I just got a PSP 3001. When I got it I noticed the interlacing problem that a lot of people are complaining about.
I also found references on the web which "explained" why the PSP-3000 seems to interlace: the pixel rows are oriented differently and the blue lines are darker, which makes there seem to be dark lines.
I tried using some Game Gear emulators. The key is that if you set an emulator to an exact 1x multiple with no smoothing, and the emulator displays something that scrolls at 1 pixel per frame, interlacing becomes very obvious:
-- Vertical lines, when you move horizontally, show a jagged effect. This is a symptom of interlacing: the odd pixels are drawn first, and then the even pixels are drawn on the next frame after the line has moved, causing the pixels to alternate positions and the line to look jagged.
-- Solid color areas, when scrolling vertically, have obvious black lines--relative to the solid color area. This again is a symptom of interlacing: first the odd lines are drawn. Then one frame later the even lines are drawn, but (due to the rate of scrolling) the entire solid color area has moved by one pixel and so relative to the start of the solid color area the odd lines are drawn again. As long as your eye follows the motion of the solid color area, you can see that only half the lines show up.
Conclusion: The PSP is actually interlacing and conventional wisdom and the "pixel rows" and "dark blue" explanations are wrong. (Also, I haven't seen a 2000's screen but I wouldn't be surprised if it was interlacing too but the ghosting prevents it from being so obvious.)
(Why I should want to set the emulator to this setting is beside the point. Clearly it's not the best setting for emulator use, but the point isn't to emulate efficiently, it's to demonstrate a problem.)
I also found references on the web which "explained" why the PSP-3000 seems to interlace: the pixel rows are oriented differently and the blue lines are darker, which makes there seem to be dark lines.
I tried using some Game Gear emulators. The key is that if you set an emulator to an exact 1x multiple with no smoothing, and the emulator displays something that scrolls at 1 pixel per frame, interlacing becomes very obvious:
-- Vertical lines, when you move horizontally, show a jagged effect. This is a symptom of interlacing: the odd pixels are drawn first, and then the even pixels are drawn on the next frame after the line has moved, causing the pixels to alternate positions and the line to look jagged.
-- Solid color areas, when scrolling vertically, have obvious black lines--relative to the solid color area. This again is a symptom of interlacing: first the odd lines are drawn. Then one frame later the even lines are drawn, but (due to the rate of scrolling) the entire solid color area has moved by one pixel and so relative to the start of the solid color area the odd lines are drawn again. As long as your eye follows the motion of the solid color area, you can see that only half the lines show up.
Conclusion: The PSP is actually interlacing and conventional wisdom and the "pixel rows" and "dark blue" explanations are wrong. (Also, I haven't seen a 2000's screen but I wouldn't be surprised if it was interlacing too but the ghosting prevents it from being so obvious.)
(Why I should want to set the emulator to this setting is beside the point. Clearly it's not the best setting for emulator use, but the point isn't to emulate efficiently, it's to demonstrate a problem.)
