I have been playing around with open source camera software that can turn most webcams or network cameras into security cameras. The software is called iSpy and is free to use and download from ispyconnect.com.
All the features are available in the base product but if you want to be able to access your camera stream from the internet you will need to pay a subscription, which starts at $8/month. That is not a big deal as you can use it for free on your home network to capture video and images. iSpy can use motion detection to start recording or trigger an alert to email. It can even detect license plate numbers which can be used to identify visiting vehicles.
iSpy offers many features and as a result can be complicated to configure, but with a bit of tinkering you can fine tune it to your needs. Depending on the features of your camera, you can use it as an intercom and even control the pan-tilt-zoom (PTZ). If your camera has this option then you can enable motion tracking which will follow moving objects (within the range of the camera movement of course). You can also setup a virtual fence so only movement within a certain zone is tracked. This is useful if you are monitoring a high traffic area but only want to detect movement in a certain area (e.g. near you front door which faces a road).
I have already mentioned license plate recognition but iSpy also has plugins for facial recognition, text overlay and detection and barcode scanning. Additional plugins can be purchased for advanced features from iplugs.eu. One thing to note is that iSpy only runs on Windows PCs. A MacOS video product is available from sighthound.com with a pro option that is chargeable.