Transition Support

[vade]

There's only one official transition in OTIO right now, and thats

SMPTE_Dissolve

Some notes about transitions in OTIO vs AVFoundation:

1. A transition is part of a track, so only involves 'adjacent media'
2. A OTIO transition can actually extend head or tail of a clip in a tracks time. ie, it can add a few frames via the in_offset and out_offset properties. This means that the actual track time from AVFoundations perspective, will require 2 logical Composition Tracks, and have all of the time of the asset of the transition + clip time.

[vade]

See visibleRange vs rangeInParent

[vade]

visibleRange is not in parent time, so this will need to be tended to.

[vade]

Also - how might we go from a composition with layer instructions to a OTIO Transition ? Is there a way to tell from OTIO that a layer instruction is a transition?