The following picture shows all parts of the application and how these working together.
The camera sent live pictures via USB or FireWire to the computer. These are interstored with gstreamer on the hard disk. From this buffer fetches qStopMotion regularly the pictures to display them. If the capture button is pressed, the just displayed picture is taken over in the animation project. If all photos are shot and brought in the right order, a video clip can be generated from it with ffmpeg. Then this can be used in every video cut programme.
The control from gstreamer and ffmpeg is taken over completely from qStopMotion, thus itself the user therefore must not concern.