After getting a Model 3 about a month ago I decided to make an app so I could view my Sentry Incidents and TeslaCam footage on my phone. It uses iOS 13's support for reading USB drives. You can download it here: Dash View for Tesla Cars. You can just plug in your drive, and then view your footage right on your phone. It has extremely smooth playback up to 4x speed and the ability to export composite videos of whichever cameras you want to export. You can also export fun time lapses. You can also jump straight to around the moment your Tesla detected the Sentry Incident. You can use any USB drive with an appropriate adaptor. For SD cards, you can use Lightning to SD Card Camera Reader — Apple, and for USB drives you can use Lightning to USB 3 Camera Adapter. Apple has a restriction on the power output for iPhones, so for some USB drives you may have to plug the adaptor into power. I'm open to suggestions for further improvement - let me know if there are any features that you would want me to add.