437.mp4 Direct

: Modern implementations, such as the OBS Hybrid MP4, support multiple video and audio tracks within a single file, which is useful for advanced broadcasting and debugging. Minor Caveats

: Some older video editors or media players may struggle to open fragmented files directly.

While highly useful, this feature has a few limitations depending on your tools: 437.mp4

: Previously, users had to record in .mkv format (which is naturally crash-safe) and then "remux" it into .mp4 for compatibility with editors. fMP4 eliminates this extra step.

Traditionally, recording directly to a "standard" MP4 was extremely risky; if your computer crashed or lost power before the recording finished, the entire file would be corrupted and unrecoverable. Key Feature: Fragmented MP4 (fMP4) : Modern implementations, such as the OBS Hybrid

: Instead of requiring the file to be "finalized" at the end, fMP4 splits the video into smaller, independently decodable segments called "fragments". If a crash occurs, everything recorded up to that moment is preserved.

: Because the segments are decodable on their own, playback can start after downloading only a tiny portion of the file, making it ideal for high-efficiency streaming. fMP4 eliminates this extra step

This newer variant solves the "corruption risk" by changing how data is stored: