Abstract: A system and method to tag portions of a video with an access-control-list (ACL) for those periods of time (e.g., video segments, series of video frames, etc.) within a video that require elevated permission to view or access is provided. At playback time, the access-control-list is dynamically enforced in real-time to ensure that a user viewing or editing the video has permissions to view upcoming portions of the video. When a user has insufficient permission to view a portion of the video, a filler frame, blurred content or blank frame is displayed in the place of the actual video content. Audio may also be muted or beeped out during the periods of the video for which there is insufficient permissions.

Abstract: A system and method to tag portions of a video with an access-control-list (ACL) for those periods of time (e.g., video segments, series of video frames, etc.) within a video that require elevated permission to view or access is provided. At playback time, the access-control-list is dynamically enforced in real-time to ensure that a user viewing or editing the video has permissions to view upcoming portions of the video. When a user has insufficient permission to view a portion of the video, a filler frame, blurred content or blank frame is displayed in the place of the actual video content. Audio may also be muted or beeped out during the periods of the video for which there is insufficient permissions.

Abstract: Improved methods and apparatus for sharing and collaborating around a video source by maintaining and providing to users a list of a plurality of contacts containing both video source device contacts and interactive message source contacts. This allows for collaboration among users by permitting them to communicate with each other around an automatically-shared video source, to interact with automatically shared video sources, and to make decisions based on these shared video sources.

Abstract: Reference frames are selected for use in a frame reference buffer in a video encoding system, so as to provide long term prediction of motion in video sequences. Candidate reference frames are characterized by characteristic vectors. From the candidate reference frames, a number of reference frames are maintained in the frame buffer so as to obtain a specified distribution of the characteristic vectors over a vector space. Frames are selected for use in encoding a current frame based on the characteristic vector of the current frame and the reference frames in the frame buffer.

Abstract: A video system and process in which a series of video frames are encoded for fast forward and/or fast reverse playback, wherein a subset of frames are encoded as reference frames that have a hierarchical relationship with each other. The reference frames are I frames and predicted frames, such as P, B, or IDR frames.

Abstract: Motion vectors for encoding a predicted frame relative to a reference frame are determined from a phase correlation of corresponding regions of the predicted frame and reference frame. Peaks in the phase correlation are identified, and the location of the peaks are used as candidate motion vectors. From this limited set of candidate motion vectors, the best motion vectors for predicting blocks within each region can be readily identified.

Abstract: Reference frames are selected for use in a frame reference buffer in a video encoding system, so as to provide long term prediction of motion in video sequences. Candidate reference frames are characterized by characteristic vectors. From the candidate reference frames, a number of reference frames are maintained in the frame buffer so as to obtain a specified distribution of the characteristic vectors over a vector space. Frames are selected for use in encoding a current frame based on the characteristic vector of the current frame and the reference frames in the frame buffer.

Abstract: Motion vectors for encoding a predicted frame relative to a reference frame are determined from a phase correlation of corresponding regions of the predicted frame and reference frame. Peaks in the phase correlation are identified, and the location of the peaks are used as candidate motion vectors. From this limited set of candidate motion vectors, the best motion vectors for predicting blocks within each region can be readily identified.

Abstract: Motion vectors for encoding a predicted frame relative to a reference frame are determined from a phase correlation of corresponding regions of the predicted frame and reference frame. Peaks in the phase correlation are identified, and the location of the peaks are used as candidate motion vectors. From this limited set of candidate motion vectors, the best motion vectors for predicting blocks within each region can be readily identified.

Abstract: A method for clock recovery comprises a series of steps to be performed in a decoder to adaptively estimate the ratio P/S of the frequency of an encoder system time clock and the frequency of a decoder. The steps include performing a series of overlapping trials N which calculate time differentials dP(n), dS(n), respectively) between selected pairs of temporally separated clock references CRs and arrival times STCs. Each trial concludes by calculating an estimated ratio X according to the formula: X(N)=(&Sgr;dP(n))/(&Sgr;dS(n)) A preferred embodiment of the present invention also includes the step of adjusting the decoder clock in accordance with a damped version of the estimate, thereby “recovering” the encoder STC in the decoder.