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From: Stefan Hakansson LK <stefan.lk.hakansson@ericsson.com>
Date: Wed, 8 Aug 2012 09:35:22 +0200
Message-ID: <502216BA.4040703@ericsson.com>
To: public-webrtc@w3.org
On 08/08/2012 02:13 AM, Justin Uberti wrote:
> Agree it would be nice to have optional local feedback, and ideally we
> could do this in a single method call (especially if sending a long
> string of DTMF). Perhaps we should allow a second MediaStreamTrack to be
> passed in for the purpose of local echo?

Still, it is more for convenience. The author could just as well use 
prerecorded audio files with the right tones in conjunction with audio 
elements. Don't know about echo problems though.

> On Tue, Aug 7, 2012 at 12:27 PM, Randell Jesup <randell-ietf@jesup.org
> <mailto:randell-ietf@jesup.org>> wrote:
>     On 8/7/2012 11:32 AM, Adam Bergkvist wrote:
>         On 2012-07-19 13:42, Stefan Hakansson LK wrote:
>             I think I proposed at one time that DTMF should be echoed
>             into the audio
>             stream. I did that for two purposes:
>             1. It seems very strange to me to have an operation on an
>             audio stream
>             track that has no meaning outside the RTP transmission of a
>             PeerConnection. What should happen if you have a MediaStream
>             locally
>             only, and do "insertDTMF"?
>             2. It would make local feedback simpler. At least on my
>             phone, when I
>             use DTMF (which may be sent over the network using DTMF
>             events - I don't
>             know really and don't care), tones are played locally as a
>             feedback. I
>             assume that many app developers would like the behavior, and if
>             "insertDTMF", for a MediaStreamTrack that is connected to an
>             audio
>             element, did play out as tones you would have that feedback
>             for free.
>             (There are other ways to do it for sure, it is more
>             nice-to-have).
>             That were my reasoning. But if "insertDTMF" should only mean
>             "transmit
>             DTMF events", perhaps is should be an operation on
>             PeerConnection
>             instead. Could we do something like Harald proposed for
>             stats: have
>             something you can do on what is in localStreams?
>         I think this is worth looking into. DTMF doesn't make sense in a
>         local only case so it would be nice to avoid having the DTMF API
>         in the MediaStream API and instead attach it to PeerConnection
>         (e.g. peerConn.sendDTFM(__targetAudioTrack, dtmfData ...);).
>     What about point 2?  I.e. if I select "send a 5" in my UI, most
>     users expect to hear feedback.  It's not mandatory, but if we don't
>     then developers will do it themselves via (unsynced, maybe
>     un-echo-cancelled) audio elements.
>     --
>     Randell Jesup
>     randell-ietf@jesup.org <mailto:randell-ietf@jesup.org>
Received on Wednesday, 8 August 2012 07:35:47 UTC

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