Sports video replay (slow-mo and frame-by-frame) program for sabre fencing in Linux OS

I am looking for a simple video replay program: to display video from a webcam, record the video into .mp4 files, and replay the video in the same screen in slow motion (quarter and half speed) and frame-by-frame. The solution must be implemented in Linux (ideally compatible with Lubuntu 10.11 running on a Samsung NC-110 netbook). The program is intended to be used as part of a video referee/replay system for the Olympic sport of sabre fencing. At its core, the program will be used to assist a fencing referee in making calls during a fencing match. Fencing actions are often very fast, and difficult for a referee to see and parse the actions to make the appropriate call. This program should be able to record a video of a fencing bout from a USB webcam. When the referee wants to review an action, they can stop the video recording and immediately play back the video at normal, half and quarter speed as required. If necessary, the referee should be able to scroll through the video frame-by-frame using the mouse (dragging across a bar, for example). Programs for this kind of analysis already exist in the marketplace, but not for Linux. See Ubersense and Coaches' Eye for examples of this kind of sports analysis software for iOS and Android, or RaceReplay for Windows XP. We would ideally want a program that provided the same functionality as Coaches' Eye.