Video tape, that perennial entry in the home-entertainment equipment sweepstakes that has always been left at the starting gate, is on the scene again - with no less than four different systems. All use one-half-inch helical-scan tape housed in cartridges (called video cassettes). They are being promoted for their ability to record from your TV set as well as "live" from an optional camera.

Operation is relatively simple via piano-type transport keys. The recorder connects to the TV sets antenna terminals. Some have built-in timers (others can be fitted with optional timers) that let the owner record while away or asleep, and most also have built-in TV tuners (VHP and UHF) so that owner can tape one program while watching another. Beyond these general similarities, the four systems are naturally incompatible, except for a limited compatibility among some models that remains undefined by the industry.

The color picture horizontal scan ranges from 220 to 240 lines, which is well below the NTSC standard of 525 lines (although it is a fine question as to how many commercial TV receivers actually do provide the full 525-line scan). Sound of the new video recorders is characterized by at least one trade publication as "passable" (which can be taken as a euphemism for not much different than what you hear from an average TV set).

The four systems include Sony's Beta, listing for $1,300: the VHS models from Japan-Victor; the Quasar developed by Matsushita; and the V-Cord from Sanyo. List price for most models is $1,300; the Quasar model VX-2000 lists for $995. Trade sources report that some dealers are offering any model for just under $1,000, and some optimists allow that between $750 and $800 will be the eventual retail price for any home VTR. Camera costs range from $260-$400 for black-and-white do-it-yourself video taping, to $1,500 for color cameras.

Tape cartridge prices start at about $17 for a two-hour length and go up to about $25 for the four-hour cartridge used in the VHS systems.

Prerecorded video cassettes, mostly containing movies, also have been announced for the Beta and VHS machines. Prices range from $70 for two-hour lengths to upward of $70 for longer programs. There even is word that X-rated films can be bought for the VTR format, costing a bit over $100 in lengths up to 100 minutes.

In video discs there is nothing new happening of any great significance. it is generally agreed that if and when they are produced in any quantity, a video disc player would cost perhaps $200 to $300 less than a video tape machine, but such a device could play only - it would lack the record capability.

All told, it appears that video tape is somewhat closer to reality as a high-ticket consumer item, but many of those interested in this medium would still prefer greater compatibility or uniformity among the various systems, improved audio and video performance, and of course lower prices.