4 ms·
Sadly CRTs are now out of production, and 480i SDTVs have whine (I can't stand my TV's whine, and IDK if it needs a recapping or if other TVs are any better) an
by nyanpasu64 4y ago
Sadly CRTs are now out of production, and 480i SDTVs have whine (I can't stand my TV's whine, and IDK if it needs a recapping or if other TVs are any better) and are particularly unsuited for modern computers and displays due to interlacing, overscan, and low pixel rate (photos of me trying to run modern PC games at 480i at https://nyanpasu64.gitlab.io/blog/amdgpu-stray-crt-480i/ https://nyanpasu64.gitlab.io/blog/amdgpu-stray-crt-480i/). And bizarrely, the prices of the same model of VGA monitor range from $10 (https://www.reddit.com/r/crtgaming/comments/s5rrf7/viewsonic_a90f_from_craigslist_for_10/ https://www.reddit.com/r/crtgaming/comments/s5rrf7/viewsonic...) to $600 in a Craigslist listing with the only photos being of a "no input" screen, not even displaying an actual picture from the VGA port (unsurprisingly the listing is 18 days old and still not sold).
I've recently ordered a GBS-Control in the hopes I'd find a VGA 31khz monitor by the time it arrived (no luck), and am now struggling with making it work with a LCD monitor. I've run into many issues so far:
- Increasing the GBS-C's width too far results in display corruption.
- The on-screen width of the picture depends both on GBS-C settings and monitor "Auto Adjust".
- The web UI places form over function. You have to enable developer mode in the web UI to even see the current settings and know what thresholds cause video corruption or cause the monitor Auto Adjust to stretch the image to full width. And the same button shape can mean either a momentary action (most buttons), a toggle checkbox action (auto gain), a radio button that takes 1.5 seconds to check when clicked (profile picker), and when you lose Wi-Fi connection with the ESP8266, the buttons do nothing and do not become checked when pressed (and may produce an on-screen and web UI response seconds later)!
- 240p Test Suite GX's grid and linearity tests have different aspect ratios, and I don't know which one to adjust to be square/circular.
- Prior to my clock generator board arriving, sync lock mode 0 resulted in the image shifting vertically by 1 scanline every 10 seconds or so on my LCD. Sync lock mode 1 worked better.
- It appears that each named slot's profiles are saved independently for each video input mode (240p=480i vs 480p). I don't know what happens when you switch modes but haven't saved a preset profile for the other video mode in your current slot. And "Reset Defaults" in the GBS-C keeps profile names but wipes the underlying settings files. I'm not aware of any way to erase slot names, and may need to dig into the firmware source code to find out.
- Tuning the GBS-C to perfectly show the full overscan region in both 240p and 480i/p modes of my Wii (generated by 240p Test Suite GX) was tricky to get right. At one point, the two modes would display 1 scanline offset vertically from each other. I don't know if this is still a problem.
- Switching video modes behaves oddly:
- Sometimes in 240p Test Suite GX, the image first displays glitched lines scrolling down the image (as if the GBS-C misdetects vblank as 1/3 Hz), before my monitor goes black and reappears even though it's receiving 960p from the GBS-C before and after the input mode changes. (Presumably this is 1280x960, but I have no clue if the dot clock is actually synced between the GBS converter and monitor, and the Wii component video signal is nowhere near 1280 dots per row of bandwidth)
- Sometimes after changing modes (IIRC both in synthetic 240p Test Suite and real Nintendont usage), the image shows up again horizontally squashed and offset on-screen, until I power-cycle the monitor.
- Sometimes the full image would be shifted downwards vertically by around 10 scanlines, until I power-cycle the GBS-C or reapply 1280x960 resolution (resync onto incoming video? IDK).
- Sometimes the web UI won't have 1280x960 checked, even if it's outputting a 960p signal. I don't know if this is connected to the vertical shift bug, or if .
Again I'd have to dig into the GBS-C source code to find out why mode changing behaves oddly. There will be a lot of learning to do, understand the software state and chip registers and how they correlate to profile settings and input/output behavior. I suppose I could file a bug at https://github.com/ramapcsx2/gbs-control/issues https://github.com/ramapcsx2/gbs-control/issues, but somehow I feel reluctant to do so, partly because I didn't fully understand the setup and don't know if many of these bugs wouldn't happen on a VGA CRT, partly just learned helplessness and not knowing if my bug report is detailed enough or will be ignored or attacked, partly because I'd prefer to chat with the developers in Discord/Matrix outside of a higher-stakes formal bug report or a forum I've never posted at before.