Ensuring the Integrity of Recorded Video – Maximizing the effectiveness of higher density recording technology
Triple density recorders are high performance products. Just like high performance automobiles – they require high-octane fuel and frequent tune-ups to operate at peak efficiency. The use of high quality video cassettes and regular maintenance will significantly enhance the useful life and functionality of these recorders.
As an industry leader in electronic security and a pioneer in time lapse video recording, Gyyr has consistently set the standard for high performance and superior customer satisfaction. Because of Gyyr’s reputation for superior performance and reliability, our time lapse video cassette recorders (TLC series) have found their way into a wide variety of demanding, mission critical surveillance environments from retail and commercial applications through government and high security installations. Industrial VCRs used in critical surveillance environments may be exposed to harsh environments and high duty cycles. As with any high performance products, proper operation and regular maintenance can significantly increase the useful life of the equipment and provide many years of trouble free performance.
Triple density recorders deserve special care by the very nature of their design. Triple density recording is exactly that, three times the video data stored in the space reserved for a single field of data in standard play VHS format. Naturally this creates an understandable tradeoff. The video signal recorded to tape in triple, or high-density mode, results in a superior number of images per second, but at a lower signal level. Also, the area allocated for each recorded image is narrower, so tracking becomes more of a challenge. This is inherent in the design of various models of all high-density type recorders regardless of the brand or manufacturer.
As a result of recent accelerated life testing at the Gyyr factory, as well as additional input from our customers, we launched a study. We have performed extensive testing with time lapse recorders from multiple vendors. We have found that various models exhibit tape oxide deposits on the head drum assembly after multiple passes on a tape including forward/reverse play. Because of the lower signal level recorded on high density VCRs, they are more susceptible to possible degradation of video due to a contaminated head drum.
Based on our analysis, Gyyr strongly recommends changes in both the operation and periodic maintenance of time lapse VCRs. A contributing factor to head drum contamination is excessive use of tapes or use of tapes that are not recommended. To reduce the amount of oxide accumulation on the drum, Gyyr recommends decreasing the time between head cleanings to 750 hours — or once a month. Gyyr further recommends the use of high quality video cassettes and limiting the number of repeat passes per tape, especially when utilizing repeated forward-reverse playback in reviewing evidence.
In summary, the most effective means to preserving the quality of recorded evidence are:
Methodical cleaning of video heads and head drum assemblies every 750 hours or once per month;
The use of high quality video cassettes;
Monitoring and limiting the number of repeat passes on each cassette.