If you are using Ubuntu and the iPhone, you may want to add some videos to your device with your computer.
Don't worry, it quite easy and does not required for you to jailbreak your iPhone.
Step 1: Install VLC for IOS
The first thing you need to do is install VLC for iOS.
Search in the AppStore for "VLC" and install the application.
Step 2: Make Sure to Have the Latest LibiMobileDevice
If you are using Ubuntu 16.04, you will need to install the latest libiMobileDevice library.
Add this PPA to your repositories:
Once that is done, you're ready to go...
Note that Ubuntu 17.04 is working out-of-the-box so you don't need to do this step.
Step 3: Plug Your IPhone to Your Computer
Unlock your iPhone and plug it in your computer.
Your iPhone will ask your to trust this computer. Just accept.
After a few seconds, Ubuntu will show-up your iPhone's Document folders.
You should see the VLC app listed
Step 4: Add Your Videos...
Simply select any videos you have on your computer and copy them into the VLC app folder of your iPhone.
Once the process is completed, you should see the new videos in the VLC app on your device.