TJohns

I had a similar issue with a few MP4 files deleted from a SanDisk card. The video files couldn't be played although the recovered files looked like valid MP4s. Eventually, I managed to repair some of the files with a video repair tool, which fixes empty headers of the video files. If you're Ok with sharing your video files, you could upload one of them to Dropbox or Google Drive and then PM the link and I will try to fix it.