For any SlingStudio project, it’s important to make sure that you have chosen consistent frame rate settings for your project, as well as for your video sources.
If a video source is set to a frame rate that’s different from the project frame rate, the project frame rate takes precedence. As an example, if your project is set to 60 frames per second (fps), but your video camera is set to 30 fps, then the video source duplicates frames to make up the difference.
Things can get even more confusing if the project frame rate is 60 fps, one video camera is set to 30 fps, and another video camera is set to 60 fps. Switching between these two video sources can introduce a number of confusing problems.
So the bottom line is: be sure to match the frame rate settings for your project and for all video sources.
Note: Although SlingStudio can accept 1080i content, wherever possible be sure to set the video camera to progressive scan (e.g. 1080p) modes to avoid any loss of resolution during processing.