G-sync / Freesync support (adaptive sync)

[demolition]

Originally Posted by mark_k

Would it be possible to have, say, each Amiga frame displayed for 1/75 sec, each black frame for 1/150 sec? That could allow increased image brightness.

That should be possible, however it would require an output display mode of >150 Hz. My monitor can go to 165 Hz so it could manage.

[Toni Wilen]

Yeah, it should work, at least technically. I can add configurable delay between "normal" frame rendering and black frame rendering.

[mark_k]

Originally Posted by demolition

That should be possible, however it would require an output display mode of >150 Hz. My monitor can go to 165 Hz so it could manage.

Ah, right.

So with a 144Hz max monitor for example, black frames need to be at least 1/144 sec. Then the longest Amiga frame could be shown for is about (1/50 - 1/144) sec. (Simplifying since Amiga PAL frame rate isn't exactly 50Hz.)

Similarly for 120Hz max, longest Amiga frame could be (1/50 - 1/120) sec.

[demolition]

You will need to add some additional headroom, so 150 Hz panel refresh would not be enough for 50 Hz 2:1 Image:Black, due to jitter I presume. Not sure how much, but I do know that 120 Hz is enough for 1:1.

But adjustable black frame time would be useful. Lower time cap would be the current display refresh rate.

[Toni Wilen]

Ok, I now have Acer Predator X34 (3440x1440 100Hz G-Sync. No ULMB/Lightboost but also no more annoying and stupid NVidia Surround issues and 100Hz is just enough for PAL emulation with black frame insertion)

Without black frame insertion G-Sync seems to work very nicely. With black frame insertion it has odd random flicker/"out of sync" updates. Not sure why yet..

G-Sync (or FreeSync, I guess) really is perfect for emulators. Very low input lag, no tearing, no doubled or missed frames.

Only remaining problem is LCD "sample and hold" blur/ghosting that is too visible in low refresh rates (50Hz/60Hz) but perhaps it will be solved with some future G-Sync/FreeSync + ULMB/Lightboost combo mode. Hopefully.. (Black frame insertion does partially solve it but there is too much flicker..)

EDIT: flickering/blank frame was caused by too high refresh rate, it seems display keeps showing same frame if rate exceeds 100Hz even by tiny amount (I need to tweak timing a bit to fix it). Forcing 49Hz (Using display panel FPS Adj) fixed it 100%. Perfect smooth black frame insertion! Yes, even FPS Adj. works perfectly with Variable sync mode, can have vsync like mode with any refresh rate that monitor supports (30Hz to max).

[demolition]

Great to hear that you can now test it yourself so we can benefit from it. And a nice monitor, although it does have fewer pixel than 3240x1920 you stated.

So the version you tested here and made to work with black frame insertion @ 49 Hz is no different from the previous one I tested? It should be fine with full 50 Hz in my case since my panel goes to 120 Hz with overclocking disabled.

So if you don't get weird artifacts with flickering at low fps like I do after using WinUAE with G-Sync, then perhaps my ASUS monitor is faulty somehow. Are you using the most recent Nvidia driver, and with which gfx card (I have a 760)?

It would be very nice if it was possible for software to force the backlight on and off, which would make it possible to do proper black frame insertion aka ULMB combined with G-Sync. My monitor can also do ULMB, but not together with G-Sync but I have not tested which one gives the best end result.

[Toni Wilen]

Originally Posted by demolition

Great to hear that you can now test it yourself so we can benefit from it. And a nice monitor, although it does have fewer pixel than 3240x1920 you stated.

Yeah but at the moment 3440x1440 seems to be max size that works with single cable + at least 100Hz and G-Sync. Extra horizontal pixels seem to be much more useful than lost vertical pixels. At least when using normal Windows programs.

So the version you tested here and made to work with black frame insertion @ 49 Hz is no different from the previous one I tested? It should be fine with full 50 Hz in my case since my panel goes to 120 Hz with overclocking disabled.

Yeah, you should only get weird behavior if you enable black frame insertion and increase fps.adj until fps.adj*2 > your monitor max refresh rate. Try it to see if it looks same or different.

So if you don't get weird artifacts with flickering at low fps like I do after using WinUAE with G-Sync, then perhaps my ASUS monitor is faulty somehow. Are you using the most recent Nvidia driver, and with which gfx card (I have a 760)?

It is perfect now, as long as I set it to 49Hz or lower. 50Hz will cause multiple duplicated frames, image sort of freezes or starts flickering oddly. (Unfortunately nominal Amiga PAL rate is 50.04Hz so technically it is always a bit too much but small hack will fix it..)

I have SLI GTX980 [365.10, latest Windows 10 Insider Preview] (but there was no difference in non-SLI, I didn't install second GPU until after testing the monitor. It was not originally installed because it died last week and I didn't bother to reinstall replacement until also monitor arrived)

It would be very nice if it was possible for software to force the backlight on and off, which would make it possible to do proper black frame insertion aka ULMB combined with G-Sync. My monitor can also do ULMB, but not together with G-Sync but I have not tested which one gives the best end result.

AFAIK it is really difficult to combine both because variable rate means variable backlight strobing which would cause change in brightness and other display parameters. We'll see if it ever happens.

http://www.winuae.net/files/b/winuae.7z updated. Now supports windowed/full-window+variable sync and also automatically disables black frame insertion if refresh rate would become larger than max. (so don't use this version to do > max test!)

EDIT: it is now called variable sync because adaptive sync is displayport variable refresh rate standard name.

EDIT2: RTG + black frame insertion is now supported.

[hexaae]

G-Sync works fine here for native resolutions (ASUS G751JY with nVidia 980m 4GB, drivers 368.95, 1080p 75Hz G-Sync).
Super smooth scrolling for platforms like BC-Kid, Lionheart, Turrican etc.

Mycfg.uae:

...
gfx_display=0
gfx_display_rtg=0
gfx_framerate=1
gfx_width=720
gfx_height=568
gfx_top_windowed=220
gfx_left_windowed=34
gfx_width_windowed=720
gfx_height_windowed=568
gfx_width_fullscreen=1920
gfx_height_fullscreen=1080
gfx_refreshrate=0
gfx_autoresolution=false
gfx_backbuffers=2
gfx_backbuffers_rtg=2
gfx_vsync=false
gfx_vsyncmode=normal
gfx_vsync_picasso=false
gfx_vsyncmode_picasso=normal
gfx_lores=false
gfx_resolution=hires
gfx_lores_mode=filtered
gfx_flickerfixer=false
gfx_linemode=double
gfx_fullscreen_amiga=true
gfx_fullscreen_picasso=fullwindow
gfx_center_horizontal=none
gfx_center_vertical=smart
gfx_colour_mode=32bit
gfx_blacker_than_black=false
gfx_api=direct3d
gfx_filter_bilinear=true
gfx_filter_keep_aspect=vga
gfx_filter_aspect_ratio=-1:-1
immediate_blits=true
ntsc=false
genlock=false
chipset=aga
chipset_refreshrate=59.825095
collision_level=full
chipset_compatible=Generic
fatgary=0
ramsey=15
fastmem_autoconfig=false
fastmem_size=0
a3000mem_size=0
mbresmem_size=0
z3mem_size=256
z3mem_start=0x10000000
bogomem_size=0
gfxcard_size=128
gfxcard_type=ZorroIII
gfxcard_hardware_vblank=false
gfxcard_hardware_sprite=false
chipmem_size=16
cpu_speed=max
cpu_throttle=0.0
cpu_type=68040
cpu_model=68040
fpu_model=68040
cpu_compatible=false
cpu_24bit_addressing=false
cpu_cycle_exact=false
blitter_cycle_exact=false
cycle_exact=false
rtg_nocustom=false
rtg_modes=0x21e
...

[vagrant]

Next week my PC will be getting some long overdue updates, including a GTX1070 & Acer Predator XB271HU gsync display.
Of course one of the first things I want try out is variable sync mode under winuae

What is the ideal output settings to use for best possible resolution and smooth display? variable sync + black frame insertion? What about native output resolution?.. I think I read that gsync modes are only available in monitor's default resolution (1440p).

Of course I'll still have my trusty CRT to fall back on if results are less than desirable

[Toni Wilen]

Always use native resolution! Monitor scaling is always bad and can't be tweaked.

Next disable all WinUAE scaling options, aspect ratio correction etc (except perhaps set scaling=2x or so to make image large enough, use only integer scaling factors at this point).

Then check that g-sync is working. (Also check that if it really works in windowed mode, it only works in full-window and "real" fullscreen here. Easy to check with black frame injection, g-sync is not working if black frame goes in and out of sync all the time. It is impossible to miss..)

Then finally adjust other filter options until image looks good to your eyes. (pixel perfect/blurriness allowed, aspect ratio, whatever.. These are personal choices, don't just blindly use someone else's settings)

[vagrant]

Great thanks toni, will try once the equipment arrives

[zambot3]

With gsync must I enable double buffering?

[Michael Sykes]

In case someone did not notice.
Works also fine with the latest nvidia cards on freesync monitors now.