Call url is not directly possible, but you can write a program that "listens" for events to occur, and the you could call the URL yourself in code. Hikvision uses ISAPI for an API and you can make calls to various channels and streams and listen for events to occur. If you are familiar with node.js, there is an NPM package that will make your life easier by doing the heavy lifting for you. In just a few lines of code, you can subscribe to motions events, and then in a callback, you could call a URL, or do anything else you wanted problematically.
node-hikvision-api