The Recording System (Tape-Based Systems)

Recording Format

Recording onto the best format will assist in the preservation of image quality.

Frame Rate

The number of images recorded per second affects the fluency of motion upon playback. Standard video records 25 frames (images) per second.

Timelapse recorders and multiplex systems fit long periods of time and/or multiple onto one tape at the expense of fluency of motion/image updates.

Multiple Camera Systems

Multiscreen (most often quad screen)

Multiple cameras are broken into a multiscreen (often quadscreen) arranged and recorded so that all cameras are seen at one time. These systems are not recommended for recording, as the resolution of each image is greatly reduced (by at least a quarter). Any system that sacrifices resolution will greatly diminish the possibility of offender identification, as resolution is often the most important factor in identification of a suspect.

Switching

In switching systems, multiple cameras are constantly being switched so that only a short section (e.g. 5 seconds) from a single camera at a time is recorded. Whilst fluency and image resolution can be maintained when the selected camera is being recorded, an offender may appear on another camera that is not being recorded at all.

Multiplex

Multiplex systems use encoders to switch multiple cameras at very high speed into a jumbled image stream. This image stream is recorded to tape. Upon playback, the image stream is played through a decoder to isolate a single camera at a time for viewing. Some resolution and fluency is lost in the encoding process. Multiplex systems are recommended over multiscreen and switching camera systems.

Tape Maintenance

Do not reuse the tape an excessive number of times.

The magnetic surface that stores the images becomes worn away, resulting in unacceptable image quality. Most manufacturers state that the life expectancy for videotape is thirty (30) playback viewings and twelve (12) record passes.

Do not pause tapes.

Again, the magnetic surface is worn away. The very frame you're looking for can be irreversibly damaged.

Do not touch the tape surface.

Oils and dirt from fingertips can make replay impossible. Likewise, don't place any other foreign substance on the surface.

Do not replay the tape excessively

If an offence has been recorded, do not replay the tape excessively, as the recorded signal becomes further degraded upon each replay. Other faults may occur (such as tape jams) and inexperienced operators can accidentally erase recordings. Remove the record inhibit tabs and store the tape in a secure place for the police.

Do not attempt to repair tapes

Damaged tapes should not be reused. Folded or wrinkled tapes or tapes "repaired" with sticky tape are irreversibly damaged. If a damaged tape contains footage relevant to a police investigation, store the tape and police will assist with the repair and retrieval of relevant footage. Further, if the tape is jammed inside a machine, do not attempt to remove it - police will assist.

System Maintenance

All surveillance systems require regular maintenance. Regular cleaning of the video heads and checks to ensure the machine is recording correctly are vital.

Logging of Tapes

At a minimum, your log should include starting and finishing times and the date of recording. An up to date and accurate log aids the identification of the correct tape when an offence has occurred.

Time and Date Recording

Recording the time and date onscreen as part of the picture information assists in the location of offences and examination of offender movements, however, care should be taken that the onscreen time and date do not interfere with the image content. The time and date should be located in the least crucial area of the image (e.g. close to the roof, close to the floor). If the time and date cannot be recorded on your system, it is suggested that a clock on the wall is situated in the target area.