[FFmpeg-devel] [PATCH] write AC-3 metadata

[Kieran Kunhya]

> clean effects ? This field indicates that the referenced
> program element has no language.
> hearing impaired ? This field indicates that the
> referenced program element is prepared for the hearing
> impaired.
> visual_impaired_commentary ? This field indicates that the
> referenced program element is prepared for the visually
> impaired viewer.
> [...]

For what it's worth, I've never seen anyone use anything other
than "undefined" for that field in MPEG-2 systems. Visual Impaired
commentary uses the country code "NAR" over here in the UK.

AC-3 metadata can be placed in AAC through "Dolby Pulse" but we
don't have any samples to see how that's done.