Double VSync

[xystus]

Did you guys ever think about adding a "double vsync" option? The framelimit would be limited to half of current refreshrate; it can work wonders for games running @30fps 60hz. RadeonPro has the option build-in (for AMD Radeon GPU's) and I use it quite a lot for PC games (without enabling the separate framerate-limiter). It sometimes works a lot better than Vsync + 30fps framelimit.

I normally don't use RadeonPro with Dolphin, because of the fact that an emulator works differently with buffering/sync than the average PC game, but I accidently left it on with Vsync enabled and.. the double-vsync result was much smoother than I could accomplish with Dolphin-only settings.


I noticed one gamecube game in particular working better with double vsync, than with limiter + vsync / just vsync / just limiter: sonic colors. Luigi's Mansion also seems to benefit from it, as well as Waverace (all 30fps games).

Curious about your thoughts on this.

EDIT: sorry, wrong forum, guess it belongs in the "general" area

[ExtremeDude2]

Why double when you can get triple?

[DJBarry004]

I read somwhere that Triple Buffering helps with speed-ups in graphics rendering... Experts here can say if it´s true or false since I´m not sure if that was the meaning... Or the way it works.

[ExtremeDude2]

Not to mention the input lag

[DJBarry004]

Uh, what lag?

[ExtremeDude2]

You get input lag with v-sync, but triple buffer reduces it

[DJBarry004]

So it seems that we found a second good point for tri-buffering...

[mbc07]

* moved to general discussions *

[NaturalViolence]

ExtremeDude2 Wrote:You get input lag with v-sync, but triple buffer reduces it

Um.....no.

You have that in reverse. Triple buffering increases input lag. You have three buffers instead of two in the chain so naturally the current image being scanned out to the display is going to be further behind the image being processed (2 images behind instead of 1). More buffering stages = longer time to get everything through the pipeline = higher latency.

Triple bufferings advantage is that it allows the framerate to run at speeds other than integer ratios of the refresh rate. So for example with double buffered vsync if your system cannot maintain 60 fps it will drop down to 30 fps since that's the next interval (1/1 or 60 fps, 1/2 or 30 fps, 1/3 or 20 fps, 1/4 or 15 fps, etc.)

The suggestion the OP is making has nothing to do with buffering though.

xystus Wrote:Did you guys ever think about adding a "double vsync" option? The framelimit would be limited to half of current refreshrate; it can work wonders for games running @30fps 60hz. RadeonPro has the option build-in (for AMD Radeon GPU's) and I use it quite a lot for PC games (without enabling the separate framerate-limiter). It sometimes works a lot better than Vsync + 30fps framelimit.

This makes no sense. At least not to me. Then again I'm not even entirely sure what you're proposing since dolphin already supports limiting games to half speed which is what you said should be added.

1. 30 fps games are already limited to half the refresh rate. That's why they're called 30 fps games.... Naturally vsync is also limited to 30 fps (1/2 ratio) in this case.
2. You can lock any game to any specific fps or vps if you want to. Although it's stupid to do that since it will throw the gamespeed out of whack.
3. You haven't explained the difference between double vsync and vsync + 30 fps framecap. In some parts of your post you imply that they're the same while in others you imply that they're different. But you haven't explained what that different behavior is. Because from what I'm reading in radeonpros docs it looks like they should be functionally identical. Unless I'm missing something.

xystus Wrote:I normally don't use RadeonPro with Dolphin, because of the fact that an emulator works differently with buffering/sync than the average PC game, but I accidently left it on with Vsync enabled and.. the double-vsync result was much smoother than I could accomplish with Dolphin-only settings.

What exactly improved? You're being vague. What does "smoother" mean? How do you propose to measure these improvements to prove that they're not a placebo effect?

[xystus]

(11-07-2013, 08:17 AM)ExtremeDude2 Wrote: Why double when you can get triple?

Double VSync is different from double/triple buffering. I never said anything about triple buffering, I was talking about double Vsync

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(11-07-2013, 02:31 PM)NaturalViolence Wrote:

xystus Wrote:Did you guys ever think about adding a "double vsync" option? The framelimit would be limited to half of current refreshrate; it can work wonders for games running @30fps 60hz. RadeonPro has the option build-in (for AMD Radeon GPU's) and I use it quite a lot for PC games (without enabling the separate framerate-limiter). It sometimes works a lot better than Vsync + 30fps framelimit.

This makes no sense. At least not to me. Then again I'm not even entirely sure what you're proposing since dolphin already supports limiting games to half speed which is what you said should be added.

1. 30 fps games are already limited to half the refresh rate. That's why they're called 30 fps games.... Naturally vsync is also limited to 30 fps (1/2 ratio) in this case.
2. You can lock any game to any specific fps or vps if you want to. Although it's stupid to do that since it will throw the gamespeed out of whack.
3. You haven't explained the difference between double vsync and vsync + 30 fps framecap. In some parts of your post you imply that they're the same while in others you imply that they're different. But you haven't explained what that different behavior is. Because from what I'm reading in radeonpros docs it looks like they should be functionally identical. Unless I'm missing something.

xystus Wrote:I normally don't use RadeonPro with Dolphin, because of the fact that an emulator works differently with buffering/sync than the average PC game, but I accidently left it on with Vsync enabled and.. the double-vsync result was much smoother than I could accomplish with Dolphin-only settings.

What exactly improved? You're being vague. What does "smoother" mean? How do you propose to measure these improvements to prove that they're not a placebo effect?

Thanks for your reply.

I'm not sure what exactly's different form double vsync compared to framelimiting, but I know the result can be different. What I do notice is this:

- when I look at the framerate (OSD) with the framelimiter on, the fps are "hard locked" @30. So the OSD always reads 30, unless it dips.
- When I look at the framerate with double vsync, the fps "hoover around" 30; like between 29,8 and 30,8 or something. Often this creates a smoother motion experience (less jerky) than the framelimit - less dips in framerate.

I use it in PC games like Crysis 2 and Far Cry 3. I noticed Far Cry 3 even had a "double vSync option" build-in! But like I said before, I noticed a similar improvement with Sonic Colors - I couldn't get the framerate really smooth no matter the settings (random jerkyness, though the fps was steady on OSD). Double VSync made it 100% smooth for me.

I hope I've explained it better, it pretty abstract stuff when I read it back.