you can recover your deleted videos as long as you didn't save any new data on the card where your lost videos located.
what you deleted is the entry index which tells where the videos are, not the video files.
in order to enhance the success chance of recovery, the most important thing you should do is to stop saving new data on it to avoid data overwriting.
then follow the below steps, you can recover your deleted files on your own.
1. Connect the card to your computer(if the deleted videos are in a card), you will see a drive letter like H:
2. Download recovery software, which can recover videos. Last time I used Wondershare Photo Recovery
software to recover both my photos, and videos.
3. select the drive where the deleted videos located. and click 'Next' to start the automatic scanning.
4. select a recovery path to save the recoverable videos.