Recording stereo line out audio into iPhone 5 while recording video?

Trying to figure out the best/easiest/cheapest way to do this.


Basically I want to use my iphone to record demo videos/live PA synth stuff and would like to record a stereo line out feed straight from my audio interface into the iphone while taking video.

What's a good way to do this?

I tried some suggestions I had read searching around of using a cheap TRRS 1/8" to 3 RCA digital camera connection cable into the iphone 1/8" jack but it doesn't seem to work when I tried and looks like that would be mono anyway and I want to record stereo straight out of ableton.

Is there a good cheapish solution anyone has tried? I really don't want to mess with recording video and audio separately and editing to sync them, too much hassle for what I want to do. Additionally after straightening out the audio in I'm looking for suggestions for a better video recording app that can do this if the default camera app can't.

Thanks.

anyone?