Hmm..Input Lag

mediamogul

I am not 100% if I understand the whole topic

Ha! you know, it's me being the one off topic here. A handful of lag threads popped up in the last week or so and I had originally responded here with info on the run-ahead feature. However, I have since moved it to a more appropriate thread. Sorry for the confusion. Nonetheless, the one point still stands that when determining input lag, you're only looking for inactive frames. Once an action animation has begun, that first frame of activity is the game being aware of and responding to input.

thelostsoul

@mediamogul Haha, no wonder, its a hot topic everyone talks about it. ;-) Can't blame for this.

Beldar

A CRT is the obvious choice to remove monitor lag. Even a really nice LCD TV can cause 5 to 7ms of input lag even in gaming mode. I spent time hunting for a low input lag TV and it still seems to produce about 3 to 5ms.

I am still on the lookout for a cheap CRT to play with, but I found the next best option. I have been using a 1ms rated gaming LCD monitor. There are several brands that sell these (my favorite is ASUS.) If you are okay with a model that's a year or two old, you can get one for less that 150USD on Amazon.

thelostsoul

@beldar I have a high end gaming monitor with very low input lag. The 4ms or 1ms time only tells how fast the grey to grey is and doesn't tell full story. There are a lot of other things going on. An IPS panel monitor with 4ms grey to grey value can have less input lag than a 1ms TN panel monitor.

Mine is AOC IPS 144Hz (up to 165hz) with G-Sync. :-) I think that I wouldn't get any noticible lag with this one. There are a number of other reason why I choice CRT for retro gaming. And I wonder if the lag on CRT setup with hdmi to vga adapter is higher than my IPS monitor. For direct measurement and comparison I have to change some settings. Still lazy on this.

Beldar

@thelostsoul I always stick with TN type computer monitors. The increased ghosting on most IPS panels makes me nutty. I don't care much about fancy colors if they go all smeary during the action. Also aside from retro gaming I like very high refresh rates on my PC games.

But I'm sure you caught my point that while there ia technically a faster response on CRTs, it is not likely to be perceived when compared to a decent quality gaming panel. The rest of the lag is going to be coming from either the Pie or singal converters/upscalers/ect.

I personally notice a huge difference on my gaming panel when compared to any of the four TVs I've recently owned. However, I notice almost no difference when reducing lag on the Pie's side (dispmanx, video threading, etc.) That leads me to believe that even decent quality LCD TVs just aren't that good for gaming.

thelostsoul

@beldar I am curious how much I can reduce lag and. You can see in my above link to the GIF (poir quality) how much the barrel fall down until a move happens. In most games this isn't critical. But playing unforgiving bullet hell shmups or classic Marios, this can have a slight real world effect. On a "regular" TV I even wouldn't bother.

https://github.com/RetroPie/RetroPie-Setup/wiki/Input-Lag
I will try some of these settings. Did the guy who wrote this article over clocked? I did quite a lot and I have a fantastic cooling (no fan), so I should be able to do what this guy did without problems right? I also play on 640x480p resolution, so its less then the default.

I wish I would have a monitor with 15khz capability (240p).

mediamogul

@thelostsoul said in Hmm..Input Lag:

Did the guy who wrote this article over clocked?

@dankcushions wrote the original doc and I expanded a bit on the unsupported tweaks. I was not overclocking when testing the effects on the NES emulators. The results, while positive, were really only noticeable in the games that needed it the most. For example, when you have 4 frames, or 66.4ms to turn corners in 'Battletoads', every little bit is very noticeable.

thelostsoul

@mediamogul And the resolution was at 1080p right?

dankcushions

resolution and overclocking only affect input lag if you’re under 60fps in the first place. at stock settings on a pi3 and 16/8-bit consoles, you won’t be.

thelostsoul

@dankcushions The reason why I ask is, because I have some more room for performance, so I can use more of these tweaks to reduce input lag, which also increases the load.

dankcushions

@thelostsoul neither @mediamogul nor myself are overclocked, but again, the performance is only an issue when you drop frames. until then, you should be good to go.

be aware that all the tweaks in the 'unsupported tweaks' section are a) unsupported, and b) likely only feasible to that degree for NES, which needs around half the power of, say, SNES emulation, which has very little headroom.

thelostsoul

@dankcushions What about the other systems? Why are most talk about NES and SNES? Just because its more popular or is there a technical reason for it?
By the way, which emulators are tested on the said article? Does it make even a difference which emulator is used? I changed most default emulators.

mediamogul

@thelostsoul said in Hmm..Input Lag:

Why are most talk about NES and SNES? Just because its more popular or is there a technical reason for it?

Popularity is likely part of it, especially for the SNES, but personally I've never seen any other game library so tightly dependent on low latency than the one belonging to the NES. Make no mistake, you'll always gain a play advantage having low latency on other systems if you can manage it, but there are several titles for the NES to where the difficulty ramps up considerably when losing more than a few frames and even some to where it's debatable if you can even complete them.

dankcushions

@thelostsoul said in Hmm..Input Lag:

@dankcushions What about the other systems? Why are most talk about NES and SNES? Just because its more popular or is there a technical reason for it?

didn't i just answer this? NES emulation needs about half the power of most other systems. it's a 'simple' system that is relatively easy to emulate. these tweaks take computational power that the pi rarely has to spare.

By the way, which emulators are tested on the said article? Does it make even a difference which emulator is used? I changed most default emulators.

the supported tweaks don't involve any changes to the pi's configuration - they're safe for all systems. the unsupported tweaks are specifically for NES - it's quite clear on this on the page. you could try them on other systems, but like i said, NES emulation is uniquely performant. the only other similar performant emulators are gambette, i would guess.

they're unsupported tweaks - it's really up to you to experiment and see what works.

mediamogul

@thelostsoul

The supported tweaks also yield the best results by far. Setting a television to game mode alone feels like the difference between night and day. Setting even all of the possible unsupported tweaks feels more like the difference between night and a bit later that night.