JVC DLA-NX7 4K Projector Review-Special Features 1

Posted on August 31, 2019 by Phil Jones

JVC DLA-NX7 4K Projector Review-Special Features 1: Native 4K Resolution, DILA LCOS Panels, Wide Color Gamut, HDR Compatible

NATIVE 4K UHD RESOLUTION

The JVC DLA-NX7 utilizes JVC’s new 0.69inch 4K D-ILA (4096 x 2160) devices x native 4K (3840 x 2160) resolution. The projector can also accept HDR signals up to 4K@60P.

Many manufacturer including JVC and Epson sell pixel shifting HD (1,920 x 1,080) projectors. Combined with good image processing, Pixel Shifting can do a very nice job emulating the original 4K content. Pixel shifting fires each pixel twice by shifting the location by 1/2 pixel diagonally. Small type and fine details that can’t be discerned on a basic 1,080p projector can often be resolved with pixel shifting. It is enough to make a real readability difference on CAD, engineering, and scientific drawings renderings and anything else demanding max detail.

In many situations the content, including movies, lacks enough fine detail required or is viewed so far away that the difference between 4K and pixel shifting cannot be perceived. Over the years, JVC has produced some great pixel shifting projectors, in fact the e-shifting JVC DLA-RS440U won a Hot Product Award in 2018.

It is only when you do a side-by-side comparison between a true 4K projector versus a 2K pixel shifting projector using highly detailed content that the resolution difference is truly noticeable. While a pixel shifting 2K projector can accept 4K content, the projector’s native resolution is only 2.3 MP, it won’t be as sharp/detailed as a true 4K projector (8,8 MP resolution).

The images below show the resolution difference between the JVC DLA-NX7 and HD projector utilizing pixel shifting for comparison when native 4K content is displayed.

JVC_NX7_PQ-6 — An 8.8MP photo of a newspaper page

4k-vs-Pixel-Shift_4K — In 4K, the line text is crisp and readable

4K-vs-Pixel-Shift-OFF - Projector Reviews Image — When displayed in native HD, the fine text blurry and unreadable

4K vs Pixel Shift-ON — Pixel shifting on a HD projector dramatically improves clarity over native 2K

A 4K native projector offers more resolution, but a good pixel shifting unit can cost less. For example, if you look at JVC’s own model lineup, the native 4K DLA-NX7 costs $8,999 while the e-shifting, higher contrast DLA-X790R retails for $3,999.

So how do I choose between a native 4K DLP projector like the DLA-NX7 or a pixel shifting 3LCD projector? To make a wise decision you must factor in your budget, what you are watching, and how far away are you are watching it.

Wide Color Gamut

The new HDR standard not only offers more dynamic range they also deliver a rich color palette. The older SDR format used the REC709 but HDR material uses the expanded color provided by the BT.2020 standard. No consumer display can reproduce 100% of the BT2020 standard, in fact most commercial device can’t either. Even if the HDR content is mastered it is probably shot in the DCI-P3 standard and BT2020 is just used as a wrapper.

While the color space of DCI-P3 is smaller than BT2020, it still has a much larger color space than REC709. The advantage of DCI-P3 is more possible colors and colors that are richer and more saturated.

CIE chart — CIE Chart showing color gamuts of REC709 (HDTV) the smallest triangle,, P3, and BT.2020 (largest).

Natively the DLA-NX7 reproduces approximately 96% of the DCI-P3 color space. To maximize color performance, some companies like JVC give you the option of adding a “cinema” filter to the light path to provide wider and more accurate color palette. By utilizing a color filter, the DLA-NX7 delivered 99% of DCI-P3 color space and good portion of the much larger BT2020. Also note that when the DLA-NX7 color filter is utilized, there is a drop in brightness.

That is much better than any of the lamp powered 4K UHD projectors can do. When you have 4K content serving up DCI-P3 or BT.2020, this DLA-NX7 is one of the few lamp-based projectors that can take advantage of the step up in color quality.

HDR COMPATIABLE – HDR10 AND HLG

The HDR provides a major 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.

There are two HDR standards, with the first being the PQ (ST2084). While there are three variations of PQ, most projectors are only compatible with HDR10 which is most commonly used for UHD Blu-ray discs (4K movies), and recorded streaming content. Dolby Vision, HDR10+ like the more mainstream HDR10 are also based on PQ (ST2084). The only difference between the three PQ based formats is what type of HDR metadata is delivered to a video display to help it tone map HDR content to fit a display’s brightness capabilities.

The second HDR standard is HLG (Hybrid Log-Gamma) and it was developed for live broadcast. The DLA-NX7 supports both HDR10 and HLG. Since most HDR10+ and Dolby Vision content is either backward compatible with or available in HDR10 you can enjoy 99% of HDR content available on the market now and in the future

HDR AUTO TONE MAPPING

There is a variety of information embedded in HDR content that an HDR display uses to make adjustments. First there is an HDR Infoframe which triggers a display device to switch to the appropriate HDR mode. Next is metadata which a display uses to tone map HDR content. Let’s discuss why tone mapping is needed.

When you go to your local HDR equipped commercial theater (like an AMC Prime) you are viewing HDR material specifically mastered for front projection with a set brightness level of 31 fL (106 nits). Unfortunately, that type of HDR material is not available to consumers. HDR consumer content (4K blu-ray and streaming) is mastered for playback on a flat panel, so it’s produced at a variety of brightness levels ranging from 1,000 nits (292 fL) to 4,000 (1167fL) nits.

Most under $10,000 4K HDR capable projectors can only deliver between 100 nits (29fL) and 200 Nits (58 fL). This means that no HDR projector is capable of reproducing all brightness found in HDR content.

As a result, HDR projectors utilize tone mapping which is a compromise between maintaining bright highlight details and delivering full screen brightness. In a perfect world, tone mapping would not be required because you are not reproducing the signal accurately which means you are deviating from the creator’s intent.

Each manufacturer tackles tone mapping differently. For example, some projector manufacturers choose to show more highlight detail, but their overall picture will appear to be a little darker. Some will raise the brightness of the overall scene; highlights will appear to be blown out. One approach is not necessarily better or worse, just different.

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.

This year JVC has introduced Auto Tone Mapping which automatically adjusts the projector’s HDR settings (tone mapping) to try to optimize HDR10 image quality. The goal is to better utilize the NX7’s brightness capabilities based on the image on screen. The NX-7 uses the static HDR metadata to make tone mapping adjustments. The two pieces of metadata that the projector’s video processor uses for HDR tone mapping are:

• MaxFALL (Maximum Frame--Average Light Level) average brightness of the brightest frame in the entire clip. Authoring guidelines state that this should not exceed 400 nits.
• MaxCLL (The Maximum Content Light Level) which is the brightest pixel in the entire clip.

The average brightness of a most HDR video frames are usually much less than 400 nits with a few peak highlights (sparks, flame tips, reflections) reaching up to 10,000 nits.

In many cases the metadata is missing or incorrect so the DLA-NX7 might not have the right information to work with. While NX-7 uses the MaxCLL and MaxFALL metadata should be embedded in the HDR Content, better LCD and OLED TVs actually measure the HDR content frame by frame to generate accurate metadata dynamically. Adding the capability of measuring HDR metadate would further improve the HDR performance of projectors.

Since the embedded static MaxCLL and MaxFALL is applied throughout the entire movie sometimes the tone mapping decisions made by the projector can be a little off.

However since the MaxFALL or MaxCLL metadata is static based on the average brightness of the brightest frame and brightest pixel in the movie, certain scenes with lower than average frame levels can still be way too dark. An example is Stranger Things season 3 episode 7 – in the JVC default setting, the brighter scenes look great, but the darker outdoor night scenes were nearly unwatchable.

The nice thing is you can fine tune the look of HDR to fit your taste by using the Mapping Level adjustment. Sony FPJ has “HDR Contrast” to adjust average screen brightness depending on customers’ environments or preferences as well.

BTW, since HLG is based on a Gamma curve just like SDR, it does not need to be tone mapped by the projector.