公开(公告)号：US20170118263A1

公开(公告)日：2017-04-27

申请号：US15129486

申请日：2015-03-24

Applicant: BRITISH TELECOMMUNICATIONS PUBLIC LIMITED COMPANY

Inventor： Ian CRABTREE ,  Michael NILSSON ,  Rory TURNBULL ,  Stephen APPLEBY

IPC: H04L29/06 ,  H04L29/08

CPC classification number: H04L65/4076 ,  H04L65/607 ,  H04L67/02 ,  H04L67/42 ,  H04N21/23439 ,  H04N21/4383 ,  H04N21/6405 ,  H04N21/6408 ,  H04N21/8456 ,  H04W76/40

Abstract: The invention presents a method of providing feedback for receipt of a multicast video stream. The feedback mechanism allows the number of clients receiving over multicast to be determined, which can then be used to manage multicast delivery, including switching decisions between multicast and unicast. Video content is delivered over a multicast stream from a content server to a plurality of client devices. The client devices are each configured to respond at regular intervals whilst receiving the multicast video stream by transmitting an HTTP HEAD request message to the content server. The HTTP HEAD request refers to metadata relating to a manifest file associated with the video stream. The number of client devices receiving the multicast video stream is determined based on the number of HEAD requests received at the content server. The multicast video delivery can then be managed accordingly, and can also take into account the number of unicast clients that are requesting the corresponding unicast stream to the multicast stream.

公开(公告)号：US20170366588A1

公开(公告)日：2017-12-21

申请号：US15540322

申请日：2015-12-14

Applicant: BRITISH TELECOMMUNICATIONS, PUBLIC LIMITED COMPANY

Inventor： Stephen APPLEBY ,  Ian CRABTREE ,  Timothy STEVENS ,  Rory TURNBULL ,  Ivan ROPER ,  Michael NILSSON

IPC: H04L29/06

CPC classification number: H04L65/4076 ,  H04L65/4084 ,  H04L65/601 ,  H04L65/605 ,  H04L65/608

Abstract: Examples of the present invention provide a method of converting a multicast stream into unicast segments. In particular, sequence identifiers are generated based on a clock reference field in the transport stream packets that make up the multicast stream. Every time a new sequence identifier is calculated, a new unicast segment is generated and assigned with the new sequence identifier. Transport stream packets are placed into the new segment until a packet is processed that causes a new sequence identifier to be generated, at which point another new segment is generated and packets placed into that segment. In an improved method, random access indicators in the transports stream packets are used to further constrain when a new segment is generated, to ensure that new segments are coincident with a packet having a random access indicator. This improvement makes random access easier back and forth between and within a stream.

公开(公告)号：US20170127147A1

公开(公告)日：2017-05-04

申请号：US15129481

申请日：2015-03-24

Applicant: BRITISH TELECOMMUNICATIONS PUBLIC LIMITED COMPANY

Inventor： Ian CRABTREE ,  Michael NILSSON ,  Rory TURNBULL ,  Stephen APPLEBY

IPC: H04N21/6405 ,  H04N21/2343 ,  H04L29/06 ,  H04N21/2187 ,  H04N21/84 ,  H04L29/08 ,  H04N21/845 ,  H04N21/438

Abstract: The invention presents a method of generating a multicast stream for transporting video content such as live TV. First, the video content is encoded, and segmented into temporal chunks. Each chunk is then encapsulated in one or more RTP pacets, depending on the size of the chunk, and each RTP packet is marked with a chunk marker to indicate which of the packets the boundaries between chunks lie. The multicast stream is then generated by encapsulating the RTP packets, preferably using UDP in IP packets. The chunk marker is provided for by a special field in the RTP payload header. The chunk marker can be a chunk index or a chunk offset. Both, individually and in combination, can be used to determine the boundary between chunks.