#187 Open ranges

[Christian Haas]

Ranges may have an open start time (e.g.: "npt=-40") that refer to the current play/pause position to be used as start.
(A sidenote: The ABNFs of the ranges don't have the first time optional)

Ranges may also be open ended (e.g.: "npt=0-") requesting to play until the end, whenever that is.

As a result, a 'fully' open range could be valid as well (e.g.: "npt=-"), meaning "Play from wherever the position is now until the end of the presentation, whenever that is".
Thinking further, would then there be a difference between "npt=-" and "npt=now-"? As a result, the "now" constant could be dropped.

[Magnus Westerlund]

Sent email to list proposing no change:

First, the current ABNF says the following:

ranges-spec = npt-range / utc-range / smpte-range
/ range-ext
smpte-range = smpte-type "=" smpte-range-spec
; See section 3.4
smpte-range-spec = ( smpte-time "-" [ smpte-time ] )
/ ( "-" smpte-time )

npt-range = "npt=" npt-range-spec
npt-range-spec = ( npt-time "-" [ npt-time ] ) / ( "-" npt-time )

utc-range = "clock=" utc-range-spec
utc-range-spec = ( utc-time "-" [ utc-time ] ) / ( "-" utc-time )

Which allows either: either value-, value-value or -value. It does not
allow just -.

I would also like to point out that there is a difference between now
and no value. No value reference the current pause-point. While now is
the currently ongoing time. In a time-progressing session with recording
(retention for some or full time) the pause point may be 2 min into the
session while now could be 1 hour into the session.

So in my mind - would mean from pause point until end. But that is
equivalent to no Range header. So we already have that functionality.

I would propose no change as a resolution.

[Magnus Westerlund]

A clarification about the usage of lists and implicit range values was added.