By design Elmedia Player PRO for Mac features interactive conversion to images, not frame-by-frame. This is done in order to screenshot even SWF movies, which contain sprites with their own timelines and can’t be converted using frame-by-frame conversion method.
You can select screenhots interval in Preferences. However, minimum screenshots interval which you can select using the slider is 0.1 sec.
In order to go beyond the limits for schreenshots intervals provided in Elemedia Player GUI and receive screenshots with higher frequency, please, execute the following command in Terminal:
defaults write com.Eltima.ElmediaPlayer ScreenShotInterval <sec></sec>
<sec> is interval in seconds.
For example, if you need to screenshot your movie with 25 fps this command will look as follows:
defaults write com.Eltima.ElmediaPlayer ScreenShotInterval 0.04
i.e.: 1 sec / 25 fps = 0.04