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

From: Cullen Jennings (fluffy) <fluffy@cisco.com>
Date: Wed, 15 Aug 2012 13:08:39 +0000
To: "<bugzilla@jessica.w3.org> " <bugzilla@jessica.w3.org>
CC: "public-webrtc@w3.org" <public-webrtc@w3.org>
Message-ID: <56227360-8901-411F-8DAB-ECFFB6832745@cisco.com>

On Aug 15, 2012, at 2:38 AM, <bugzilla@jessica.w3.org>

> --- 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. Is there a way to specify pause or long pound or long star in the tones?
Received on Wednesday, 15 August 2012 13:09:07 UTC

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