Yeah, sorry, you can't do anything with that cellphone video because it's in some stupid format, right? and yeah no your conversion software will convert it... into some special magical mp4 file that can be played by your player but not opened by your video editing software... especially if you're trying to use Ableton Live for video editing. Which you can do. It's great. Shut up. It's awesome. It can only open mp4s and movs if you have QuickTime installed and nobody bothers to document that but whatever, that's OK. It's software. Accountability. It has no meaning.
So anyway, give up on your encoder and just upload the offending video in its crazy format to Google Drive, or YouTube, and then rip it back out of the YouTube player using Firefox Video Download Helper.
Yet another classic instance of having to use software that's legal but in the process of getting shut down for enabling hacking and piracy, in order to do something that's totally legal, but made difficult by companies that want you to pay for your right to edit the videos that you yourself record using the camera in your phone... instead of just sharing it.
So, yeah, the solution is basically to share it, to nobody, then rip it, using software used almost exclusively for piracy, and then you can edit it. Don't be surprised if you can't even see the video clip when surfing your cellphone's hard drive from your PC while it's tethered. Maybe it'll be visible, maybe it'll be invisible. It's software. Literally half a person at Google cares what your experience is like with it. There's somebody around there that's just a pair of legs (no ears so they can't hear your usability problems).