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Re: [Bug 18485] Change DTMF API to be on PeerConnection

From: Stefan Hakansson LK <stefan.lk.hakansson@ericsson.com>
Date: Wed, 15 Aug 2012 15:49:24 +0200
Message-ID: <502BA8E4.8010307@ericsson.com>
To: public-webrtc@w3.org
On 08/15/2012 03:08 PM, Cullen Jennings (fluffy) wrote:
> On Aug 15, 2012, at 2:38 AM, <bugzilla@jessica.w3.org> wrote:
>> --- Comment #5 from Harald Alvestrand <harald@alvestrand.no>
>> 2012-08-15 08:38:15 UTC --- Based on further discussion, a need has
>> been identified to play back tones in synchronity with the DTMF
>> signals going out. This functionality removes the need for the
>> ability to play out tones on local streams only, since it solves
>> the use case that was intended for. The interface should then
>> become:
>> pc.canSendDTMF(MediaStreamTrack) pc.sendDTMF(MediaStreamTrack
>> outTrack, tones, duration, optional MediaStreamTrack localTrack)
>> with the handling rule being:
>> 1) If the outTrack argument to sendDTMF is not an audio track
>> connected to this PeerConnection on an outgoing SSRC where use of
>> RFC 4733 DTMF has been negotiated, throw a <ArgumentError?>
>> exception. 2) Simultaneously do the following: - Send the tones
>> using RFC 4733 signalling on the outTrack
>> - If the localTrack is specified, play out an appropriate audio
>> feedback signal using this track, making sure that sound from
>> localTrack does not feed back into outTrack.
> Given that it is impossible to implement a system that makes sure
> there is no feedback, I sugest that what is played into the
> localTrack is simply a single beep for each tone played and not the
> actually DTMF tone. Most the better devices deployed today have
> already moved to this to avoid double press problems.

I've also noted that behavior on some recently acquired (the annual 
thunderstorm that kills some of the telco equipment happened a few weeks 
back) stuff I use, and it seems like a good idea to me. Another thing I 
noted was that the "beep" is of fixed length and does not depend on how 
long I keep the button pressed. Perhaps that is OK for webrtc as well 
and we would not need "startTone" and "endTone" API calls.

> Is there a way
> to specify pause or long pound or long star in the tones?
Received on Wednesday, 15 August 2012 13:49:49 UTC

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