70 likes | 195 Views
RTP Payload Format for Real-Time Pointers. M. Reha Civanlar AT&T Labs - Research 45 th IETF Oslo, Norway. Why do we need this?. In presentations, it is essential to transmit viewgraphs & real-time pointers A straightforward approach, using a video codec, is not feasible because:
E N D
RTP Payload Format for Real-Time Pointers M. Reha Civanlar AT&T Labs - Research 45th IETF Oslo, Norway
Why do we need this? • In presentations, it is essential to transmit viewgraphs & real-time pointers • A straightforward approach, using a video codec, is not feasible because: • Viewgraphs require high spatial resolution • Pointer requires high temporal resolution 45th IETF - Oslo, Norway
Capturing the pointer, e.g. Document Camera Network Baseband Video Network Interface Video Capture VGA Interface Mouse Interface Projector Pointer Mouse (Pointer) Display PC, Workstation 45th IETF - Oslo, Norway
Payload format • draft-civanlar-pointer • 0 1 2 3 • 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 • +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ • |V=2|P|X| CC |M| PT | sequence number | • +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ • | timestamp | • +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ • | synchronization source (SSRC) identifier | • +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ • : contributing source (CSRC) identifiers : • +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ • |L| | x coordinate |R| | y coordinate | • +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ • MBZ MBZ 45th IETF - Oslo, Norway
Payload format • Payload: • The pointer's x and y coordinates are measured from the upper left corner of the associated display window in pixels. The associated window SHOULD be specified out-of-band. The coordinates are represented as 14 bit, unsigned integers. • When the M bit is set to one, L (left) and/or R (right) bits are set to one if their respective mouse buttons are down at the sampling time. • RTP Header Usage: • Marker (M) bit: Set to one if the payload carries information about mouse buttons. • Timestamp: The sampling time for the pointer location measured by a 1KHz clock. 45th IETF - Oslo, Norway
Issues: • More buttons • how many? • Represent pointer position as a fraction from 0 to 1 in both x and y directions. • resolution? • computational overhead • Loss resilience? 45th IETF - Oslo, Norway
Issues • Should this be a workgroup item? • Should we extend this to generic mouse coordinate transport? 45th IETF - Oslo, Norway