Software black frame insertion option on the Mister to get a motion blur free image

Discussion of developmental aspects of the MiSTer Project.
Neocaron
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Software black frame insertion option on the Mister to get a motion blur free image

Unread post by Neocaron »

Hello there!

So I was wondering if a software based black frame insertion setting would be possible on the Mister? While it's available on select TVs to great effect and almost completely remove motion blur at just a small brightness cost, a software based solution would make it work on every LCD panel. Nothing should prevent this from being possible right? Is it feasible? Would the team be interested in doing it?

For people not familiar with it, here's a pretty old but detailed article explaining the whole process:
https://www.cnet.com/tech/home-entertai ... o-lcd-tvs/
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darksakul
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by darksakul »

Not saying it's impossible, but you have to make the changes in each FPGA Core to support this.
The DE 10 Nano mostly runs on the FPGA Chip, the Arm processor side is mostly for file management/house keeping duties.

My Question is if this feature used on Low Level Software Emulation yet or not.
It is my great regret that we live in an age that is proud of machines that think and suspicious of people who try to.
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by H6rdc0re »

Even with BFI a LCD won’t have a completely blur free image. OLED however will be completely blur free with a 100% BFI cycle. Even older OLED displays. Brightness might suffer too much. You won’t be able to run both BFI and scanlines with ample brightness.
Neocaron
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by Neocaron »

H6rdc0re wrote: Wed Oct 13, 2021 5:42 pm Even with BFI a LCD won’t have a completely blur free image. OLED however will be completely blur free with a 100% BFI cycle. Even older OLED displays. Brightness might suffer too much. You won’t be able to run both BFI and scanlines with ample brightness.
Yes you are right, but it will still look much better than it does now on LCD as well. The idea here would be to have the option.

And to answer the previews question, I haven't heard of black frame insertion on any emulator outhere. I feel like this is not broadly known for now and use only on the TV hardware side of things. I truly believe that the impact on retro gaming especially is massive as long as you have a decent amount of brightness on your screen in the first place. But basically you're saying this could not be applied as a general option? But only per core? It more complicated to do then, but still it would be awesome. :D
hooxxx
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by hooxxx »

retroarch has a black frame insertion option that works on every core when activated
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by Neocaron »

hooxxx wrote: Wed Oct 13, 2021 7:48 pm retroarch has a black frame insertion option that works on every core when activated
I had no idea!
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by sonik »

For BFI to work the output has to be 120hz right?
There's some videos of mister outputting at 120hz (I have not tested it myself)
https://www.youtube.com/watch?v=vte-f1KKCg8

So it might be possible to handle the BFI at the framebuffer/scaler pass?

I do use the native BFI feature on my oled tv and it's amazing but it adds some latency.
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by Neocaron »

sonik wrote: Thu Oct 14, 2021 12:26 pm For BFI to work the output has to be 120hz right?
There's some videos of mister outputting at 120hz (I have not tested it myself)
https://www.youtube.com/watch?v=vte-f1KKCg8

So it might be possible to handle the BFI at the framebuffer/scaler pass?

I do use the native BFI feature on my oled tv and it's amazing but it adds some latency.
Yeah since it's basically using the frametime between 60 and 120 to insert a blackframe right?
I don't know how it would work at a lower refresh rate...
hooxxx
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by hooxxx »

I'm no expert but black frame insertion should double the Hz of orignal refresh rate so pal content (50Hz) should be 100Hz etc.
I wonder if universal option (like video filters) could be implemented in mister?
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by SuperBabyHix »

I think even before you get to how to insert black frames you are going to run into a limitation with the Mister's HDMI output. I believe the pixel clock limit is somewhere around 180Mhz, I can't remember.
A 720p 120hz video mode is going to be around 160Mhz.
Using reduced blanking and a 4:3 screen mode would let you reduce that a bit, but I doubt you can get a much higher resolution than that.
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by FoxbatStargazer »

I'd really like to see a closely related feature, an exact doubling of the core's refresh. This would be useful for reducing flicker on VGA CRTs, especially for PAL content. Kinda niche but there you have it. :p

I imagine these could both be new modes for vsync_adjust. Probably based on vsync_adjust=1 except that it doubles the core's refresh (and does black frames in one case). Bufferring is probably required to make this work so there would be a bit more lag compared to vsync_adjust=2.

I think there would also be demand for a locked 120hz version of BFI, in case of display incompatibility. Especially since it is important to keep the black frames consistently spaced, and not double up a black or image every so often. In that case it would be more like just doing the usual interpolation to 60 and put black frames between. In this case you would probably base on the video_mode's refresh rather than the core.
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by Newsdee »

FoxbatStargazer wrote: Fri Oct 15, 2021 1:34 pm I'd really like to see a closely related feature, an exact doubling of the core's refresh
This is what this option does :)
forced_scandoubler=1
It makes it go from 15khz to 30khz
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Re: Software black frame insertion option on the Mister to get a motion blur free image

Unread post by FoxbatStargazer »

I meant vertical refresh, not horizontal. 50hz -> 100hz for example, doubling every frame.
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