If this file is part of a mystery game or interactive media, here is a general guide on how to approach and analyze such files:
If the video is part of a horror or mystery experience, pay attention to these common elements: 29082020b.mp4
While a standard .mp4 typically does not contain executable code, it is best to use a reliable player like VLC Media Player or the default players in Windows or macOS. If this file is part of a mystery