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 Post subject: Re: Upergrafx
PostPosted: Mon Aug 12, 2019 7:19 pm 



Joined: 19 Jul 2017
Posts: 1367
CZroe wrote:
Thanks. I think I understand. This is talking about how to transmit 240p over HDMI, but it does so by essentially multiplying pixels and lines... so it's no longer 15khz 240p which can be easily be converted back to 15khz 240p RGBHV using a VGA adapter. That's the kind of 240p he is saying would be incompatible but we see others doing it all the time.

...or have I been wrong this whole time and "direct mode" for UltraHDMI, RetroTink 2X, and OSSC are putting line-doubled 240p (480p) through those VGA adapters?

I don't know for sure, but it sounds like the pixel doubling only a horizontal double (so 720x240->1440x240) for the purpose of meeting that minimum throughput threshold for transmission over the wire; but does that mean that it gets interpreted that way at the end, or does it get decoded/desampled back to its pre-transmission format? I would think that if the TX chip has to transform the video in that way, and with that transformation being defined in the spec, that there would be some kind of flag signalling to the downstream processor that the image has been altered and that it needs to be transformed back to its original state.

As for the Passthrough modes for at least the OSSC, my understanding is that the image is pixel-doubled horizontally; whether or not that means that the connected display or video processor will correctly interpret that resulting signal is beyond me. I imagine that UltraHDMI's Direct Mode necessarily does the same thing, additionally with the selection of using the native refresh rates or the framerate-converted 50 or 60Hz.


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 Post subject: Re: Upergrafx
PostPosted: Mon Aug 12, 2019 7:30 pm 


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Joined: 25 May 2014
Posts: 494
nmalinoski wrote:
I don't know for sure, but it sounds like the pixel doubling only a horizontal double (so 720x240->1440x240) for the purpose of meeting that minimum throughput threshold for transmission over the wire

It's only pixel doubling, not line doubling - every pixel is sent twice, the horizontal and vertical sync frequencies stay the same.

Quote:
but does that mean that it gets interpreted that way at the end, or does it get decoded/desampled back to its pre-transmission format?

If it's implemented correctly, the receiver discards all copies of the pixel except the first one - but if it's a DAC it doesn't really matter because you would get essentially the same output if it either drops every second pixel or if it outputs all of the copies.

Quote:
I would think that if the TX chip has to transform the video in that way, and with that transformation being defined in the spec, that there would be some kind of flag signalling to the downstream processor that the image has been altered and that it needs to be transformed back to its original state.

There is a field for that in the AVI infoframe.


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 Post subject: Re: Upergrafx "UGX-02" - TG16/PCE DVI Upscaler w/SD CDROM2
PostPosted: Mon Aug 12, 2019 10:51 pm 



Joined: 05 Dec 2012
Posts: 454
Digital 240p -> HDMI to VGA converter -> Sync Combiner has worked in every analog RGBs scenario I've tested. I can try to test with my TG-16 through the OSSC in passthrough mode this week to triple check, but every other console and arcade board I tested in that setup worked fine.

If he can implement it, that makes this a plug-and-play, jailbar-free RGB option, with less than $40 worth of parts.


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 Post subject: Re: Upergrafx "UGX-02" - TG16/PCE DVI Upscaler w/SD CDROM2
PostPosted: Mon Aug 12, 2019 11:45 pm 



Joined: 04 Mar 2018
Posts: 42
nmalinoski wrote:
CZroe wrote:
Thanks. I think I understand. This is talking about how to transmit 240p over HDMI, but it does so by essentially multiplying pixels and lines... so it's no longer 15khz 240p which can be easily be converted back to 15khz 240p RGBHV using a VGA adapter. That's the kind of 240p he is saying would be incompatible but we see others doing it all the time.

...or have I been wrong this whole time and "direct mode" for UltraHDMI, RetroTink 2X, and OSSC are putting line-doubled 240p (480p) through those VGA adapters?

I don't know for sure, but it sounds like the pixel doubling only a horizontal double (so 720x240->1440x240) for the purpose of meeting that minimum throughput threshold for transmission over the wire; but does that mean that it gets interpreted that way at the end, or does it get decoded/desampled back to its pre-transmission format? I would think that if the TX chip has to transform the video in that way, and with that transformation being defined in the spec, that there would be some kind of flag signalling to the downstream processor that the image has been altered and that it needs to be transformed back to its original state.

As for the Passthrough modes for at least the OSSC, my understanding is that the image is pixel-doubled horizontally; whether or not that means that the connected display or video processor will correctly interpret that resulting signal is beyond me. I imagine that UltraHDMI's Direct Mode necessarily does the same thing, additionally with the selection of using the native refresh rates or the framerate-converted 50 or 60Hz.
OK, that makes a lot more sense. Thanks. Reading back through the thread I see references to this even way back in 2017 when many still thought it was sampling and scaling an analog source.

retrorgb wrote:
Digital 240p -> HDMI to VGA converter -> Sync Combiner has worked in every analog RGBs scenario I've tested. I can try to test with my TG-16 through the OSSC in passthrough mode this week to triple check, but every other console and arcade board I tested in that setup worked fine.

If he can implement it, that makes this a plug-and-play, jailbar-free RGB option, with less than $40 worth of parts.


Since he's the engineering type and I'm not and there is a language barrier, I'm having difficulty convincing him that it's a real thing that is possible, works, and that there is demand for it. I'm going to collect every quote I see and hit him with them to see if it will change his tune on that. :)


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 Post subject: Re: Upergrafx "UGX-02" - TG16/PCE DVI Upscaler w/SD CDROM2
PostPosted: Mon Aug 12, 2019 11:57 pm 



Joined: 14 Aug 2017
Posts: 520
CZroe wrote:
Since he's the engineering type and I'm not and there is a language barrier, I'm having difficulty convincing him that it's a real thing that is possible, works, and that there is demand for it. I'm going to collect every quote I see and hit him with them to see if it will change his tune on that.


Doing god's work.


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 Post subject: Re: Upergrafx
PostPosted: Tue Aug 13, 2019 2:22 pm 



Joined: 05 Dec 2012
Posts: 454
CZroe wrote:
Since he's the engineering type and I'm not and there is a language barrier, I'm having difficulty convincing him that it's a real thing that is possible, works, and that there is demand for it. I'm going to collect every quote I see and hit him with them to see if it will change his tune on that. :)

It seems you're having the same frustrations I had with him - There should be no need to "convince" him of a lot of this. His stubbornness is maddening and I'm glad you're the one dealing with him and not me. LOL, no offense :)

I don't have original PCE/TG-16 hardware with me now, so I shot a video with the MiSTer outputting 1:1 original "240p" signal through the converters (ignnore the speckles in the 1st part, that was my fault). If he needs proof that original hardware will work, I'll borrow some equipment and run it through the OSSC in passthrough mode and demonstrate the same tests...but I've already tested that with many consoles and arcade boards.

It works.

There are more converters coming out soon to make this easier too. Please just add this feature ;/ https://youtu.be/bHvIiT_RsFw


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 Post subject: Re: Upergrafx
PostPosted: Tue Aug 13, 2019 8:22 pm 



Joined: 04 Mar 2018
Posts: 42
retrorgb wrote:
CZroe wrote:
Since he's the engineering type and I'm not and there is a language barrier, I'm having difficulty convincing him that it's a real thing that is possible, works, and that there is demand for it. I'm going to collect every quote I see and hit him with them to see if it will change his tune on that. :)

It seems you're having the same frustrations I had with him - There should be no need to "convince" him of a lot of this. His stubbornness is maddening and I'm glad you're the one dealing with him and not me. LOL, no offense :)

I don't have original PCE/TG-16 hardware with me now, so I shot a video with the MiSTer outputting 1:1 original "240p" signal through the converters (ignnore the speckles in the 1st part, that was my fault). If he needs proof that original hardware will work, I'll borrow some equipment and run it through the OSSC in passthrough mode and demonstrate the same tests...but I've already tested that with many consoles and arcade boards.

It works.

There are more converters coming out soon to make this easier too. Please just add this feature ;/ https://youtu.be/bHvIiT_RsFw

LOL! Thanks.

Yeah, I understand where the communication is breaking down tho' so I don't think it's just him being stubborn, per se:
He thinks he gave me an engineering reason why it won't work and, since I clearly know much less than him about EE stuff (especially regarding DVI/HDMI), he has no reason to second-guess himself. If I insist without irrefutable examples he might just assume that I'm simply wrong. To him, I'm just some random guy on the Internet who knows far less than him about the matter, and he's right... though I don't know the how or why, I just know this particular thing is possible anyway thanks to you guys. ;)


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 Post subject: Re: Upergrafx "UGX-02" - TG16/PCE DVI Upscaler w/SD CDROM2
PostPosted: Wed Aug 14, 2019 5:02 pm 



Joined: 05 Dec 2012
Posts: 454
Cool. You keep at him and I'll keep finding & testing better HDMI to SCART solutions.


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