Q: if i have to restore to factory settings will i lose all my photos and videos?

Yes, unless you have backed up on the computer or iCloud.

About backups in iCloud and iTunes

iCloud- iCloud storage and backup overview

iTunes- About iOS backups

Choosing an iOS Backup Method (Should I Use iTunes or iCloud to back up ...)

https://support.apple.com/kb/HT5262

Back up and Restore your iOS Device with iCloud or iTunes

http://support.apple.com/kb/ht1766

iTunes: About iOS Backups

http://support.apple.com/kb/ht4946

Create and Delete iPhone, iPad and iPod Touch Backups in iTunes

http://support.apple.com/kb/ht4946

iOS: Troubleshooting Encrypted Backups

http://support.apple.com/kb/TS5162

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