Re: [MMUSIC] Magnus Westerlund's Discuss on draft-ietf-mmusic-data-channel-sdpneg-25: (with DISCUSS and COMMENT)

Adam Roach <adam@nostrum.com> Mon, 15 April 2019 21:52 UTC

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To: Magnus Westerlund <magnus.westerlund@ericsson.com>, "Roni Even (A)" <roni.even@huawei.com>
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From: Adam Roach <adam@nostrum.com>
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Subject: Re: [MMUSIC] Magnus Westerlund's Discuss on draft-ietf-mmusic-data-channel-sdpneg-25: (with DISCUSS and COMMENT)
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On 4/15/19 3:25 AM, Magnus Westerlund wrote:
> Hi,
>
> I think you need to split this into two parts. One is the general 
> quoting of the UTF-8 string in the label parameter. The other part is 
> the serialization of the WebRTC label into an UTF-8 string.


I'm not sure what you mean by the second operation ("the other part") 
here. A USVString represents a sequence of Unicode codepoints ("USV" 
stands for "Unicode Scalar Values"). The procedure for going from a 
sequence of Unicode code points to a UTF-8 string is defined in RFC 
3629. Are you simply asking for a reference to RFC 3629 here?


> Also, I don't get my head around the USVString if that has any 
> additional data in addition to the sequence of the Unicode scalar 
> values and if there are any action that are needed to be done in the 
> seralization to an UTF-8 string?


I'm pretty comfortable asserting that the answers are "no" and "no" 
respectively. While it's not part of the spec, MDN (which hews very 
close to an "as built" description of web standards) makes this pretty 
clear: "USVString is equivalent to DOMString except for not allowing 
unpaired surrogate codepoints."

/a