A system and method for generating an MPEG compliant video stream with satisfactory visual quality. The method employs re-encoding at a higher (or lower) bit rate, only the segments with unsatisfactory visual picture quality while retaining other parts of the original video stream and then merging the re-encoded segments with the remaining original portions. If the original video stream is coded at a reasonable bit rate, the number and length of those segments with unsatisfactory visual picture quality will be few and short. Re-encoding only those segments can save very significant amount of cost and only requires minimal additional storage space. Furthermore, the portions with satisfactory picture quality will be retained. The system and method is applicable to MPEG and non-MPEG compliant data streams.

In predictive encoders that support both intra-frame and inter-frame coding, the coding of intermediate dissolve frames (i.e., those falling between the first and last dissolve frames) is restricted, such that either (1) no intermediate dissolve frame is coded as an anchor frame (e.g., MPEG I or P frame) or (2) only a specific number of frames at specific locations within the dissolve are encoded as anchor frames. In certain MPEG implementations, all intermediate dissolve frames are coded as B frames, while the first and last frames are coded as anchor frames (e.g., I or P frames). In other implementations, particular intermediate dissolve frames may be coded as anchor frames with the other intermediate frames coded as B frames. The present invention can provide improved coding results in terms of both bit rate and video quality by avoiding the accumulation of predication errors that can otherwise occur when fixed GOP patterns are applied during dissolves.

A video encoding method with support for editing when scene changed. The video encoding method reads and stores the pictures by the display order and detects whether the scene change occurred. The method encodes the pictures by the coding order when there are not scenes changed and encodes the pictures by a special coding process when there are scenes changed. Because the video encoding method encodes the pictures with considering the states of scenes changed and generates a new GOP when a scene change occurred, the video sequence can be cut into two parts by an image editing process without re-encoding. Therefore, the video can be edited without any loss and the editing performance of the editing process can be better.

An encoder to encode video streams representing a moving picture is provided whose video encoder calculates a bit storage quantity an STD video buffer should have when input of a stream ending with a first picture to the STD video buffer ends, calculates an initial bit storage quantity of a second picture of a stream concatenated to the end of the first picture and starting with the second picture, in a VBV buffer, based on the calculated bit storage quantity of the STD buffer, and encodes the stream based on the bit storage quantity. The video encoder further calculates a bit storage quantity of the STD video buffer, for decoding a picture of the stream in the STD video buffer, calculates, based on the calculated bit storage quantity, a bit storage quantity the VBV buffer should have for ending decoding of a fourth picture of a second stream concatenated to the beginning of a third picture and ending with the fourth picture, and encodes the stream based on the calculated bit storage quantity. With such encoding, a part of video streams can be re-coded without referencing to information indicative of an initial status of a video buffer when editing the video streams.

A picture signal processing system is disclosed, that comprises a decoder for generating the number of encoded bits and/or an average quantizing scale as representative value(s) of encoding parameters of an input encoded picture signal, decoding the input encoded picture signal, generating the decoded picture signal, and outputting the encoding parameters along with the generated decoded picture signal, and an encoder for encoding the decoded picture signal with the encoding parameters.