Can I digitalize a video with a RCA-Jack adapter?
The cable in the picture is an analogue cable, so it's getting an analogue signal from your camera. It's just a cable, so the signal at one end is exactly(ish) the same as the other. To digitise it you'll need a device to convert the analogue signal into digital code. There is a big range of these devices, from cheap USB dongles on ebay like this to broadcast standard boxes like this. The quality of hardware and software will vary, I'd hazard a guess that you'll mostly get what you pay for.

When looking for a converter you have to make sure that it is converting from analogue to digital. No cable alone can do this, it needs some sort of processing. Basically if you find something that has analogue sockets on one end (like the red white and yellow plugs on your cable, you call them AUX, but they're more commonly called RCA connectors. Professional equipment may have BNC connectors instead) and a digital plug on the other (usb, firewire, thunderbolt, etc. – but probably not HDMI because you generally can't record HDMI without specialised equipment) that you can plug into a computer then you're good to go.