Re: [AVT] I-D ACTION:draft-ietf-avt-rtp-jpeg2000-17.txt

[Magnus Westerlund <magnus.westerlund at ericsson.com>]

Hi,

there is an error in the application of rate in the example in section 8.2:

      m=video 49170/2 RTP/AVP 98 99
      a=rtpmap:98 jpeg2000/27000000
      a=rtpmap:99 jpeg2000/90000
      a=fmtp:98 rate=27000000;sampling=YCbCr-4:2:0;width=128;height=128
      a=fmtp:99 rate=90000;sampling=YCbCr-4:2:0;width=128;height=128

"rate=27000000" and "rate=90000" should not be in the a=fmtp line. RFC
4855 the common mapping to SDP rules in section 3 says the following:

      o  The general (possibly optional) parameters "rate" and
         "channels" also go in "a=rtpmap" as clock rate and encoding
         parameters, respectively.

I don't see any reason for having the value appear twice in the
declaration. The rate value in the rtpmap line is sufficent.

Thus the current text in section 8.2 of the draft should be changed:

   o  The REQUIRED parameters, "rate" and "sampling", MUST be included
      in the "a=fmtp" line of SDP.

I think simply remomve the "rate" and plural for "parameters" from this
line should fix it.

Then you need to fix all the examples in the draft and in the "BEAM" draft.

Best regards

Magnus Westerlund

IETF Transport Area Director & TSVWG Chair
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Multimedia Technologies, Ericsson Research EAB/TVM/M
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Ericsson AB                | Phone +46 8 4048287
Torshamsgatan 23           | Fax   +46 8 7575550
S-164 80 Stockholm, Sweden | mailto: magnus.westerlund at ericsson.com
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