My HTC One recorded several videos but cannot play them. {HELP}

[rtb2]

My HTC One recorded several videos but cannot play them. On my camera roll in gallery, you see the videos but they appear grey and have the play symbol in the center. The other videos in gallery you can see a picture from the video with the play symbol in the center while you are in gallery. I tried emailing the video, and posting the video to google+ but all that is sent is the picture of a play symbol with a line through it.
When I clicked on 'details' for the not working videos what came up is;
'file path' 'Date' 'size' 'type' and 'status'
only for 'type' was there no information, it is just blank underneath.
So it does not seem to recognize the video as video/mp4
What do you think is the problem and can I fix it or can I never be able to retrieve the videos?
Thank you

 

[B. Diddy]

Welcome to Android Central! These were actual videos you took, and not Zoes? Can you connect the phone to your computer and copy the videos over to your computer using the computer's file browser, and then try to play them on your computer?

 

[rtb2]

I synced the videos onto my computer through HTC sync manager and tried to open a video through Quicktime, but it says that it can't open the video. I tried through iMovie and it said it could not be imported because it is in an unrecognizable format.

 

[B. Diddy]

What format are the videos? Here are the supported formats for iMovie: iMovie HD: Supported video formats