Default FPS value
This FPS value only applies if there is neither a multimedia file available nor a file specific FPS value entered into the File properties of the current document.
The number defined as default FPS value, is used for every new data file you create - if no multimedia file was open. This is mainly important for live observations, because there is no multimedia file available (yet) in that case.
The current FPS value regulates the length of your frame by frame steps through the video and specifies how the collected 100 Nanosecond time information is displayed.
For example: At 25 fps, one frame has a duration of 40 milliseconds, thus each frame forward moves the video for 40 milliseconds.
The time position reflected at frame :10 at 25 fps will be displayed as frame :04 at 10 fps; in both cases it corresponds with 400 milliseconds.
IMPORTANT: The moment Events are logged, the current video fps value is entered into the file properties of the data file and this automatically overrules this default setting.
Current File-FPS versus video FPS
Whenever a video is opened, INTERACT recognizes the fps value of the multimedia file(s) automatically - presuming that the codec in use gives the correct time information.
•The current video fps is displayed in the upper left corner of the multimedia window.
•The current file fps value is shown in the lower left file window.
If those values do not match, and INTERACT detects logged data in the data file, you are not able to log new Events within this same data file. INTERACT instructs you to create a new data file.