Alternative "audio only" version
This term is defined by more than one standard, and the wording differs. Each definition below is the one that applies to that standard’s criteria.
Definition in RAWeb 1.1
An "audio only" version is an audio version, in the form of a simple file in MP3 format for example, used as an alternative to a video only (video without audio information). As the only users affected by accessibility are blind people, who cannot see the video, WCAG considers it acceptable to offer an audio version as an alternative.
The "audio only" version must contain all the important visual information in the video.
It is generally easier to produce an audio version than a text version when the video is very descriptive (transcript often requires a great deal of editorial work). It should be remembered, however, that only a transcript provides universal access to the information in the video, in the event that a user is unable to launch the video, for example.
Definition in RAAM 1.1
An "audio only" version is an audio version, in the form of a simple file in MP3 format for example, used as an alternative to a video only (video without audio information). The only users affected by accessibility are blind people, who cannot see the video.
The "audio only" version must contain all the important visual information in the video.
Generally speaking, it is easier to produce an audio version than a text version when the video is highly descriptive (text transcription often requires a great deal of editorial work). It should be remembered, however, that only a text transcript provides universal access to the information in the video, in the event that a user is unable to launch the video, for example.