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Re: EME and timed text

From: David Singer <singer@apple.com>
Date: Tue, 02 Apr 2013 09:44:20 -0700
Cc: public-html-media@w3.org
Message-id: <AF95BBBB-66E3-4F59-A22C-9AFE172A144A@apple.com>
To: Pierre-Anthony Lemieux <pal@sandflow.com>

On Apr 2, 2013, at 7:50 , Pierre-Anthony Lemieux <pal@sandflow.com> wrote:

> Couple of thoughts on EME and timed text following up on our last call.
> - requirements for captions can be different from other kinds of timed
> text, e.g. subtitles and karaoke. I am not convinced the possibility
> of encrypted timed text can be excluded.
> - the (proposed) MPEG Part 30 allows carriage of timed text (WebVTT
> and TTML) as part of the media data. Shouldn't EME apply in that case?
> If not why? If yes, the following note in EME probably needs to be
> revised: "Q: Can I encrypt captions / <track> elements? A: No, this
> proposal only supports decrypting audio and video that are part of the
> media data."

I rather think it should say that it only supports decrypting the media data that's delivered, perhaps?  If there is a timed text track in the (say) MP4 file, why wouldn't the EME and MSE just work?

> Looking forward to the discussion.
> Best,
> -- Pierre

David Singer
Multimedia and Software Standards, Apple Inc.
Received on Tuesday, 2 April 2013 16:44:48 UTC

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