Initial addition results with duplicates:
sd 0, Ambient viewing environment
sd 1, Content light level metadata: MaxCLL: 1
sd 2, Content light level metadata: MaxCLL: 2
sd 3, Content light level metadata: MaxCLL: 3
sd 4, Spherical Mapping
sd 5, Content light level metadata: MaxCLL: 4
sd 6, Content light level metadata: MaxCLL: 5
sd 7, Content light level metadata: MaxCLL: 6

Final state after a single 'no-duplicates' addition:
sd 0, Ambient viewing environment
sd 1, Spherical Mapping
sd 2, Content light level metadata: MaxCLL: 1337