SCENE CUT DETECTION FOR VIDEO STREAM COMPRESSION

摘要

A method and apparatus for detecting (51) in a video stream a scene cut (11, 12) between a current field of the video stream and an immediately preceding field includes determining (61) differences for a first plurality of image parameters between values of the image parameters for a current field and for one or more immediately preceding fields. A flag value is set (62) for each parameter indicating whether a possible scene break exists between the current field and the immediately preceding field dependent on the respective differences. The flag values for each parameter are combined (63) to form a combined parameter and a scene break trigger signal generated (64) indicating a scene break between the current field and the immediately preceding field if the combined parameter exceeds a predetermined trigger threshold. A change of criticality is determined (52) at a forthcoming scene cut. A quantisation parameter is adjusted (53) dependent on the criticality change to avoid overflowing a buffer on encoding of a field following the scene cut as an intra-coded field. A field following the scene cut is encoded (54) as an intra-coded field having a quantisation parameter dependent on the criticality change; such that encoding of forward or backward coded fields prior to or following the scene change is based only on fields preceding or following the scene change, respectively.