| 摘要 |
A system includes an encoder, transcoder or similar and a decoder. A video bit stream containing frames made up of blocks of pixels is transmitted from the encoder to the decoder. The present invention aims to transmit an encoded version of the video bit stream from the encoder to the decoder with as little auxiliary (i.e. error concealment) information as possible for enabling reconstruction of frames of the video bit stream in the case of a slice of the frame being lost in transit. This is performed by the encoder extracting motion vectors from a frame I(t-1) 400 preceding the frame I(t) being encoded and processing them to create an estimated motion vector field I(t) for the frame being encoded. A minimized difference between the motion vector field of the frame being encoded and the estimated motion vector field 403 is used to generate transform parameters, which are transmitted to the decoder as auxiliary information along with the usual motion prediction information (i.e. the motion vector field and residuals of the blocks) of the frames (at least frames I(t-2), I(t-1) and I(t)). The decoder receives the transform parameters. The decoder also creates an estimated motion vector field I(t) based on a preceding frame I(t-1) and applies the transform parameters to the estimated motion vector field 403 to obtain missing motion vectors. The motion vector field rebuilt using the reconstructed missing motion vectors is used for subsequent error concealment/decoding/displaying. A transformation from the motion vector field of a previous frame to that of a subsequent frame may also be used for generation of transform parameters. |
