System and Method of Streaming 3-D Wireframe Animations

Abstract

Optimal resilience to errors in packetized streaming 3-D wireframe animation is achieved by partitioning the stream into layers and applying unequal error correction coding to each layer independently to maintain the same overall bitrate. The unequal error protection scheme for each of the layers combined with error concealment at the receiver achieves graceful degradation of streamed animation at higher packet loss rates than approaches that do not account for subjective parameters such as visual smoothness.

We claim: 
     
         1 . A method comprising:
 allocating a first amount of redundancy to a layer of a plurality of layers that exhibits a greatest visual distortion of the plurality of layers, the first amount of redundancy allocated to the layer being relatively more than a respective second amount of redundancy allocated to other layers of the plurality of layers;   gradually reducing the respective second amount of redundancy on layers having less contribution to visual smoothness; and   applying an interpolation-based concealment to each layer of the plurality of layers where an irrecoverable loss of packets occurs only within a respective layer of the plurality of layers.   
     
     
         2 . The method of  claim 1 , wherein plurality of layers is associated with a three-dimensional wireframe mesh of an object. 
     
     
         3 . The method of  claim 2 , wherein the three-dimensional wireframe mesh corresponds to a video scene and wherein the method further comprises:
 partitioning, via a processor, the three-dimensional wireframe mesh according to (1) the object within the three-dimensional wireframe mesh and (2) a motion of the object, to yield a first partition comprising the object and a second partition;   organizing the first partition and the second partition into chosen layers of the plurality of layers based on a first visual smoothness value for the first partition and a second visual smoothness value associated with the second partition; and   generating one or more bitstreams comprising the chosen layers for transmission.   
     
     
         4 . The method of  claim 3 , wherein the second partition comprises a second object having a second motion. 
     
     
         5 . The method of  claim 4 , further comprising:
 computing the first visual smoothness value for the first partition; and   computing the second visual smoothness value for the second partition.   
     
     
         6 . The method of  claim 1 , further comprising:
 applying unequal error protection to the respective layer, wherein the unequal error protection applied to each respective layer is based on a respective bitrate value for each respective layer.   
     
     
         7 . The method of  claim 2 , wherein each respective layer comprises one of a node and a group of nodes within the three-dimensional wireframe mesh. 
     
     
         8 . The method of  claim 1 , further comprising encoding a particular layer in the plurality of layers to be resilient to packet errors. 
     
     
         9 . The method of  claim 1 , wherein a number of nodes within a portion of the plurality of layers is associated with an output bit rate of the portion. 
     
     
         10 . A system comprising:
 a processor; and   a computer-readable storage medium storing instructions which, when executed by the processor, cause the processor to perform operations comprising:
 allocating a first amount of redundancy to a layer of a plurality of layers that exhibits a greatest visual distortion of the plurality of layers, the first amount of redundancy allocated to the layer being relatively more than a respective second amount of redundancy allocated to other layers of the plurality of layers; 
 gradually reducing the respective second amount of redundancy on layers having less contribution to visual smoothness; and 
 applying an interpolation-based concealment to each layer of the plurality of layers where an irrecoverable loss of packets occurs only within a respective layer of the plurality of layers. 
   
     
     
         11 . The system of  claim 10 , wherein plurality of layers is associated with a three-dimensional wireframe mesh of an object. 
     
     
         12 . The system of  claim 11 , wherein the three-dimensional wireframe mesh corresponds to a video scene and wherein the computer-readable storage medium stores additional instructions which, when executed by the processor, cause the processor to perform operations further comprising:
 partitioning the three-dimensional wireframe mesh according to (1) the object within the three-dimensional wireframe mesh and (2) a motion of the object, to yield a first partition comprising the object and a second partition;   organizing the first partition and the second partition into chosen layers of the plurality of layers based on a first visual smoothness value for the first partition and a second visual smoothness value associated with the second partition; and   generating one or more bitstreams comprising the chosen layers for transmission.   
     
     
         13 . The system of  claim 12 , wherein the second partition comprises a second object having a second motion. 
     
     
         14 . The system of  claim 13 , wherein the computer-readable storage medium stores additional instructions which, when executed by the processor, cause the processor to perform operations further comprising:
 computing the first visual smoothness value for the first partition; and   computing the second visual smoothness value for the second partition.   
     
     
         15 . The system of  claim 10 , wherein the computer-readable storage medium stores additional instructions which, when executed by the processor, cause the processor to perform operations further comprising:
 applying unequal error protection to the respective layer, wherein the unequal error protection applied to each respective layer is based on a respective bitrate value for each respective layer.   
     
     
         16 . The system of  claim 11 , wherein each respective layer comprises one of a node and a group of nodes within the three-dimensional wireframe mesh. 
     
     
         17 . The system of  claim 10 , wherein the computer-readable storage medium stores additional instructions which, when executed by the processor, cause the processor to perform operations further comprising:
 encoding a particular layer in the plurality of layers to be resilient to packet errors.   
     
     
         18 . The system of  claim 10 , wherein a number of nodes within a portion of the plurality of layers is associated with an output bit rate of the portion. 
     
     
         19 . A computer-readable storage device storing instructions which, when executed by a processor, cause the processor to perform operations comprising:
 allocating a first amount of redundancy to a layer of a plurality of layers that exhibits a greatest visual distortion of the plurality of layers, the first amount of redundancy allocated to the layer being relatively more than a respective second amount of redundancy allocated to other layers of the plurality of layers;   gradually reducing the respective second amount of redundancy on layers having less contribution to visual smoothness; and   applying an interpolation-based concealment to each layer of the plurality of layers where an irrecoverable loss of packets occurs only within a respective layer of the plurality of layers.   
     
     
         20 . The computer-readable storage device of  claim 19 , wherein plurality of layers is associated with a three-dimensional wireframe mesh of an object.