Originally Posted by brazen1
The picture VideoPlayer produces is on par with the Oppo the author provided using snapshots.
That is factually incorrect. That single, zoomed-out screenshot does not qualify as a critical analysis of image quality between a high-end Oppo video player and Nvidia DXVA2 video rendering through VideoPlayer.
There will always be a visible difference between these players, but given the source is a native 4K UHD video played on a native 4K UHD display, that visual difference may be small or even unnoticeable to most viewers. Many video calibration experts would testify that the image quality between the Oppo and Kodi VideoPlayer are not entirely identical. This has been true in previous comparisons between the Oppo players and other lower-quality Blu-ray players, of which VideoPlayer would be associated with, where the Oppo has been considered the better reference video player.
A better way to say it is that the visual differences between Nvidia DXVA2 video rendering and the Oppo player is not significant enough to ignore Windows and Kodi VideoPlayer as a viable way to watch and enjoy 4K UHD content on Windows.
Originally Posted by brazen1
I see at least one poster here prefers madVR tone mapping instead of passthrough on his $450 55" panel. I thought tone mapping was for 1080p SDR PJ's with huge screens that wanted to simulate HDR most of us with UHD chains simply passthrough. I wonder what benefits the tone mapping improvements vs passing through provide on that 55" entry level panel thus requiring madVR? Maybe I haven't taken something obvious into account?
Imo, madVR processing on a 55" UHD panel isn't even needed nor will you notice any big improvements now that there are other non-madVR HDR switching players using private GPU API's.
brazen, I think you are a fine contributor to the forums, but this is a horrible and uneducated statement about tone mapping and watching 4K HDR content on a TV.
Presenting HDR content on any display type has NOTHING to do with screen size or resolution. HDR video is about using a much larger range of brightness and contrast. In SDR video, blue peaks at only 8 nits. In HDR video, bright blue on a 1,000 nit display peaks at 80 nits, and HDR peak white can be as high as 10,000 nits. That is a massive increase in peak brightness that must be mapped from top to bottom by the display panel without clipping or dimming the image. The less peak brightness a display has, the less bright blue becomes and the more difficult it becomes to display that 10,000 nit highlight without clipping it or making the rest of the image too dim.
On Whiteboy's display, the image tends to be mapped with less accurate EOTF tracking and clipped highlight detail because it lacks the necessary peak brightness (range) to accurately display HDR video. Using madVR's tone mapping can offer a significant improvement in image quality by improving the display's gamma tracking at the low end to make the whole image brighter and by doing a far better job not clipping the specular highlights at the top of the range. This is no small thing for less bright displays.
Simply watching a video from start to end and saying I saw no visual loss of quality is not proof of faithful and accurate rendition of HDR video. With the right demonstration content, most displays will show obvious deficiencies in tone mapping quality during difficult scenes. Your edge-lit display with 500 nits of peak brightness cannot accurately represent the bright HDR highlights that occupy less than 10% of the screen area (e.g., most HDR specular highlights in HDR videos) without having a huge number of local dimming zones positioned at the back of the display and an appreciable increase in peak brightness to go with it. It is simply not possible with edge-lit LED technology to balance the dark parts and bright parts of the image at the same time to produce proper HDR highlights. If you don't object to watching any HDR scenes on your TV, then your display is doing a very good job of tone mapping. But that is not the case for many high-quality HDR displays.
Even the best current HDR displays struggle with this task at times. Take this brand new, expensive Sony A9F OLED for example. This image was posted in the Spears & Munsil UHD HDR Benchmark thread:
This screenshot comparison comes from the Spears & Munsil UHD HDR Benchmark disc. The first image is presented in Dolby Vision and shows a faithful rendition of the scene with a good tone mapping curve. However, when the display is asked to do the tone mapping itself with a HDR10 input, severe clipping of the highlights occurs, even when the source is first tone mapped to 1,000 nits by a Panasonic Blu-ray player. The peak brightness of this scene can't be managed by the display when taking the 1,000 nits input from the Blu-ray player, that has been already been tone mapped from 4,000 nits to 1,000 nits, and mapped to the 650-700 nits that the display can actually produce. Even with the small amount of tone mapping required, the display tone mapping still fails to preserve the majority of the highlights in the image. As a result, the whole image is blown out due to poor tone mapping.
Pixel shader tone mapping in madVR set to 650-700 nits could bring all of this highlight detail back into the image to look more like the Dolby Vision example. On a projector, even more tone mapping would be required to represent this scene, and converting the source to SDR would help balance the lower part of the image without dimming it too much while still leaving room to map the highlights and avoid blowing out the image. Again, for a projector owner, this type of tone mapping is no small thing.
This is a video that explains how HDR highlights are mapped back into display range with good tone mapping on TVs with proper HDR brightness levels, but static and ineffective tone mapping curves. It is called the Panasonic HDR Optimizer and is similar to the option available in madVR when you choose pixel shaders with HDR output:
This form of tone mapping can even benefit bright HDR TVs that use straight HDR passthrough because the shape of the tone curve used by madVR is better at preserving bright specular highlight detail and the tone mapping can be done dynamically for each scene.