FFmpeg H.264 DVR Conversion

I have a batch of raw, proprietary DVR recordings that appear to be H.264 streams with no standard container. They refuse to open in VLC or any regular player, so I need a reliable FFmpeg-based workflow that will:

• ingest these raw files,
• wrap the result in a standard container such as MP4 or MKV that plays everywhere.

Please deliver a tested command line (or a short Bash/PowerShell script) plus notes that explain any flags or filter chains you use, so I can replicate the process on similar footage in the future. If remuxing alone isn’t enough because of non-standard headers, include the steps you take to strip or patch them before conversion.

I’ll supply a sample clip as soon as we start; you return a working output file for that sample and the commands/scripts you used.