If you downloaded this file and it won't play, it may be corrupted or require a specific codec.
A standard MP4 file should be several megabytes in size. If it is only a few kilobytes, it may be a shortcut or a failed download. 2. Check the Source
If a website tells you to download a "new codec" to view this specific 632827.mp4 file, it is often a phishing attempt.
Could you tell me or what you expect the video to contain? This will help me find a more specific guide for you.
Use a tool like VirusTotal to upload the file (or its URL) and check for hidden scripts.