RE: DTMF - the "Object Oriented" approach

Yang
Huawei


> -----Original Message-----
> From: Harald Alvestrand [mailto:harald@alvestrand.no]
> Sent: Friday, November 16, 2012 6:00 AM
> To: public-webrtc@w3.org
> Subject: Re: DTMF - the "Object Oriented" approach
> 
> On 11/15/2012 12:07 PM, Stefan Hakansson LK wrote:
> > On 11/14/2012 03:46 PM, Harald Alvestrand wrote:
> >> Takeaways from Lyon were that:
> >>
> >> - Executing DTMF needs reference to an audio track (to know where to
> >> send the data) and to a PeerConnection (to know that we've successfully
> >> negotiated use of the DTMF codec).
> >> - The WG preferred an "object oriented" model: creating a DTMF handler
> >> object, rather than the "fortran" approach of having all functions
> >> directly on the PeerConnection.
> >>
> >> Suggested edits, delta from the October 19 version of the spec:
> >>
> >> - In section 8.4, rename AudioMediaStreamTrack to
> >> DTMFSendingMediaStreamTrack.
> >> Add the following text:
> >>
> >> A RTCDTMFSendingMediaStreamTrack is created by calling the
> >> createDTMFSender() method on a PeerConnection. This constructs an
> object
> >> that decorates a MediaStreamTrack with the functions required to send
> >> DTMF.
> >>
> >>
> >> - In section 4.3.2, add the function
> >>
> >> RTCDTMFSendingMediaStreamTrack
> createDTMFSender(MediaStreamTrack track);
> >>
> >> - In section 4.3.2.2, add the paragraph
> >>
> >> createDTMFSender
> >>
> >> The createDTMFSender() creates an RTCDTMFSendingMediaStreamTrack
> that
> >> references the given MediaStreamTrack. The MediaStreamTrack MUST be
> an
> >> element of a MediaStream that's currently in the PC's localStreams
> >> attribute; if not, throw an Illegal Argument Exception. [NOTE - get
> >> correct name for exception before inserting]
> >>
> > This looks good to me. I think we also need to specify:
> >
> > * What happens if the MediaStream with the track that the
> > RTCDTMFSendingMediaStreamTrack is associated to is removed from the
> > PeerConnection? I assume there would be an error event next time the
> > app tries to send DTMF.
> My thought:
> 
> I think that if it's removed from the PC, canSendDTMF should change to
> false.
> Any time canSendDTMF is false, sendDTMF should throw an exception.
> 
> Do we need to find a way to throw an event if it's removed from its PC
> while in the middle of sending tones, or can we just ignore that situation?


Support to have a canSendDTMF in PC, thus we can judge the canSendDTMF before calling senDTMF.
I think a event is needed, thus it can trigger to remind user or change some object and method in the page unavailable.




> 
> >
> > Stefan
> >
>

Received on Friday, 16 November 2012 08:13:00 UTC