A plurality of bit streams are seamlessly spliced. Separate decoders decode each bit stream. A controller selects the decoded pictures according to a re-encoding range in the vicinity of a splicing point of the bit streams. Pictures presenting a reordering of the streams are excluded in the selection of the decoded pictures. An encoder re-encodes the pictures within the re-encoding range. When it is determined that crossover motion compensation exists between pictures of different streams, the controller changes the motion prediction direction of the problematic picture. The controller changes a motion prediction picture type of a picture which is improperly motion predicted with reference to another stream. A quantization characteristic or motion vectors for the new picture type are generated by the controller. The controller effects the encoding in accordance with a target amount of bits to prevent a breakdown of a buffer and a discontinuation of an amount of data occupancy thereof. A multiplexer multiplexes the original streams with the re-encoded stream to produce a seamless bit stream.