Hi,
Maybe I can offer you a (temporary) sollution.
Maybe you can try to recode the files using a video decoder or converter into a format APP accepts?
Then at least you can start editing the files. Also you will find out if the files are corrupted. And maybe later you will find a sollution for the original material. That is, if the result of decoding is less then your demands. After the edit: Just make the converted footage offline and then “link media” to the original footage.
Cheers from Amsterdam.
Daniël.