Secondary Audio Program

What Does Secondary Audio Program Mean?

Secondary Audio Program (SAP) is an auxiliary audio channel alternative to standard television (TV) stations or programs. SAP is transmitted via sub video carriers (for example, color TV) vs. audio carriers like FM radio. SAP is accessible via wireless, TV, videocassette recorder (VCR) or portable receiver.


Most TVs and VCRs manufactured after 1995 are SAP-enabled.

Techopedia Explains Secondary Audio Program

In 1984, the National Television System Committee (NTSC) incorporated SAP as part of its multichannel television sound (MTS) specification. NTSC and MTS specifications are applied in Canada, the United States, Mexico, Chile, Brazil, Argentina, the Philippines and Taiwan.

As of June 2009, the United States only uses MTS in analog TV because of the digital transition.

The following are SAP application examples:

  • (US) Public Broadcasting Service (PBS)
  • (US) Student radio stations: Used with limited FM signals
  • Canada’s Cable Public Affairs Channel (CPAC): Applies SAP in English and French

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