You can verify the integrity of the downloaded file by checking if its hash matches the provided string using a tool like JosePedroDias/video-hash .
If this link was provided by a specific streaming service, you typically download the dashinit.mp4 first, followed by the individual data segments ( .m4s or numbered .mp4 chunks).
A dashinit file cannot be played on its own. It must be combined with the media segments of the same ID. Developers often use command-line tools like MP4Box to handle these files for progressive download or streaming.