Deterministic Playback - AJA Ki Pro Ultra Control Manual

Chapter 4 – Deterministic Playback
The amount of time between the issuance of a normal play command and when
the device actually begins to play is variable and dependent on several factors
like the type of storage media in the device and the clip media type.
If it becomes necessary to start playback in a frame accurate manner, you can
choose to use the device's deterministic playback functionality. This functionality
assumes that the device is locked to an external video reference and the
controller is receiving this same reference. It also assumes that the controller is
timing the transmission of commands to the device at the beginning of each
frame (as determined by the video reference).
In order to arm for deterministic playback, the device must have previously been
put into still playback. If you attempt to arm deterministic playback without
having done this, the arm will fail and the deterministic playback arm enable bit
in the status will never go high.
Here is the basic strategy for using the deterministic playback functionality. This
example assumes the controller is controlling multiple devices and is making
sure they all start at the same point in time (thus ensuring all the device's
playback is synchronized).
1. Controller should cue all devices to their start timecode using the cue up
command (0x24 0x31). This will put all the devices into still playback and parked
on the frame that was given as part of the cue command.
2. Poll the status and check for one of the following:
3. Wait an additional two seconds. This delay takes allows for the worst case of the
device coming out of EtoE mode (which will require some settling time).
4. Issue a sync playback arm command (0x20 0x08). This will setup the device to
prepare for sync playback. After this command is issued, the "sync playback
armed" status bit will be high (Bit 0, Byte Offset 0x0A). You can clear the sync
playback arming by issuing the sync playback disarm command (0x20 0x09).
This will put the device back into normal playback mode (and still playback on
the current frame). It will also clear the bit mentioned previously. Any transport
command (besides play) will clear the sync playback arming.
5. Wait for the "sync playback ready" status bit (Bit 1, Byte Offset 0x0A) to go high.
When this bit goes high, this is an indication that the device is now ready to
accept a play command and it will be guaranteed to start with a fixed delay.
6. Issue the play command (0x20 0x01). At this point, the device will start playback
after some fixed number of frames from the frame of command issue. When
controlling multiple devices, it is important that timing of the play command to
each device happen at roughly the same time.
Ki Pro Ultra and Ki Pro Ultra Plus Machine Control Guide
1. "Cue up Complete" flag (Bit 0, Byte Offset 2)
2. "Function Abort" flag (Bit 7, Byte Offset 9)
3. Timeout (5 seconds is reasonable)
If Function Abort or Timeout, this is an error condition, sync will not
be possible.
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