The videocassette recorder, VCR, or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other source on a removable, magnetic tape videocassette, and can play back the recording.
Use of a VCR to record a television program to play back at a more convenient time is commonly referred to as timeshifting.
VCRs can also play back prerecorded tapes. In the 1980s and 1990s, until the VCR was superseded by the DVD player and PVR, prerecorded videotapes were widely available for purchase and rental, and blank tapes were sold to make recordings.
Most domestic VCRs are equipped with a television broadcast receiver (tuner) for TV reception, and a programmable clock (timer) for unattended recording of a television channel from a start time to an end time specified by the user.
These features began as simple mechanical counter-based single-event timers, but were later replaced by more flexible multiple-event digital clock timers.
In later models the multiple timer events could be programmed through a menu interface displayed on the playback TV screen ("on-screen display" or OSD).
This feature allowed several programs to be recorded at different times without further user intervention, and became a major selling point.
One of the problems faced with the use of video recorders was especially the exchange of recordings between PAL and NTSC countries. Multi Standard video recorders and TV sets gradually overcame these incompatibility problems.
Stereo Sound and HiFi
The U-matic machines were always made with Stereo, and Beta and VHS started out splitting the audio track on the tape, but the slow tape speed of Beta and VHS limited the sound quality. This led to the introduction of HiFi, whose left and right sound tracks were modulated as FM on the video portion of the tape. The 8 mm format always used the video portion of the tape for sound, with an FM carrier between the band space of the chrominance and luminance on the tape. 8 mm could be upgraded to Stereo, by adding an extra FM signal for Stereo difference.
Introduced in 1983, Macrovision is a system that reduces the quality of recordings made from commercial video tapes, DVDs and pay-per-view broadcasts by adding random peaks of luminance to the video signal during vertical blanking. These confuse the automatic level adjustment of the recording VCR which causes the brightness of the picture to constantly change, rendering the recording unwatchable.
When creating a copy-protected videocassette, the Macrovision-distorted signal is stored on the tape itself by special recording equipment. By contrast, on DVDs there is just a marker asking the player to produce such a distortion during playback. All standard DVD players include this protection and obey the marker, though unofficially many models can be modified or adjusted to disable it.
Also, the Macrovision protection system may fail to work on older VCR's made before 1986 and some high end decks built afterwards, usually due to the lack of an AGC system. Newer VHS and S-VHS machines (and DVD recorders) are susceptible to this signal; generally, machines of other tape formats are unaffected, such as all 3 Betamax variants. VCRs designated for "professional" usage typically have an adjustable AGC system, a specific "Macrovision removing" circuit, or Time Base Corrector (TBC) and can thus copy protected tapes with or without preserving the protection. Such VCRs are usually overpriced and sold exclusively to certified professionals (linear editing using the 9-Pin Protocol, TV stations etc.) via controlled distribution channels in order to prevent their being used by the general public (however, said professional VCRs can be purchased reasonably by consumers on the second-hand/used market, depending on the VCR's condition). Nowadays, most DVDs still have copyright protection, but certain DVDs do not have it, usually pornography and bootlegs. However, some DVDs, such as certain DVD sets, do not have the protection against VHS copying, possibly due to the VHS format no longer used as a major retail medium for home video.
Flying erase heads
The flying erase head is a feature that may be found in some high end home VCRs as well as some broadcast grade VCRs to cleanly edit the video.
Normally, the tape is passed longitudinally through two fixed erase heads, one located just before the tape moves to the video head drum and the other right next to the audio/control head stack. Upon recording, the erase heads erase any old recording contained on the tape to prevent anything already recorded on it from interfering with what is being recorded.
However, when trying to edit footage deck to deck, portions of the old recording's video may be between the erase head and video recording heads. This results in a faint rainbow-like noise at and briefly after the point of the cut as the old video recording missed by the fixed erase head is never completely erased as the new recording is printed.
The flying erase head is so-called because an erase head is mounted on the video head drum and rotates around in the same manner as the video heads. In the record mode, the erase head is active and erases the video precisely down to the recorded video fields. The flying erase head runs over the tape and the video heads record the signal virtually instantly after the flying erase head has passed.
Since the erase head erases the old signal right before the video heads write onto the tape, there is no remnant of the old signal to cause visible distortion at and after the moment a cut is made, resulting in a clean edit. In addition, the ability of flying erase heads to erase old video off the tape right before recording new video on it allows the ability to perform insert editing, where new footage can be placed within an existing recording with clean cuts at the beginning and end of the edit.