W3C home > Mailing lists > Public > public-webrtc@w3.org > February 2012

Re: Mute and MediaStream repointing

From: Stefan Hakansson LK <stefan.lk.hakansson@ericsson.com>
Date: Mon, 13 Feb 2012 18:04:36 +0100
Message-ID: <4F3942A4.8090101@ericsson.com>
To: public-webrtc@w3.org
On 02/13/2012 04:05 PM, Randell Jesup wrote:
> On 2/13/2012 9:49 AM, Stefan Hakansson LK wrote:
>> On 02/13/2012 03:23 PM, Randell Jesup wrote:
>>> We've discussed it once or twice - muted tracks should generate
>>> *something* until/unless signaling allows them to be turned off. We
>>> found in our videophone company that 'black' was a bad choice for video,
>>> as it confuses users ("is something broken?")
>>
>> My thinking was not that the black video would ever be shown, but rather
>> that the application receiving it would detect that is was black and
>> replace it with some image (detecting a certain color is quite simple
>> with a canvas element). Not that I am saying black is a good choice. I
>> guess transparency can be detected as well - so it could even be
>> transparent.
>
> You can't guarantee what a destination will do with 'black' (even
> assuming it goes through unmolested), and if gatewayed to other
> equipment/networks ("legacy"), you're right out of luck.

I think we know what will happen if the other side is another browser, 
but you're 100% correct that in a gatewayed scenario we may have worse 
success.

> We (WorldGate) originally had a closed network, and just used
> side-signaling over RTCP APP and 'black' for mute.  When we started
> interoperating with other devices, we had to replace black with a mute
> image to avoid confusion.
>
> Also, 'black' means you ust run a "is frame black" test on every
> frame...  Just to support a mute image.  Ugh. :-)

I think you can do some smarter processing (test every nth frame, select 
a subset of the pixels).

But I think your proposal of sending a mute image is interesting, and 
much more robust.

>
Received on Monday, 13 February 2012 17:05:00 UTC

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