TT030 VGA picture quality

[susher]

Their web page is back.

[dhedberg]

Their web page is back.

Good to hear!

[Atari030]

Has anyone tried a VGA-HDMI adapter on a TT?

[dhedberg]

Has anyone tried a VGA-HDMI adapter on a TT?

Nope, but the sampling of TT's signal will still be a problem. The picture will still be "off". The OSSC will take VGA and output HDMI and let you adjust the sampling to match the pixel clock of the TT.

[susher]

Has anyone tried a VGA-HDMI adapter on a TT?

Yes, it has the same problem as other devices which sample the signal at precisely the resolution it believes it should be (rather than sampling the scan line at double the frequency and then averaging pixels), i.e. is misses most of the data in the TT's output as it's stuffed in the first two thirds of the scan line.

[Atari030]

I thought as much. I was just thinking, rather than figuring a VGA solution, in this day and age a DVI one would be ideal. Especially if it could handle ECL input as well.

Wishful thinking, I guess.

[dhedberg]

I thought as much. I was just thinking, rather than figuring a VGA solution, in this day and age a DVI one would be ideal. Especially if it could handle ECL input as well.
Wishful thinking, I guess.

Like previously stated, the OSSC will take VGA in and output HDMI and give you a lot of control over how the analog signal is converted to digital. It's not cheap but it has a lot of different inputs so it can be used with basically any old computer or video game console.

[susher]

Well, as soon as the web site came up on Monday I ordered and OSSC and it arrived today.

I've so far managed to get a nice display, despite there being no instructions. However I've yet to find out how to stretch the display horizontally and centre it and also to shift the display down so that the top few pixels are viewable. Otherwise it's amazingly good.

See:

[susher]

I've now found the optimum settings for all the display modes (the timing for ST Low & TT Medium slightly change re: "sample rate").

Sampling opt>
640x480 Adv Timing>
H.samplerate: 1023
H.backporch: 128
V.backporch: 29

Allow upsample2x: on

Output opt>
480p/576p proc>
Line 2x

Sample images (iPhone doesn't get the quality you see):

TT Medium


ST High


ST Medium


ST Low

[dhedberg]

Yup, that's it! You got it! Isn't it nice? That thing is awesome!

[leech]

Just to add to this, my OSSC was used on the STe and got a perfectly (well stretched) widescreen picture on my 55" TV. But also I have my Jaguar and Sega Genesis/CD hooked up through SCART on it. Overall, an excellent piece of hardware.

[wongck]

I've now found the optimum settings for all the display modes (the timing for ST Low & TT Medium slightly change re: "sample rate").

Sampling opt>
640x480 Adv Timing>
H.samplerate: 1023
H.backporch: 128
V.backporch: 29

Allow upsample2x: on

Output opt>
480p/576p proc>
Line 2x

Sample images (iPhone doesn't get the quality you see):

Wow... very nice albeit expensive £162.00 but well worth it
that's nearly half the price of my tt

[stormy]

I just went and ordered an OSSC after seeing your photos guys, thanks lol

[stormy]

I've now found the optimum settings for all the display modes (the timing for ST Low & TT Medium slightly change re: "sample rate").

Sampling opt>
640x480 Adv Timing>
H.samplerate: 1023
H.backporch: 128
V.backporch: 29

Allow upsample2x: on

Output opt>
480p/576p proc>
Line 2x

Hey man, I got my OSSC but these settings don't work for me. I get to H.samplerate 955 and anything higher just makes my monitor turn off. Any ideas? Thx

[edingacic]

what is the highest rez it can go? I run ECL to VGA adapter for high res mono on Cubase. I found a good 21inch CRT and the picture is really sharp and fine. Here link on facebook group you can see it in action in my studio. https://www.facebook.com/filmtoolslinz/ ... 161706799/

[dhedberg]

I've now found the optimum settings for all the display modes (the timing for ST Low & TT Medium slightly change re: "sample rate").

Sampling opt>
640x480 Adv Timing>
H.samplerate: 1023
H.backporch: 128
V.backporch: 29

Allow upsample2x: on

Output opt>
480p/576p proc>
Line 2x

Hey man, I got my OSSC but these settings don't work for me. I get to H.samplerate 955 and anything higher just makes my monitor turn off. Any ideas? Thx

Try a different monitor?

[susher]

I've now found the optimum settings for all the display modes (the timing for ST Low & TT Medium slightly change re: "sample rate").

Sampling opt>
640x480 Adv Timing>
H.samplerate: 1023
H.backporch: 128
V.backporch: 29

Allow upsample2x: on

Output opt>
480p/576p proc>
Line 2x

Hey man, I got my OSSC but these settings don't work for me. I get to H.samplerate 955 and anything higher just makes my monitor turn off. Any ideas? Thx

Interesting.

Is this a monitor using an HDMI to DVI adapter by any chance?

I am using a FullHD TV connected by HDMI (probably version 1.2).

[azzyish12]

Ditto, I also have an old LCD and same as DarkLord, I use the controls to center and stretch TT desktop screen horizontally.

It is unfortunate that the VGA specifications changed after the TT came out.
So the VGA output will not be looking "correct" against the standard spec.

this is an 'official' story.
unofficial story is that was done on purpose. TT video pixel clock is generated from main clock, in order to have synchronized main memory bus with TT Shifter. I guess it is done in that way due to cost cutting.
Finally TT pixel clock is 32MHz, and is higher than VGA standard - 25MHz.

VGA horizontal frequency is fixed at ~31.468 kHz and with TT 32MHz video pixel clock, every line has 1024 pixels (in ST MID/HIGH / TT MID mode), 640 pixels are for desktop and 384 are border.

TT 32MHz / 31.5 kHz = 1024 pixels: 640px screen + 384px border
VGA 25MHz / 31.5 kHz = 800 pixels: 640px screen + 160px border Notepad++ Malwarebytes FileZilla

Therefore TT architecture just forces VGA to show so huge border. That issue is fixed in Falcon, it uses 32MHz for TV mode and 25MHz for VGA mode.

to check for poor associations, however would someone be able to let me know whether this is typical? The screen works fine on a ST in high-rez mode (utilizing a connector), since it is mature enough to have the capacity to sync directly down to 60hz. I truly would prefer not to send it back as broken... since they are so uncommon...

[stormy]

Ok I'll try a different monitor. Although this is a 'sampling option' so it should not effect the digital output, my logical brain tells me

[Frank B]

Mine is a bit more low tech. It’s a crappy old 15 inch VGA monitor with digital controls The controls remember their state per screen mode. I use them to adjust the position etc of the screen. The monitor doesn’t half make a noise when you turn it on though!

[azzyish12]

Ditto, I also have an old LCD and same as DarkLord, I use the controls to center and stretch TT desktop screen horizontally.

It is unfortunate that the VGA specifications changed after the TT came out.
So the VGA output will not be looking "correct" against the standard spec.

this is an 'official' story.
unofficial story is that was done on purpose. TT video pixel clock is generated from main clock, in order to have synchronized main memory bus with TT Shifter. I guess it is done in that way due to cost cutting.
Finally TT pixel clock is 32MHz, and is higher than VGA standard - 25MHz.

VGA horizontal frequency is fixed at ~31.468 kHz and with TT 32MHz video pixel clock, every line has 1024 pixels (in ST MID/HIGH / TT MID mode), 640 pixels are for desktop and 384 are border.

TT 32MHz / 31.5 kHz = 1024 pixels: 640px screen + 384px border
VGA 25MHz / 31.5 kHz = 800 pixels: 640px screen + 160px border

Therefore TT architecture just forces VGA to show so huge border. That issue is fixed in Falcon, it uses 32MHz for TV mode and 25MHz for VGA mode.

[stormy]

I've now found the optimum settings for all the display modes (the timing for ST Low & TT Medium slightly change re: "sample rate").

Sampling opt>
640x480 Adv Timing>
H.samplerate: 1023
H.backporch: 128
V.backporch: 29

Allow upsample2x: on

Output opt>
480p/576p proc>
Line 2x

Hey man, I got my OSSC but these settings don't work for me. I get to H.samplerate 955 and anything higher just makes my monitor turn off. Any ideas? Thx

Interesting.

Is this a monitor using an HDMI to DVI adapter by any chance?

I am using a FullHD TV connected by HDMI (probably version 1.2).

Just a late update, I finally got it working, as suggested I changed monitor. Thanks for the settings they're great!