User`s guide

118 007-4403-003
9: Introduction to MVCP
8. Play U2 as with U1 above.
% /SEQA /SYNR PLAY U2
200 OK
9. Load next clip into U1.
% LOAD U1 clip3 OUT
202 OK
clip3 movie/dif/dvcpro 108969984 108969984 00:00:00.00
00:00:30.08 * * 29.97 19990415T004148.636950Z CL
10. Cue U1 with a queued command.
% /SEQA CUE U1
200 OK
11. Play U1 as above.
% /SEQA /SYNR PLAY U1
200 OK
Monitoring Unit State
When executing a play list, you can display the state of the list execution. Using MVCP
this can be accomplished by polling, but a more efficient solution is to utilize unit
monitoring. Unit monitoring provides asynchronous events describing the change in
state of a unit, such as execution state, loaded clips, or timecode location. Details of unit
monitoring can be found in the section “Monitoring” on page 119. Typically, a separate
MVCP connection will be initiated for monitoring.
In the play list algorithm in the preceding paragraph, a unit monitor could be started
after the units are created to trace unit execution. This would allow a control application
to trace which clip was being played and the timecode location of the unit in the clip.
Note that the information provided by unit monitoring describes the unit state and
locations. The actual video frame timecode leaving the server port will be some fixed
number of frames behind that time due to codec delays. This delay is format-dependent
and can be found in Table 9-1. The table shows the difference between the time reported
by the unit and the actual video frame at the server port at that time. For instance, with
DVCPRO 25 on record the unit status reports three frames behind the frame on the input