Sinclair QL Composite Video Out
Re: Sinclair QL Composite Video Out
You are right - i've tried it with pin 2 (gnd) - I've mixed it up in the post above.
Re: Sinclair QL Composite Video Out
Hi!
Just a saw this post and ...
A year ago or more I tried to take signal from RGB output, well... the image looks fine, but... actually when I enter into another video mode (split-ed screen) the frame is displaced to the left, hiding part of the screen.
Anybody could tell me why that happen?
Thanks
Just a saw this post and ...
A year ago or more I tried to take signal from RGB output, well... the image looks fine, but... actually when I enter into another video mode (split-ed screen) the frame is displaced to the left, hiding part of the screen.
Anybody could tell me why that happen?
Thanks
-
martyn_hill
- Aurora
- Posts: 933
- Joined: Sat Oct 25, 2014 9:53 am
Re: Sinclair QL Composite Video Out
Good morning Popopo
The effect you are observing is due to the 'overscan' of the QL's video timing, which is slightly extended compared to the standard PAL specification.
Different monitors and TVs respond variously to the extended image - some start correctly at the left-hand side but crop more at the right, whilst others will attempt to centre across the extended line-width, as we see in your images.
Just for reference, it's not an artefact of either of the two QL modes - both 4 and 8 exhibit this overscan - just that the default SuperBASIC WINDOWs in each mode differ such that in mode 8, the entire window contents are visible - i.e. they are deliberately configured to be narrow enough to fit within the standard PAL timing/line width.
Minerva actually starts up on Mode 4, but also restricts it's window contents to within the PAL line width as we see in the start-up screen.
Good luck!
The effect you are observing is due to the 'overscan' of the QL's video timing, which is slightly extended compared to the standard PAL specification.
Different monitors and TVs respond variously to the extended image - some start correctly at the left-hand side but crop more at the right, whilst others will attempt to centre across the extended line-width, as we see in your images.
Just for reference, it's not an artefact of either of the two QL modes - both 4 and 8 exhibit this overscan - just that the default SuperBASIC WINDOWs in each mode differ such that in mode 8, the entire window contents are visible - i.e. they are deliberately configured to be narrow enough to fit within the standard PAL timing/line width.
Minerva actually starts up on Mode 4, but also restricts it's window contents to within the PAL line width as we see in the start-up screen.
Good luck!
Re: Sinclair QL Composite Video Out
If you are looking for a way to display the full QL video resolution, then stay away from Composite.
The "period-correct" way would be to find a Microvitec Monitor, that was specifically designed to display the QL's non-standard video. (That's probably also the most difficult and expensive way).
Some other solutions (Marcel's QL-VGA and some Chinese HDMI converters) can also display the full QL screen on VGA or HDMI displays. But the most cost-effective version at this point in time is probably Holmatic's video_if_ql_vga. Based on a Raspberry Pi Pico plus some electrical chicken food and some genius software, this is capable to display the full QL screen on a VGA monitor. You need to be able to tell the hot end of a soldering iron from the proper one, but: Definitly recomended!
The "period-correct" way would be to find a Microvitec Monitor, that was specifically designed to display the QL's non-standard video. (That's probably also the most difficult and expensive way).
Some other solutions (Marcel's QL-VGA and some Chinese HDMI converters) can also display the full QL screen on VGA or HDMI displays. But the most cost-effective version at this point in time is probably Holmatic's video_if_ql_vga. Based on a Raspberry Pi Pico plus some electrical chicken food and some genius software, this is capable to display the full QL screen on a VGA monitor. You need to be able to tell the hot end of a soldering iron from the proper one, but: Definitly recomended!
ʎɐqǝ ɯoɹɟ ǝq oʇ ƃuᴉoƃ ʇou sᴉ pɹɐoqʎǝʞ ʇxǝu ʎɯ 'ɹɐǝp ɥO
Re: Sinclair QL Composite Video Out
Thanks both for answers, explanation and exposure of patches & solutions.tofro wrote: ↑Tue Oct 10, 2023 4:24 pm If you are looking for a way to display the full QL video resolution, then stay away from Composite.
The "period-correct" way would be to find a Microvitec Monitor, that was specifically designed to display the QL's non-standard video. (That's probably also the most difficult and expensive way).
Some other solutions (Marcel's QL-VGA and some Chinese HDMI converters) can also display the full QL screen on VGA or HDMI displays. But the most cost-effective version at this point in time is probably Holmatic's video_if_ql_vga. Based on a Raspberry Pi Pico plus some electrical chicken food and some genius software, this is capable to display the full QL screen on a VGA monitor. You need to be able to tell the hot end of a soldering iron from the proper one, but: Definitly recomended!
In fact, we are already in contact with Marcel, and with a the great hobbyist Alberto (a genius from Amiga scene) improving the Marcel's solution with a suitable input filter for RGB signal. So that is my bet. 100% on this great device that has the power to work with any device with a RGB output.
By the way, anyone who would like to collaborate to adjust timings, line definitions ... whatever, is more than welcome.