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[apis] Cross-review of HNReq document and current list of use cases

From: Olivier Thereaux <Olivier.Thereaux@bbc.co.uk>
Date: Thu, 4 Jul 2013 16:23:15 +0000
To: "public-web-and-tv@w3.org IG" <public-web-and-tv@w3.org>
Message-ID: <8EC4928E-1CE2-4A40-8483-8FCEE63DA064@bbc.co.uk>
Hello,

At the most recent teleconference of the Media APIs task force, we agreed to review our proposed use cases in light of the existing work of the (now closed) Home Network Task Force. In particular, we all committed to review the list of use cases and requirements published at http://www.w3.org/TR/hnreq/ (abbreviated in this message as HNReq).

I would like to start this discussion with the following review.

Let me stress that it is a *strawman* review, meant to elicit a conversation. My interpretation of the matches between the various documents and their coverage is very much open to disagreement. My goal is for us to determine remaining gaps we may want to focus on.



** From Media APIs/Use Cases
   ( http://www.w3.org/2011/webtv/wiki/Media_APIs/Use_Cases )


1. "Use Case One  Tablet Joins Home Network"

This use cases seems to be fully covered by the HNReq use cases:
 - U2. Discovered Content Host
 - U6. Application Exposing a Service
 - U7. Application Discovering a Service

I can see no obvious gap between the use case and what is already documented in HNReq.


2. "Use Case Two  TV Triggers 2nd Screen"

This use case appears to be covert partially by the HNReq use cases:
  - U10. Media Identification

However, I could not find a clear mention of timed metadata in the programme stream, nor any mention of events triggered by metadata in a programme. These may be additional requirements.


3. "Use Case Three  Tablet EPG"

This use case appears to mirror the HNReq Use case:
  - U15. Home Network Enabled User-Agent - Network Media Player

I can see no obvious gap between the use case and what is already documented in HNReq.


4. "Use Case Four  Content Sharing"

This use case appears to be original. My interpretation of it, however, is that its specific requirements are all covered by the following HNReq use case:
  - U10. Media Identification

I can see no obvious gap between the use case and what is already documented in HNReq.


5. "Use Case Five  Content Search"

My understanding is that this use case is covered almost entirely by a combination of the following HNReq use cases:
  - U4. Service Distribution
  - U8. Application Push-Migration
  - U10. Media Identification

I can see no obvious gap between the use case and what is already documented in HNReq.


6. "Use Case Six  Tuner Control thru EPG Application"

This looks very similar to "Use Case Three  Tablet EPG". I would encourage the Use Case authors to detail how the use cases differ.


7. "Use Case Seven  Channel Bounded Applications"

This use case shares some similarities with the following HNReq use case:
  - U12. Time Synchronization

However, there seem to be some unique characteristics to this use case which I do not find in HNReq, such as the switching of applications on the "slave" device based on channel change in the "master" device. This could be an additional requirement worth exploring.



** From Media APIs/Terminal Use Cases
   ( http://www.w3.org/2011/webtv/wiki/Media_APIs/Terminal_Use_Cases )


1. "Channel"

This use case seems to be partially covered by the following HNReq use cases:
  - U10. Media Identification
  - U11. TV Control
  - U12. Time Synchronization

I believe, however, that there are some details in the use case not fully covered by e.g. the "U11. TV Control" HNReq use case. Expanding the TV Control use case may be an interesting next step.


2. recording

This use case is still WIP, but currently is covered by the following HNReq use case:
  - U18. Home Network Enabled User-Agent - Network Record Controller



3. Device capability information / conflict detection
4. Channel List
5. CA and CI
6. Video output control

These are WIP and it is hard to determine if their full scope would be covered by HNReq.


7. TV Applications

This use case looks like a collection of use cases. I would encourage its authors to split it into more atomic use cases which we could then analyse for gaps.


** From http://www.w3.org/2011/webtv/wiki/Media_APIs/Record_and_Download_Use_Cases

1. Download and Go

I could be wrong but this use case looks genuinely new to me, and not covered in any depth by HNReq.


2. Watch and Record

This use case looks in some aspects like a subset of the following HNReq use case:
  - U18. Home Network Enabled User-Agent - Network Record Controller

However, the Use Case also appears to be fundamentally different from anything in HNReq, largely because it is not situated in a multi-device home network but rather in a web/mobile context which could be in any kind of network. I suggest the group should look at the gaps this use case identifies as a prime candidate for our attention in the near future.



Any thought? Agreement, disagreement, different perspective? I would very much welcome others' take on a review, to see if we independently reach similar conclusions.

Thanks,
--
Olivier





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Received on Thursday, 4 July 2013 16:23:48 UTC

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