ISO/IEC 20071-23 (2018-09)

ISO/IEC 20071-23:2018 This document provides guidance for producers, exhibitors, and distributors on the visual presentation of alternatives to audio information in audiovisual content, such as captions/subtitles.
This document provides requirements and recommendations that are intended to support users who are not able to use the audio information, prefer to use a visual representation of audio information, or prefer both audio and visual presentations.
NOTE Many users do not have a choice, for instance, when in a noisy environment (e.g. bar, restaurant, etc.). In these situations, the user does not select a visual presentation of audio information but is offered the content with captions/subtitles.
This document acknowledges the various needs and preferences of viewers (end users) as well as the different approaches to visual presentation of audio information. It applies to all presentations of visual alternatives to audio information intended to be presented as captions/subtitles.
This document does not apply to the presentation devices or transmission mechanisms used to deliver the content or visual presentations of audio information. These devices could include, but are not limited to: televisions, computers, wireless devices, projection equipment, DVD and home cinema equipment, video game consoles, and other forms of user interfaces technology. This document does not apply to transcoding files and formats for the various video outputs.
This document gives guidance on visual presentations which are delivered in the same language as in the audio (i.e., intra-lingual captions/subtitles) and visual presentations which are translated into a different language (i.e., inter-lingual captions/subtitles). This document does not apply to the specific process of language translation.
This document helps to improve accessibility. This document does not establish requirements on specific industries (e.g. television broadcasting, motion pictures) nor is it intended to supersede specific international standards within their domain.