While the HU85LS is focused on business/education applications, they are equipped with video processors similar to those utilized in LG’s 4K HDR TVs. One benefit of using such a powerful processor is the HU85LS can dynamically tone map HDR content.
The HDR provides a significant improvement in dynamic range as well as color. It lets you see more detail in the shadows and the bright areas and delivers more saturated lifelike colors.
HDR consumer content (4K blu-ray and streaming) is mastered for playback on a flat panel not a projector, so it’s produced at a variety of brightness levels ranging from 1,000 nits (292 fL) to 4,000 (1167fL) nits.
Most 4K HDR-capable projectors can only deliver between 100 nits (29fL) and 200 nits (58 fL). This means no HDR-compatible Home Theater projector can reproduce all the brightness found in consumer HDR content.
HDR projectors utilize tone mapping, which compromises maintaining bright highlight details and delivering full-screen brightness. There is a variety of information embedded in HDR content that an HDR display uses to make picture adjustments. There’s an HDR Infoframe that triggers the projector to switch to the appropriate HDR mode.
When the HDR info frame is detected, most HDR projectors switch to HDR mode with a fixed tone map. It is basically one size fits all, which hurts HDR performance.
Since the MaxFALL/MaxCLL metadata is based on the brightest frame’s average brightness and brightest pixel in the movie, certain scenes with lower than average frame levels can still look way too dark.
Higher-end LCD and OLED TVs have been able to measure the HDR content frame-by-frame to generate accurate metadata dynamically for years. Like LG’s Flat panels, the HU85LS can dynamically measure HDR metadata, which further improves the projector’s HDR performance. The goal is to utilize better the HU85LS’s brightness capabilities based on the content being shown.