FSI DM160 - HDR Preview Modes

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HDR Preview
The ST2084 HDR Preview Modes have been designed to provide an affordable monitoring option for PQ (ST2084) signals.
These modes are not a replacement for proper HDR monitoring and all reference level HDR evaluation should be done on a
true HDR reference display. However, the HDR Preview Modes are useful in production, broadcast, and other environments
where a PQ signal is being distributed beyond just the master reference display(s). HDR Preview Modes allow for approxi-
mate/rough normalization of PQ signals that can be both more useful and visually pleasing to operators than just monitoring
the PQ signal without adaptation on SDR monitors.
Two basic ST2084 (PQ) Preview Modes are offered, ST2084-Clip and ST2084-SoftRoll. These can then be further com-
bined with a variable gamut selection. Before exploring the difference between Clip and SoftRoll options let’s review some
key monitor settings normally used when in HDR Preview Mode. PQ is nominally full range so (assuming a normal HDR
workow) you will want to ensure that the monitor is congured in full range:
Color Management -> SDI Black Level -> Data
Color Management -> Video Clipping -> Off
Next, you will select the appropriate color gamut on the monitor. The HDR Preview Modes will work with any color gamut
selection, but typically HDR is intended for use in Rec2020 or P3 gamut. A white point of 6500K is also typical and should
be selected if not already active.
Color Management -> Color Space -> DCI P3 or BT.2020
Color Management -> Color Temperature -> 6500K
Next, activate one of the two available HDR Preview Modes:
Color Management -> HDR - ST2084-Clip or ST2084-SoftRoll
present in the signal remains visually distinguishable. This can be a great tool for ensuring that information is not being
sensor-clipped at the camera and it more generally gives operators a usable image even when the signal represents higher
average picture levels.
When activated, the monitor is automatically congured to a custom 300nit peak luminance output so the normal Luminance
Mode toggles will become greyed out.
The two ST2084 Preview Modes serve two distinct purposes and switching between them depending on the application
needs or shot parameters is common.
ST2084-Clip will follow the PQ EOTF response precisely up to 300nits. For code values representing luminance targets
over 300nits the signal is simply clipped. Under 300nits the on screen mapping will be very similar to a true HDR reference
monitor. ST2084-Clip is ideal when monitoring signals with relatively low average picture levels and/or with peak signal
levels generally limited to 300nits. When dealing with HDR signals in this range the ST2084-Clip mode will do a surprisingly
good job of matching HDR reference displays. ST2084-Clip mode is not well suited to monitoring high average picture level
signals or signals with a signicant amount of highlight detail over 300nits. For such signals, ST2084-SoftRoll is much more
suitable.
ST2084-SoftRoll follows a PQ EOTF reference response accurately to approximately 100nits. Above 100nits a soft roll is
implemented in the EOTF, whereby the output luminance level no longer corresponds precisely with the input code value’s
target luminance, but importantly increasing signal code value levels continue to result in actual increasing luminance output
on screen. The result is that while the monitor no longer tracks along the PQ reference EOTF exactly, highlight detail
Color Management Menu - HDR Preview