: If recording live, use the Hybrid MP4 format in OBS Studio to prevent loss of footage if the program closes unexpectedly.

Split screen showing a "Fragmented MP4" versus a standard one.

: If the file doesn't open in standard apps, try the VLC Media Player , which supports almost all MP4 codecs. Writing an MP4 Muxer for Fun and Profit - OBS Studio

Final logo with "Produced from 0gtngisdkg5hbmjz6vxdq_720p.mp4." "Ready to create? Let's get to work."