Abstract: There is provided a method and apparatus for scene change detection for use with bit-rate control of a video compression system. The method and apparatus may be used for scene change detection in intra-coded and/or inter-coded pictures. The method comprises the steps of: compressing each picture in a video signal in turn; determining complexity data from the compressed signal for each picture after partial compression of the picture; determining from the complexity data whether a scene change may have taken place; and adjusting the compression step and allocated compressed bit number for pictures after a scene change detection in dependence on the result of the determination. For an intra-coded picture, the complexity data is a monotonically increasing function of a quantisation parameter and a compressed bit number used in the compression step for the partial compression from which the complexity data is determined.

Abstract: A method of determining run-out in a disc drive involving steps of performing a direct current erase, selecting a reference track, writing a sinusoidal signal into a first track at a first offset from the reference track, sensing a read signal along the reference track, and analyzing the read signal to extract run-out information.

Abstract: A method is disclosed for detecting defects in a recordable medium such as a hard disc drive based on error energy. The method may include the steps of writing test data to the medium and reading back the test data. The method may also include the steps of computing an error energy based on the square of the difference between the read back data and an ideal version of the test data and comparing the error energy with an energy threshold. The method generates a defect signal when the error energy exceeds the energy threshold. The method may also be used to identify the media defect according to its error energy profile. An apparatus for detecting defects in a recordable medium is also disclosed.

Abstract: A method is disclosed for detecting defects in a recordable medium such as a hard disc drive based on error energy. The method may include the steps of writing test data to the medium and reading back the test data. The method may also include the steps of computing an error energy based on the square of the difference between the read back data and an ideal version of the test data and comparing the error energy with an energy threshold. The method generates a defect signal when the error energy exceeds the energy threshold. The method may also be used to identify the media defect according to its error energy profile. An apparatus for detecting defects in a recordable medium is also disclosed.