I would like to copy the file creation date of an mp4 file into the file's metadata. I'm pretty sure this can be done with ffmpeg and some nifty Linux commands.
A part of answer using exiftool.
exiftool -tagsFromFile inputfile.mov -MediaCreateDate outputfile.mp4
This could be done after ffmpeg conversion.
This rely not on file modification time but rather on the time the video was created, which can be different from file creation.
Depending on the device that created the video metadata can be DateTimeOriginal, MediaCreateDate, ContentCreateDate and probably others. Check with
exiftool -s -time:all inputfile.mov
You can set metadata with FFmpeg via the
MP4s support the year attribute according to this, but I only got it to work with the "date" field which is shown in VLC (if it is only a year) and in MPlayer and Winamp without a problem as full date.
I found the
date attribute by setting the year via VLC and dumping the metadata with FFmpeg
To set the date to the time of the last modification (as a complete date like
2014-11-13) use something like:
ffmpeg -i inputfile.mp4 -metadata date="$(stat --printf='%y' inputfile.mp4 | cut -d ' ' -f1)" -codec copy outputfile.mp4
The last modified detection could most definitely be done nicer, plus, I am not sure how widespread the usage of the date metadata is, but it worked in my case.