Videos' size became 0byte. I don't know what happened. But some of the videos work, those recently played became 0byte.
On Totem says: Stream contains no data. And on other player they don't play they are loaded but stuck.
This normally happens when you start to copy several files but it never completes. The only solution is copying it again from the original source, or preventing it by doing backups. To be on the safe side, you must check the size of the total of the files you are copying in the original folder and in the final one; if they match, everything is [probably] okay.