AMD Adding Experimental Video Mode Optimization To FreeSync

[BlueCrayon]

So I don't see what's so great about this patch.

This is what HDMI 2.1 refers to as Quick Media Switching. The primary consumer of this would be Kodi, if you configure it to switch your display to the video framerate (which you should). Without it your display blanks everytime the UI has to switch from 60Hz to 24Hz and back. I can imagine they would also wire this up to generic HDMI VRR support, and not just limit it to Freesync

[theriddick]

Linux needs freesync with multi screen setups and within windows (provided their drawn on the freesync screen). I hear that can only happen under wayland, but when I last tested wayland (couple weeks ago), it left allot to be desired! (mostly window and app drawing artefact issues),.

[clapbr]

Nice, I see this being very useful for Kodi. I will try it in mpv, might work with https://gitlab.com/lvml/mpv-plugin-xrandr

[fenixex]

In mpv and ffmpeg you've been able to use the fps filter to move film fps into a monitor's higher freesync range since freesync hit the market. A simple lua script does this matching automatically in mpv. The result is of course choppy like the source material.
....
Otherwise your freesync monitor has to have a min->max frequency range that includes those film rates. And the patch doesn't change that.

This is not an fps filter. If you were to play a 24fps movie, this would make your monitor drop down to 48Hz so each frame is displayed twice.

That's why mpv also offers interpolation, which drastically reduces judder ... and headaches.

I don't know of any movie that dropped so many frames that it caused headaches. Can you name one?

So if there's proper freesync support (at least for fullscreen applications) then you don't need to switch to those modes. That also circumvents the problem of player clock vs monitor clock drift that you get with a fixed refresh rate.

So I don't see what's so great about this patch.

I don't know of any monitor that can go as low as 24Hz and not shimmer. Right now, a 90Hz monitor won't go to 48 when you play a 24fps video. This patch makes that possible.
Getting something on linux 6 years after it has been added to the standard is nice. The only remaining part would be to implement power-saving for desktop.

[coder]

I don't know of any movie that dropped so many frames that it caused headaches. Can you name one?

When I got my Panasonic plasma TV, I started playing with the motion smoother. One of the first blu-rays I watched on it was L.A. Confidential. There was an outdoor scene set in the early morning, where the sky was already bright, but the foreground was still dark. As I watched the sky go skipping across the screen during camera pans, it appeared as though the foreground was actually moving at different framerate (I assume this was merely a perceptual effect, though I'm not sure whether it was more a function of the phosphors' persistence or that of my retinas). Once I turned on the motion smoother to max, the entire frame appeared to move in unison, and I quickly discovered I could resolve much more detail in moving objects or during camera pans. Since then, I never turned it off again (except for a little more experimentation). Even its (few) artifacts are better than the juddery, blurry mess of watching with it off. I got over the "soap opera effect" after a couple movies and found I could even see more subtlety in actors' expressions with it on.

A couple times, the TV got in a weird state where I guess it failed to detect the native framerate and the smoother shut off. I found the result virtually unwatchable, especially for 3D content.

I don't know of any monitor that can go as low as 24Hz and not shimmer. Right now, a 90Hz monitor won't go to 48 when you play a 24fps video. This patch makes that possible.

Poineer plasma TVs were famous for their 72 Hz mode for playing 24 Hz material. Panasonic eventually countered with 48 and 96 Hz modes. 48 is too flickery, even though it's allegedly what film projectors actually did.

[fenixex]

Oh, I misunderstood you then. I am not familiar with TVs at all.

[xnor]

This is not an fps filter. If you were to play a 24fps movie, this would make your monitor drop down to 48Hz so each frame is displayed twice.

That's pretty much what the fps filter can be used for though, displaying each frame twice, doubling the fps to lift it into a range that's within the monitor's. And you don't need to set any different mode for that at all.

I don't know of any movie that dropped so many frames that it caused headaches. Can you name one?

This was hyporbole but just take a look at any panning shot at 24 fps with a player on a big monitor/TV that displays this without any interpolation. There are some test video like Big Buck Bunny rendered at 24 fps that show the worst case.

So, I don't see why anyone would want this except maybe some purists. Especially with mpv that offers configurable frame interpolation (that doesn't result in a soap opera effect like the motion interpolation algorithms as e.g. used in many TVs), but you can also do motion interpolation.

I don't know of any monitor that can go as low as 24Hz and not shimmer. Right now, a 90Hz monitor won't go to 48 when you play a 24fps video. This patch makes that possible.
Getting something on linux 6 years after it has been added to the standard is nice. The only remaining part would be to implement power-saving for desktop.

How does the patch make that possible?
The patch skips on rates that are outside the monitor's reported range. And too low refresh rates (for the panel) are handled by the driver through LFC, but that requires the monitor to have a wide enough freesync range to begin with.

[gsedej]

I am also a bit confused about Freesync on Linux.

I was looking to upgrade my "normal 1080p" monitor with 1440p freesync 120Hz monitor when I found this.
According to https://linuxreviews.org/HOWTO_enabl...c)_on_AMD_GPUs
You need:
- freesync/VRR monitor
- displayport cable
- new kernel and mesa
- supported window manager (compositor?)
- xorg configuration
- single monitor - must disconnect the other monitors via cable (?)
- with all this, only one app support freesync: https://github.com/dahenry/gl-gsync-demo

No games, no other apps???
Each game needs to implement support for freesync? How is this on windows?
So today freesync is essentially useless on linux?

Or am I wrong?

[ripper81]

Linux needs freesync with multi screen setups and within windows (provided their drawn on the freesync screen). I hear that can only happen under wayland, but when I last tested wayland (couple weeks ago), it left allot to be desired! (mostly window and app drawing artefact issues),.

I am using Freesync with my AMD Radeon RX 5700. It is working very well on my system. However there are linuxspecific limitations to Freesync and G-Sync:

1. Both VRR Methods will only work with one active display due to limitations of X.org.
2. Both VRR Methods will only work with X.org. For Wayland the support needs to be implemented within the Waylandcompositor (Kwin,Mutter etc.)
3. Both VRR Methods will only work with exclusive fullscreen applications.
4. AMD Freesync will only work for displays connected via displayport.

[MrCooper]

1. Both VRR Methods will only work with one active display due to limitations of X.org.

This statement is incorrect for FreeSync as is, as discussed before in this very thread (and others before).