Add provides property to Using Caption and Subtitle Files with Video Content recipe

[elynema]

Recipe info:

• Name: Using Caption and Subtitle Files with Video Content
• link: https://iiif.io/api/cookbook/recipe/0219-using-caption-file/

Correction request

With the proposed new provides property, we'd like to add provides:openCaptions to the annotation containing the caption to demonstrate its use to the AV community.

In addition, this recipe uses the language 'caption' and 'subtitle' interchangeably. We'd prefer if this recipe just refers to captions, as subtitles should be identified separately from captions. Captions can still be made available as .srt files.

Comments from the AV Annotations TSG.