Liaison statement
LS to IETF on Video Region-of-Interest (ROI)

1. Overall Description:
Regarding the new IETF draft in draft-huang-avtext-feedback-image-control-00,
3GPP SA4 would like to inform IETF that 3GPP has already specified a related
solution in 3GPP TS 26.114 as part of the Release 13 work item on “Video
Enhancements by Region-of-Interest (ROI) Information Signaling”. Attached is
the specification TS 26.114 v13.0.0, containing the adopted ROI signaling
framework described in clauses 6.2.3.4 and 7.3.7.

In particular, the ROI signaling framework in 3GPP TS 26.114 is composed of the
following modes:

•       ‘FECC’ mode, in which the receiving client uses the Far End Camera
Control (FECC) protocol based on ITU-T H.281 over H.224 to signal ROI
information as a sequence of ‘Pan’, ‘Tilt’, ‘Zoom’ and ‘Focus’ (PTZF) commands.

•       ‘Arbitrary ROI’ mode, in which the receiving client determines a
specific ROI and signals the corresponding ROI coordinates to the sender using
RTCP feedback messages.

•       ‘Pre-defined ROI’ mode, in which the receiving client selects one of
the ROIs pre-determined by the sender and signals this ROI to the sender using
RTCP feedback messages. In this mode, the receiving client obtains the set of
pre-defined ROI coordinates from the sender during the SDP capability
negotiation.

Moreover, 3GPP TS 26.114 also specifies the ‘Sent ROI’ mode based on the use of
RTP header extensions, enabling the sender to signal to the receiver the
actually sent ROI corresponding to the video transmitted by the sender (which
may or may not agree with the ROI requested by the receiver).

Among these modes, we believe that the ‘Arbitrary ROI’ framework is well
aligned with the method described in
draft-huang-avtext-feedback-image-control-00. It would be desirable to ensure
that IETF considers 3GPP’s ROI signaling framework during the course of their
specification work, and that IETF and 3GPP coordinate on this matter to ensure
alignment of their specifications.

2. Actions:
To IETF:
3GPP SA4 kindly requests IETF to take the information above into account, and
maintain coordination with SA4 during the course of the development of
draft-huang-avtext-feedback-image-control-00 toward ensuring the alignment
between 3GPP and IETF specifications.

3. Date of Upcoming TSG-SA WG4 Meetings:
TSG SA WG4 Meeting #85  24 - 28 Aug 2015        Venue: Kobe, Japan
TSG SA WG4 Meeting #86  26 - 30 Oct 2015                Venue: San Jose Del
Cabo, Mexico