Besides controlling your streams at the computer, you can do pretty much the same from a Mobile App.
The app is free to download from Android and Apple markets. In order to use the app outside of your home network, you will need to set up external access to your Synology NAS device.
Initial configuration of the app requires a valid IP address of the NAS and credentials. The app is simple to operate and offers basic functionalities such as live streaming and playback of the recordings. If your cameras support tilt/pan capabilities the control of these functions is also allowed from the App.