K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

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K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by gogol1 on Tue Sep 26, 2017 5:53 pm

Tell me how it will feel K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on). Can there be any problems? Does MadVR work properly with 240Hz and Gsync?

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Re: K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by notcyf on Tue Sep 26, 2017 6:15 pm

gogol1 wrote:Tell me how it will feel K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on). Can there be any problems? Does MadVR work properly with 240Hz and Gsync?

G-Sync isn't meant for watching movies, it works, but it won't affect madVR. There can be no proper G-Sync support in madVR because there are no real API's that madshi can implement in madVR. G-sync is meant to reduce tearing in content have a variable frame rate(games mostly). Videos don't have a variable framerate.

I don't know any monitor that can properly sync to 24Hz there's no real way to eliminate tearing for normal monitors that do cause tearing(for whatever reason). AFAIK only certain TV's have a 24Hz mode for 100% tearless playback.

On the other hand i've never noticed any tearing on my pretty cheap Samsung 60Hz monitor(running 59(.94)Hz mode). I recommend disabling G-sync when using madVR.

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Re: K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by Admin on Wed Sep 27, 2017 10:31 am

G-Sync does not have any benefits for video playback. You can disable it for MPC-HC using the application presets in the NVIDIA control panel. The preset is called "Media Player Classic".

MadVR should work with any refreshrate. You can use its "smooth motion" options to improve smoothness of playback. I would not recommend using 240 Hz, as that might give reduced performance. Better would be to use 120 HZ instead.

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Re: K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by notcyf on Wed Sep 27, 2017 1:37 pm

Admin wrote:G-Sync does not have any benefits for video playback. You can disable it for MPC-HC using the application presets in the NVIDIA control panel. The preset is called "Media Player Classic".

MadVR should work with any refreshrate. You can use its "smooth motion" options to improve smoothness of playback. I would not recommend using 240 Hz, as that might give reduced performance. Better would be to use 120 HZ instead.

Smooth motion won't actually eliminate tearing though, since that's a GPU<->Monitor related problem. The best way to eliminate tearing is by enabling the "Use Direct3D11 for presentation" and enabling the V-sync sub-option.

Only D3D11/DXGI has the capability to V-sync windowed programs(DXGI applications can achieve this by using the DXGI flip model through DWM). With D3D9 you can only use V-sync if the application is in fullscreen exclusive mode and even then, i don't know if MadVR actually does this.

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Re: K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by Admin on Wed Sep 27, 2017 8:00 pm

Tearing in video playback should not be a problem on most systems. The V-Sync you are talking about is mostly for variable framerate stuff (games).

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Re: K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by notcyf on Wed Sep 27, 2017 10:36 pm

So I guess the option in madVR is placeboo for people who still want vsync enabled even though it has no real benefit? It seems to be enabled by default if you enable D3D11. The only downside of having Vsync is that there's a single frame of delay which is not an issue for pre rendered content such as videos. I'm not really sure if in some cases it can actually help since I've always had it enabled.

The way v sync works is that it creates a frame buffer and a back buffer. The GPU draws all frames to the back buffer while the monitor only reads the frame buffer.

I'm not entirely sure how this works with prerendered content but if say you have a 75Hz screen and you have 50fps content this happens
1) monitor refreshed
2) frame 1 gets copied to frame buffer
3) 2/3rd of frame 2 is drawn in the background
4) monitor refreshed.
5) now what happens is that only 2/3rd of the frame is rendered it still has 1/3rd of a frame that's "old data" and that gets used to try and draw a full image on the screen which is why the image chops off.

This can happen even if there's only a marginal difference. Because madVR rendering relies on a system clock that is not 100% accurate, this can cause very minor (probably invisible) tearing. This is prevented with Vsync because it creates a rule that a frame will only be sent from the back buffer to the frame buffer right after the monitor refreshes and thus always receiving a full frame of data. Vsync does not work if the renderer can't keep up with the refresh rate of the monitor and will copy every drawn frame if the GPU can't keep up (effectively halving framerate immediately but ensures Vsync will keep working. This handled on driver level).

The goal of gsync and freesync is letting the GPU handle all drawing of frames on the monitor so that the monitor only refreshes when a new frame is fully drawn. The monitor will basically be capable of knowing when the GPU has finished drawing a frame. This could definitely have an effect in the smoothness of videos and eliminates the need of smooth motion.

It's just sad there's no public API available for it and thus G-sync won't know when madVR renders a frame, rendering it useless. Pun intended.


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Re: K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by Admin on Thu Sep 28, 2017 12:26 pm

MadVR always performs (its own) VSync handling.

That specific option that you are referring to is only for the way repeat frames are handled. If enabled, MadVR handles the repeats and presents a frame each VSync interval. If disabled, only new frames are presented and repeating is handled by D3D11.

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Re: K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by notcyf on Thu Sep 28, 2017 3:06 pm

Admin wrote:MadVR always performs (its own) VSync handling.

That specific option that you are referring to is only for the way repeat frames are handled. If enabled, MadVR handles the repeats and presents a frame each VSync interval. If disabled, only new frames are presented and repeating is handled by D3D11.

Ah, so that does mean there should never be any screen tearing w/ madVR unless there's something horribly wrong with your PC/GPU.

@OP
If there ever comes an API for controlling monitor refresh rate handling(FreeSync/G-Sync) madshi will implement it. For now that is not the case and it (most likely) won't be the case for the foreseeable future. The way G-Sync and FreeSync work now is that the GPU detects the frames rendered from the game engine on driver level rather than the application level. But as Admin said, you won't really need it w/ smooth motion and Vsync is already taken care of.

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Re: K-Lite Codec Pack (LAV and MadVR) + Monitor 240Hz and Gsync (on).

Post by Admin on Fri Sep 29, 2017 12:51 pm

Under normal circumstances there should not be any tearing. Also not with EVR.

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