RTP Payload Format for Real-Time Pointers (RFC2862)
Original Publication Date: 2000-Jun-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
M. Civanlar: AUTHOR [+2]
This document describes an RTP  payload format for transporting the coordinates of a dynamic pointer that may be used during a presentation. Although a mouse can be used as the pointer, this payload format is not intended and may not have all functionalities needed to implement a general mouse event transmission mechanism.
Network Working Group M. Civanlar
Request for Comments: 2862 G. Cash
Category: Standards Track AT&T
RTP Payload Format for Real-Time Pointers
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (2000). All Rights Reserved.
This document describes an RTP  payload format for transporting
the coordinates of a dynamic pointer that may be used during a
presentation. Although a mouse can be used as the pointer, this
payload format is not intended and may not have all functionalities
needed to implement a general mouse event transmission mechanism.
In most presentations, significant information is conveyed through
the use of viewgraphs and a pointer. This makes accurate transmission
of them vital in remote conferencing applications. Using regular
video of a presenter's display for this purpose is problematic
because, while the viewgraphs require a high spatial resolution, the
pointer movements need to be sampled and transmitted at a high
temporal resolution so that the presenter's pointing actions can be
displayed synchronously with the corresponding audio and video
signals. In many instances, this synchronization carries vital
information. As an example, consider a speaker pointing at two
alternatives on a viewgraph in sequence and saying "this one is
better than this". To satisfy both high spatial and high temporal
resolution requirements, at least S-VHS quality video may need to be
used. Codecs that can compress S-VHS video effectively in real-time
are expensive for this purpose, and transmitting such video
uncompressed requires very high bandwidths.
A much simpler and economical system can be designed by capturing and
transmitting the pointer coordinates separately . The pointer
coordinates with respect to a displayed viewgraph can easily be
obtained in electronic presentation systems. For presentations
prepared for optical systems, such as transparencies for overhead
projectors, an arrangement where the viewgraph is captured in a frame
buffer on a computer can be used to ass...