VOGONS


frameskip question

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First post, by user222

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Why won't DOSBox let you set the frameskip higher than 10 using the hotkeys, even though it works if you set it from the config file?

Reply 1 of 16, by Qbix

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bug in the configfile interpreter.
we forget to impose the max 10 value there.

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Reply 2 of 16, by user222

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Qbix wrote:

bug in the configfile interpreter.
we forget to impose the max 10 value there.

Please, don't impose the limit, I actually like to set the frameskip to 100 and above, to get the lowest possible CPU usage. At lease don't impose the limit until DOSBox would update the screen only when something is changed.

Reply 3 of 16, by Qbix

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well frameskip=10
means that only 6-7 frames per second are drawn

If that is too much for you, you might consider getting a faster pc.

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Reply 4 of 16, by user222

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Qbix wrote:

well frameskip=10
means that only 6-7 frames per second are drawn

If that is too much for you, you might consider getting a faster pc.

OH MY GOD!!!, THAT WAS ACTUALLY AN ADVANTAGE, NOT A BUG!!!!!

Reply 5 of 16, by `Moe`

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shhhh, we're not deaf!

But I agree, the limit could be raised a bit - I've found 25 to be a nice limit, on my old 300MHz laptop I've been around 15-20 usually. 100 is pointless, IMHO, since there's already very little difference between 15 and 20. Raising frameskip to 100 instead of 20 won't buy you anything.

Reply 6 of 16, by user222

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`Moe` wrote:

shhhh, we're not deaf!

But I agree, the limit could be raised a bit - I've found 25 to be a nice limit, on my old 300MHz laptop I've been around 15-20 usually. 100 is pointless, IMHO, since there's already very little difference between 15 and 20. Raising frameskip to 100 instead of 20 won't buy you anything.

Anyway, I don't think a frameskip limit would be necessary, unless it would create problems.

Reply 7 of 16, by Qbix

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hehe. well people setting useless high numbers like 200 😀

and then complain: " my mouse lags 3 seconds !!! Fix it!!"

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Reply 8 of 16, by user222

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Qbix wrote:

hehe. well people setting useless high numbers like 200 😀

and then complain: " my mouse lags 3 seconds !!! Fix it!!"

It's because that people don't know what "frameskip" means in DOSBox. In most game console emulators, increasing the "frameskip" usually increases the emulation speed, rather than to skip drawing some frames.

Reply 9 of 16, by Snover

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Um, no, it does exactly what it says in every application. It skips rendering of frames. This reduces processor usage and can help things run better, just like DOSBox's frameskip. But if your hardware is too slow in the first place, frameskip won't help, and if you turn it really high it makes things worse.

Yes, it’s my fault.

Reply 10 of 16, by user222

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Snover wrote:

Um, no, it does exactly what it says in every application. It skips rendering of frames. This reduces processor usage and can help things run better, just like DOSBox's frameskip. But if your hardware is too slow in the first place, frameskip won't help, and if you turn it really high it makes things worse.

Sorry, in most games emulators, they do skip drawing some frames, but at the same time, they increase the emulation speed. Try increasing the frameskip in the ZSNES SNES emulator, you will notice it increases the emulation speed. Run the Windows version of ZSNES, don't run the DOS version ZSNES in DOSBox.

Reply 11 of 16, by HunterZ

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Sounds like a pretty crappy emulator that times itself by number of frames drawn rather than actually using time. I never use manual frameskip in any emulators anyways.

Reply 12 of 16, by user222

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HunterZ wrote:

Sounds like a pretty crappy emulator that times itself by number of frames drawn rather than actually using time. I never use manual frameskip in any emulators anyways.

Most game console emulators manage frameskip like that.

Reply 13 of 16, by Qbix

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there is a difference between dosbox and console emulators.

console emulators run at a defined speed. (snes 3.86 mhz)
so they try to reach that.

dosbox/pc on the otherhand doesn't have a defined speed.
(only what you set by cycles). So if you set cycles too high for your machine, then increasing the frameskip will speed dosbox up as it can meet those high cycles then.

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Reply 14 of 16, by user222

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user222 wrote:
HunterZ wrote:

Sounds like a pretty crappy emulator that times itself by number of frames drawn rather than actually using time. I never use manual frameskip in any emulators anyways.

Most game console emulators manage frameskip like that.

Or because in game console emulators, "frameskip" is often used interchangeably for "FPS (frames per second)"?

Reply 15 of 16, by wd

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> "frameskip" is often used interchangeably for "FPS"?

Surely not.

Reply 16 of 16, by Snover

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What a brilliantly inane and pointless thread we have here from 2005. Closed.

Yes, it’s my fault.