Patent ID: 8374480

Claim:
A video recording method implemented in a system which includes a video data transmitting device and a video data recording device, wherein a recording process implemented in the video data recording device comprises: (a) receiving input video data, wherein the input video data include a plurality of initial blocks of data collectively representing an initial frame of video image, and further include, for each subsequent changed frame of video image, a time stamp for the changed frame and one or more subsequent blocks of data representing changed blocks of that frame, and wherein the input video data further include a block index associated with each initial and subsequent block of data to indicate a position of the block within the frame of video image; (b) storing the initial blocks of data with the associated block indices in a data file, and storing a data location for each initial block in a virtual frame table, wherein the data location for a block indicates a location in the data file where the block is stored; (c) for each subsequent changed frame of video image, storing the changed blocks of data with the associated block indices in the data file, and updating the virtual frame table by replacing existing data locations for the changed blocks with new data locations; and (d) at each of a plurality of predetermined time points, storing in a snapshot file a time stamp for the time point, a current copy of the virtual frame table at the time point, and a next changed frame location indicating a location in the data file where data for a next changed frame after the time point will be stored, wherein the initial blocks for the initial frame and the changed blocks for the subsequent frames are stored in the data file sequentially.