FAQ: Understanding HDMI Quick Frame Transport (lower lag)

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Re: FAQ: Understanding HDMI Quick Frame Transport (lower lag)

Post by Chief Blur Buster » 05 Jan 2021, 15:40

TheInventor wrote:
05 Jan 2021, 07:02
So, I assert that VRR alone is not as good as VRR plus QFT. For my 1080p example, VRR+QFT would technically be equivalent to VRR+864Hz refresh rate.
Terminologically, all VRR already always include QFT for framerates below max Hz.

What you mean extra QFT above and beyond -- so that max Hz is still QFT.

This is already possible on some monitors if you create it in a Custom Resolution Utility and then add FreeSync range to it.

One problem is that this will only work to reduce lag, IF the panel can scanout faster. In that situation, sometimes it's favourable to raise the refresh rate support of the display, so it's not uselessly idling between refresh rates.

In that sense, a true-864Hz VRR display (i.e. 48Hz-864Hz VRR range with 1/864sec delivery) is MORE LIKELY to happen than a 48Hz-240Hz range with 1/864sec QFT -- because if a panel can refresh faster, why hold back the max Hz? Manufacturers want to be able to advertise higher Hz.
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Re: FAQ: Understanding HDMI Quick Frame Transport (lower lag)

Post by Chief Blur Buster » 14 Jan 2021, 20:13

This Year 2021, Blur Busters Will Start a Plug-And-Play Quick Frame Transport Initiative

Ideally, monitors need to be able to support Quick Frame Transport in the menus, where turning ON/OFF that setting, automatically enables an alternate set of EDIDs with plug-and-play Large Vertical Totals.

FreeSync ON/OFF toggle already modifies the monitor's EDIDs in real time (causing Windows to re-detect the monitor), so naturally, Quick Frame Transport ON/OFF should also modify the monitor's EDIDs in real time, for user friendly lower strobe lag + user friendly lower-lag VSYNC ON.

All FreeSync-compatible panels already support fixed-Hz QFT in the scaler/TCON level, because VRR is a superset of QFT (Because VRR is essentially QFT for all lower refresh rates / frame rates below max Hz). What QFT is simply a fixed-Hz equivalent.
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Re: FAQ: Understanding HDMI Quick Frame Transport (lower lag)

Post by Kamen Rider Blade » 09 May 2021, 14:34

When do you think we'll get 1 Hz as the low end of the VRR spectrum to be common?

Apple pulled it off with a low end 1 Hz on their Apple Watch Series 5 in late 2019

https://www.wired.com/review/apple-watch-series-5/

Where's the rest of the Display Panel industry?

The gold standard for Low End of VRR is obviously 1 Hz.

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Re: FAQ: Understanding HDMI Quick Frame Transport (lower lag)

Post by Chief Blur Buster » 10 Aug 2021, 14:35

1 Hz is not easy to do with LCDs without flicker, and things can get so bad that LFC actually improves image quality at a certain point.
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Re: FAQ: Understanding HDMI Quick Frame Transport (lower lag)

Post by Chief Blur Buster » 10 Aug 2021, 14:36

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