How do you take screenshots of games?

[DEBRO]

Hi there,

 

I was wondering how do you take screen shots of games that flicker. Taking a screenshot of a game that doesn't flicker is easy through an emulator but for one that flickers at say 20Hz it's hard to capture every object. Do you take multiple shots and merge them with something like Photoshop?

[Gregory DG]

I guess it depends on what emulator you use. I use z26 and there is a switch (which I can't remember) that keeps it from flickering.

[DEBRO]

I guess it depends on what emulator you use. I use z26 and there is a switch (which I can't remember) that keeps it from flickering.

I assume you mean -f but even using that at 20Hz you don't capture all the objects in a screenshot.

[Albert]

You can do this easily using Stella. Load up a game, then hit "Tab" then "Game Properties". Click on the "Display" tab. Then set "Use Phosphor" to "Yes". You can then adjust the blend. You should then be able to take spiffy screenshots without any hassles.

 

..Al

[+Nathan Strum]

I was wondering how do you take screen shots of games that flicker. Taking a screenshot of a game that doesn't flicker is easy through an emulator but for one that flickers at say 20Hz it's hard to capture every object. Do you take multiple shots and merge them with something like Photoshop?

Yep. Although the phosphor mode in Stella helps with some games.

 

For this one, I used the Stella debugger, since it allows me to step a frame at a time:

 

 

I took a screenshot of the debugger window three frames in a row, and cropped them. Then combined them in Photoshop:

 

 

I've had to do this a few times when creating game manuals.

 

Ideally, it would be nice to be able to save a screenshot from the debugger. Another future feature request. That, or if you could tell Stella how many frames to use to take a single screenshot of a game. Now that would be nice.

 

Here's the Photoshop file, so you can see how the layers are composited:

pacman.psd.zip

Edited March 23, 2007 by Nathan Strum

[+Nathan Strum]

Hmm... just read Albert's reply.

 

Guess I need to download a newer version of Stella.

 

Edit: Just downloaded the latest Stella. It won't blend more than 2 frames, so it doesn't work with 20 Hz (or slower) flicker.

Edited March 23, 2007 by Nathan Strum

[Albert]

Hmm... just read Albert's reply.

 

Guess I need to download a newer version of Stella.

 

Edit: Just downloaded the latest Stella. It won't blend more than 2 frames, so it doesn't work with 20 Hz (or slower) flicker.

Damn.

 

..Al

[DEBRO]

Hmm... just read Albert's reply.

 

Guess I need to download a newer version of Stella.

 

Edit: Just downloaded the latest Stella. It won't blend more than 2 frames, so it doesn't work with 20 Hz (or slower) flicker.

Yep, that's the problem I was having with this one. I guess it does flicker too much

 

Thanks for the tip Nathan. I'll use your method with Photoshop.

[Marc Oberhäuser]

I use FRAPS for screens and movies.

[SeaGtGruff]

I guess it depends on what emulator you use. I use z26 and there is a switch (which I can't remember) that keeps it from flickering.

I assume you mean -f but even using that at 20Hz you don't capture all the objects in a screenshot.

Yes, the -f switch. But as I found out last night, it doesn't work if you're using the -r switch, too, so take off -r to use -f. (-r lets you run flickered games at monitor speed so the screen flickering doesn't "tear.")

 

Michael

[+stephena]

Ideally, it would be nice to be able to save a screenshot from the debugger. Another future feature request. That, or if you could tell Stella how many frames to use to take a single screenshot of a game. Now that would be nice.

 

Here's the Photoshop file, so you can see how the layers are composited:

Stella only blends two frames at a time, so it only takes care of 30Hz flicker. I'd need to think about how to deal with 20Hz flicker, since that means *3* frames have to be blended. However, the internal framebuffer only remembers two frames at a time, so something else is required ...

 

As for the other requests, it would be quite easy to add a command to save a snapshot from the debugger. The other request (specifying how many frames to use) will require a little more thought, but it should be doable.

 

Also, I'm pretty sure the 'non-flicker' command in z26 only works with 30Hz flicker too.

[+Nathan Strum]

As for the other requests, it would be quite easy to add a command to save a snapshot from the debugger.

That would be excellent!

 

Something MAME uses could also be handy. You can hold down a couple of keys (shift + esc) and step the emulator ahead while paused, a frame at a time. Then you just hit F12 as needed. You still have to combine the screenshots together, but it gives you really good control over what you're taking pictures of. (I used this a lot, when working on the MacMAME Screenshot Library.)

 

Effectively, it would be the same thing as saving screenshots from the debugger, but it would keep your display settings intact.

Edited March 23, 2007 by Nathan Strum

[SeaGtGruff]

Also, I'm pretty sure the 'non-flicker' command in z26 only works with 30Hz flicker too.

That is correct.

 

Doing frame-by-frame screenshots and then combining them is the best approach, but this raises the issue of how to handle the flickered areas when combining the screenshots. If they're just copied and pasted from one frameshot into the other frameshot, then that makes it look like the colors are nice and strong, flicker-free. Are there any graphics programs that can take three or more bitmaps and blend them together? Two isn't an issue, since we can just capture them using the phosphorescence effect.

 

Michael

[+Nathan Strum]

There are ways to do it in Photoshop, so you can control how much of each layer is composited into the final image.

[+stephena]

Also, I'm pretty sure the 'non-flicker' command in z26 only works with 30Hz flicker too.

That is correct.

 

Doing frame-by-frame screenshots and then combining them is the best approach, but this raises the issue of how to handle the flickered areas when combining the screenshots. If they're just copied and pasted from one frameshot into the other frameshot, then that makes it look like the colors are nice and strong, flicker-free. Are there any graphics programs that can take three or more bitmaps and blend them together? Two isn't an issue, since we can just capture them using the phosphorescence effect.

 

Michael

Well, I still haven't had time to give this extensive thought, and graphics processing isn't exactly my area ... But the phosphor effect is already combining two fields, and it isn't a simple copy & paste. What about the first two are composited, and then the third composited into that result?

[Thomas Jentzsch]

But the phosphor effect is already combining two fields, and it isn't a simple copy & paste. What about the first two are composited, and then the third composited into that result?

Something like that, yes.

 

Take the result of the previous frame and combine it with the current frame. Best would be a variable parameter for defining the weights of the two frames.

[as_the_gavel_falls]

Hi there,

 

I was wondering how do you take screen shots of games that flicker. Taking a screenshot of a game that doesn't flicker is easy through an emulator but for one that flickers at say 20Hz it's hard to capture every object. Do you take multiple shots and merge them with something like Photoshop?

 

I wrote some software for this: http://www.atariguide.com/ss/pacman.gif

 

Take the result of the previous frame and combine it with the current frame. Best would be a variable parameter for defining the weights of the two frames.

 

This is a nice idea, but it voids the idea of "previous" frame by it's definition. I thought and thought but the enemy still starts disappearing before the bullet shows up.

[Rik]

Yes,but how did people in the early 80's take such clear screenshots to send to say"ACTIVISION"for proof of high score,to earn a patch,there was no photo shop or fancy software back then,or even pc's like we know today.!?!?

Edited October 3, 2007 by Rik

[+remowilliams]

Yes,but how did people in the early 80's take such clear screenshots to send to say"ACTIVISION"for proof of high score,to earn a patch,there was no photo shop or fancy software back then,or even pc's like we know today.!?!?

Photographs, not screenshots.

 

http://en.wikipedia.org/wiki/Instant_camera

[Rik]

Yes,but how did people in the early 80's take such clear screenshots to send to say"ACTIVISION"for proof of high score,to earn a patch,there was no photo shop or fancy software back then,or even pc's like we know today.!?!?

Photographs, not screenshots.

 

http://en.wikipedia.org/wiki/Instant_camera

Oh sh^t,you're right,i failed to realize there's a difference between a SCREENSHOT and a PHOTOGRAPH,MY EMBARASSED APOLOGIES!.