Repair MP4 Video with broken header (but with 2 video and 1 audio stream)
Have you recorded the video with a GoPro camera?

If yes, then the two video streams may be a low-res preview video followed by the regular video stream. To repair such file, you would have to filter out the low-res stream.

So far as I know, the new version of the recover_mp4 has an algorithm of filtering out low-res streams of the GoPro cameras. The tool is now called Restore.Media. You can try repairing your MP4 with this tool and watch a full-time preview for free just to see if it works. Also, here is their article about repairing GoPro video files.