Proper timestamps on snapshots

Will files as enhancement, but comes close to being a bug.

Quoting Blingzer:

Could you change the filename of snapshots to be the time of the frame within the video rather than the date and time at which the snapshot is taken? Or maybe append this info? Or make filenaming changeable within preferences?

Thanks for your consideration.

https://forum.videolan.org/viewtopic.php?f=7&t=136357

I suggest having an option under preferences to choose between playtime and system time. But have playtime as default!