Hey everyone, I have 3 videos mp4 with 2 variations each. I am trying to concatenate them in all the possible variations (maintaining the audio too)

I'm pretty sure is possible using the FFmpeg encode but how? Tried a lot of different things but they all require images sequences

Im trying like this, filtering the videos with the tag in their name (a,b,c..)

I was able to combine them as I want, the last piece is that the file output is not the mp4s combined but are just the clips.
If I enable the concat expression it throws an error "unknown keyword 'ftypisom'" And looking online it is about the concatenation of two mp4