Bringing back 480P/i w/o passthrough, issues with Dreamcast and overscan

[wryguy87]

Hi, starting off I love the OSSC and I plan to purchase new versions of the unit. I wanted the best color quality and the lowest lag possible and the OSSC is basically made for me and it’s great.

I have several requests I’d like to suggest, and I’m going to list them in order of how useful I think they would be to more people than just myself.

#1) Can we bring back the ability to have the OSSC handle 480p/480i x 1 again? We of course lose the ability to add scanlines and other OSSC features if passthrough is the only option, and honestly the picture quality is so many times better if the OSSC handles it instead of my TV. 960p/960i is an unusual resolution that can break a lot of TVs, so being able to use 480p/480i through the OSSC is probably an essential feature for certain users.

#2) Profile Quick Select. This is fairly simple. You know how the button that used to switch between Line Doubling and Line Tripling now asks you to select a number of 1-5 to determine scaling?

I think that would be useful to everyone in general if there was a button that acted the same for profiles. Hit the button, it asks you the number of the profile you want to load, hit 0-9 and there you go.

This would be particularly useful to myself because I use a Logitech Harmony universal remote and it would allow me to easily program my remote so that when I choose a console on the remote that the OSSC can also switch profiles with a simple pre-programmed two step command.

#3) This is the most challenging to troubleshoot. There are certain Dreamcast games that scale past the full size of the screen for me, unless I play in 960p mode, which doesn’t completely break my TV but it does cause a lot of problems when I switch between the Dreamcast and another console that is just using line double or line triple.

The best game I can suggest to see this issue first hand is Capcom vs SNK 2. I don’t know why this happens. The only way I’ve been able to get 480p to display the full image on my TV (back when I could access 480p x 1 through the OSSC) was to reduce the vertical active setting by about 5 pixels. This likewise will break my TV the same way 960p does, so it’s not ideal, but this was my fix before 960p was an option and I am hoping it provides someone a hint as to why Dreamcast output is being so problematic compared to something like a Genesis or N64.

Thanks very much for reading all that.

[Harrumph]

#1 Passthrough was not removed so I don’t know what you mean.
#2 is already implemented since some time. On the chunghop you press the -/– button, dunno what that corresponds to on your Harmony though.

[wryguy87]

Nonono, unless I’m misunderstood we no longer have the option to have the OSSC process 480p video before sending to the TV. I can only seem to enable passthrough or line doubling to 960p. Both of which have issues in that passthrough looks awful on my TV in addition to not being able to display the full image on certain games like Capcom vs SNK 2, and 960p semi-breaks my TV even if the full image displays.

Thanks for the note about #2, I’ll check that today.

[Harrumph]

…to have the OSSC process 480p video before sending to the TV.

I’m sorry but I don’t understand. What kind of processing are you after? Passthrough is the same as “x1”, ie no line doubling, the image digitized but otherwise identical. Afaik you can always enable scanlines if you want by setting it to Manual.

Edit: if you mean the input sampling modes (DTV or VESA) they are still under Sampling options. You should use DTV for Dreamcast, but you can try to manually set H.Active to 640 as that may look better on your TV depending on how it treats the signal.

[paulb_nl]

#3 Most displays will hide the overscan with 480p so you lose 16 rows top and bottom. You can also see this with the OSSC’s test pattern. You should look at your TV settings for turning off overscan for 480p.

[wryguy87]

Unfortunately I don’t think my TV has that option. It’s a 55″ 4K Samsung set from around 2015. Will see if I can find anything relating to overscan.

For passthrough, the image looks like it has a distinctly lower level of color quality and sharpness compared to before. It feels like the HDMI signal is being passed straight to the TV and its scaler is doing all the work, resulting in a lower quality picture than what older versions of the firmware provided. You are right through that I can turn on scanlines which implies the OSSC is not just passing the signal along so maybe this is just in my head.

When I switch between passthrough and 960p though there is a very distinct difference in sharpness to the picture. 480p is blurry and 960p is sharp and pixelated.

[wryguy87]

Also thanks for the tip about #2. If you’re curious about how this would work with a harmony, the remote can learn and imitate the signals from another existing remote. It simply asks you to point the old remote at the Harmony’s receiver as you’re pressing a button so it can learn the input. I’ve transferred all the actions that I knew the original OSSC remote was capable of to the Harmony but I missed that one.

It can also perform sets of inputs in a pre-specified order. As part of changing consoles, the remote will of course change inputs for the TV and AV Receiver, but in addition to changing the input on the OSSC there will be a two step command where it sends the input of the -/– button, waits one second, then pressed the input of the appropriate profile.

It’s a very handy remote, even if they’re a bit on the expensive side. I was lucky to get it for sale during a Black Friday clearance.

https://support.myharmony.com/en-us/adding-a-device-thats-not-found-in-the-harmony-database

[wryguy87]

So thanks to the input here, I suppose I at least understand the issue with why the Dreamcast image only fits in the screen in 960p. It is in fact an overscan issue, as when I switch to the Wii 480p fits the screen perfectly and 960p there is empty space.

So clearly certain Dreamcast games are making use of the overscan area and the Wii does not. Of course I do see the same issue with the Wii in 480p where the image is distinctly blurry and washed out via the use of passthrough.

Unfortunately I have no way to address it via TV settings, particularly for the Wii because 960p breaks certain settings on my TV such as the ability to customize the screen size. That would at least fix the issue with Wii games not taking up the full screen, though even using passthrough on the Dreamcast I can’t do a thing to get the full image on the screen even with all the normal TV settings.

If the OSSC can’t offer some kind of overscan solution in the future there’s probably no helping it for the Dreamcast.

Switching back and forth between Wii and Dreamcast brings up something else I’d like to suggest.

#4: The option to choose between 4:3 and 16:9 for 480p x1 and x2 (960p) outputs.

Like with about everything I mentioned here, the issue is with switching between the Dreamcast and everything else. The Wii is of course a widescreen console, and because you can choose 16:9 for retro devices like the Genesis and Nintendo 64 that all plays nicely together. But because you can’t choose to optimize for 4:3 for 480p the same way you can for 240p, the Dreamcast image will be stretched.

There could very well be a solution I don’t know of, since that’s already happened once or twice but just trying to contribute to the project.

[marqs]

#1: are you certain that there’s difference in passthrough quality between recent fw versions? The only things changed that could affect that are some Infoframe parameters. Did you try if “HDMI ITC” option makes any difference?

#2-3: these seem to be resolved now.

#4: You need to use you TV to switch to 4:3 aspect 480p. Both 16:9 and 4:3 480p use 720×480 resolution, but the latter is non-anamorphic format and needs to be handled differently by the display.

[wryguy87]

Will take a look at HDMI ITC and see what happens. I’ll also try to take some photos of the blurriness I’ve referred to for your reference when I can.

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