All questions answered
What is GhostFrame?
GhostFrame is a powerful suite of features for virtual production and XR stages, broadcast, film and live production. GhostFrame makes it possible to simultaneously capture multiple independent images on camera by interleaving multiple frames of different content between each regular video frame. For this to work, the camera is required to run at a high frame rate.
How will this make my LED screen look?
The innovative and patented technology of GhostFrame allows the multiple content feeds for be played out while the human eye sees only one, still allowing the camera to capture each of the desired content frames.
How does GhostFrame affect the pixel capacity of the complete system?
When using GhostFrame Chroma and GhostFrame Track, there is no reduction of system capacity or reduction in how many LED panels can be connected on an Ethernet chain. Furthermore, there is also no burden to your render engine. This is a significant benefit over other systems.
How does GhostFrame affect the bit depth?
As the number of slices increases, the LED panel will dynamically reduce bit depth as needed.
Typical bit depth depends on the LED panel but is typically around 16-bit. It depends on the LED panel design, but it may drop the bit depth down to 12-bit grayscale when using the maximum number of slices. Bit depth is affected equally across all slices. Driver data is always sent as 16-bit, but grayscale clock limitations for increased slices will reduce the effective grayscale bit depth.
Will I experience luminance loss on the screen?
As more slices are added, it does drop the driver efficiency somewhat. This is LED panel design-dependent, but it won't typically cause the screen output to get visibly dimmer.
Which LED panels are supported with GhostFrame
GhostFrame only works in combination with ROE Visual LED panels and HELIOS Processing. ROE Visual Black Marble BM4, Black Pearl BP2 and BP2V2, Black Quartz BQ3.9, and Ruby RB2.3 all are tested to work with GhostFrame. Please contact ROE Visual for uptodate information, since extensive testing is ongoing.
How multiple source is Multiple Source?
You can actually add 4 different inputs simultaneaously in the system. Of course these inputs need to be synced. This will allow you to have 4 independent video feeds resulting in maximum of 4x4K input.
How do I select what's visible on the screen?
With up to four different inputs you need to be able to select what input is shown on the screen. This is done in the GhostFrame matrix in the HELIOS processor and works as simple as just selecting the content you want to display.
How is GhostFrame supported?
All technical experts involved in the GhostFrame development will host regular online seminars and demos. The GhostFrame features come with compulsory initial training before starting; this will help you understand the process and workflow.
Which shutter types are compatible with GhostFrame?
GhostFrame is compatible with both global and rolling shutter types. Because of the ramp-up time in a rolling shutter, it accommodates fewer slices. You need to tweak the settings to find the sweet spot where the sensor is active. The advantage is that due to this, you have less-to-no artifacts. Tweaking the slices' timing will also help ensure the video is only displayed when the sensor is fully active (after ramp-up and before ramp-down).
Which adjustments do you need to make on the camera to tune it to a particular slice?
Using the ECS - electronic shutter – of the camera, you tune it to one slice, setting the other slices to black while adjusting. Play around with the settings till its' perfect. You'll have to sync the camera each time again.
Can you mathematically calculate the exact sensor setting, or does this require tweaking?
The timing can be calculated, and we'd like to make it an automated process; however, every camera sensor is different. They all have different tolerances, so manual tweaking or fine-tuning is always needed. In the processor, you can offset slices per nanosecond to align your systems.
Will you lose light/brightness by adding the GhostFrame features, requiring you to adjust the brightness?
You will both lose some greyscale/bit depth and light with each feature added. However, ROE Visual LED panels can do a much higher brightness than what is typically needed for shooting with a camera. Hence, loss of brightness is not an issue for most situations.
Does hiding the feeds, chroma key, and/or tracking markers for the naked eye cost any pixel capacity bandwidth?
No. All this is handled in the receiver card.
How much of the tracking do you need to see to keep the tracking system working?
Even when you only see 20% of the screen, e.g., due to a large set-piece, the tracking system will still work correctly.
How often does the tracking system need to be re-calibrated?
Once installed and calibrated, re-calibration of the tracking system is not needed; this is done automatically.
What is the feedback loop/lag for the tracking compared with other systems?
The delay or latency, or lag, is essentially caused by the processing. For GhostFrame, this is only one frame delay.
Can you store the tracking data?
Yes, you can export the coordinates to the cloud to use these, e.g., for unreal engine to match it with real objects.
You can export tracking data and time codes for reference and store this in a file.
What camera framerate is required to utilize GhostFrame?
A high framerate broadcast camera running at a multiple of the LED screen's framerate will be needed to capture, seperate, and output multiple video feeds, while a camera running at the same rate as the LED screen will only capture one feed but can still benefit from artifact reduction.
Will GhostFrame work with cell phone cameras of live viewers?
GhostFrame requires running at the same frame rate and requires tight synchronization of the camera’s shutter/exposure time to the LED wall in order to tune to alignment with the sub-frames being displayed. As cell phones do not have this capability, it will not be able to tune and distinguish specific sub-frames.