Hideki Ohtaka

A Study On Trick Plays For Digital VCR

Approaches to improving the picture quality in high speed play while keeping sufficient picture quality in normal play are described. According to the approaches considered, variable length coding is controlled to be completed within a synchronized block. Each compression block is constructed of DCT (discrete cosine transform) blocks, which separate each other on the screen. The DCT blocks which are in the adjacent synchronized block on the tape are in the adjacent position on the screen. Lower-frequency components are located in the first half of the synchronized block. Computer simulation concerning an evaluation of reproduced picture quality in high-speed play showed that the best method of coding for high-speed play is to form a compression block with DCT blocks adjacent on the screen. >

Digital Video Signal Processing in Home VTRs

Considerable attention has been given to digital signal processing technology to replace analog video signal processing circuits with digital circuits in home VTRs of VHS. Beta or other format[1]. Inherent capabilities of digital signal processing including (1) improvement in picture quality, (2) ease of providing multiple functions, (3) improvement in performances, and (4) considerable reduction both in component count of outboard analog devices and in the number of factory adjusted components, are becoming more and more realistic thanks to rapid advancement in semiconductor technology. On-chip digital signal processing is quite promising not only in reliability but also in economy in the long run.