If the file won't open, use VLC Media Player as it supports almost all MP4 encoding variations.
Specifically, DOD Tech is a known manufacturer of high-end dashcams. Dod (309) mp4
A Japanese video game series (known as Drakengard in the West) often referred to as "DOD" in fan communities. Day of Defeat : A classic World War II shooter. If the file won't open, use VLC Media
If you have encountered this file and are unsure of its safety: If the file won't open
Right-click the file and view "Properties" to see if the "Origin" or "Date Created" provides more clues.