Ampex Corporation

John P Watney

Richard K Brush

George A Stadelmann

The invention provides techniques for changing the quantization used in multiple generations of selected complexity of data quantization such that the errors incurred in subsequent generations are substantially the same as the error incurred in a generation given the same complexity of data. To this end, in a preferred embodiment, quantizing factors are selected from a preselected finite non-degenerative set of quantizing factors provided in the form of arrays of a periodic series of individual quantizer values, wherein a special numerical relationship is maintained between corresponding quantizer values in successive arrays. A different quantizing factor may be selected for each generation of compression/decompression as required by changing data complexity as when performing a layering process during the generations. In another embodiment, an over-quantizing factor is chosen large enough to compress the data to a greater extent than that required in the first generation, such that sufficient compression still is provided in subsequent generations even though the same quantizing factor is used while the complexity of the data is being changed. Adjunct features include the determination of an unknown quantizing factor applied in a previous generation, and a dither rounding process to compensate for an increase in noise due to changing a quantizing factor in the embodiment which uses the over-quantizing factor.

Method and apparatus for determining a quantizing factor for

A system to improve image quality during shuttling of a video tape in a record and playback machine of the type in which each image field is recorded on one or more tracks on video tape. The system includes an offset signal source coupled to a displaceable mechanism during shuttling to provide relative displacement between a reproduce transducer and a video tape to cause the transducer to cross tracks of recorded information irregularly, thereby providing frequent updating of substantially all regions of an image field by information stored on the tape.

System and method to improve picture quality during shuttling of video

A reference track is recorded in a longitudinal direction on a recording medium. During recording of an information signal along parallel tracks on the medium a deviation of the reference track in a transverse direction from its nominal position with respect to the medium transport is detected by one or more sensor heads mounted in a fixed relationship with respect to the medium transport. A positionably mounted data head is moved in transverse direction in accordance with the sense and magnitude of the detected deviation, thereby maintaining the data head in a known geometric relationship with the reference track during the recording process. During playback the same reference track may be utilized to follow the thusly recorded parallel tracks.

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Los Altos, CA, United States of America

John P Watney