[Gen-art] Re: draft-ietf-avtcore-rtp-haptics-09 ietf last call Genart review

[Hyunsik Yang <[e-mail]>]

Thanks Christer,

We updated the draft based on your feedback.
You can find the details below

Thanks.
Best regards,
-----Original Message-----
From: Christer Holmberg <[e-mail]> 
Sent: Monday, December 8, 2025 4:12 AM
To: [e-mail]; Hyunsik Yang <[e-mail]>
Cc: [e-mail]; [e-mail]; [e-mail]
Subject: RE: [Gen-art] draft-ietf-avtcore-rtp-haptics-09 ietf last call Genart review

Hi,

Thanks for the reply! Please see inline (I have removed the comments where I am ok with your suggestion).

Summary: The draft is well written, and in general easy to read. However, I do have a number of questions and issues, mostly related to SDP, that I would like the authors to address.

GENERAL:
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Q_GEN_1:

The draft says that the new parameters are OPTIONAL, but if a parameter is not present Section 7.1 defines which default value SHOULD be used. So, while it may be optional to explicitly include the parameters in SDP, my understanding is that it is still mandatory to support them, and assume the default value if they are not present in SDP. Or? I think it would be useful to clarify that.

[HY] We added the following sentence in Section 6.2, and added text to SDP parameters with default values, to further clarify a default value should be inferred for those parameters. 
“Among the optional SDP parameters defined in this section, some parameters have a default value which SHOULD be inferred if the parameter is not present, unless an out-of-band agreement indicates a different value, as described in SDP consideration section.”

[Christer] That is still confusing, as you mix "optional" with default values. And, what about parameters that do NOT have a default value? Could you say something like:

"It is optional to include the SDP parameters in this section. Some parameters have a default value which SHOULD be inferred if the parameter is not present in the SDP, unless an out-of-band agreement indicates a different value, as described in SDP consideration section.”

[HY] Thank you for your suggestions. To clarify it, We have revised sentence based on your comments.
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Q_GEN_3:

The draft does not define SDP BUNDLE considerations.

[HY] While haptic streams may in some cases be bundled with audio and video streams, we think that SDP BUNDLE considerations would be out of the scope of this draft.

[Christer] I personally think people would want to use BUNDLE with this. But, if you have decided to not define the BUNDLE considerations I suggest that you explicitly specify it.

[HY] Thank you for providing more context about your comment on this. We agree that this RTP payload format can be used with BUNDLE (e.g., within WebRTC). However, we think we should rely on the generic BUNDLE mechanism, since we have nothing to add with regard to it. We also did not find BUNDLE-related statements in other payload format RFCs we consulted, which seems to confirm our understanding. To conclude on this, based on our current understanding we don’t think there is a need to mention BUNDLE, for those reasons (no specific consideration, and the general trend is not to have any). But we are opened to continue the discussion, since there may be other arguments that we did not take into account.
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Regards,

Christer