture to a finer quantization.

2. A method according to claim 1 including, in respect of such identified area of an access picture, suppressing transmission of any prediction error.