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Old 08 July 2015, 01:07   #61
Retro-Nerd
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Even the C64 can output interlace, but that's not the point here. On the 16bit computers/consoles it was rarely used for static title screens, option screens etc. which flickers badly on 15KHz screens.
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Old 08 July 2015, 01:10   #62
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it was rarely used for anything to be honest

Great Giana Sisters loading screen springs to mind though
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Old 08 July 2015, 03:51   #63
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How does this adapter handle mixed resolution screens like the disposable hero title screen?
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Old 08 July 2015, 11:14   #64
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Originally Posted by Retro-Nerd View Post
Even the C64 can output interlace, but that's not the point here. On the 16bit computers/consoles it was rarely used for static title screens, option screens etc. which flickers badly on 15KHz screens.
Actually, no. The C-64's "interlace" modes output each field on the same lines every time, not alternating lines. They are just flicking between two images per alternating frame in software, not true interlace.

Last edited by Jope; 08 July 2015 at 11:20.
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Old 08 July 2015, 12:17   #65
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Even the C64 can output interlace, but that's not the point here. On the 16bit computers/consoles it was rarely used for static title screens, option screens etc. which flickers badly on 15KHz screens.
Nope - AFAIR C64 have no interlace capability (unless you can create video with 625 lines or generally odd number of lines - AFAIR VIC is not capable to do this).

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Sorry Jope - seem You was first.
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Old 08 July 2015, 12:19   #66
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How does this adapter handle mixed resolution screens like the disposable hero title screen?

Video from Amiga is sampled with Hires pixel clock (sort of) - to be fully transparent - real HDMI converter should assume always S-Hires pixel (so 28.xxxMHz clock for pixel).
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Old 08 July 2015, 12:37   #67
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from what i can tell C64 interlace is a hack that only works on certain monitors that don't handle progressive modes properly.
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Old 08 July 2015, 12:38   #68
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Actually, no. The C-64's "interlace" modes output each field on the same lines every time, not alternating lines. They are just flicking between two images per alternating frame in software, not true interlace.
Ah, just a dirty trick to use more colors in higher resolutions. Nice anyway.

http://www.studiostyle.sk/dmagic/gallery/gfxmodes.htm

Last edited by Retro-Nerd; 08 July 2015 at 12:49.
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Old 08 July 2015, 12:49   #69
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Ah, just a dirty trick to get a higher resolution and more colors. Nice anyway.

http://www.studiostyle.sk/dmagic/gallery/gfxmodes.htm
oh so those are "sideways" interlace!

but i found that the usual interlace is also possible:
http://www.lemon64.com/forum/viewtopic.php?t=15560

(to be clear, the C64 is not emitting an interlaced signal, but the new TV is still interpreting it as such)
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Old 08 July 2015, 19:18   #70
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Hi again,

I had some time over today so I fixed the last of the bugs. Seems Amiga has a pixel clock that is 14,18758Mhz, you learn something new every day...

I think this is as good as it gets. It is hard filming an LCD screen and get decent quality through youtube, lets just say that it looks better in real life... :P

[ Show youtube player ]

Regards,
StaingL
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Old 08 July 2015, 19:30   #71
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How does this adapter handle mixed resolution screens like the disposable hero title screen?
This is interesting, please tell me more about this.
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Old 08 July 2015, 20:30   #72
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Do you have any spare PCBs? ;-)
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Old 09 July 2015, 00:38   #73
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Amiga HDMI output

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This is interesting, please tell me more about this.

I think it splits low res and hires vertically. Basically i think the pixel clock doubles for the hires portion.

We discussed it here. http://eab.abime.net/showthread.php?t=75157. Toni gives the info.

Last edited by Vot; 09 July 2015 at 01:11.
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Old 09 July 2015, 00:41   #74
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Video from Amiga is sampled with Hires pixel clock (sort of) - to be fully transparent - real HDMI converter should assume always S-Hires pixel (so 28.xxxMHz clock for pixel).

Yea thats what i think he may have to do.
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Old 09 July 2015, 15:02   #75
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Yea thats what i think he may have to do.
But this means only one - 1920x1080p50(60) mode must be at the output.
Video can be resized to fill area or not (for pixel acurate just pixel replication/repetition and line replication/repetition mode) - this should create also possible to recreate all 50/60Hz related modes - of course to recreate non TV mode (such as 68, 72 Hz etc modes probably other video modes must be used - list of all HDMI modes is long but not many of them seem to be useful - btw 24Hz modes can be used to emulate A2024 and other non standard video modes - OCS can cheat and ECS/AGA are almost fully reprogrammable - there is only 1 thing constant in Amiga video signal - Pixel clock which in extreme case of S_Hires is equal to 28.xxxx MHz).
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Old 10 July 2015, 00:52   #76
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Do you have any spare PCBs? ;-)
Sure, I have a couple of them over if you would like to have a go. Send me message in that case.
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Old 10 July 2015, 01:26   #77
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But this means only one - 1920x1080p50(60) mode must be at the output.
Video can be resized to fill area or not (for pixel acurate just pixel replication/repetition and line replication/repetition mode) - this should create also possible to recreate all 50/60Hz related modes - of course to recreate non TV mode (such as 68, 72 Hz etc modes probably other video modes must be used - list of all HDMI modes is long but not many of them seem to be useful - btw 24Hz modes can be used to emulate A2024 and other non standard video modes - OCS can cheat and ECS/AGA are almost fully reprogrammable - there is only 1 thing constant in Amiga video signal - Pixel clock which in extreme case of S_Hires is equal to 28.xxxx MHz).
Unfortunately, after some testing and tweaking I think 720p is the limit for this hardware. The reason for stretching out the screen is not just to fill up empty space, it is simply because I do not have the time to both read and write from/to 8ns sram at the speed required (74.25Mhz reading and 28Mhz/14Mhz writing). The solution is to read pixels from sram at half rate (e.g. display each pixel twice), then I get a very manageable total maximum speed of 65,125Mhz read/write. Perhaps we will revisit the schematics and come up with something faster, still keeping the price tag down.
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Old 10 July 2015, 03:49   #78
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As a consumer, I'd be happy with 720p output if it gave a clear picture in amiga Laced(640x512 min) modes.

The hw side is far out of my league, but a device that plugs into the 1200's existing ports and outputs HDMI-friendly signal without internal mods is something I want a lot.
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Old 10 July 2015, 19:45   #79
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if i were to use this on my A1200 i would prefer if it could handle SuperHires
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Old 10 July 2015, 20:10   #80
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As a consumer, I'd be happy with 720p output if it gave a clear picture in amiga Laced(640x512 min) modes.

The hw side is far out of my league, but a device that plugs into the 1200's existing ports and outputs HDMI-friendly signal without internal mods is something I want a lot.
As a big fan of the Amiga but without knowing every intricate detail about the hardware, what you write was actually the thing that I was aiming for when I created the device.

Perhaps it will be possible to create 2 devices, one that supports PAL only and one with more juicy hardware that can handle pretty much anything. I will come back on this.
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