DIGITAL CAMCORDERS AND VCRS
Like DTV broadcasting, digital video recording only became possible with the introduction of a practical data-compression system and mass-produced LSI processing and memory chips. The mechanics of DVC recorders have much in common with the decks described in the previous chapter of this book (especially Video 8 types), and the electronics and data-processing sections are akin to those dealt with in Chapter 12, ‘Digital TV’.
DVC FORMAT
DVC stands for Digital Video Cassette, a format agreed between 56 electronic equipment companies as a uniform digital standard for consumer video. DVC embraces different cassette sizes and formats: the standard DV cassette can run for 270 minutes and the mini-DV cassette for 60 minutes in SP mode, offering about 500 lines resolu- tion in a standard 625-line 50-field picture. The format also includes HD (high-definition) standards.
DVC has many advantages over analogue tape recording formats. It offers higher picture resolution, with an almost-complete absence of colour blur; a higher-quality and more versatile sound system; loss- less copying and editing using the IEE 1394 Firewire data transfer system; the facility to dub sound or vision onto previously made recordings; stable, jitter-free signal reproduction; the facility to record auxiliary and subcode data for (e.g.) quick, accurate access to individual frames and programme segments; and a very high informa- tion density in a small tape package. Table 19.1 compares DV format with analogue ones, while Fig. 19.1 shows dimensional tape, drum and cassette comparisons between the formats.