tips on saving checkerboard files into a movie?

1
Hi all:

We have generated a left-right visual field (VF) alternating checkerboard for about 4 minutes
in Mac OS (and it has worked fine). Our collaborator who use PC would likes to ask for a
movie that can show the same length and same temporal precision (8 frames per sec), so
they can play (using QuickTime player, etc) on their site. Searching the Screen Help and other
matlab help files, I got the idea that PTB Screen can only play QT-movie, set different speed,
etc, but not record the movie (unless connected to a external videocapture device), right? If
using Screen is not possible, there are matlab functions like avifile that seems to be able to
generate movie with adding frames, but also have to tweak with best temporal and spatial
precision. I have not delved into this in greater detail, and would appreciate any suggestions
that could shorten the trial-and-error process.

thx, chun-chia
2
Hi Chun-Chia,

Making movies from psychtoolbox stimuli is a bit of a pain. You can
do it by capturing the screen and using the Matlab avi functions,
like you say. You could try this, but it might result in a huge
movie. PTB3 works fine on a PC, so your collaborators could get
Matlab. Another way to do it, since you have a flickering
checkerboard with only four unique frames (right?) would be to make
an animated GIF file.

keith

On Oct 30, 2007, at 11:09 AM, Chun-Chia wrote:

> Hi all:
>
> We have generated a left-right visual field (VF) alternating
> checkerboard for about 4 minutes
> in Mac OS (and it has worked fine). Our collaborator who use PC
> would likes to ask for a
> movie that can show the same length and same temporal precision (8
> frames per sec), so
> they can play (using QuickTime player, etc) on their site.
> Searching the Screen Help and other
> matlab help files, I got the idea that PTB Screen can only play QT-
> movie, set different speed,
> etc, but not record the movie (unless connected to a external
> videocapture device), right? If
> using Screen is not possible, there are matlab functions like
> avifile that seems to be able to
> generate movie with adding frames, but also have to tweak with best
> temporal and spatial
> precision. I have not delved into this in greater detail, and would
> appreciate any suggestions
> that could shorten the trial-and-error process.
>
> thx, chun-chia
>
>
>
> Post your message to: psychtoolbox@yahoogroups.com
> Please indicate OS9, OSX, or WIN version, and include your full name.
> Denis Pelli, David Brainard, and Allen Ingling.
> http://psychtoolbox.org
>
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>
>
>