Abstract: A method and system for streaming media data to a fixed client and/or a mobile client. In one method embodiment, the present invention recites encoding media data to be streamed to a client into a first multiple description bitstream and into a second multiple description bitstream. The present embodiment then recites distributing the first and second multiple description bitstreams to a plurality of servers placed at intermediate nodes throughout a network such that a client is provided with access to the media data via a plurality of transmission paths.

Abstract: A method for performing a soft-handoff in a mobile streaming media system, and a method for performing a hard-handoff in a mobile streaming media system are is disclosed. In the soft-handoff embodiment, the present invention detects that a channel quality between a mobile client and a first base station remains above a drop threshold and that a channel quality between the mobile client and a second base station increases from below to above an add threshold. The present embodiment then sends a first multiple description bitstream from the first base station to the mobile client and sends a complementary second multiple description bitstream from the second base station to the mobile client. This method thereby provides improved utilization of wireless bandwidth during soft-handoffs, in contrast to conventional systems where the same bitstream is transmitted from each base station.

Abstract: A method for handing off to a second server, in either a fixed or mobile streaming media system, a multiple description streaming session between a first server and either a fixed or mobile client. In one embodiment, the present invention recites selecting a second server to receive a handoff of a multiple description streaming media session between the first server and the client. In this embodiment, the multiple description streaming media session is comprised of a first multiple description bitstream and a second multiple description bitstream. The present embodiment further recites receiving at the second server, the second multiple description bitstream for streaming to the client. This embodiment further recites sending the second multiple description bitstream from the second server to the client.

Abstract: A method and system for securely and scalably encoding data are disclosed. A method and system for decoding data which has been securely and scalably encoding are also disclosed. In one encoding method embodiment, the present invention recites receiving data. The present method then segments the data into corresponding regions. The regions are then scalably encoded into scalable data. The present embodiment then progressively encrypts the scalable data to generate progressively encrypted scalable data. Next, the present embodiment, packetizes the progressively encrypted scalable data.

Abstract: A method and system for transcoding a stream of data packets are disclosed. The data packets are received from a source node and include data that are encrypted. The stream of data packets is operated on by a function that configures the stream according to downstream attributes, such as the attributes of a receiving node or of the communication channel. Significantly, the function is performed without decrypting the encrypted media data. The steam of data packets configured for the downstream attributes is sent to the receiving node. Because the encrypted data do not need to be decrypted and then encrypted again, the computational resources needed for transcoding the stream of data packets is significantly reduced, and the security of the data is not compromised.

Abstract: A computer readable medium having a data packet stored therein for causing a functional change in the operation of a device is disclosed. In one embodiment, the data packet is comprised of a scalably encoded, progressively encrypted data portion. In the present embodiment, the data packet further includes a header data portion corresponding to the scalably encoded, progressively encrypted data portion. The header data portion includes information adapted to be used by a transcoder to transcode the scalably encoded, progressively encrypted, data portion.

Abstract: Communication over lossy packet networks such as the Internet is hampered by limited bandwidth and packet loss. The present invention provides a path diversity transmission system for improving the quality of communication over a lossy packet network. The path diversity transmission system explicitly sends different subsets of packets over different paths, thereby enabling the end-to-end application to effectively see an average path behavior. Generally, seeing this average path behavior provides better performance than seeing the behavior of any individual random path. For example, the probability that all of the multiple paths are simultaneously congested is much less than the probability that a single path is congested. The resulting path diversity can provide a number of benefits, including enabling real-time multimedia communication and simplifying system design (e.g., error correction system design). Two exemplary architectures for achieving path diversity are described herein.

Abstract: Video communication over lossy packet networks such as the Internet is hampered by limited bandwidth and packet loss. The present invention provides a system for providing reliable video communication over these networks, where the system includes at least two jointly designed subsystems: (1) multiple state video coding system and (2) path diversity transmission system. Multiple state video coding combats the problem of error propagation that results from packet loss by coding the video into multiple independently decodable streams, each with its own prediction process and state. If one stream is lost the other streams can still be decoded to produce usable video, and furthermore, the correctly received streams provide bidirectional (i.e., previous and future) information that enables improved state recovery for the corrupted stream.

Abstract: A system and method for client-assisted motion estimation for client-server video communication is disclosed. The present invention includes the steps of receiving a request to update a current set of pixels within a video display on a client computer, and generating a motion vector for moving the current set of pixels within the video display using video information obtained only from the request and the client computer. In addition to sets of pixels, the present invention operates as well on objects, blocks and frames of video information.

Abstract: A predictively-coded object-based picture signal representing a group of pictures is transcoded into a predictively-coded block-based picture signal representing the group of pictures by extracting a coded scene descriptor and coded object descriptors from the predictively-coded object-based picture signal. The coded scene descriptor is decoded to generate a scene descriptor. The coded object descriptors are partially decoded to generate respective partially-decoded object descriptors. The decoding extracts coding information that describes the predictive coding of the coded object descriptors. In response to the scene descriptor, a frame of a partially-encoded block-based picture signal representing one of the pictures as a current picture is generated from the partially-decoded object descriptors.

Abstract: The invention is an image transmitting method and system including receiving encoded images, decoding those images and post-processing the decoded images. The post-processing reduces visual artifacts, such as blocking artifacts and mosquito noise, through separate detection, mapping and smoothing operations while avoiding many of the complexities associated with existing techniques. In detecting blocking artifacts, the inventive method employs DCT-domain detection rather than edge detection in the pixel domain. Also, the interior of a detected block is updated based on the surrounding blocks without disturbing the surrounding blocks. In reducing mosquito noise, the inventive method smooths the non-edge pixels within blocks containing edge pixels rather than smoothing the edge pixels. Also, distortion-induced false edge pixels are distinguished from true edge pixels and heavily smoothed.