Re: [tvcontrol-api] Why retrieve a list of tuners instead of just one tuner?

That seems like a very good starting point for the terminology section
 of the spec, @stevem-tw :)

One comment about the `TVMediaStream` definition: it seems to imply 
that `TVMediaStream` are attached to `TVChannel`. That's what I 
proposed initially at TPAC, but we also discussed the possibility to 
reuse the same stream across channels, which seems possible, similar 
to the way `getUserMedia` operates, and also aligned with how a WebRTC
 peer "sees" an incoming media stream: even if the stream changes, 
e.g. because the user switched to another camera, I think the peer 
still receives the same stream.

In this vision, a `TVSource` would produce a `TVMediaStream` that can 
be further "constrained" afterwards (typically by allowing to switch 
to another channel). A `TVMediaStream` represents "the stream data for
 all components within a channel" but may also represent the stream 
data of another channel later on.

This also seems to be the approach the TAG suggests in issue #20 as 
well (the TAG's comment uses `TVTuner` but I think that's only because
 it is the main entry point right now).

One thing that makes this a bit more complex is that a `TVSource` can 
produce more than one `TVMediaStream` in some cases. This is where 
some of notion of `TVTuner`, defined as a `TVMediaStream` **wrapper 
and controller**,  could perhaps be useful, although it may not be 
really needed in practice. Now, that probably matches "the end to end 
decoder chain" that you allude to, so I may just be paraphrasing your 
comment here ;)

One of the arguments mentioned at TPAC in favor of keeping a `TVTuner`
 class was to provide an extension point to the API. I feel that this 
can be achieved in the definition of capabilities and constraints 
associated with a `TVSource` though.

All in all, I guess I would start the source-centric design 
**without** the `TVTuner` interface... and only re-introduce it if 
design looks clumsy, if things break or if requirements cannot be 
satisfied.

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Received on Wednesday, 9 November 2016 17:06:56 UTC