Online Games, But How Come They Don't Lag?
summary
A prototype ports Super Mario World to online co-op and evaluates netcode design choices: replacing JSON with a compact binary format reduced payload size by about 5×, and switching from TCP to UDP combined with binary delta compression solved ordering and bandwidth issues. The system batches inputs at a 20–30 Hz tickrate to lower server CPU per player, uses client-side prediction with server reconciliation and interpolation to mask latency, and relies on rollback/lag compensation by storing roughly 3 seconds (~9 MB) of past game state to reconcile high‑ping players.
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chapters (17)
- 0:00Introduction
- 1:23Network latency-free gaming
- 3:50Game state and objects
- 6:19Server overload issues
- 7:23Tick rate and optimization
- 8:26TCP vs UDP for gaming
- 10:51Network data format
- 11:53Input lag and prediction
- 13:17Server reconciliation
- 16:23Entity interpolation
- 19:29Battle Royale mechanics
- 21:16Latency and disadvantaged players
- 21:37Delta compression
- 26:36Lag compensation
- 29:07Rollback netcode
- 32:36Results and 100% MetaCritic
- 34:00Q&A
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