W3C home > Mailing lists > Public > public-html@w3.org > February 2012

RE: Encrypted Media proposal (was RE: ISSUE-179: av_param - Chairs Solicit Alternate Proposals or Counter-Proposals)

From: Adrian Bateman <adrianba@microsoft.com>
Date: Wed, 22 Feb 2012 01:35:55 +0000
To: Glenn Adams <glenn@skynav.com>
CC: "HTML WG (public-html@w3.org)" <public-html@w3.org>, David Dorwin <ddorwin@google.com>, Mark Watson <watsonm@netflix.com>
Message-ID: <6895C7B67488C14AA23F0E079F0D7E8F385384@TK5EX14MBXC283.redmond.corp.microsoft.com>
On Tuesday, February 21, 2012 4:00 PM, Glenn Adams wrote:
> This a lengthy proposal that is not directly related to the general issue of
> interchanging decoding and/or protocol parameters between author and user
> agent for the purpose of performing audio and/or video playback.
> 
> Could you point out the specific elements of the proposal that deals with
> such parameter interchange? If this proposal offers an alternative mechanism
> to perform such interchange, then is that mechanism suitable for purposes not
> related to encrypted media playback?

Hi Glenn,

Rather than introducing a mechanism that supports generic parameter exchange,
this proposal shows how it is possible to write an extension specification
to add specific functionality to the existing media elements. User Agents
supporting this proposal would be interoperable if they implement the
extension according to the spec.

Having a generic mechanism doesn't guarantee interoperability because you still
need to specify what happens for each potential value. I argue that you don't
need <param> to do that, you just write the specification that defines
the new capabilities you want the media element to support. You can do that with
an extension at the time you define the values.

This specification doesn't provide a mechanism for values used outside
encrypted media playback. However, you could write an extension specification
for whatever those other values you have in mind are whenever you come up with
them so not having <param> in HTML5 isn't restricting that ability.

Cheers,

Adrian.

> On Tue, Feb 21, 2012 at 4:16 PM, Adrian Bateman <adrianba@microsoft.com>
> wrote:
> This has been raised in the Web & TV Interest Group [1] and mentioned in
> their
> feedback [2]. We believe this extension specification supports the counter
> proposal [3]
> for ISSUE-179 [4]. It demonstrates how to provide additional functionality to
> the
> HTML5 media element without requiring a generic mechanism like <param>.

> [1] http://www.w3.org/2011/webtv/wiki/MPTF#Content_Protection

> [2] http://lists.w3.org/Archives/Public/public-html/2011Dec/0120.html

> [3] http://www.w3.org/html/wg/wiki/ChangeProposals/issue-179_no_change

> [4] http://www.w3.org/html/wg/tracker/issues/179

Received on Wednesday, 22 February 2012 01:36:32 UTC

This archive was generated by hypermail 2.3.1 : Monday, 29 September 2014 09:39:30 UTC