ANSI SCTE 248:2018 pdf free download – Operational Practice on Multiple Audio Signaling
1.1. Executive Summary
Cable operators, many program networks, and local broadcast affiliates routinely support up to two audio streams for programs they distribute. The first audio stream contains the main or primary audio for the program, typically in English; the second audio stream contains the audio description or a second language (typically Spanish). However, this legacy two-stream model can conflict with the desire to offer additional languages, video description service (VDS), emergency information and other audio services simultaneously. Newer equipment, including set-top boxes, and IP delivered content can support this capability; advanced audio technologies, such as object-based audio, will allow the consumer more choice of what they hear. This document provides guidance and recommendations to cable operators and program providers on distributing multiple audio streams, languages and services while supporting legacy requirements.
1.1.1. Background
The technical capability to offer more than one audio service was born of a desire to provide stereo audio in analog television channels to consumers. The method chosen to do this also allowed for a lower bandwidth Second Audio Program (SAP) channel. The cable industry embraced this capability and began delivering a second language in analog channels via the SAP feature, part of the Multichannel Television Sound (MTS) standard developed by the National Television Systems Committee (NTSC). This method of delivering program audio in English as well as in a second language was carried forward and replicated in the digital delivery of video services provided today.
In 2011, pursuant to the Twenty-First Century Communications and Video Accessibility Act of 2010, (CVAA), the Federal Communications Commission (FCC) reinstated video description rules requiring MVPDs serving 50,000 or more subscribers to provide 50 hours of video-described prime time or children’s programming per calendar quarter on each of the top five non-broadcast networks – currently USA, TNT, TBS, History, and Disney Channel. In July 2017 the FCC increased the total number of required video-described hours by 75%, up to 87.5 hours per calendar quarter, as of the calendar quarter beginning July 1, 2018. 1 Also pursuant to the CVAA, in April 2013 the FCC adopted revised “emergency information” rules that make emergency information provided in non-news video programming accessible to individuals who are blind or visually impaired. Cable operators retransmitting emergency information audio, typically from broadcast stations, must pass through that audio in the secondary audio stream to customers. Emergency information audio supersedes all other programming on the secondary audio stream, including VDS and second language. The regulatory requirement to carry an increasing number of hours of video described programming, emergency information, and the business interest in supporting second language audio must now be considered when planning the delivery of audio service to customers.