On 4/11/19 4:14 AM, Magnus Westerlund wrote:
MMUSIC WG, Document Editors
In the processing of draft-ietf-mmusic-data-channel-sdpneg-25 an
interesting question arose regarding text strings in SDP attribute values.
Currently the document says:
4.5. Internationalization
The SDP specification recommends the use of the ISO 10646 character
set in the UTF-8 encoding [RFC3629] to allow many different languages
to be represented. However, to assist in compact representations,
SDP also allows other character sets such as ISO 8859-1 to be used
when desired. Internationalization only applies to free-text sub-
fields (session name and background information), and not to SDP as a
whole.
If one like to include UTF-8 field for attributes it would be good if
the requirement would be clear going forward that there is an expectancy
that at least parser can process any UTF-8 strings that may occur in any
fields.
That would allow future SDP field values to use UTF-8 strings without risks
and simplify processing. Like in the case of the data channel SDP mapping
where the extra step of encoding lable characters not visually safe as escaped
characters could be avoided.
Does anyone have input if making such a change would have significant impact on
the interoperability?
I'm inclined to just say that attribute values are limited to values
that are natively representable in the chosen charset. That will impose
limitations on use with charsets more limited than UTF-8.
Thanks,
Paul
