Basically this thread is for raising awareness that there are some possibilities to mitigate motion blur on an lcd to get a tad nearer to a crt in terms of motion clarity
Also hopefully some devs see this and no longer hardlock the framerate to 60fps in shmups.
First I want to say thanks to blurbusters.com, for the huge amount of technical details, ressources and articles that gave me an in-depth understanding of the whole topic.
Most of the info in the summary below will be found in some form or another on this site, so I recommend everyone to take a look at their articles who want to further immerse in this topic.
So how does motion blur look, and what are the difference compared to a crt?
Ok, so how do I reduce this this problem?
Basically with modern LCD's the major solution to this problem is:
- Higher Refresh Rate e.g 120hz,144hz...
But this does only work with newer games, that support this high refreshrates and which are not framelocked at 60fps.
So, how does a higher refresh rate reduce blur?
Lcd\Led Monitors are based on the sample and hold technique. Basically when you have 60fps, one frame has a duration of 1/60fps = ~16ms
The leds hold the frame for this amount of time, and then change to the next.
This is what generates the motion blur for the human eye.
When you have a higher refresh rate, e.g 120hz the perceived motion blur is cut in half since the sample and hold delay is now only 1/120fps = ~8ms
When you take a look at the graphic above, you'll see it improves quite a lot. But it is still not on crt level which has a picture persistence of just 1.4ms due to phosphor glow.
It flickers, but motion blur is kinda non-existent because of that flicker.
However you can still improve it a bit further, by using the following feature:
- Backlight Strobing
Backlight Strobing
It basically turns the backlight from the screen off for a certain amount of time for an ongoing frame, producing a crt like flicker.
This feature is called Lightboost, Blur Reduction, or Ultra Low Motion Blur(Nvidia cards only) depending on the monitor you have.
Most of the time this feature is only available at 120hz Refresh Rate or more, so you can't use it with older games or games that are framelocked at 60fps.
Some monitors allow for single strobing (Backlight strobing at 60hz), however this flickers more notably than a crt with 60hz
To get a list of supported monitors for this feature:
https://www.blurbusters.com/faq/120hz-monitors/
The shorter the strobe light flash, the more clearer the motion but the more screen brightness you will lose.
Black Frame Insertion
Good news on this one. It can be used for old games that are run on an emulator. Groovymame and retroarch support it perfectly.
Since the Framerate is locked on older Spritebase shmups and you can't really do anything about it, this is a nice solution to still get your blur reduction fix.
Basically your screen refresh rate is 120hz, but you'll spread out the 60fps while rendering, each 2nd frame is a completely black picture.
Screen brightness is reduced to 50%, however motion blur is also reduced quite significantly.
You can combine this feature with Backlight strobing for even more blur reduction.
The list
I'm trying to compile a list of shmups for PC to give an overview of which games are framelocked and which games natively support more than 60fps, so that screens with 120hz or more can be used for blur reduction.
Hopefully this list will grow a bit in the future with more shmups that are not tied to 60fps.
So, if you know any shmups on steam that are framelocked or not framelocked, please tell me, so I can add it to the list.
A good way to find out: Turn Vsync off in the control panel of your graphics card, activate a framecounter in steam or use something like fraps.
Set your screen Refreshrate to 120hz or more.
If the framecounter in the game still says 60fps after that, or the game is running at turbo speed, it is locked/tied to 60fps