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Re: New issue: switching sources

From: Jim Barnett <1jhbarnett@gmail.com>
Date: Tue, 20 May 2014 13:20:54 -0400
Message-ID: <537B8EF6.9090708@gmail.com>
To: "Suhas Nandakumar (snandaku)" <snandaku@cisco.com>, Peter Thatcher <pthatcher@google.com>
CC: Martin Thomson <martin.thomson@gmail.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>
If it raises an negotationNeeded event, it can't start transmitting 
until the negotiation is complete.   (If it raises an error, it wouldn't 
transmit either.)

- Jim

On 5/20/2014 12:24 PM, Suhas Nandakumar (snandaku) wrote:
>
> ------------------------------------------------------------------------
> *From:* Peter Thatcher [pthatcher@google.com]
> *Sent:* Tuesday, May 20, 2014 9:17 AM
> *To:* Jim Barnett
> *Cc:* Martin Thomson; public-webrtc@w3.org
> *Subject:* Re: New issue: switching sources
>
> The idea is that the SDP is unchanged.  Only the source of the video 
> frames (or the audio) is changed.  If that is impossible for some 
> reason, then the UA could raise an error.
>
> [Suhas]
> Or raise negotiationNeeded event
>
>
> On Tue, May 20, 2014 at 9:14 AM, Jim Barnett <1jhbarnett@gmail.com 
> <mailto:1jhbarnett@gmail.com>> wrote:
>
>     So is the idea that when switching tracks, the new one must match
>     (all?, most?) of the SDP that described the old one?  Must the UA
>     raise an error if it can't do so?
>
>     On 5/20/2014 12:05 PM, Peter Thatcher wrote:
>>     Ah, good point.  So via setLocalDescription and
>>     setRemoteDescription, the JS tells the browser to send codec X,
>>     but then tells it to send from source Y with hardware codec Z.
>>      Well, in that case, I'd say do what the JS told the browser to
>>     do: send with codec X (without hardware encoding).  Yes, that is
>>     a danger and we should document it clearly if we decide to
>>     support this.
>>
>>
>>     On Tue, May 20, 2014 at 7:58 AM, Martin Thomson
>>     <martin.thomson@gmail.com <mailto:martin.thomson@gmail.com>> wrote:
>>
>>         On 20 May 2014 07:27, Peter Thatcher <pthatcher@google.com
>>         <mailto:pthatcher@google.com>> wrote:
>>         > What do you mean by "understand the dangers"?  What dangers
>>         are there?
>>
>>
>>         Like the one where you have negotiated codec X and you switch
>>         in a
>>         stream that is attached to a hardware encoder with only codec Y.
>>
>>
>
>     -- 
>     Jim Barnett
>     Genesys
>
>

-- 
Jim Barnett
Genesys
Received on Tuesday, 20 May 2014 17:22:02 UTC

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