- From: John Kemp <john@jkemp.net>
- Date: Wed, 3 Apr 2013 15:45:07 -0400
- To: Janina Sajka <janina@rednote.net>
- Cc: Mark Watson <watsonm@netflix.com>, Glenn Adams <glenn@skynav.com>, Henri Sivonen <hsivonen@iki.fi>, Steve Faulkner <faulkner.steve@gmail.com>, HTMLWG WG <public-html-media@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
On Apr 3, 2013, at 11:50 AM, Janina Sajka wrote: > Am I wrong? Is there any actual use case for encrypting captions? What > did I miss here? I think the *potential* use-case here is that a piece of encrypted content (ie. that which will be sent to the CDM for decryption) may already contain captions (or other textual content) which may not be otherwise available as a separate, already-cleartext track (regardless of whether that is best practice or not). Should it be the responsibility of the CDM to provide captions in decrypted form? How? In particular, this would seem to apply to an MPEG-2 elementary stream, where closed captions may be present in the MPEG user data section of the stream (as specified in CEA-708). Are we then saying that if someone wanted to write a CDM that would decrypt or render an MPEG-2 elementary stream, they would not be required by the specification to make the captions carried within that stream available to the viewer? Regards, JohnK > > Janina > > > -- > > Janina Sajka, Phone: +1.443.300.2200 > sip:janina@asterisk.rednote.net > Email: janina@rednote.net > > Linux Foundation Fellow > Executive Chair, Accessibility Workgroup: http://a11y.org > > The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI) > Chair, Protocols & Formats http://www.w3.org/wai/pf > Indie UI http://www.w3.org/WAI/IndieUI/ > >
Received on Wednesday, 3 April 2013 19:46:33 UTC