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

I've tried re-phrasing the definitions from up-thread to more 
accurately reflect the discussions around TVMediaStream from TPAC.  
I've left TVTuner out of this for now, because I don't think we're 
close enough to agreement on that at the moment.

- **TVSource**: a logical source of TV/Radio channels. This may 
represent a physical tuner or a "virtual" tuner for IP multicast. The 
TVSource exposes the list of TVChannel objects available through that 
source. For devices with more than one type of tuner (e.g. cable and 
terrestrial), each tuner type may be represented by a different 
TVSource. A TVSource is not a physical tuner - it is a way of 
discovering channels, getting the corresponding TVChannel objects and 
obtaining the resources to present them. Because there is not a 
one-to-one mapping between a TVSource and a tuner, more than one 
channel from a given TVSource may be presented at the same time if the
 device has enough resources.

- **TVChannel**: represents a single TV or radio channel and provides 
metadata about it. Each TVChannel object represents a single channel 
that is available through one TVSource. If the same channel (e.g. VH1)
 is available through two different sources (e.g. over cable and 
terrestrial) then each TVSource will return a different TVChannel 
object.

- **TVMediaStream**: represents the stream data for all components 
within a channel being presented. This can be passed to an HTML5 media
 element to play the channel. A TVMediaStream is obtained from a 
TVSource, and when a TVMediaStream object is created it means that all
 of the resources needed to receive and present that channel have been
 successfully allocated.  A TVMediaStream object may be re-used when 
selecting a different channel, to indicate that tuning and decoding 
resources currently used to present that TVMediaStream may be re-used 
for the new channel.

One thing that springs to mind is that in this model a TVMediaStream 
can also act as a representation of the set of resources needed to 
receive, decode and present the channel that it's currently being used
 for.  I'm not sure how or if we can use that information, but it's 
something that may prove useful so I thought I'd bring it to people's 
attention.

-- 
GitHub Notification of comment by stevem-tw
Please view or discuss this issue at 
https://github.com/w3c/tvcontrol-api/issues/4#issuecomment-259982530 
using your GitHub account

Received on Friday, 11 November 2016 15:32:07 UTC