Currently the iOS Plex and PlexAmp apps sync music/video to their own sandboxed app storage, which makes the synced media inaccessible to other apps.
With iOS 13 Apple has opened up local file storage so apps can store files to a shared storage location, which can be viewed in Files.app, Locations, “On My iPhone”.
If Plex would store its synced files there, this would allow other apps like djay or iMovie, GarageBand, VLC, etc to utilize Plex-synced music and video, read-only.
I don’t think that is what “On my iPhone” is. I think it is a filter, so you can see files which are local as opposed to in iCloud, etc.
I don’t think there is any file storage available outside a program’s sandbox, and we are stuck with the miserable “Share To” workflow.
I would be delighted to be wrong and for your request to be possible, because I hate everything about iOS file management.
No it does work like that. See the Apple developer documentation. You can also see here how Safari can be configured to use it, for example. Same with djay (you can set it to look for songs in “On My iPhone”), or for example iMovie (you can load audio or video files from that location).
Fascinating, thanks! That is really great news. I spent 10 minutes Googling after I read your post and could not find this information.
Man, I was even in the iOS 13 beta and didn’t know about this. Everything about file handling on iOS is bananas!
On my iPhone 11 Pro @ iOS 14.4, nPlayer can browse the local file storage and see into InFuse’s documents folder.
It would be great if Plex iOS would work this way. The Plex media player is perfectly-suited to 90% of my content, and it would be great to have synced files stored where I can view the other 10% when there is a problem.
The problems are lip-sync when watching a movie in my car and using BT to play the audio (nPlayer has an audio delay feature) and occasionally my trashy old BT speaker gets out of sync. Also, sometimes I want to crank up the audio in the headphones, and Plex iOS has its limits (nPlayer and InFuse have audio boost).
Typically I pop open InFuse and download the media to the local file store and play it with nPlayer. Sometimes I’ll use nPlayer to directly browse the media library with SMB (over VPN if necessary), and download the file to the nPlayer data store, but Plex can’t track viewing progress when I do that.
I feel like if the Plex iOS app just saved synced files where they can be browsed by other iOS apps, I’d be in great shape.
Of course none of this would be necessary if the Plex media player iOS had audio delay and boost capabilities, or if my car’s BT was newer, and my ears better 
…but I digress.
The odd thing I just discovered, PlexAmp currently uses Local Storage for a number of settings files like Metrics.json and PlayQueue.json and what I think is the local db RCTAsyncLocalStorage_V1 . Only thing it doesn’t store there is the actual music files…
