'The person I'm playing with seems to be moving around strangely but he says that I'm the one moving weirdly. What happened?'

This is a desync. Basically what both of you are seeing are two different games. See Desync Troubleshooting

3Hosting or Joining a Session
- 3.1General Configuration
- 3.2Graphics Configuration
4Netplay Settings

Requirements

Netplay is a defining feature of Dolphin: it allows you to set up online sessions for any GameCube or Wii title with a local multiplayer mode, without the problems or limitations of the Nintendo Wi-Fi Connection or hassle of the BBA. It is improving regularly, and GameCube Netplay should be painless. This emulator also empowers you to play some games online and utilize the multiplayer mode, where possible. Dolphin features external controller support, which means you can connect your favorite gamepad to your PC and start playing GameCube titles in the old-fashioned way. Just make sure to use an appropriate USB adapter for this purpose. The GameCube is one of Nintendo's home video game consoles and part of the sixth generation of video game consoles.Although the competing PlayStation 2 and Xbox consoles supported substantial amounts of online games, the GameCube had only eight games with internet or local area network (LAN) support. Nintendo never commissioned any servers or internet services to interface with the console.

Bandwidth requirements are very light: any DSL or Cable internet connection should do. However, the internet demands rapidly increase as more players are added. Because the latency (ping) of the internet connection determines how low input latency can get, using Ethernet instead of Wi-Fi usually improves the gameplay experience.
Each player must have their own copy of the game, and the region and game revision of all copies must match. While most compressed game formats are compatible with standard ISOs (with NKit being a notable exception), it is heavily recommended that all players use identical dumps.
All players must use the same Dolphin version. Newer Dolphin versions are more likely to have fixes for Netplay. Many users opt to use the latest beta versions from the official website. It can be isolated from your main Dolphin profile by using 'portable.txt' or creating a special shortcut. Dolphin will not allow users to use mismatched versions for Netplay, to prevent desyncs.

Play the best free Cube Games on GamesGames.com. Online Game Play As of April 2007, the three Nintendo GameCube games to feature online play, Sega's Phantasy Star Online series, are no longer being supported for online play.

Play Nintendo Gamecube Games Online

Setting Up Dolphin

Your Netplay Experience will greatly vary depending on what version you tend to use. Because Dolphin 5.0 is lacking so many Netplay features at this point, it cannot be recommended for use. It is missing important features like Wii Save Synchronization (5.0-8478), Automated Settings Synchronization (5.0-8502), Cheat Code Synchronization (5.0-9032), Synchronize All Wii Saves (5.0-9037) as well as protections for recovering saves if Netplay is to crash.

Rule of thumb is that most settings should be set to default and you are expected to follow specific settings where the instruction (made by host or matchmaking websites) has told you to set before playing online.

Hosting or Joining a Session

Under the tools menu, you can find the option to 'Start Netplay Session'. From there you have several options.

Hosting a session allows you to pick a game and host it for others to join. If you use version 5.0-8478 or newer, you can also host these games publicly with the 'Netplay Server Browser'.
When hosting a session, you can choose whether to Direct Connect or use a Traversal Server. Both will have the same latency, however using the traversal server allows you to use a host code instead of your IP Address. Depending on your router, you may not even need to port forward when using the traversal server.
You can join a session by browsing public Netplay sessions or going to 'Start Netplay Session' to get to the page where you can join sessions. You can enter a host code or IP Address as needed in the 'Connect' tab.

While Dolphin does try to automatically configure and sync settings to be correct, it is important to be familiar with settings that can affect Netplay.

General Configuration

General

Basic Settings
Enable Dual Core: ON Enable Cheats: OFF Speed Limit: 100%

Audio

DSP Emulator Engine
DSP HLE emulation

GameCube

Device Settings
Slot A: Memory Card Slot B: <Nothing> SP1: <Nothing>

Wii

Device Settings
Insert SD Card: OFF

Deterministic Dual Core Netplay is now merged into master. While compatibility is not perfect, it should allow more games to work on dual core with three exceptions. Games that require Skip EFB Access to CPU, Store EFB Copies to Texture Only and/or Store XFB Copies to Texture Only unchecked in the Graphics > Hacks settings are not guaranteed to run correctly. Deterministic Dual Core can be faster than Single Core in some games, but may also be much slower if a game relies on certain visual effects. Single Core mode in Netplay is the same single core mode used outside of Netplay and has no compatibility penalty.
SD cards do work on Netplay but must be manually synchronized. Any difference at all in the SD card, no matter how minor, will cause desyncs in games that access the SD card.

Settings Synced

As of 5.0-8502, most settings that affect determinism will be synced to other clients, so only the host needs to ensure correct settings. Games which use EFB reads or EFB to RAM are likely to desync with mismatched graphics settings, therefore Strict Settings Sync should be used, which will additionally sync most graphics settings except for backend.

On older revisions, only these settings will be synced over:

Advanced Settings from General menu
Misc Settings from Wii menu
CPU Options from Advanced menu

Note that over long periods of time, using different video backends may eventually cause a detected desync. However, because not all target operating systems support all backends, Dolphin will never attempt to synchronize graphics backends. If you do see a seemingly random detected desync during very long play sessions and you are using different graphics backends, this is usually the cause. These desyncs usually do not manifest in anything immediately broken, but it is still recommended you save and restart to prevent issues.

Graphics Configuration

Enhancements

(No desync in most games)

Hacks

Embedded Frame Buffer
Skip EFB Access from CPU: ON Store EFB Copies to Texture Only: ON

Most settings under Enhancements menu can mostly be turned on or off without incident on higher end processors. The only exception to this is when an enhancement breaks a game, such EFB Copy readback. If a game requires EFB Access from CPU or EFB Copies Stored to RAM for game mechanics, the game may freeze or run slowly unl

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