Method and apparatus for increasing the recording time of a digital video tape recorder

摘要

Method for increasing the recording time of a digital video tape recorder ("VTR") and for supporting multiple normal play modes of digital VTR operation, e.g., a standard play mode of operation and one or more long play modes of operation. To achieve long play mode operation data reduction is performed on a received full rate video data stream to generate a reduced rate video data stream. Data reduction is performed using data prioritization and selection, requantization of full rate data stream, and/or by selecting data to be included in the reduced rate data stream as a function of what portion of a video frame the data represents. The reduced rate data stream is generated to be compliant with the data format of the full rate data stream. During long play mode recording operation the data in the reduced rate data stream is recorded on a tape at the same tape data density as used during standard mode VTR operation. In accordance with each of the recording methods of the present invention the rotational rate of the digital VTRs headwheel is the same for both standard and long play modes of VTR operation. In addition, the present invention is directed to several methods of reading data from a tape at a reduced data rate.