Does the Dreamcast use 480i/576i for the boot splash and then switch to 480p, or is it 480p the whole time?
I’m not actually sure. I think it’s 480p the entire time. How would I confirm?
Watch the screen on the OSSC when you turn the console on. If it says 525p the entire time, it’s 480p. If it says 525i/625i, then it’s 480i/576i. (I also have a Dreamcast with a Toro and OSSC hooked up; I’m just not at home right now.)
Side note: You may want to consider picking up a SCART cable to connect the Toro to the OSSC; the Dreamcast can benefit from the low-pass filtering that is available on AV1 (also AV2) that isn’t present on AV3.
I tried this, but was not able to get a 480p signal, only 480i. I tried every combination of VGA/RBG and RGBHV/RGBS on the Toro, but the TV only accepted the signal when it was 480i, and it seemed like a very low-quality, shimmery 480i at that.
On the Toro, you need to have the Dreamcast mode switch (the one in the bank of four closest to the console) set to ‘VGA’, so the console will output 31kHz RGBHV (480p). Then you need to run a fully-wired male-to-male SCART cable from the Toro to AV1, and change the input on the OSSC to AV1-RGBS. The other RGBHV/RGBS toggle, the one between the DE-15 and SCART outputs on the Toro, only changes between RGBHV and RGBS on the DE-15 output; the SCART output is full-time RGBS, regardless of what the console is outputting.
That ugly, shimmery 480i is the OSSC bob-deinterlacing 480i to 480p. It’s never going to look good.