8k UHD vs 8k HD Playback

[Jarilo]

What would cause an issue where specifically the 8192 x 4096 (8k UHD) resolution would start to play just fine but a minute into the video would stutter and stop playing ( sound continues ) where as 7680 x 3840 (8k HD) is perfectly fine. This happens in or out of VR on any player (VLC, WMP, Whirligig). CPU is around 25% usage during both and GPU is on new drivers etc. Hardware is claimed to support both. Codec pack is installed by LAV, unless it's missing something.

[JazzKungFu]

Origineel geplaatst door Jarilo:

Perhaps this card has some kind of video rendering limitations on the codecs.

Origineel geplaatst door GT500:

It may not be an issue with how fast the GPU can decode the video, but rather an issue with PCI-Express bandwidth or memory bandwidth (that's a lot of data to be handling).

I tell you again that PotPlayer using the same LAV codec does not stutter at all (if the DXVA2 (copy-back), D3D11 or NVIDIA CUVID (old) methods are selected in the LAV settings)! And in the task manager you can see that the video card is used for decoding by 80-90% (not even 100%), and the CPU is not loaded at all. This means that this is not a limitation of the video card or a problem with PCI-Express bandwidth or memory bandwidth! After all, the video card does an excellent job of decoding 8K, but not in Whirligig! And for some reason, the DXVA2 (copy-back) and D3D11 methods do not yet work in Whirligig, although they work great in PotPlayer. Perhaps one of these decoding methods would solve the problem if the developer found a way to make them work in his program.

[GT500]

Origineel geplaatst door JazzKungFu:

I tell you again that PotPlayer using the same LAV codec does not stutter at all (if the DXVA2 (copy-back), D3D11 or NVIDIA CUVID (old) methods are selected in the LAV settings)! And in the task manager you can see that the video card is used for decoding by 80-90% (not even 100%), and the CPU is not loaded at all. This means that this is not a limitation of the video card or a problem with PCI-Express bandwidth or memory bandwidth! After all, the video card does an excellent job of decoding 8K, but not in Whirligig! And for some reason, the DXVA2 (copy-back) and D3D11 methods do not yet work in Whirligig, although they work great in PotPlayer. Perhaps one of these decoding methods would solve the problem if the developer found a way to make them work in his program.

Whirligig isn't a desktop media player. It's technically a video game made in Unity and probably isn't going to be as efficient. There's also the fact that it's trying to post-process the video into separate images for right and left eyes, and depending on your VR HMD and SteamVR resolution settings it may be doing it at a higher resolution than a media player on your desktop.

BTW: The Task Manager's video decoding percentage doesn't tell you how much PCI-Express bandwidth is in use, nor does it tell you how much of the GPU's memory bandwidth is in use. You also don't know how much of your PC's RAM bandwidth is in use. I think there are tools that can show these things (maybe HWiNFO) but as far as I can remember the built-in Windows tools don't show this information.

[GT500]

FYI: I just tested a VR (180 degree SBS) video that was 8192x4096 and was in H.265 (HEVC) and it played smoothly in Whirligig. I had also transcoded the first 9 minutes of the video into VP9 at the same resolution, and that played fine as well. I first tested with DirectShow, and then with VLC and Whirligig was able to play the video without visible stuttering using either.

My system specs:

CPU: AMD Ryzen 7 3800X
RAM: G.SKILL Trident Z Neo 64GB DDR4-3600
GPU: ASUS ROG STRIX RTX 3070 Ti
Motherboard: ASUS ROG Crosshair VIII Hero
Hard drive Whirligig, SteamVR, and Windows were installed on: 4TB Samsung 860 Pro
Hard drive video was on: 4TB WD Gold
VR HMD: HTC Vive Pro 2
SteamVR render resolution: 5000x2500 (it was technically a little higher than this, but it's somewhat random and I can't check what it was at time of testing)
Whirligig render resolution: 130% of SteamVR render resolution

[JazzKungFu]

Origineel geplaatst door GT500:

FYI: I just tested a VR (180 degree SBS) video that was 8192x4096 and was in H.265 (HEVC) and it played smoothly in Whirligig.

Wow! So you're saying that these VR videos in 8K H.265 (HEVC) play great on your computer without stutters?! How did you achieve this?! What happens, our 1080Ti video card is weak?!

Origineel geplaatst door GT500:

I first tested with DirectShow, and then with VLC and Whirligig was able to play the video without visible stuttering using either.

Have you tested it in Media Foundation mode? Did you play back in DirectShow using LAVFilters? In LAV Video Configuration, which “Hardware Decoder to use” method did you choose: DXVA2 (copy-back), D3D11 or NVIDIA CUVID (old)? Your picture does not break up into squares when you select the VLC Videolan mode?

[GT500]

Origineel geplaatst door JazzKungFu:

Wow! So you're saying that these VR videos in 8K H.265 (HEVC) play great on your computer without stutters?! How did you achieve this?! What happens, our 1080Ti video card is weak?!

I can't say for certain if the 1080 Ti is just too weak to play H.265 (HEVC) video at that resolution in Whirligig (It's been over a year since I switched from a 1080 Ti to a 3070 Ti). I know the RTX 20 and RTX 30 series cards have better video encoders than the GTX 10 series do, and the RTX 30 series cards support AV1 encoding so they may have a better video decoder as well. I did notice that in SMPlayer when using my GPU to decode the video the video decoder's usage was only around 53%, whereas someone here mentioned it was over 90% (I don't know if that was just GPU usage or if it was specifically the video decoder usage).

Normally I have MSI Afterburner running when in VR, but when I tested I think I had already exited MSI Afterburner in order to lock my PC for the night. Maybe not having MSI Afterburner running made the difference? I know that if you don't turn off some of the power related monitors in MSI Afterburner that it can cause major stutter and FPS issues in VR, but I don't usually have problems with all of the power monitoring turned off in MSI Afterburner.

Origineel geplaatst door JazzKungFu:

Have you tested it in Media Foundation mode? Did you play back in DirectShow using LAVFilters? In LAV Video Configuration, which “Hardware Decoder to use” method did you choose: DXVA2 (copy-back), D3D11 or NVIDIA CUVID (old)? Your picture does not break up into squares when you select the VLC Videolan mode?

I have not tested with Media Foundation mode. I only tested with DirectShow using LAV Filters, and with the updated VLC mode in the latest stable release. The video played just fine in both modes, and there were no visual abnormalities or glitches that I noticed (no little squares).

I currently have LAV Filters set for DXVA2 (copy-back) as DXVA2 is the most modern and up-to-date method on Windows, and "copy-back" sends the decoded image back to the media player in a way that allows for post-processing effects. Here's a screenshot of my current settings (in US English of course):

https://i.imgur.com/oQS8Lc3.png

[JazzKungFu]

Origineel geplaatst door GT500:

I currently have LAV Filters set for DXVA2 (copy-back) as DXVA2 is the most modern and up-to-date method on Windows, and "copy-back" sends the decoded image back to the media player in a way that allows for post-processing effects.

It's strange why this method works for you, but not for me. As I already wrote, for some reason the DXVA2 (copy-back) and D3D11 methods do not work for me in Whirligig. Videos can't even start playing in these modes, there's a toy windmill spinning endlessly on a black background and no matter how long I wait, nothing changes. Only the NVIDIA CUVID (old) method works for me in Whirligig. Although all three methods work fine in the regular PotPlayer player.

[JazzKungFu]

Is there really such a big point in downloading 8K versions of videos if my helmet is an Oculus Rift S? Is the difference between 8K and 4K visible on this helmet model?

[GT500]

Origineel geplaatst door JazzKungFu:

It's strange why this method works for you, but not for me. As I already wrote, for some reason the DXVA2 (copy-back) and D3D11 methods do not work for me in Whirligig. Videos can't even start playing in these modes, there's a toy windmill spinning endlessly on a black background and no matter how long I wait, nothing changes. Only the NVIDIA CUVID (old) method works for me in Whirligig. Although all three methods work fine in the regular PotPlayer player.

I think I used DXVA2 (copy-back) on my GTX 1080 Ti, so as far as I know it should work on yours too. Are you using Windows 10 or 11? Older versions of Windows may not work right with DXVA2 decoding. As for the D3D11 decoding I don't know why that wouldn't work, as it's older than DXVA2. Maybe it's a bug in LAV Filters?

Origineel geplaatst door JazzKungFu:

Is there really such a big point in downloading 8K versions of videos if my helmet is an Oculus Rift S? Is the difference between 8K and 4K visible on this helmet model?

The Oculus Rift S has a screen resolution of 2560×1440, or 1280×1440 per eye. By contrast my HTC Vive Pro 2 has a screen resolution of 4896×2448, or 2448×2448 per eye, and I'm reasonably happy with 180 degree SBS VR videos that are 5400x2700 (this was the highest resolution that would play smoothly for me before the recent performance updates to Whirligig). I don't know if you would be able to notice a quality difference between 5400x2700 and anything larger than that on an Oculus Rift S. Anything that's sufficiently larger than your VR render resolution should be good.