Game Boy Advance Capture
From SDA Knowledge Base
If you want to speedrun a Game Boy Advance game, you are REQUIRED to use a Game Boy Player to capture the A/V footage.
The Game Boy player is an add-on to the Nintendo Game Cube that enabled the GameCube to play both Game Boy and Game Boy Advance games. The add-on contained a slot to load Game Boy / Advance games and a disc to boot up the player. Either a GameCube controller or a GameBoy Advance (with an adapter) could be used as a controller. While the Game Boy player still doesn't play games at a speed identical to the original Game Boy Advance, it is pretty close.
Required Settings
The Game Boy Player contains some picture filter and border options that you must configure properly before recording a speedrun. You can access the settings menu by pressing the Z button on a GameCube controller.
Make sure that the screen filter is set to "Sharp", the frame is set to #20, and that the screen size is set to "Normal." Please be sure to use these settings. If you don't configure these settings correctly your speedrun will be rejected. After you have that set up, just record as you would record a normal GameCube game. For reference, the GameCube video signal is 480i. This signal should be compatible with standard definition capture devices and some high definition capture devices.
As a side note, if you aren't a fan of playing Game Boy Games using the GameCube controller, the website Retro USB sells some controller adapters that will let you use an NES or SNES controller instead.