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Re: EME and timed text

From: Pierre-Anthony Lemieux <pal@sandflow.com>
Date: Wed, 3 Apr 2013 09:05:11 -0700
Message-ID: <CAF_7JxBH14k45ZLWsWN03U25PrhRqkgrQcbWMuEfw5mcSy9UoQ@mail.gmail.com>
To: Mark Watson <watsonm@netflix.com>
Cc: David Singer <singer@apple.com>, Henri Sivonen <hsivonen@iki.fi>, "<public-html-media@w3.org>" <public-html-media@w3.org>
Since EME is designed to merely handle encrypted blocks, why could it
not handle encrypted timed text -- or is there? The CDM can choose to
expose the decrypted timed text back to the UA.

> It has a lot of technical implications, as Henri points out.

Can we list them?

Thanks,

-- Pierre

On Wed, Apr 3, 2013 at 8:58 AM, Mark Watson <watsonm@netflix.com> wrote:
>
>
> On Wed, Apr 3, 2013 at 8:44 AM, David Singer <singer@apple.com> wrote:
>>
>>
>> On Apr 3, 2013, at 3:00 , Henri Sivonen <hsivonen@iki.fi> wrote:
>>
>> >  Timed text should not be DRMable just for principled
>> > symmetry with video and audio.
>>
>> There are some cases where people want to supply text tracks 'in
>> multiplex' (and meta-data tracks, and so on).  It seems to me that though,
>> as you say, we shouldn't spend our time optimizing the EME and MSE for other
>> track types, we shouldn't try to stop them working (or ban them from these
>> interfaces) just for principled considerations from some people, either.
>
>
> There is a difference, though, between the CDM decrypting a multiplexed text
> track and simply passing that decrypted text data to the browser and the CDM
> being responsible for rendering. We need CDM rendering to be possible for
> audio and video, but I am not sure anyone is asking for that for text. It
> has a lot of technical implications, as Henri points out. Given what we've
> already said in the specification, it seems like scope creep for this first
> version.
>
> ...Mark
>
>>
>>
>>
>> David Singer
>> Multimedia and Software Standards, Apple Inc.
>>
>>
>
Received on Wednesday, 3 April 2013 16:06:03 UTC

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