Systems And Methods For Error Resilience In Video Communication Systems

Abstract

Systems and methods for error resilient transmission and for random access in video communication systems are provided. The video communication systems are based on single-layer, scalable video, or simulcast video coding with temporal scalability, which may be used in video communication systems. A set of video frames or pictures in a video signal transmission is designated for reliable or guaranteed delivery to receivers using secure or high reliability links, or by retransmission techniques. The reliably-delivered video frames are used as reference pictures for resynchronization of receivers with the transmitted video signal after error incidence and for random access.

What is claimed is: 
     
         1 . A system for media communications between a transmitting endpoint or server and one or more receiving endpoint(s) or server(s) over a packet-based communication network, the system comprising:
 an encoder configured to use a temporal coding structure having a number of different layers including a lowest temporal layer, wherein each picture is associated with a picture index number;   
       wherein data corresponding to a single picture is portioned and transmitted in one or more individual data packets, 
       wherein an individual data packet comprises data elements that indicate:
 for the lowest temporal layer pictures, a sequence number identifying said pictures, 
 for other temporal layer pictures, a reference to the sequence number of the most recent, in decoding order, lowest temporal layer picture, and 
 for all pictures, a ‘start’ flag and an ‘end’ flag that respectively indicate if the individual data packet contains the first or last data portions of the picture. 
 
     
     
         2 . The system of  claim 1  wherein the data elements additionally indicate a series number associated with each spatial or quality layer, 
       wherein the receiving endpoint or server detects if a lowest temporal layer picture of a particular spatial or quality layer is lost by determining if the picture corresponding to the referenced series number and sequence number has been received at the receiving endpoint or server. 
     
     
         3 . The system of  claim 2  wherein the communication network uses the Internet Protocol, media transport is performed using real-time transport protocol (RIP), and the data elements include data to indicate presence of a lowest temporal layer frame or fragment thereof in the packet. 
     
     
         4 . The system of  claim 3  wherein a receiving endpoint or server sends a negative acknowledgment message to the transmitting endpoint or server in response to the receiving endpoint's or server's detection of a lost lowest temporal layer picture or portion of such picture. 
     
     
         5 . The system of  claim 4  wherein the transmitting endpoint or server upon receiving the negative acknowledgment message retransmit the lost lowest temporal layer picture or portion of such picture. 
     
     
         6 . The system of  claim 1 , wherein the encoder conforms to H.264 Scalable Video Coding (SVC), and the data elements are carried in Network Adaptation Layer (NAL) unit header extension for SVC elements. 
     
     
         7 . The system of  claim 1 , wherein the encoder conforms to H.264 SVC, and the data elements are carried in a Supplemental Enhancement Information (SET) message. 
     
     
         8 . A method for media communications between a transmitting endpoint or server and one or more receiving endpoint(s) or server(s) over a packet-based communication network, wherein an encoder is configured to use a temporal coding structure having a number of different layers including a lowest temporal layer, and wherein data corresponding to a single picture is portioned and transmitted in one or more individual data packets, the method comprising:
 placing in each individual data packet data elements that indicate:
 for the lowest temporal layer pictures, a sequence or index number identifying said pictures, 
 for other temporal layer pictures, a reference to the sequence number of the most recent, in decoding order, lowest temporal layer picture, and 
   for all pictures, a ‘start’ flag and an ‘end’ flag that indicate if the individual data packet contains the first or last, respectively, data portions of the picture.   
     
     
         9 . The method of  claim 8 , wherein the data elements additionally indicate a series number associated with each spatial or quality layer, 
       so that the receiving endpoint or server detects if a lowest temporal layer picture of a particular spatial or quality layer is lost by determining if the picture corresponding to the referenced series number and sequence number has been received at the receiving endpoint or server. 
     
     
         10 . The method of  claim 8 , wherein the communication network uses the Internet Protocol, media transport is performed using real-time transport protocol (RTP), and the data elements include data to indicate presence of a lowest temporal layer picture or fragment thereof in the packet. 
     
     
         11 . The method of  claim 10 , wherein a receiving endpoint or server sends a negative acknowledgment message to the transmitting endpoint or server in response to the receiving endpoint's or server's detection of a lost lowest temporal layer picture or portion of such picture. 
     
     
         12 . The method of  claim 11 , wherein the transmitting endpoint or server upon receiving the negative acknowledgment message retransmit the lost lowest temporal layer picture or portion of such picture. 
     
     
         13 . The method of  claim 12 , wherein the encoder conforms to H.264 Scalable Video Coding (SVC), and the data elements are carried in Network Adaptation Layer (NAL) unit header extension for SVC elements. 
     
     
         14 . The method of  claim 8 , wherein the encoder conforms to H.264 SVC, and the data elements are carried in a Supplemental Enhancement Information (SEI) message. 
     
     
         15 . A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method recited in  claim 8 . 
     
     
         16 . A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method recited in  claim 9 . 
     
     
         17 . A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method recited in  claim 10 . 
     
     
         18 . A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method recited in  claim 11 . 
     
     
         19 . A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method recited in  claim 12 . 
     
     
         20 . A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method recited in  claim 14 .