bobrocks95 wrote:If those videos are your basis for determining the Super Gameboy 2 is running at 59.7Hz, know that the Gameboy Player isn't running at 59.7Hz either. Those videos basically confirm that it's running at the typical NTSC 59.94Hz actually.
Actually, look at the second video. While the Super GameBoy is obviously faster, you'll notice that the GameBoy Player and Super GameBoy 2 both run at different speeds as well.
They're equally out of sync the whole video, one isn't drifting from the other as you would expect. I'll dig around some speedrunning forums I'm sure they know the exact framerate it's outputting to like the 4th decimal place.
The clockspeed of the Game Boy Player is independent of the output framerate of the Game Cube it's connected to. The clockspeed of the Game Boy Player is, as far as I know, equal to that of a real Game Boy Advance.
AFAIK, these are the output framerates of the three versions of GBI:
GBA internally: 59.7275 Hz <-- This is in essence the "actual Game Boy framerate"
GBI-ULL: 59.7276 Hz
GBI-LL: 59.8261 Hz
GBI: 59.94 Hz
In all cases, the Game Boy Player runs at the same speed, and GBI accounts for the difference in framerate between the GameBoy and the GameCube by doing, as far as I can tell (I could be wrong about my understanding):
GBI-ULL: The cube outputs video right out of the same framebuffer that the GBA is being drawn to, which does lead to occasional tearing as they drift in and out of sync. How bad this is depends on the specific hardware.
GBI-LL: Use a single buffer, with the cube outputting frames a little faster than the gameboy is drawing them to the buffer. Every ~10 seconds, the cube needs to draw a new frame, but the GBA hasn't completed a new one yet, so the cube duplicates the previous frame. Adding only one duplicate frame every 10 seconds isn't very noticeable, and the higher output framerate greatly improves compatibility with displays, and solves the tearing issue. Still better than the official disc, which I believe duplicates a frame every ~5 seconds.
GBI: Multiple buffers, pure NTSC refresh rate, using interpolation between frames to maintain a constant output framerate. Upside: no tearing, no incompatibility, no stutter. Downside: interpolation could be considered a sort of motion blur.
GBI-ULL is obviously the most accurate, essentially running at the same framerate as the GBA, but not actually synchronized (hence the drift), so it also has the lowest possible latency. But not many displays like the strange framerate, and the lack of sync means tearing.
