From:  Marco Zehe <>
Date:  11 Nov 2015 19:14:04 Hong Kong Time

Re: Muting web audio when a screenreader is saying something


Some screen readers, such as VoiceOver on the Mac and iOS, as well as
TalkBack on Android, have a feature commonly called audio ducking. Since
they know when they want to speak something, Apple created this concept
where it turns down the volume of any other audio output when VoiceOver
speaks. This first appeared on iOS, was then brought to OS X in Mavericks,
and also got adopted by TalkBack on Android recently. On all platforms, the
feature is on by default, but can be turned off if need be.

For some reason, none of the Windows screen readers, including NVDA, has
adopted this concept. I am also not aware whether Orca is doing this on
Linux or not.


On Tue, Nov 10, 2015 at 10:47 PM, Silvia Pfeiffer  wrote:

> On Wed, Nov 11, 2015 at 12:52 AM, Chris Mills  wrote:
> > I was having an interesting conversation with Henny Swan from The
> Paciello Group last week - she was saying that a very common complaint from
> screenreader users that she hears is web-based audio drowning out
> screenreader output when users navigate to a web page that features audio
> or video tags, etc. Especially ones set to autoplay.
> >
> > I was wondering if it would be possible to write an addon that mutes (or
> at least reduces the volume of) audio coming from a webpage when a
> screenreader is saying something. Is there any kind of custom event we can
> use for this?
> For audio and video elements, there is an extensive API that can be
> used, including reading and setting volume. That could be exposed
> through an extension to a specific key-combination (if there is any
> key-combintation still available that the screenreader isn't using)
> and thus the user could control the volume manually.
> > I am guessing the answer might be no, as screenreaders tend to work on
> the OS level rather than the browser level, but I might be surprised.
> Yeah, the Web page and often also the browser generally doesn't know
> that a screenreader is running (except when the screenreader is a
> browser extension itself), so anything along these lines is a bit hard
> to do. We had been thinking about such a feature also for audio
> descriptions that would be read out by a screenreader at the same time
> that a video is playing and that requires both: a new API in the
> screenreaders and a new API in the browsers.
> Would be worthwhile if somebody wants to attack this problem!
> Cheers,
> Silvia.
> >
> > Thanks,
> >
> > Chris Mills
> >  Senior tech writer || Mozilla
> > || MDN
> > || @chrisdavidmills
> >
> > _______________________________________________
> > accessibility mailing list
> >
> >
> _______________________________________________
> accessibility mailing list