well i'd be using a console but i'm not to sure what ya mean by platform, as in windows? yes then. it really is just supposed to be a program where you literally just enter the filename and press enter, then something else to stop and thats it, nothing complicated at all.
In that case you would want a log file. Actuall screen capturing software in Windows requires a hardware driver and those are a good three month project to write if you have never done it before. Don't kill a fly with a cannon ball.