May 12, 2019 at 4:48 PM #26179
Hi, does anyone else get slight jitter/stutter with some 240P 60HZ sources on their VP30 (1.14 with ABT102)? Its most noticable on 2d side scrolling games.
Its doing it on my PSone with pal Oscillator RGB or S-Video, also on my 3 megadrives (mix of pal and NTSC oscillators) over RGBs, S-Video, Composite.
Ive tried various things to resolve it Csync, sync over composite and luma, messing with the VP30 various sync methods, different output resolutions, 3 different displays , 4 hdmi cables including an mcable, converting the RGB to Component via a JS Scart to component box (these are very good btw if anyone needs a transcoder). Also tried using the VP30 BNC output to component same thing still stutters 🙁
Im wondering if its something to do with the de-interlacing from the ABT card, strange as 50HZ is perfect and its not happening on a 60HZ PS2 (same PS1 games tested) or Wii in the 240P test suite.
Real shame as the device is great and I can live with the noise and interpolation from game mode 1 with 240P, it may be time to get an OSSC?
Any advice would be appreciated, thanks.May 13, 2019 at 7:43 PM #26191
Had a thought I could check my various sync levels and work out what the VP30 likes on the RGBs inputs.
If that doesnt work i’ll order an OSSC.
Thanks.May 14, 2019 at 10:37 PM #26201
Have you tried a different monitor/TV? Could be your monitor can’t frame lock to some off spec signals.May 15, 2019 at 1:18 AM #26210
Hi thanks for the reply, I tried 3 TVs and one monitor so far so will test a couple more monitors.
Weird thing is I dont get it on my iScan Pro with the same equipment, and if I switch the NTSC MD/Gen to 50hz its judderless locked with a 53.693Mhz Oscillator?
Will try and work it out, cheers.May 21, 2019 at 5:09 PM #26295
Very strange, I’ve not ever owned a VP30 so I don’t really have any other ideas…May 24, 2019 at 3:53 PM #26340
Like you say its probably due to being off (below) spec and the VP30 is inserting frames, think im going to buy a cheap pal MD and experiment with the master oscillator frequency.
Setting the refresh to unlocked 60.8 on the VP30 is as smooth as I can get it but its still annoying, chaining the iscan pro gets rid of the judder but bumps things up to about 20ms lag, you get used to the low input lag of game mode 1 🙁
Thanks.June 2, 2019 at 11:59 PM #26465
I tried a 54MHz crystal and it moved the issue but still as bad, think it works out at approx 60.2 refresh. Interestingly it made overclocking the MD very stable and I didnt need to halt certain games to OC them anymore.
Think a 53.6931 and 53.7087 MHz DFO would give perfect scrolling for both formats on the VP30.
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