Data placement on tape for a digital video tape recorder suitable for high speed picture playback

摘要

A video tape includes a plurality of parallel slant tracks formed therein. Each track includes a plurality of successively recorded sync blocks. In each sync block, a respective portion of a first digital signal recorded therein represents a predetermined portion of an input image with relatively low resolution, and a respective portion of a second digital signal recorded therein represents substantially the same predetermined portion of the input image with relatively high resolution. Successive sync blocks include consecutive portions of the first digital signal, which portions correspond to spatially adjacent portions of the input image. Preferably, each sync block includes a fixed number of bits of the first digital signal, which is decodable without reference to any image coded signal from other sync blocks. The first digital signal codes the input images as raster scanned in reduced-resolution form for reproduction during a trickplay mode and the second digital signal comprises variable-bit-length codes permitting reproduction of the input images in full-resolution form during a normal-play mode. The second digital signal is not decodable unless there is reference to the portion of the first digital signal recorded in the same sync block, or portions of the second digital signal in other ones of the sync blocks, or to the portion of the first digital signal recorded in the same sync block and portions of the second digital signal in other ones of the sync blocks.