[BUG] Caption synchronization for multi-sourced Canvas

[Dananji]

Description

The IA Manifest is a single Canvas Manifest with multiple items in the same Canvas.

This particular IA Manifest has a supplementing annotation that is displayed as a captions file in the player. The cues are created with time-stamps relative to the entire duration of the Canvas, where they are time-stamped in the range 00:02 -> 13:02.
When each source is loaded into the player the cues from the time range 00:00 -> 01:00 in the VTT are repeated since VideoJS is not aware of the relative timestamp of the current source in the Canvas. This leads to the repetition of the same set of cues in this particular time range because each source segment in the Canvas is exactly 60 seconds.

Done Looks Like

• Investigate how VideoJS handle cue synchronization with media playback
• Display the correct cues for the current time of the player during playback and scrubbing

[joncameron]

Timeboxed investigation; can add points as needed for implementation or create a new issue for putting a fix in place.