If you're still here, I have a solution! I also had this problem when I used any of the recovery programs, I researched this for quite some time and I found out that the software returned two types of files, one very short MPEG and a longer MOV, I found out that the software reads the video file as two different parts, one with the video information and one with the header information. You need to combine them for the video to play properly. So I use the command prompt to merge the files together.
Here's what I did, Make a copy of your original files! The uppercase bracketed letter are paths that are specific to your computer. So you open the command prompt, and it will say something like this:
C:\Users\(NAME)>
...and the (NAME) would contain whatever your username is for your computer.
1) So step one would be to direct the command prompt to wherever your video files are. You might be able to copy from the address bar then right click on the command prompt and paste.
C:\Users\(NAME)>cd /d (PATH OF FILES, Example: E:\Video\Private)
Press Enter, and in a new line, it should display the path that you typed.
2) in this new path, type copy /b (VIDEO).mpeg+(VIDEOB).mov E:\MERGED.mpeg
The copy command will merge the files, then the new path will be where the new file will be placed. Replace the uppercase bracketed portions with the actual file names.
VERY IMPORTANT!!! You must choose a different folder and file name, otherwise the original files will be overwritten!
3) Press enter and then it should list the two files in two different lines, then say 1 files(s) copied. Check the video to see if it works, the shorter video usually should go before the longer one.
Hope this helps!