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Systems and methods for error resilience and random access in video communication systems

  • US 8,804,848 B2
  • Filed: 09/21/2011
  • Issued: 08/12/2014
  • Est. Priority Date: 12/08/2005
  • Status: Active Grant
First Claim
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1. A system for media communications between a transmitting endpoint and one or more receiving endpoint(s) over a communications network, the network having one or more layered media transport link(s) including a more reliable media transport link to or from each endpoint, the system comprising:

  • an encoder which encodes transmitted media as frames in a threaded coding structure having a number of different frame types, the frames including a sequence of reference frames;

    a decoder which decodes received media based on reference frames therein; and

    a particular select subset of the frames in the threaded coding structure that is designated as a type (“

    R”

    ) for reliable transport to the one or more receiving endpoint(s) over the more reliable transport link,wherein the subset of the frames of the type R is particularly selected to include at least the frames of the lowest temporal layer in the threaded coding structure and such that the decoder can decode at least a portion of the received media based on a reliably received frame of the type R after packet loss or error and thereafter is synchronized with the encoder,wherein reliable transport of the reference frames of the type R comprises retransmissions over the more reliable transport link based on a protocol of Acknowledgment (ACK) and/or No Acknowledgment (NACK) messages, andwherein the particular select subset of the frames that is designated as a type R for reliable transport to the decoder over the more reliable transport link comprises intra and inter macroblocks, and wherein the encoder further comprises a reliability and random access (RRC) module that recalculates the allocation of intra macroblocks in coding future frames in response to packet loss in or a new endpoint joining a current communication session.

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