Scart to HDMI upscaler

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Kermit
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Re: Scart to HDMI upscaler

Postby Kermit » Thu Sep 21, 2017 9:16 pm

Sorry, to clarify I'm using Rgb scart to both crts.


stephen_usher
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Re: Scart to HDMI upscaler

Postby stephen_usher » Sun Sep 24, 2017 9:17 am

That's because the QL's output is outside the standard for 4:3 TV scan lines. This is why there was a special monitor sold to complement the machine.


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dilwyn
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Re: Scart to HDMI upscaler

Postby dilwyn » Sun Sep 24, 2017 6:32 pm

stephen_usher wrote:That's because the QL's output is outside the standard for 4:3 TV scan lines. This is why there was a special monitor sold to complement the machine.

We all know that, but some of these units can auto scale to show full 85 characters. One of my tv sets loses the usual couple of characters either side with scart connection, but the auto scale of the older hdmi converter brings up the full 85 characters. I was just wondering if these newer cheaper units manage as well as the older ones.


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stephen_usher
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Re: Scart to HDMI upscaler

Postby stephen_usher » Sun Oct 01, 2017 12:24 pm

I've just tested one of the metal box with white lettering units from eBay and it loses 4 characters from the right-side of the screen.


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Re: Scart to HDMI upscaler

Postby Dave » Sun Oct 01, 2017 4:17 pm

Some units re-synch and some units re-time the information.

Units that re-synch the information will lose characters, either at the beginning, or the end if they move the front porch synch. They don't re-time the content, but can reconstruct the synch information either based on the beginning or end of the line or some complex formula involving both if there is a lot of jitter.

Units that re-time the information are doing a more complex job, run hotter, create a blurrier image and get considered poorer quality converters, but at the end of the day they're more capable.

The challenge in all of this is maintaining sub-tick accuracy of the clock to prevent dot-crawl.


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Derek_Stewart
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Re: Scart to HDMI upscaler

Postby Derek_Stewart » Sun Oct 01, 2017 6:34 pm

stephen_usher wrote:I've just tested one of the metal box with white lettering units from eBay and it loses 4 characters from the right-side of the screen.


The QL uses 85 column display, which is non-standard.

The makers of the upscalers only know about 80 column display. Maybe care little about anybody else.

Probably the Jammar board approach is the best, but need carefully cabling.

But maybe there is need for specific QL upscaler, maybe RGB -DVI tailored for the QL Mode 4/8 display.


Regards,

Derek

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