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RE: [apis] Download and Go use case

From: HU, BIN <bh526r@att.com>
Date: Wed, 15 May 2013 20:24:34 +0000
To: JC Verdié <jc.verdie@mstarsemi.com>, Web & TV IG <public-web-and-tv@w3.org>
Message-ID: <179FD336116F754C876A9347238FE29A01032390@WABOTH9MSGUSR8L.ITServices.sbc.com>
Hello JC,

Thank you for your comments, and those are very valuable to improve our use cases and hence the requirement.

I have made the changes of your first 2 comments, i.e. transferring media and accounting the number of coexisting instances. Please see [1].

With regard to your 3rd comment, i.e. "+ a method for accessing to file access validity (including an offline clearance method)", I am not quite sure if I understand it correctly. Do you mean that the offline storage of the content should only be valid for a limited lifecycle, e.g. 24 hours? Once the time expires, the content storage should be cleared?

Thank you
Bin

[1] http://www.w3.org/2011/webtv/wiki/Download#Download_and_Go

-----Original Message-----
From: JC Verdié [mailto:jc.verdie@mstarsemi.com] 
Sent: Wednesday, May 15, 2013 2:39 AM
To: Web & TV IG
Subject: [apis] Download and Go use case

Dear TF,

I have a few comments on the Download and Go use case [1]: Some content 
providers (or content owners) do not allow multiple instances of the 
same protected content to coexist. For instance if you rent a movie on 
iTunes from your computer and decide to watch it on your iPad, you will 
have to "transfer" it. The movie being now visible on the iPad but not 
anymore on the computer. On the same vein of constraints, other media 
can coexit in multiple but limited places (e.g. only X copies of the 
same protected file). I appreciate that these constraints probably fall 
in EME's basket but I feel uncomfortable with not seeing them in the use 
case description.

I would suggest the following modifications on the use case (lines 
starting with a +)

Requirements:

Download
A method of referencing video sources for download, e.g. using anchor 
elements with the download attribute.
Content protection
Ability to store video content in a protected format, as applicable.
Ability to view previously stored protected video content, e.g. via the 
HTML5 Encrypted Media Extensions
+ Ability to transfer media in a single operation (not copy-then-delete)
+ Ability to account & verify the number of coexisting instances of the 
media

Storage
An adequately-sized storage medium; at least enough to store several 
full movies, e.g. 32GB
A method of accessing the storage medium to save videos, e.g.
For local filesystem storage, the File Writer API
For browser-internal storage, the IndexedDB API
+ a method for accessing to file access validity (including an offline 
clearance method)

Playback
A method of accessing the storage medium for video playback, e.g.
The File API
IndexedDB API
Ability to view previously stored video content, e.g. via
The HTML5 video element using a reference to a locally-stored file, 
provided through the File API
The HTML5 video element using a reference to a video stored in 
browser-internal storage, and accessed via the IndexedDB API
Ability to view previously stored protected video content, e.g. via the 
HTML5 Encrypted Media Extensions

Regards,
JC


[1] http://www.w3.org/2011/webtv/wiki/Download#Download_and_Go
Received on Wednesday, 15 May 2013 20:29:55 UTC

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