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Author Topic: 8K video playback problem  (Read 1605 times)

madbrain

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8K video playback problem
« on: April 07, 2021, 10:15:58 pm »

8K / 24p clips from my Samsung Galaxy Note 20 Ultra have problems playing back with MC27 / x32 on my system.
For example : https://drive.google.com/file/d/1PeMXN7xeVJKuiAGm-XDodtAz7ddSsqBZ/view?usp=sharing . Be sure to clip the download button to get the original clip.
This plays very choppy, at something like 4 fps. The 8 second clip takes about 30 seconds to play, and skips frames.
While this one is a vertical clip, horizontal clips have the same problem.
I am using Red October HQ . Host PC has 32GB of RAM . GPU is GTX 960 with 4GB of RAM. There are 3 displays (2 x 4K, 1 x HD).
I'm forced to use the x32 version rather than x64 due a compatibility issue between MC x64 and my ECHO ASIO drivers.

All non-8K video clips play fine, even 4K 60.

The same clip plays fine in several other apps including Windows 10 Movies & TV video player. Windows Media Player chokes on it, though.

Log attached.

Edit: also tried to play this file on my HTPC using the x64 version of MC as it uses a different soundcard. The playback of this file was still problematic. So the issue isn't limited to x32. The HTPC has a GTX1050Ti and Ryzen 2 CPU.
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Manfred

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Re: 8K video playback problem
« Reply #1 on: April 08, 2021, 03:15:50 am »

I tested it with GTX 1070 8 GB but only with a UW display 3440x1440. What I see is that rendering time >> vsync (Jinc AR for Chroma,  Cubic SL AR for image downscaling and Lanczos 4taps AR for image upscaling) (Press CTRL J during playback). That means the GPU is to week. You should use also task manager to verify if any other ressources are on its limit (CPU, RAM, GPU). Try also using RO Std. In RO HQ you could try to use DXVA for image up/Downscaling and bicubic for chroma.
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madbrain

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Re: 8K video playback problem
« Reply #2 on: April 08, 2021, 05:31:42 am »

I tested it with GTX 1070 8 GB but only with a UW display 3440x1440. What I see is that rendering time >> vsync (Jinc AR for Chroma,  Cubic SL AR for image downscaling and Lanczos 4taps AR for image upscaling) (Press CTRL J during playback). That means the GPU is to week. You should use also task manager to verify if any other ressources are on its limit (CPU, RAM, GPU). Try also using RO Std. In RO HQ you could try to use DXVA for image up/Downscaling and bicubic for chroma.

In RO Std, there is still major stutter. But the vertical video plays horizontally instead, which is wrong. So I really can't use RO Std.

The GPU shows at only 9% in 3D in task manager. Video decode stays at 0%, despite hardware decoding being checked.
CPU usage is at about 25%.

On the same system, in Windows Movies & TV, when playing this video successfully on one of my 4K displays, the CPU is at about 80%, and GPU 3D is at 22%. GPU video decode remains at 0%. CPU is an i7-5820k overclocked to 4.4 GHz on all 6 cores / 12 threads.
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Hendrik

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Re: 8K video playback problem
« Reply #3 on: April 08, 2021, 06:01:14 am »

The GPU shows at only 9% in 3D in task manager. Video decode stays at 0%, despite hardware decoding being checked.

Hardware decoding of 8K is only supported in 64-bit builds due to memory requirements (this is a driver limitation, not anything we can do).
Overall, 64-bit builds are much faster in video decoding as well.
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LilyAarseth

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Re: 8K video playback problem
« Reply #4 on: April 08, 2021, 07:02:30 am »

I find it interesting that you're able to play it at all on that computer since the GTX 960 (GM206) doesn't have the capability to HW decode 8K HEVC at all according to this: https://developer.nvidia.com/nvidia-video-codec-sdk#NVDECFeatures
Also I'm not 100% sure if this is the general rule, but when I did video encoding a while back with a nearly identical CPU and clock I noticed a ~10% performance hit when using 32 bit vs 64 bit. Not sure if it's the same the other way around for decoding though. Maybe because of running MC in 32 bit the headroom left of your CPU to handle the decoding a tiny bit too small?
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madbrain

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Re: 8K video playback problem
« Reply #5 on: April 08, 2021, 08:16:48 pm »

Hardware decoding of 8K is only supported in 64-bit builds due to memory requirements (this is a driver limitation, not anything we can do).
Overall, 64-bit builds are much faster in video decoding as well.

OK, that's too bad. It seems it's doing software decoding, but somehow MC27 (and MC25) aren't utilizing the entire CPU - far from it at just about 25% (meaning 3 out of 12 threads) and plays at about 4fps. Whereas Windows Movies & TV utilizes between 70 - 80% and manages to do software playback at 24 fps. Seems like MC isn't utilizing all the CPU cores/threads. Is there a setting to tune that somewhere? Or is the low CPU usage due to lock contention ?

Also, is there a GPU that will hardware-decode the video I attached, and if so, which one ? The clip is H.265 8K 24p, vertically shot, from a smartphone - probably variable bit rate.

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madbrain

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Re: 8K video playback problem
« Reply #6 on: April 08, 2021, 08:50:39 pm »

BTW, I also tried MC27 64-bit, using DirectSound instead of ASIO as a workaround. It plays the video about twice as fast as the 32-bit version, but that's still twice as long as it should take. And it's not utilizing any more CPU than the 32-bit version, unfortunately, about 30%.

Here are some clips that show the playback on my center monitor (4K), and task manager with CPU on the third monitor on the right (HD display).
These are 4K60, and the CPU % is readable on a 4K display. Be sure to download the clips if you want to do that. Google hasn't processed the videos yet.
Windows Movies & TV : https://drive.google.com/file/d/1oJJX0BD6YIkN6ZtcazdRSAUlxBxhKGPl/view?usp=sharing
MC27 x32 : https://drive.google.com/file/d/1PHZ0k5_oxOKxiHerzT99o9IxspxU-_qf/view?usp=sharing
MC27 x64 : https://drive.google.com/file/d/1bRLe4V5XbnmWANCvrZ1zgSR7_pJefo3N/view?usp=sharing

This is all on the i7-5820k CPU . It's actually OC'ed at 4.3 GHz, not 4.4 . Still a workhorse of a CPU even after over 5 years. I haven't found much reason to upgrade it until these 8K clips. My local store has the Ryzen 5900x / 5950x in stock, but it's not clear they would really help in this instance as the problem seems to be MC not utilizing the entire CPU.

GPUs are horribly overpriced at the moment, so I'm probably not upgrading my GTX960 until they go back to earth.
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madbrain

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Re: 8K video playback problem
« Reply #7 on: April 08, 2021, 09:17:51 pm »

Also, is there a GPU that will hardware-decode the video I attached, and if so, which one ? The clip is H.265 8K 24p, vertically shot, from a smartphone - probably variable bit rate.

Answering my own question here. I went back to my HTPC which has a GTX 1050Ti GPU. Looks like I had disabled hardware decoding in MC x64.

As I recall, it's because of issues when playing back UHD Blu-Rays discs. When moving the mouse and having OSD overlay, it causes the video mode to switch. The projector is very slow with mode switches (about 5 seconds). By the time they are displayed after a mouse motion, MC is ready to switch the OSD off due to timeout, and goes back to original video mode, without the OSD.

I switched HW decoding back on, and the 8K / 24 vertical clip played fine in MC, utilizing 5% CPU only, and 65% on GPU video decode. That is nice.
But I would rather keep HW decoding off, due to the mode switch issues with the projector.

And the CPU in that machine (Ryzen 2700, no OC there) is powerful enough to do 8K software decode in Windows Movies & TV. The problem is with the 8K software decode in MC.

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tij

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Re: 8K video playback problem
« Reply #8 on: April 09, 2021, 10:45:35 am »

From what i recall ... mode switch on OSD only happens if you passthrough HDR (on OSD display ... MC stops passing through HDR metadata and TV exits HDR mode until OSD dissapears)

I note you using projector ... and have decent GPU ... i would suggest you use MadVR to tone map without HDR metadata (its better for projectors anyway ... unless you have MadVR Envy or Lumagen lol) ... this will elimimate mode switching on OSD
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madbrain

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Re: 8K video playback problem
« Reply #9 on: April 09, 2021, 04:28:14 pm »

Hi,

From what i recall ... mode switch on OSD only happens if you passthrough HDR (on OSD display ... MC stops passing through HDR metadata and TV exits HDR mode until OSD dissapears)

I note you using projector ... and have decent GPU ... i would suggest you use MadVR to tone map without HDR metadata (its better for projectors anyway ... unless you have MadVR Envy or Lumagen lol) ... this will elimimate mode switching on OSD

I do use passthrough HDR . I have experimented with MadVR tone mapping without HDR metadata, but haven't yet found a result I liked as much as my Optoma UHD65 HDR tone mapping.
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tij

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Re: 8K video playback problem
« Reply #10 on: April 09, 2021, 10:24:24 pm »

Current stable MadVR shipped with MC ... has not many options ... get brightness to the right level by lowering targeted nits ... lower the value - brighter the image, but also lowers "hdr effect" ... so need to strikd balance here.

Once you have targeted nits set to your liking, you can experimemt with other settings (higlight recovery, etc)

What I like about MadVR tone mapping ... it does not change hue/color while doing tone mapping (so red explosion dont turn orange).

If you insist on passing HDR metadata ... OSD can be avoided by using up/right/left/right buttons that csn be mapped to remote control ... menu those buttons bring up dont change display mode.
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