analog protection system (copy protection) (APS)

The Analog Protection System(APS) developed by Macrovision impairs the copying of video tapes to DVDs.

In the analog APS process, the synchronization pulse of the video signal is altered by mixing in interference signals, so-called trigger bits, in such a way that image synchronization and line synchronization are no longer possible and the dubbed video cannot be viewed. These additional signals interfere with picture synchronization and automatic recording control. Copy protection is activated via a header in the sector and can include parts of the stored video recordings.

InDVD players, the trigger bits are generated during DVD authoring to inform the APS system that it can display analog video signals from DVD players or from personalcomputers during playback.

In set-top boxes, the APS signal is inserted into the Entitlement Control Message( ECM) in the data stream of the set-top box.