Donald Duck Quack Attack - unplayable camera

[sundance]

I've been recently playing Donald Duck Going Quakers, also known as Quack Attack, on our old-time PAL Dreamcast, using a VGA->HDMI cable.
My son loves Disney characters, and especially Donald, so it was a great hit.

Unfortunately, something strange happened : over time, as I was progressing through the level, the camera drifted further away from the action, and the main character, Donald, ends up standing more and more at the top of the screen. After some time, way before reaching the end of level 1, Donald is so much at the top of the screen that it's impossible to see what's in front of him. Eventually, he even manages to get out of the screen, at which point the game remains stuck.

That's weird. It's no simple immediate crash / bug, but a slow camera drift over time.

And another weird thing : when I use the same disc image on a PC emulator, such as ReDream, this effect doesn't happen !
The game remains fully playable throughout the levels.
The drifting camera only happens on the _real_ Dreamcast.

That's really reverse from expectation : I would expect the emulation to be glitchy, while actual hardware should work fine.
Anyone having experimented something equivalent ? Any idea ?

[Ian Micheal]

You would think that but many thing work worst on hardware.. lot of my homebrew thing work perfect on emulators not because there better but because they dont follow strict timing and hardware rules.. so the game is got a bug which dont show up on emulator.. dreamcast hardware is very strict..

[beanboy]

Which stage in the first level?

[sundance]

> Which stage in the first level?

The camera drifting is gradual.
But it starts to become pretty bad on reaching the bridge, with a reindeer,
and basically unplayable on reaching the first skunk.

> my homebrew thing work perfect on emulators not because there better but because they dont follow strict timing and hardware rules

Speaking of which :
I'm playing using an SD card reader on the serial port.
I noticed that the port is constantly active (activity led blinking fast). It seems to be loading something (music maybe ?).
Also, the game is not completely smooth on the Dreamcast, while it was perfectly smooth on the emulator. It is still certainly playable, but I perceive some stuttering which seems related to the blink (activity signal) on the SD card.

Speaking of timing : I'm wondering about this scenario : could the "stuttering" suffered due to constant activity on the serial port trigger some kind of discrepancy between the character and the camera ?

[Ian Micheal]

Playing the game from dreamshell might be the problem with that game you should try it from a burned copy on a cdr

[Wombat]

Playing games from an SD-card (ODE's aside) can be very trivial because the reading speed is way lower vs actual GD-ROMS. So basically it's not recommended if you want to have a trouble free gameplay experience.