| 摘要 |
Methods and systems for encoding data representative of a sequence of video frames for transmission to a decoder. A motion compensated predictive coder (24) substantially losslessly compresses the data, computes a motion vector, and forms an intermediate coded representation which includes the compressed data and the motion vector. A frame detector (26), which detects frames having a prediction error which exceeds a predetermined threshold, is coupled to the motion compensated predictive coder (24). A digital storage device (22) is coupled to the motion compensated predictive coder (24) and the frame detector (26). The digital storage device (22) stores the intermediate coded representation and stores a representation of the frames having the prediction error which exceeds the predetermined threshold. A lossless decoder (29), coupled to the digital storage device (22), substantially losslessly decodes the intermediate coded representation to form a decoded representation. A recoder (28), which compresses the decoded representation at a compression ratio in dependence upon a selectable bit rate for transmission, is coupled to the digital storage device (22) and the lossless decoder (29).
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