Re: Clarification on the notion of "Second Screen"?

Dear Janina,

Thanks for the response.

Your question applies to the Remote Playback API and the Open Screen 
Protocol on top of which the Remote Playback API may be built. I confirm 
that the Open Screen Protocol has all the necessary features to 
communicate all the alternative media. I also confirm that the Remote 
Playback API asks user agents to synchronize the media element state 
(the set of all single media element properties observable by the page 
and/or the user) between the controller and the receiver.

As such, I believe that the API handles all of the concerns that you 
raise. Captions and subtitles will be present along with the main 
audio/video content. That includes audio or text descriptions of video, 
provided that these descriptions are represented as audio and text 
tracks (in other words that they are part of the media element state, 
and not some DOM content available elsewhere on the page).

I would just note that the spec leaves the implementation of the 
synchronization step up to the controller and receiver (the Open Screen 
Protocol defines one way to do it but there is no requirement that the 
Open Screen Protocol be supported), and that it does not take for 
granted that the receiver supports the exact same set of capabilities as 
the controller.


------ Original message ------
From: "Janina Sajka (" <>
To: "Francois Daoust" <>
Cc: "Michael Cooper" <>; "APA Chairs" 
Date: 14/12/2021 14:24:30

>Dear Francois:
>First, my apologies for my silence over the past week. I'm not intending
>to block your charter unnecessarily.
>So, let me ask my question a different way. Let's forget about braille
>displays (or any particular second screen device). We know there are a
>range of devices, some smart enough to serve as second screen devices,
>others just what we used to call "dumb terminals."
>The core concern for APA is whether all the alternative media is being
>communicated via the API you're proposing. Can we count on the API for
>captions? As many different languages of captions and subtitles as might
>be available? Also for descriptions of video, whether audio or text
>descriptions of video?
>If all of that is facilitated, then I think APA can sign off. Does this
>restatement of our concern help clarify?
>Francois Daoust writes:
>>  Hi Janina,
>>  I confirm that Bluetooth headset, and speakers, are included in the
>>  definition of "screen" (the charter rather uses the term "presentation
>>  display"). In particular, the draft charter explicitly mentions Bluetooth
>>  and includes the following sentence: "For the purposes of this charter,
>>  presentation displays include wireless speakers as well".
>>  That said, I am not sure whether the group considers refreshable braille
>>  displays to be a possible "presentation display" as well. My limited
>>  understanding of refreshable braille displays is that they are meant to
>>  display characters, whereas the presentation displays being considered by
>>  the Second Screen Working Group are either those capable of rendering audio
>>  or video streams, or those capable of running HTML applications.
>>  Said differently, the APIs developed by the group may be used to stream
>>  audio and/or video content to a presentation display, or to establish a
>>  communication channel between a web application running on a controller
>>  device and a web application running on the presentation display. However,
>>  there are no provisions to stream pure text content to a presentation
>>  display.
>>  Or do I misunderstand what refreshable braille displays encompass?
>>  Thanks,
>>  Francois.
>>  ------ Original message ------
>>  From: "Janina Sajka (" <>
>>  To: "Francois Daoust" <>
>>  Cc: "Michael Cooper" <>
>>  Date: 07/12/2021 15:48:32
>>  > Hi, Francois:
>>  >
>>  > My apologies for being slow to follow up on this. Our main concern is to
>>  > continue to capture what we agreed some years back, perhaps 2015-2016?,
>>  > that "screen" should be understood to be generic, meaning that the
>>  > screen might be a bluetooth headset, or speaker pair, or a refreshable
>>  > braille display.
>>  >
>>  > This understanding grew out of our work on media accessibility in HTML
>>  > 5, and we did have an exchange at some point years ago clarifying this
>>  > understanding. Our issue is really just that, and nothing more. We did
>>  > thing it worth clarifying because several years have passed, and it's
>>  > likely many participants in Second Screen may be newer than that old
>>  > exchange of understanding.
>>  >
>>  > I will be in other meetings for the next few hours, but will get back to
>>  > you with more later today. Again, sorry for holding things up!
>>  >
>>  > Janina
>>  >
>>  > Francois Daoust writes:
>>  > >  Hi Janina,
>>  > >
>>  > >  Michael noted that APA reviewed the proposed Second Screen Working Group
>>  > >  charter and would like a clarification about the meaning of the term "second
>>  > >  screen". Could you provide more detail as to what APA is wondering about?
>>  > >
>>  > >  The proposed charter is at:
>>  > >
>>  > >
>>  > >  Thanks,
>>  > >  Francois, staff contact for the Second Screen Working Group.
>>  >
>>  > --
>>  >
>>  > Janina Sajka
>>  >
>>  >
>>  > Linux Foundation Fellow
>>  > Executive Chair, Accessibility Workgroup:
>>  >
>>  > The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
>>  > Co-Chair, Accessible Platform Architectures
>>  >
>Janina Sajka
>Linux Foundation Fellow
>Executive Chair, Accessibility Workgroup:
>The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
>Co-Chair, Accessible Platform Architectures

Received on Wednesday, 15 December 2021 15:48:31 UTC