enable setPlaybackStartTime on live streams

[baconz]

It is nice to be able to set the playhead position on in-progress recordings, which use "live" manifests.

Interesting note:

We ran into this because we were setting the starting playback position by changing currentTime directly on the video node. Big, big, big mistake for in progress recordings! If we set the playhead too far into the past before beginPlayback gets called, the liveEdgeOffset gets very large, and users are unable to scrub into the future. It may be worth updating docs so that others don't run into this same trap.

[joeyparrish]

Hi @baconz,

This is definitely something we should support. Thanks for the pull request.

This may also have helped us identify the cause of #185, which we had not been able to reproduce previously.

We need one thing from you before we can accept this PR. Please read CONTRIBUTING.md for instructions on signing the contributor license agreement and adding yourself to AUTHORS and CONTRIBUTORS.

[baconz]

Sweet, thanks, Joey.

I added us into AUTHORS and CONTRIBUTORS. CLA should be forthcoming.

[joeyparrish]

Thanks, Seth. Just ping me here when the CLA is done.

[baconz]

Andrew signed it on Friday. It is associated with the philo-shaka google group, but I'm unable to "manage" it?

Let me know if I need to give this another shot.

[joeyparrish]

I don't see Philo on our list of corporate CLA signers yet. I'll do some digging internally and see if there is perhaps some kind of queue where new corp CLAs have to be approved by a human.

[baconz]

Ok, let me know if I should try initiating again.

[shaka-bot]

Testing in progress...

[shaka-bot]

All tests passed!

[joeyparrish]

Turns out I was simply not patient enough. I see your CLA now. Thanks for the contribution!