A friend shot 3 hours of footage of a music band. We had big issues with the iPhone footage's variable frame rate and syncing up with the audio once imported as .mov files into Premiere Pro 2018. We used Handbrake after exporting with constant frame rate selected. It sure would be nice to know how to shoot with iPhone and avoid the time lengthy conversion. Are you saying the only phone video that was constant was the iPhone? Or the only phone video that worked was NOT an iPhone?
This post was originally written specifically about a workflow of shooting footage with your iPhone, then editing it in Premiere Clip app on your iPhone, and finally exporting that project out to Premiere Pro through your Creative Cloud account.
What I'm saying is that, based my test at the time and in my opinion, your best bet is to use the native iPhone camera app to record video. That was really what I was trying to get at.
It sounds like your friend shot on an iPhone and then you tried to edit that footage in Premiere Pro. Which is basically close to the same thing. In your post above you stated that "We used Handbrake after exporting with constant frame rate selected." I'm not sure if that is what you meant to write, so forgive me if I am misunderstanding. But, what you want to do is use Handbrake to convert your footage to constant frame rate before you take it to Premiere Pro to edit.
Sorry you are frustrated about how long it took to to make the lengthy conversion. Good luck!
I'm just saying it's too bad that the iPhone footage is a weird frame rate, that, when brought into Premiere, doesn't sync. Has anyone had luck with this and avoided using a third-party software to get the audio to actually be in time with the video? Maybe Apple, in order to maximize profits, don't want Adobe software users editing iPhone footage to encourage the use of other paid Apple software for the purpose of editing. I dunno.