Document fragment-based MSF URL structure

[wilaw]

Adds new section on MSF URL construction that is #fragment-based.

Example MSF URLs:

URl with a Webtransport connection pointing at a catalog track

https://example.com/server/config?a=1&b=2#customer-livestream-123--catalog

* Session: https://example.com/server/config?a=1&b=2

* Namespace: ('customer', 'livestream', '123')

* Track Name: 'catalog'

URL with a raw QUIC connection pointing at a catalog

moqt://example.com/relay-app/relayID#customerID-broadcastID--catalog

URL pointing at a non-catalog track

https://example.com/relay-app/relayID#customerID-broadcastID--video

URL pointing at a subclip of a catalog

https://example.com/relay-app/relayID?location-range=34-0-64-16#customerID-broadcastID--catalog

URL pointing at a catalog and supplying a token

https://example.com/relay-app/relayID?c4m=gqhkYWxnIGVzaGFyqGR0eXBNhdZ9hdWQAY3VybGZ

lbWlzcwZleWV2aW5uZWlhdGVwQWNyZW5lYnJmcmVqMTIzNDU2NzgwMHZpc3VlZF9hdD0xNzMwNDM#cust

omerID-broadcastID--catalog

Fixes: #60

[michalhosna]

Thanks, Will! This addresses a lot of my nitpicks from #72, sorry for them.
I do expect some MSF URL definitions may need additional work once the text on the URL handling exists.

[michalhosna]

For reasons mentioned before. I would still suggest a different scheme than HTTPS for the WT implementation.

(Suggestion, non-blocking, free-to-ignore)

[michalhosna]

Suggested change

	* location-range - a range defined by start and end media MOQT Location tuples and
	expressed as Start Group ID, Start Object ID, End Group ID, End Object ID, each
	separated by a "-" dash. The End Group ID and End Object ID MAY be omitted to
	indicate an open range in which the first two values are interpreted as
	StartGroupID-StartObjectID.
	* location-range - a range defined by start and end media MOQT Location
	separated by a "-" dash. MOQT Location is expressed as Group ID and Object ID
	separated by a "." dot. End Location may be omitted to indicate an open range.
	End Object ID may be ommited, indicating the whole end group is included in
	the range. The "." dot and "-" dash separators MUST be omitted when the second value is ommited.

I think separating 4 values of different types with the same character with the possibility of omitting some is confusing. I would fear that StartGroupID-StartObjectID may be easily confused for a case of StartGroupID-EndGroupID. Which I think also makes sense to support. Or at least support not sending the end object ID.

[michalhosna]

Suggested change

	* location-range=34-0-2145-16
	* location-range=16-24
	* location-range=34.0-2145.16
	* location-range=16.24

If https://github.com/moq-wg/msf/pull/87/changes#r2700596913 is accepted

[michalhosna]

Is there a reason to not at least note that this is following MOQT formatting recommendations?

[michalhosna]

Suggested change

	start-loc = group-id "-" object-id
	end-loc = group-id "-" object-id
	start-loc = group-id "." object-id
	end-loc = group-id [ "." object-id ]

Maybe also making Start object id optional with default value of 0 makes sense?

[suhasHere]

For my own understanding, any reason why we moved away from query parameter. Fragments have its own shortcomings.

[mondain]

Idea for fragment parameters #117