Rendering resolution - 480p possible ?

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Rendering resolution - 480p possible ?

Post by DD-Indeed » October 8th, 2017, 7:51 pm

This has been on my mind for some time over recent months. I've been testing some games with emulator and decided to run them with double resolution mode, which apparrently renders the games in 480p resolution, making significant difference in terms of gameplay even without any other optional plugins or features. Just the stock game with stock setting, only 480p rendering selected.

Now, this brings in a question: Is it completely impossible to do that with the original hardware ? It may sound crazy, but I was just wondering about this. Propably it would need something attached to the console, like extra RAM or would require modded BIOS/hardware tweaks. 480p rendering is something that wouldn't be too ludicrous when thinking about the late 90's gaming.
Last edited by DD-Indeed on October 9th, 2017, 5:29 pm, edited 1 time in total.

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Re: Rendering resultion - 480p possible ?

Post by Orion_ » October 8th, 2017, 9:16 pm

the limitation would be the GPU speed, and the vram size
Some PS1 games renders in 480i but this require the game to run at 60Hz, which means less texture, less detailed 3D models, and this uses almost 3/4 of the vram space just for the game image (so, less texture space available)
an example is Tobal 2 (maybe the 1 too), and the Ridge Racer 1 hispec demo that was bundled with Ridge racer 4
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Re: Rendering resultion - 480p possible ?

Post by DD-Indeed » October 8th, 2017, 9:48 pm

Okay, so there is a way to do so, but the hardware capabilities hit their limits ? Shame, would have been great to investigate more about it. So far, many games do support it without any issues, but some games have some minor or game breaking issues of what I've seen.

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Re: Rendering resultion - 480p possible ?

Post by likeabaus » October 8th, 2017, 10:03 pm

I wonder if overclocking the psx would help with this? I did this before and in theory (I don't own an oscilloscope, so could not test it) you can double the clock speed of the CPU (its 66mhz before it goes through a frequency divider and into the CPU at 33mhz) and the GPU is capped at 40mhz for unknown reasons (to me, could be a hardware limitation or due to another frequency divider I'm not sure). The CPU and GPU running out of sync like that of course causes stability issues and graphical glitches but theoretically this could be resolved using a custom kernel. I'm thinking maybe the slightly faster clock speed on the GPU might help with rendering at 480p. You also have to properly cool the CPU (a 486 CPU heatsink and some thermal paste will do the trick) which helps stabilize things and what not, but yeah.

Sadly, I damaged my overclocked board trying to solder an Arduino to it for PSNee (in my defense, I was really over tired lol) so its FUBAR, but if I can get another psx (that's overclockable) I'd be willing to play around with this. As far as developing kernels for the PSX I don't have a clue, still very new to coding on this thing, but there is this custom kernel by nocash that could potentially be tweaked to help handle stability issues and glitches etc : viewtopic.php?f=76&t=1319
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Re: Rendering resultion - 480p possible ?

Post by rama3 » October 9th, 2017, 2:52 am

Likeabaus:
I recently worked on overclocking and the results aren't so hot.
I used clock synthesis boards and fed custom clocks into various domains.
Unfortunately, the only things that can be overclocked without serious drawbacks are the CD controller and the GPU memory controller.
The CD controller is probably pointless and doing it requires a customized timing modchip.
The GPU memory is a bit better. It overclocks to around +7% with the stock kernel. (I don't know if kernel mods are possible, nor if they would help.)

Overclocking the CPU only works when you accept a faster SPU + higher CD-ROM speed as well. It appears it's not possible to drive the SPU asynchronously from the CPU. But again, maybe a custom kernel could help :)

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Re: Rendering resultion - 480p possible ?

Post by LameGuy64 » October 9th, 2017, 11:13 am

According to the PlayStation Programmer's Tool SDK docs, it is kinda possible to achieve non-interlaced hi-res mode (in other words, 480p) on the console but only when using an RGB cable. I don't know if it is valid though because where does the PlayStation output a progressive sync signal when running in 480p mode and nocash's hardware docs say that if you don't turn on interlaced mode in 480 line mode, you'll only see half of the 480 lines.
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Re: Rendering resultion - 480p possible ?

Post by DD-Indeed » October 9th, 2017, 4:07 pm

LameGuy64 wrote:According to the PlayStation Programmer's Tool SDK docs, it is kinda possible to achieve non-interlaced hi-res mode (in other words, 480p) on the console but only when using an RGB cable. I don't know if it is valid though because where does the PlayStation output a progressive sync signal when running in 480p mode and nocash's hardware docs say that if you don't turn on interlaced mode in 480 line mode, you'll only see half of the 480 lines.

So you mean 480i, not 480p ?

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Re: Rendering resolution - 480p possible ?

Post by LameGuy64 » October 9th, 2017, 6:31 pm

More like 240p but with a 480 line framebuffer with only the odd or even rows displayed. I'm not quite sure though.
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Re: Rendering resolution - 480p possible ?

Post by DD-Indeed » October 9th, 2017, 10:38 pm

That's a bit complicated for my head haha.

But anyway, this is interesting thought, so that's why I wanted to bring this up. If someone is willing to investigate and have knowledge about these things, that would be interesting and cool. Who knows, maybe you guys find some neat ideas for console modding in this area.

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Re: Rendering resolution - 480p possible ?

Post by rama3 » October 10th, 2017, 12:07 am

I seem to remember that regular RGB over SCART isn't even 480p/576p certified.
Unfortunately, I can't find information on that anymore.

Also, all the video processing chips would have to support the higher scan rate of 31khz and I really don't think they do.
(RGB DAC, RGB encoder)

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Re: Rendering resolution - 480p possible ?

Post by DD-Indeed » October 10th, 2017, 12:51 am

rama3 wrote:I seem to remember that regular RGB over SCART isn't even 480p/576p certified.
Unfortunately, I can't find information on that anymore.

Also, all the video processing chips would have to support the higher scan rate of 31khz and I really don't think they do.
(RGB DAC, RGB encoder)

I just checked, seems that the SCART only supports RGB 480i max, so for 480p, it would require something else. However, I saw one page on the internet, where someone had shoveled this analog to digital video converter into PS1, so he had HDMI output straight out back of the box. That would be the key thing to make such thing to work.

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Re: Rendering resolution - 480p possible ?

Post by DD-Indeed » October 14th, 2017, 10:14 pm

Since this was discussed to be ''plausible'' to archieve, but would propably require some hardware improvements, how about using Parallel Port for such things ? I mean, it's afterall designed for additional hardware attachments for sure, so how about the possibilities with that ?

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