Where does YouTube's offline feature store video files? I'm using YouTube offline feature on my Android device, so that I can playback the offline videos within the YouTube app even there is no internet connection. When I searched for any of the video files, I can't find them on device/SD card memory. Are they encrypting the file so that it can be played only with YouTube app? Does anyone know the specific folder for offline video data?
The location for those videos on my Samsung Galaxy Tab 2 is as below:


  Internal
  storage/Android/data/com.google.android.youtube/files/Offline/(system
  generated folder name)/streams


There might be a minor change to this location or path on other Android devices, but all those downloaded files are saved as .exo files, in an Internal Storage of a device!

But it is also true (to the best of my knowledge) that those "offline" videos can only be played using official YouTube App, and those videos simply can not be played using any other Video/Media player application.

YouTube (means Google) controls the access to the offline file. 

The permission is controlled on their server per account basis, to access those downloaded files.

There are 2 other discussions related to offline functionality here and here, which should be helpful to enrich the info about YouTube offline feature.