HDR Video Explained
Sunset HDR
HDR video works by mastering content in a way that maximizes peak white luminance to allow for brighter highlights and more texture detail in bright image areas. Colorists have worked with a peak brightness limit of 100 nits for BT.709 HD content for decades. However, current displays are now much brighter than 100 nits and have been so for a long time, so this legacy SDR contrast range is severely restrictive and often leads to clipping at the top of the range and the need to compress high-contrast footage.
HDR enhancement also defines reference white (normal diffuse white) as 100 nits, but avoids clipping the brightest details by leaving room for specular highlight detail up to 10,000 nits. Because most of what we can see was already contained in the SDR range, the Average Picture Level, or APL, of HDR video still remains largely under 100 nits, but the increased range of brightness allows for the creation of scenes with more natural contrast and lighting with realistic brightness peaks for very bright elements like the midday sun or the chrome reflection on a car.
This increase in peak brightness doesn’t just benefit the highlights. Many colors are now able to be brighter and more colorful in HDR, even current BT.709 colors in the SDR range, due to the freedom provided by a much higher peak white limit. Combined with an expanded color gamut, the result can be images with significantly improved color volume and contrast.
Understanding UHDTV Displays with PQ/HLG HDR and WCG
High Dynamic Range (HDR): An Explanation of Dynamic Range, Resolution, Color, and Calibration
TVs Are Only Getting Brighter, but How Much Light Is Enough?
Comparison Photos of HDR and SDR and Information on HDR Mastering
Grading, Mastering, and Delivering HDR
HDR Video & Color Volume
The HDR Ecosystem Tracker (mid-2019)
I've found something odd about madVR. I initially tested the scaling settings with a 1080p Blu-ray of high quality. It didn't drop any frames and everything was fine. However I then tried some lower quality 720p and 1080p sources and all of a suddenly I had massive framedrops. I have a 980 Ti so I shouldn't have this problem right?
depends on your settings.
there are settings no card can do.
(2016-05-27, 13:08)dolken Wrote: [ -> ]I've found something odd about madVR. I initially tested the scaling settings with a 1080p Blu-ray of high quality. It didn't drop any frames and everything was fine. However I then tried some lower quality 720p and 1080p sources and all of a suddenly I had massive framedrops. I have a 980 Ti so I shouldn't have this problem right?
Your settings must be too aggressive. Are you using high values of NNEDI3? Are you upscaling to 4K?
(2016-05-27, 14:42)huhn Wrote: [ -> ]depends on your settings.
there are settings no card can do.
(2016-05-27, 18:53)Warner306 Wrote: [ -> ]Your settings must be too aggressive. Are you using high values of NNEDI3? Are you upscaling to 4K?
I cant' remember as I've since changed the settings to default madVR ones, but I believe I was using NNEDI3 at 128 neurons for upscaling and doubling and it worked fine with the high quality source but not with the lower quality source. Is it possible for video files to be encoded so badly that they require more resources or have bugs in them that make the player drop frames?
(2016-05-28, 00:59)dolken Wrote: [ -> ] (2016-05-27, 14:42)huhn Wrote: [ -> ]depends on your settings.
there are settings no card can do.
(2016-05-27, 18:53)Warner306 Wrote: [ -> ]Your settings must be too aggressive. Are you using high values of NNEDI3? Are you upscaling to 4K?
I cant' remember as I've since changed the settings to default madVR ones, but I believe I was using NNEDI3 at 128 neurons for upscaling and doubling and it worked fine with the high quality source but not with the lower quality source. Is it possible for video files to be encoded so badly that they require more resources or have bugs in them that make the player drop frames?
The quality of the video isn't the problem; it is the use of image upscaling. madVR uses a lot resources adding pixels to the image. At 1080p, a 720p -> 1080p upscale requires the most resources.
(2016-05-28, 03:11)Warner306 Wrote: [ -> ]The quality of the video isn't the problem; it is the use of image upscaling. madVR uses a lot resources adding pixels to the image. At 1080p, a 720p -> 1080p upscale requires the most resources.
But how does that mean that the high source 1080p video doesn't have frame drops but the low source 1080p video does? This is really weird.
(2016-05-28, 18:30)dolken Wrote: [ -> ] (2016-05-28, 03:11)Warner306 Wrote: [ -> ]The quality of the video isn't the problem; it is the use of image upscaling. madVR uses a lot resources adding pixels to the image. At 1080p, a 720p -> 1080p upscale requires the most resources.
But how does that mean that the high source 1080p video doesn't have frame drops but the low source 1080p video does? This is really weird.
Maybe the low quality 1080p source is missing pixels and needs to be upscaled slightly. Otherwise, it shouldn't matter.
(2016-05-28, 19:11)Warner306 Wrote: [ -> ]Maybe the low quality 1080p source is missing pixels and needs to be upscaled slightly. Otherwise, it shouldn't matter.
Sounds weird. On another note, is it normal for madVR to drop frames in the very start of the video but never again later?
(2016-05-29, 02:21)dolken Wrote: [ -> ] (2016-05-28, 19:11)Warner306 Wrote: [ -> ]Maybe the low quality 1080p source is missing pixels and needs to be upscaled slightly. Otherwise, it shouldn't matter.
Sounds weird. On another note, is it normal for madVR to drop frames in the very start of the video but never again later?
pretty much normal for every renderer.
you can try delay playback start until render queue is full
(2016-05-29, 07:09)huhn Wrote: [ -> ]pretty much normal for every renderer.
you can try delay playback start until render queue is full
Thanks, though I'm pretty sure I ticked both boxes for delaying playback until the queue is full. But maybe it has to do with me entering exclusive fullscreen mode?
that's normal too it has to re render all buffered frames at a different resolution.
(2016-05-30, 04:53)huhn Wrote: [ -> ]that's normal too it has to re render all buffered frames at a different resolution.
Thanks, seems there's nothing wrong with my GPU or madVR after all.
So I'm getting quite annoyed by this:
I've configured my MadVR to maximize the full extent of my GPU and have setup various profiles for the various types of content I'm playing on my 4K screen.
For some reason, at various points throughout playback, I start skipping frames and find that my GPU usage, GPU temperatures,GPU fan speed and Power utilization fall in conjunction with the frame skipping. This seems to imply that the frame skipping is being caused by my GPU performance taking a sudden hit, or something else is causing both.
Does anyone have any ideas? I thought it may be the temperature of the GPU causing it to throttle, but I have an Asus Strix Nvidia 980 Ti and I don't believe it is meant to auto-throttle until it hits 83 degrees C, and I have setup my fan profiles such that the temperature reading maxes out at 80.
Please help me out with this - I'm worried it's a problem with the GPU - but it also seems to be something more than an actual hardware failure.
Thanks!
(2016-07-01, 21:29)hassanmahmood Wrote: [ -> ]So I'm getting quite annoyed by this:
I've configured my MadVR to maximize the full extent of my GPU and have setup various profiles for the various types of content I'm playing on my 4K screen.
For some reason, at various points throughout playback, I start skipping frames and find that my GPU usage, GPU temperatures,GPU fan speed and Power utilization fall in conjunction with the frame skipping. This seems to imply that the frame skipping is being caused by my GPU performance taking a sudden hit, or something else is causing both.
Does anyone have any ideas? I thought it may be the temperature of the GPU causing it to throttle, but I have an Asus Strix Nvidia 980 Ti and I don't believe it is meant to auto-throttle until it hits 83 degrees C, and I have setup my fan profiles such that the temperature reading maxes out at 80.
Please help me out with this - I'm worried it's a problem with the GPU - but it also seems to be something more than an actual hardware failure.
Thanks!
Have you tried going from NNEDI3 to super-xbr to reduce the load on the GPU?