Synchronization
When working with external synchronization sources such as Genlock, the internal timing reference of the system should also be verified.
Grid Studio normally uses the sound card quartz clock as a stable internal timing source when no external clock is available. However, some systems expose audio interfaces through devices such as HDMI outputs, webcams, or virtual audio drivers that do not provide a stable hardware clock.
In time-critical setups (such as tracking pipelines or synchronized render systems), these devices can introduce timing instability or jitter.
If no proper sound card is available, it is recommended to set the Sound Device to None in the Project Settings.
See Sound Card → Timing Source for more details.
Overview
For time-critical systems, Grid Studio can synchronize its internal processing to an external clock source.
This is commonly required when working with systems such as:
camera tracking pipelines
media servers
real-time engines (for example Unreal Engine)
broadcast or virtual production setups
Instead of relying on internal timing, Grid Studio can lock its frame processing to an external video signal that is synchronized via Genlock.
This ensures that all systems in the pipeline operate on the same frame timing.
Genlock Input Setup
To synchronize Grid Studio with an external Genlock signal, a MediaInput object must be created in the Project Tree.
Most SDI capture cards unfortunately do not expose the Genlock pin to software. The Genlock signal is typically used internally by the card only for synchronizing outgoing signals. Because of this limitation, Grid Studio must instead synchronize using the incoming SDI video signal.
This SDI signal should itself be synchronized to the external Genlock clock.
Recommended Signal Source
While it is technically possible to use a camera feed, it is recommended to use a dedicated video test signal generator that is synchronized to the Genlock clock.
Example device:
https://lynx-technik.com/p/pvd-1800/
These devices generate a stable SDI test image that is synchronized to the external clock.
Using a signal generator ensures that:
a valid signal is always present
synchronization remains stable
the system continues to run even if a camera is powered off
Configuring the MediaInput
Inside the MediaInput object, select the SDI input device in the Device setting.
Use as ImageProvider
This option should only be enabled temporarily for debugging purposes.
When enabled, the incoming signal can be inspected in the Viewer view to confirm that the signal is received correctly.
Once the signal has been verified, this option should be disabled again.
Disabling the ImageProvider ensures that Grid Studio attaches directly to the frame receive timing without performing unnecessary image processing.
This improves synchronization accuracy.
Project Frame Rate
Before configuring Genlock synchronization, the Project Frame Rate must be set correctly.
The project frame rate should match the expected system timing.
Configuring the Genlock Provider
Open the Time Manager.
This can be accessed through the System Status Bar by clicking the TC indicator.
Inside the Time Manager, open the Genlock Provider tab.
Select the MediaInput object as the Genlock provider.
Genlock Interpolation
Two interpolation modes are available:
None Interpolation
Adaptive Interpolation
None Interpolation
If the Project FPS matches the SDI signal frame rate, interpolation must be set to None.
Example:
SDI signal: 60 fps and project FPS: 60 fps
In this case the system can lock directly to the incoming frame ticks.
Adaptive Interpolation
If the Project FPS is higher than the SDI frame rate, Adaptive Interpolation must be enabled.
Example:
SDI signal: 30 fps and project FPS: 60 fps
In this situation Grid Studio interpolates additional ticks between incoming frames.
For stable behavior, the project frame rate should be a multiple of the SDI frame rate.
Examples that work well:
30 → 60 fps
60 → 120 fps
30 → 120 fps
Examples that should be avoided: 30 → 50 fps
Interlaced Signals
A special case occurs when the incoming SDI signal is interlaced.
With interlaced signals, only every second frame is received by the system.
Example:
60 fps interlaced signal → effectively becomes 30 fps frame updates
If the project frame rate is configured to 60 fps, Adaptive Interpolation must be enabled in order to generate the missing frames.
Synchronization Status
When a Genlock provider is configured, the Project FPS indicator in the System Status Bar changes color depending on the synchronization state.
Four status colors exist:
Gray — Freerun No external synchronization is active.
Red — No Signal A Genlock provider is defined, but no signal is received.
Orange — FPS Mismatch The provider frame rate does not match the project frame rate.
Green — Locked Grid Studio is successfully synchronized to the external clock.
Debugging Synchronization
The Time Manager provides analysis tools that can help diagnose synchronization behavior.
Inside the Timecode tab, a timing analyzer can be used to inspect the delta between frame ticks.
This helps verify whether the system is receiving a stable and consistent external clock.
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