Audiodescripción estándar o extendida

La audiodescripción, llamada en algunos países videodescripción, "consiste en la información sonora que se intercala en los huecos de mensaje en las producciones audiovisuales y que explica a las personas con discapacidad visual los aspectos más significativos de la imagen que no pueden percibir. Estos comentarios se refieren a la descripción de personajes (gestos, vestimenta, etc.), datos sobre el lugar donde suceden los hechos y acerca de la acción que se desarrolla en cada momento" (La Audiodescripción).

En Does your video need standard or extended description? se explica que existen dos tipos de audiodescripción, la estándar y la extendida:

• Estándar: Standard description is when the snippets of description are inserted into the natural pauses of the content being described. This type of audio description works very well for videos that have lengthy pauses in dialogue or that do not contain speech at all. The describer can add concise descriptions of the visual content where space allows. You will notice that the original video source plays continuously, and information is described in the pauses throughout.
• Extendida: Unlike standard audio description, extended description does not have to be constrained to the natural pauses of a video. Extended description allows you to pause the video content in order to make room for description, as needed. When you press play, the video and description begin playing. Then, the source video pauses temporarily, while the description continues. After that portion of the description is complete, the video resumes playing again. 

¿Cuándo es necesaria la audiodescripción?

As a general guideline, audio description should be used when there is critical information portrayed solely through visual means. For instance, on-screen text, changes in speaker, facial expressions, costumes, and scene changes all give context that help us better understand and enjoy content.