feat: support MPD.Location

[gkatsev]

Depends on videojs/mpd-parser#102
With it, I can see that we properly update the srcUrl internally based on the location, for example with a stream like https://livesim.dashif.org/livesim/startrel_-20/stoprel_20/timeoffset_0/testpic_2s/Manifest.mpd

TODO

• Add some tests
• Make sure that a more streams with Location that don't also do a 302 redirect on the main manifest function properly
• update mpd-parser

[gkatsev]

Are we supposed to use Location as the new baseUrl as well, if a baseUrl isn't provided?
At the very least I think with the above stream and https://livesim.dashif.org/livesim/startrel_-60/stoprel_-20/timeoffset_0/testpic_2s/Manifest.mpd, we need to update the baseUrl based on the 302 redirect.

[gkatsev]

Seems like handleManifestRedirect seems to make those streams work without requiring this change, so, we'll want to get another stream to test that we actually make subsequent requests appropriately.

[gkatsev]

OK, I've confirmed this does the right thing and requests the updates from the MPD.Location. I did so by grabbing https://livesim.dashif.org/livesim/startrel_-60/stoprel_-20/timeoffset_0/testpic_2s/Manifest.mpd locally, adding an MPD.BaseURL with the same url as MPD.Location. I also added a minimumUpdatePeriod so that we request updates to the manifest. I can confirm that when MPD.Location is present, it'll make requests there instead of localhost.

[gkatsev]

Tests will start passing once mpd-parser is updated and released.

[gesinger]

Can also update https://github.com/videojs/http-streaming/blob/main/docs/supported-features.md#dash-missing-features 👍

[brandonocasey]

should this just be !this.master.locations || !this.master.locations.length

[gkatsev]

Let me check. I thought I tried this and it was showing an error but I may have tried it with &&?

[gkatsev]

yeah, I think I had && locally. with || seems to work.