[GnomeMeeting-devel-list] Speex

["Olaf Conradi" <oohlaf gmail com>]

Hello,

I am testing Ekiga with the latest Debian snapshot (march 8th) to see
how it works with my Speex plugin for Yate.

I noticed Ekiga was the first softphone I came across which sets the
SDP payload type to "SPEEX" and not "speex". Digging into the RFCs of
AVT payloads [1] it does say:

"Note that the payload format (encoding) names defined in the RTP
Profile are commonly shown in upper case.  Media subtype names are
commonly shown in lower case.  These names are case-insensitive in
both places."

But the latest speex RFC [2] says:

"When conveying information by SDP [4], the encoding name MUST be set
to "speex"."

Thought you might want to know. Maybe you want to change this (just as
iLBC is shown as "iLBC" by Ekiga in SDP payloads).

I did some testing between my codec and Ekiga and noticed Ekiga advertises this:

m=audio 5018 RTP/AVP 101 110
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=rtpmap:110 SPEEX/8000

If I respond with:

m=audio 17002 RTP/AVP 110 101
a=rtpmap:110 speex/8000
a=fmtp:110 mode=5
a=fmtp:110 ebw=narrow
a=rtpmap:101 telephone-event/8000

Then Ekiga does not pickup that the other side wants to use mode 5
(speex-nb-15k), not mode 3 (speex-nb-8k). The connection succeeds and
all Ekiga hears is garbage as speex decodes in the wrong mode.

Why does Ekiga not request mode 3 if it does not cope with other modes
or accept other modes? The Speex RFC [2] does state mode 3 is default,
but both parties still have to agree.


Cheers
 -Olaf

[1] http://www.ietf.org/internet-drafts/draft-ietf-avt-rfc3555bis-02.txt
[2] http://www.ietf.org/internet-drafts/draft-ietf-avt-rtp-speex-00.txt