What is Macrovision?
Macrovision is the name of a company which manufactures copy-protection systems. The name "Macrovision" is commonly used to refer to the product which is officially called "Macrovision Video Copy Protection".
The original Macrovision copy protection system was developed for VHS and has been expanded to include DVD, VOD (video on demand), PPV (pay per view) and other formats.
How Does Macrovision Work?
Macrovision uses two main techniques to prevent copying (i.e. playing from one machine while recording on another):
- Vertical Blanking Signal
Macrovision inserts Pseudo-Sync Pulses (PSPs) into the vertical blanking signal. This confuses the automatic gain control (AGC) circuitry used by most video recorders. The result is picture tearing, video noise, loss of brightness and colour.
Macrovision creates a rapidly modulated colorburst signal. This confuses the chroma processing circuitry used in NTSC video recorders. The result is a picture spoiled by horizontal stripes or other unwanted effects.
Either or both of these techniques can be used - it is up to the content producer.