After searching around on the internet I found two apps, one called
WalkieTooth and another called
WalkieTooth allows video and audio chat over WiFi, WiFi Hotspots, Bluetooth and WiFi Direct. To set it up:
- Download from Google Play on both devices
- Select the Camera icon on both devices
- On the first device select 'Server', under 'WiFi'
- On the second device select 'Client', under 'WiFi' and input the IP address displayed on the first.
- You should now be in a video call, press the camera icon to turn on your camera
Walkietooth allows to establish a full duplex communication channel between two Android devices, letting them to communicate for all the time needed, better than having two walkie talkies.
- Download the APK from the 'official' site
- Install the APK by opening it (You may need to enable 'Unknown Sources' in Settings > Security first)
- Open the app and press the menu button on the navigation bar
- Select 'Settings' to open the settings page
- Find the option named 'Camera' and choose which camera you want to use
- Repeat process on other device and press Menu > Refresh List to scan for devices
For just WiFi chat, files and audio calls, then these apps support it: