Unable to import mp4 or quicktime to the timeline. Unable to convert.

Hello,

I'm unable to import mp4 or quicktime videos to the timeline in my project.

I know this is a known/common issue as I've spent a lot of time on this forum, other forums, youtube videos, etc.. and nothing is fixing the issue. I'm aware it has something to do with the codec used, but I'm not sure how to get around this.

So far I've tried converting the files using Media Encoder, Quicktime, VLC, Handbrake, Squared 5, MPEG-Streamclip.. no luck.

I've also tried updating my Premiere Pro to 11.1.2 just incase the bug fixes address this (I read in notes it addresses this with a specific type of camera - which I'm not using, but thought it couldn't hurt to try).

I've also cleared the cache files, renamed the files I'm trying to import, and stored them in a different folder. Nothing.

I've been reading the camera type the footage comes from might be important in the solution.. which is difficult, because it's a mixed bag of footage.

I know for sure one of the clips I'm trying to use is screen capture footage from Quicktime Player on a Mac. That doesn't work.

The other footage comes from a IP Camera on the other side of the country from me. I've used footage from this exact camera before with no problems, but now I have them.

I've noticed too that it does allow me to use SOME mp4s.. just not ALL of them. I have no idea why. The mp4s it allows me to use show the purple "footage only" icon. The clips I can't use it shows the "footage and audio" icon like here. Even though there is no audio associated with the clips.

When I try to drag to the timeline it shows the little circle with the cross through it symbolizing "this is not allowed". The audio will drop on the timeline just fine - but no footage. I don't care about audio I ONLY need this footage. (there isn't any audio in the clips anyway)

In other solutions I've read people have had - it worked when they tried doing some sort of converting, or it had something to do with their windows OS - I'm on macOS El Capitan 10.11.6 and Adobe Premiere is on 11.1.2.

I've been thinking I would need to do some sort of conversion of the file or the codec itself (I've never ran into a situation where I only needed to convert a codec, so I'm not sure what other challenges/limitations this brings with it). But thats as far as I can get. 

Please help nothing seems to work!!

Thanks!