# OSSC for PCBs

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• #27719
marqs
Participant

384×240 optim mode could be added which would use 4x horizontal multiplier (1536 width) for line4x and line5x.

#27722

Fantastic!

Will post data from a Psikyo board next…

#27731

Gunbird 2 has a samplerate of 456 which puts it in the difficult 423-532 range so will have to wait for 384×240 optim mode to get it dialed in but OSSC reports 261 lines and 60.14Hz. The dotclk is 57.2727Mhz / 8 = 7.1590875Mhz.

#27751

Truxton has samplerate 450 so not possible to use optim mode there either.

270 lines
57.6Hz
7Mhz dotclk (according to https://pineight.com/mw/index.php?title=Dot_clock_rates)

7000000 / ( 270 * 57.6 ) = 450.10288

Is it normal for OSSC to report the number of lines and refresh rate inconsistently? For example trying this again I get 269 lines and 57.78Hz.

#27826

Doesn’t Garegga look vertically compressed on my screen?

View post on imgur.com

That is in 384×240 optim mode (thanks @marqs!). It looks normal in Generic mode.

#27833
Harrumph
Participant

Yes that’s not surprising when using 384×240 mode on a 320×240 game. Remember that optimized mode can only scale by pixel repetition, i.e. integer scaling.
Since it then multiplies by 4x on the horizontal (i.e. vertical for a TATE game), but vertical by 5x, it will look squished compared to both original or square pixel 4:3.

Original: 320*10/11 / 240 = 1.21 (this is what you see in generic mode)
384×240 opt: 320*4 / 240*5 = 1.067, however your screen probably also stretches the 1536 width (height in this case) to 1600 so
1.067* 1600/1536 = 1.11
If your screen would accept 320×240 in 5x mode, aspect would of course be full 4:3
320*5 / 240*5 = 1.33

Exactly these disturbances to aspect ratio is why I don’t personally like optimized modes too much. 🙂

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