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Exploration of an opera soundtrack use-case for #1070

We want to describe an opera recording and to provide the following navigation:

  • A Very Short Opera
    • Act 1
      • Famous Aria
    • Act 2

Over a soundtrack that is divided into sections:

  • t=0,100 - Overture
  • t=100,1000 - Act 1
  • t=500,600 - Famous Aria
  • t=1000,2000 - Act 2

Where the desired behaviours are:

  • Selecting "A Very Short Opera" in navigation will play the whole opera including the overture (sub-sections may highlighted at appropriate points).
  • Selecting "Act 1" or "Act 2" in navigation will play the entirity of that act.
  • Selecting "Famous Aria" will play just that aria within act 1.

For the sake of simplicity, the entire soundtrack for this opera is one canvas with a duration of 2000s. There would be no significant changes in structure if it were split over more than one canvas.

Extents derived from hierarchy of parts

  • members is used to indicate the list of parts within a struture. The extent is the concatenation of the members. It is expected that a viewer would be smart enough to stitch together contiguous members, but out-of-order arrangements (e.g. [ { #t=1,2 }, { #t=0,1 }, { #t=2,3} ]) are allowed.
  • viewingHint of no-nav is used to indicate portions that should not appear in the navigation hierarchy (re-use of none is tempting be has potential conflict with use to control rendering of content)

Example Manifest

Extents embedded and nested, Ranges nav, Canvases no-nav

  • members indicates list of parts.
  • Ranges are always in the navigation
  • Canvases can be members along with Ranges, and provide extent
  • viewingHint possible, but so far unnecessary

Example Manifest

Extents specified separately from hierarchy

  • extents is used to provide the list of parts within a struture.
  • members is used to provide the list of navigation components within a structure. The content of the members SHOULD be included with the extents. Would need to define expected behavior if this is not the case (error or whether it is OK for viewer to play part that does not include the sub-parts).

Example Manifest