Cloud QR and Cloud QR has an awesome feature that let's you make QR codes available offline and scanned without an internet connection. To use this feature you need to download Cloud QR or Cloud QR Scanner from the AppStore.
You can make QR codes with images, sounds, documents, text and videos stored on Google Drive or OneDrive available offline.
Scan it with internet connection the first time, then select Share, Make available offline.
Now you can scan the same QR code even without an internet connection, like when you are outside.
This feature is only available on iOS.