Use a reputable tool like the NordVPN File Checker or VirusTotal to analyze the file for malware.
Malicious actors sometimes give dangerous files boring, numerical names to bypass your suspicion. They may use "codec exploitation" to hide scripts inside the video's metadata.
Ensure the file ends in exactly .mp4 and doesn't have a hidden secondary extension.
In some academic studies, "1000145.mp4" is a placeholder for observation footage, such as monitoring sleep patterns in animals.