Publications that are both full audio and synchronized audio/text

[HadrienGardeur]

Looking at the technique for displaying metadata for pre-recorded audio in EPUB I noticed that it's not currently possible to combine "Audio only" and "Synchronized audio and text".

While it's true that some EPUB publications with Media Overlay only provide pre-recorded audio for some resources, there are a number of publications that also provide synchronized pre-recorded audio and text over the entire publication.

I think that we should re-consider instructions for this technique to check for the case where accessModeSufficient contains auditory on its own AND accessibilityFeature contains synchronizedAudioText (a typo for this value is repeated multiple times throughout the current draft).

The same technique for ONIX covers this use case with its third step:

ELSE IF all_content_pre_recorded AND synchronised_pre_recorded_audio:
THEN display "Synchronized audio and text".