MultiView — merge multi-player Flashback replays

MultiView is a Fabric add-on for Flashback. Each player records their own POV with Flashback; MultiView fuses those recordings into one unified replay that behaves as if a single omniscient observer had captured the whole session.

• ✅ Every chunk explored by any POV is included
• ✅ Every recording player is visible at the same time
• ✅ Every entity and event seen by at least one POV is kept
• ✅ Free camera or Spectate Player on the merged replay
• ✅ Tick-perfect time alignment, atomic rollback on failure

Who is this for?

• Content creators — SMP recaps, PvP tournaments, machinima with multi-angle coverage from a single replay file.
• Server staff — multi-angle review of incidents, anti-cheat investigations from every involved player's POV.
• Cinematographers — free camera through a multiplayer scene with no information loss.

How to merge two replays

1. Each player records their POV with Flashback during the same session.
2. Drop the resulting .zip files into <gameDir>/flashback/replays/.
3. Launch Minecraft with Flashback + MultiView installed.
4. Click the camera icon → Select Replay.
5. Tick the checkbox to the right of each replay (minimum two).
6. Click Merge N Replays in the top-right corner.
7. The merged replay merged_<timestamp>.zip appears in the list once the progress screen finishes.

Compatibility

Minecraft	Flashback	MultiView
1.21.9 / 1.21.10	0.39.x	0.3.2+mc1.21.9
1.21.11	0.39.4	0.3.2+mc1.21.11
26.1 / 26.1.1 / 26.1.2	0.40.0	0.3.2+mc26.1

Requires Fabric API. Java 21 on 1.21.x, Java 25 on 26.1+.

Features

• N-way merge — works from 2 up to many POVs.
• Tick-perfect alignment via ClientboundSetTimePacket with metadata fallback.
• Cross-source deduplication — chunks (SHA-256 128-bit content hash), player info, system chat by visible text, entity moves.
• Multi-dimension — secondary POV dimension changes preserved as markers.
• Aggregated markers from every POV on a single timeline.
• Atomic write — .part file + atomic rename; a failed merge never destroys an existing replay.
• Bounded memory — LRU-capped chat dedup, cryptographic chunk hashing, safe on multi-hour sessions.
• i18n — French and English.

Known limitations

• Secondary POVs appear as regular player entities (Flashback only supports one local player; the camera follows the first POV to start recording).
• 4+ POV merges may produce minor visual artefacts in zones where conflicting chunk versions overlap.
• Full technical limitations and roadmap in SPEC.md.

Links

• 🔗 GitHub repository
• 🐛 Report an issue
• 📜 Full changelog

License

MIT — free to use, modify and redistribute. Flashback remains under its proprietary license by Moulberry; MultiView is a fully independent add-on and does not redistribute any Flashback code.