Re: DTMF

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?




On Tue, Aug 7, 2012 at 12:27 PM, Randell Jesup <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
>
>
>