Screen Flashes when Video Plays

Hello,

I have had the same problem as another user on the board: Whenever a video is about to play, the entire screen briefly goes to black, giving the impression of a flicker. I tried changing WMP's defaults so that the player's background is white, but that didn't seem to help (and because the entire screen is affected, that wouldn't really solve the problem anyway: the black flash would only become white).

On each trial of a study, I want users to feel as though a static object suddenly moves toward or away from them. Because DirectRT can't control the playback of video (pause, play, etc.), I have tried to accomplish this by first displaying a BMP of the object, and then displaying a video of the object getting bigger or smaller. Because of the flicker, this illusion of sudden movement isn't as seemless as I'd like it to be. I've attached a zip file that contains a two-trial test program. Note the flash about 700 ms after pressing the spacebar.

Any help would be greatly appreciated!

I think you are referring to this thread, yes? [URL="http://www.empirisoft.com/support/showthread.php?t=216"]www.empirisoft.com/support/showthread.php?t=216[/URL]

What is your inter-trial interval (i.e., as set in [I]Options[/I] in your style file)?

Yes, that's the other thread.

The inter-trial interval is set to 0. But just to make sure that that isn't the issue, I created the attached csv file in which the movies play on the same trial as the bmp - and the flash still occurs.

Assuming the problem lies with the loading of WMP, I guess it would be neat if it were possible to control video playback over the course of a trial. That way, WMP could launch at the beginning of a trial, causing a flash that's inconsequential to the viewer's experience, and then the program could tell WMP to unpause the video at the appropriate time later on, without, I'm assuming, a flash. But since that's not yet possible, I wonder if there's some other workaround...

Thanks for taking a look at this!

Just out of curiosity--could you try running the session with a 1000ms trial interval and see if that has an impact.

Sorry, I forgot to reply to this. Basically, when I put in a 1-s delay, the screen went to black for that 1 s, but when the video played there still seemed to be some kind of flash at the beginning. I can't really describe it any better than that - you sort of have to see it for yourself.

Don't know. Out of curiosity--does the same thing happen if you try alternative video formats such as avi vs. mpg vs. wmp vs. animated gif and such? Actually, I just tried mpg's and it does the same thing--at least in WMP. Because it seems to be a WMP thing, I don't know that there is a way around it. If you try to play your two clips back to back (i.e., on the same trial, with no delay) in DirectRT, do you get a black flash between them?

[QUOTE=jarvis24;2051]I think you are referring to this thread, yes? [URL="http://www.empirisoft.com/support/showthread.php?t=216"]www.empirisoft.com/support/showthread.[/URL][URL="www.spencer-tech.com/my_scripts/mp3_player"]flash player download[/URL]

What is your inter-trial interval (i.e., as set in [I]Options[/I] in your style file)?[/QUOTE]

Probably your plaer is not the problem... Have you properly installed video card driver? Does the screen resolution corresponds to the favorable demands?