search

Dash-Industry-Forum / Guidelines-TimingModel

DASH-IF implementation guidelines: the DASH timing model
9 stars 1 forks source link

@availabilityTimeOffset - are different values per representation OK? #21

Closed sandersaares closed 4 years ago

sandersaares commented 5 years ago

Is it OK interoperability-wise to specify different @availabilityTimeOffset for representations in the same adaptation set? Do we expect interoperable players to successfully handle this?

There is currently nothing that contradicts this in the IOP but it is also not explicitly listed as a thing one might want to do, so I wonder what the interoperability implications are. Do existing players actually execute per-representation availability logic? It feels to me that perhaps this might not be the case.

If there is no obvious use case here, we might be better off defining some constraints. I request expert opinions.

haudiobe commented 5 years ago

IOP 19/01/29 Generally yes this is permitted, reasons are that you might a certain Representation only at the live edge, others stay in the buffer. This was primarily permitted for cases with Broadcast TV profile in MPEG-DASH.

In DASH-IF IOP we may restrict @availabilityTimeOffset to not be present on Representations. If no comments until next week, we go with this restriction.

sandersaares commented 4 years ago

OK, addressed by defining the above mentioned restriction.