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Re: [webrtc-pc] Need to specify which members of the encodings in "sendEncodings" are actually used

From: Taylor Brandstetter <deadbeef@google.com>
Date: Tue, 14 Mar 2017 15:51:23 -0700
Message-ID: <CAK35n0ZJ7ESCFZYY-Ps46D0GKYhxva_wS1EHeVE_S1EQzMfn0g@mail.gmail.com>
To: Bernard Aboba <Bernard.Aboba@microsoft.com>
Cc: Taylor Brandstetter via GitHub <sysbot+gh@w3.org>, "public-webrtc@w3.org" <public-webrtc@w3.org>
I think rather than using this table, it would be simpler to just say "only
the 'rid' member is used" in the description of
sendEncodings/addTransceiver. Or define a new dictionary type that only has
a "rid" member.

On Tue, Mar 14, 2017 at 9:17 AM, Bernard Aboba <Bernard.Aboba@microsoft.com>
wrote:

> The table in Section 5.2 describes which RTCRtpEncodings dictionary
> members apply to RtpReceiver/RtpSender and which are Read/Write versus
> Read-only:
>
>
>
> *Attribute*
>
> *Type*
>
> *Receiver/Sender*
>
> *Read/Write*
>
> *ssrc*
>
> unsigned long
>
> Receiver/Sender
>
> Read-only
>
> *fec*
>
> RTCRtpFecParameters
> <https://rawgit.com/w3c/webrtc-pc/master/webrtc.html#dom-rtcrtpfecparameters>
>
> Receiver/Sender
>
> Read-only
>
> *dtx*
>
> RTCDtxStatus
> <https://rawgit.com/w3c/webrtc-pc/master/webrtc.html#dom-rtcdtxstatus>
>
> Sender
>
> Read/Write
>
> *rtx*
>
> RTCRtpRtxParameters
> <https://rawgit.com/w3c/webrtc-pc/master/webrtc.html#dom-rtcrtprtxparameters>
>
> Receiver/Sender
>
> Read-only
>
> *active*
>
> boolean
>
> Sender
>
> Read/Write
>
> *priority*
>
> RTCPriorityType
> <https://rawgit.com/w3c/webrtc-pc/master/webrtc.html#dom-rtcprioritytype>
>
> Sender
>
> Read/Write
>
> *maxBitrate*
>
> unsigned long
>
> Sender
>
> Read/Write
>
> *maxFramerate*
>
> unsigned long
>
> Sender
>
> Read/Write
>
> *scaleResolutionDownBy*
>
> double
>
> Sender
>
> Read/Write
>
> *rid*
>
> DOMString
>
> Receiver/Sender
>
> Read-only
>
>
>
> Since setParameters() cannot set the “negotiation-needed” flag, members
> that are Read/Write cannot affect the SDP generated in an offer (or
> answer).
>
>
>
> This leaves only rid, rtx, fec and ssrc as possibilities that could affect
> the offer SDP.  Since in WebRTC RTCRtpRtxParameters and RTCRtpFecParameters
> only contain ssrc as a member, if we don’t let the application choose
> ssrcs, that leaves only the rid.
>
>
>
> Perhaps we need another column in the table to clarify this?
>
>
>
>
>
> -----Original Message-----
> From: Taylor Brandstetter via GitHub [mailto:sysbot+gh@w3.org]
> Sent: Monday, March 13, 2017 4:14 PM
> To: public-webrtc@w3.org
> Subject: [webrtc-pc] Need to specify which members of the encodings in
> "sendEncodings" are actually used
>
>
>
> taylor-b has just created a new issue for https://github.com/w3c/webrtc-pc
> :
>
>
>
> == Need to specify which members of the encodings in "sendEncodings" are
> actually used == The description of the `sendEncodings` member of
> `RTCRtpTransceiverInit` is currently:
>
>
>
> > A sequence containing parameters for sending RTP encodings of media.
>
>
>
> This somewhat implies that the full contents of the
> `RTCRtpEncodingParameters` are processed and used when generating an offer.
> But the only member that appears used by JSEP is `rid`. If this is correct,
> it should be clarified somewhere, either in the description of
> `sendEncodings` or in the `addTransceiver` steps.
>
>
>
> Please view or discuss this issue at https://github.com/w3c/webrtc-
> pc/issues/1073 using your GitHub account
>
>
>
Received on Tuesday, 14 March 2017 22:51:56 UTC

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