H. Samplerate & H.Active values for N64 480i Passthru mode

[Daneeall]

It seems like bob-deinterlacer is killing my LCD somehow. In StarCraft64 I left the static screen with text for about 15-20min, and when the screen changed I noticed that the remnants of the text are still left on the screen. I turned off OSSC and noticed that the edges of the text of where it once was are still on the screen. Needless to say I was a little disappointed. After about 20min the LCD came back to normal. I did the same test on PS1 on the memory card bios screen which is also 480i and got the same behavior. I suspect that this BOB flickering is damaging the LCD screen somehow.
I decided to set 480i in passthru mode. But I could’t find correct values for H. Samplerate & H.Active for N64 and PS1, or the way I could calculate it myself. Any help is appreciated.

[Zacabeb]

The flickering interferes with the polarity inversion done in the LCD to reduces image retention, with some models of panel being more sensitive than others.

I don’t know the exact timings for the N64 but I checked the optimized mode for it in the OSSC Pro. There the sample rate is set to 773.5 samples per line and 640×240 active pixels, so that could be a starting point for the OSSC Classic as well (the other parameters don’t carry over directly from the OSSC Pro to OSSC Classic.)

Given that the horizontal sync in 480i is 4.7 µs out of about 63.55 µs, the horizontal sync length should be set to around 57 or 58 and vertical sync left at 3. From there you can then adjust the horizontal and vertical backporches to align the picture.

For the PS1, from what I can find the sample rate should be 853.25 (rounded to either .20 or .30 I guess) with an active area of 640×240 and a horizontal sync of 63. The dot clock reportedly varies between hardware revisions though, so it might not be correct for your PS1.

Hope it helps. 🙂

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