Macrovision is a company that creates copy protection mechanisms. A variety of tools have been created to override the Macrovision systems used in VHS video tapes. It is important to familiarise yourself with the law in this area before proceeding.
In most jurisdictions, including in the United States, it is illegal to override copy protection mechanisms for the purpose of making unauthorised copies of material. There are exceptions to this rule for "fair use" materials and authorised copies.
Colorstripe is one of two ways Macrovision enables copy protection. Colorstripe creates a colorburst signal that can be nullified by using a component output that does not support it.
Automatic gain control (AGC) was also used under the Macrovision system. AGC used pulses in the blanking signal to confuse synchronisation circuitry. A number of off-the-shelf hardware devices are available that nullify this signal when passed from a VCR to a DVD recorder. This can also be done with software if a computer is present in the line between the VCR and the DVD.