Previzion UDP output protocol

Revision 1.4

October 1, 2008





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The message contains 59 bytes as follows:



Item Bytes Description



<HEADER> 1 The Packet Header is [D1] hexadecimal

<CAMERA> 1 Camera ID

<HOURS>  1 Timecode Hours

<MINUTES>1 Timecode Minutes

<SECONDS>1 Timecode Seconds

<FRAMES> 1 Timecode Frames

<PAN>    3 Camera Pan Angle in units of 1/32768 degree

<TILT>   3 Camera Tilt Angle in units of 1/32768 degree

<ROLL>   3 Camera Roll Angle in units of 1/32768 degree

<X>      3 Camera X-Position in mm

<Y>      3 Camera Y-Position in mm (Y is vertical axis)

<Z>      3 Camera Z-Position in mm

<DPAN>   2 Camera Pan rate in units of degrees/second

<DTILT>  2 Camera Tilt rate in units of degrees/second

<DROLL>  2 Camera Roll rate in units of degrees/second

<DX>     2 Camera X translation rate in units of mm/sec

<DY>     2 Camera Y translation rate in units of mm/sec

<DZ>     2 Camera Z translation rate in units of mm/sec

<ZOOM>   3 Focal length (000.00 - 167,772.15 mm). 

<FOCUS>  3 Focus        (000.00 - 1,677,721.5 mm). 

<IRIS>   2 Iris         (000.00 - 655.35 T). 

<IO>     3 Interocular distance (000.00 - 1,677,721.5 mm)

<CONV>   3 Convergence  (000.00 - 1,677,721.5 mm)

<HFOV>   3 Horizontal Field of View (000.00 - 1677.7215 deg)

<VFOV>   3 Vertical Field of View   (000.00 - 1677.7215 deg)

<STATUS> 2 Spare / User Defined (16 bits)

<SUM>    1 Checksum (sum of Bytes 1 to 58, mod 256)



The Camera Pan and Tilt angles are expressed in degrees as a 24-bit twos-complement

signed number, where the most-significant bit (bit 23) is the sign bit, the next 8 bits

(bits 22 to 15) are the integer part and the remaining bits (bits 14 to 0) are the

fractional part; alternatively, this may be thought of as a signed integer value in units

of 1/32768 degree. The range of values is from -180.0 degrees (A60000 hex) to

+180.0 degrees (5A0000 hex).



The Camera X, Y and Z-Positions are expressed in millimetres as a 24-bit twos-complement

signed number, where the most-significant bit (bit 23) is the sign bit, the

next 17 bits (bits 22 to 6) are the integer part and the remaining bits (bits 5 to 0) are

the fractional part; alternatively, this may be thought of as a signed integer value in

units of 1/64 mm. The range of values is from -131,072.0 mm (800000 hex) to nearly

+131,072.0 mm (7FFFFF hex).



The Camera X, Y, and Z positions are located at the center of a line between the two nodal

points of the cameras, with that line's length being the interocular distance. 



Camera DPAN, DTILT, AND DROLL are expressed in degrees/sec as a 16-bit twos-complement signed number,

where the most-significant bit (bit 15) is the sign bit. The range of values is -3,276.7 

degrees/second to 3,276.7 degrees/second.



Camera DX, DY, and DZ are expressed in mm/sec as a 16-bit twos-complement signed number,

where the most-significant bit (bit 15) is the sign bit. The range of values is -32,767 mm/sec

to 32,767 mm/sec. 



Zoom, Focus, Interocular, and Convergence are three byte, unsigned hex distance values. The most 

significant byte is transmitted first. Range is from 0x00 0x00 0x00 to 0xFF 0xFF 0xFF, 

corresponding to a real world value of 0 to 167,772.15 mm (Zoom) or 0 to 1,677,721.5 mm 

(Focus, Interocular, Convergence.)



Horizontal and Vertical Field of View are three byte, unsigned hex angular values. 

The most significant byte is transmitted first. Range is from 0x00 0x00 0x00 to 0xFF 0xFF 0xFF, 

corresponding to a real world value of 0 to 1677.7215 degrees. 



The Convergence distance represents the distance from the Camera Position XYZ point to the point

where the two axes of the left and right virtual cameras cross the axis of the central Camera.



Iris is a two byte unsigned hex value. Most significant byte transmitted first. 

Range is 0 to 655.35 T.