Secondary Audio Program

What does Secondary Audio Program mean?

A Secondary Audio Program (SAP) is an additional audio channel that can be broadcasted simultaneously with the primary audio channel. It provides viewers with an alternative audio option, typically featuring a different language, audio description for the visually impaired, or an alternative soundtrack. SAP is used in television, radio, and streaming services to accommodate diverse audiences and enhance accessibility.

SAP is transmitted using a separate Audio Codec, allowing it to be played independently of the primary audio channel. This enables viewers to seamlessly switch between the two audio options without interrupting their viewing experience. The SAP audio is typically identified through an on-screen indicator or through a dedicated button on the remote control.

Applications

Secondary Audio Programs serve various essential applications in modern technology:

• Multilingual Broadcasting: SAP allows broadcasters to offer multiple audio channels in different languages, accommodating a diverse viewer base. This is particularly important in regions with multiple spoken languages, ensuring that all viewers have access to media content in their preferred language.

• Audio Description for the Visually Impaired: SAP can carry audio descriptions that provide detailed narration of the visual elements of a program. This Assistive Technology enables visually impaired viewers to enjoy television shows, movies, and other media by understanding the on-screen actions and scenes.

• Alternative Soundtracks: SAP can offer alternative soundtracks for a program, such as background music or isolated sound effects. This option allows viewers to tailor their audio experience to their preferences or explore different perspectives on the content.

History

The development of Secondary Audio Programs can be traced back to the early days of television broadcasting:

• 1950s: Early television sets included a “mux” switch that allowed viewers to choose between two audio channels. However, these channels were typically used for transmitting a monophonic Signal and a stereo signal rather than for providing separate audio programs.

• 1970s: The introduction of cable television created a demand for more audio channels to accommodate the increasing number of programming options. SAP was developed as a way to transmit an additional audio channel alongside the primary channel, without requiring a separate audio carrier.

• 1980s and 1990s: SAP became widely adopted in television broadcasting, particularly for multilingual programming and audio description services.

• 2000s and beyond: SAP has continued to evolve with the advent of digital broadcasting and streaming services. It is now an essential feature in modern multimedia systems, providing viewers with more flexibility and accessibility in their audio listening experience.