11 September 2019, 19:10 | #1 |
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Extra bottom line on native screens, chipset feature or WinUAE?
When I tried to display a PAL HiRes Interlaced screen optimal on my FullHD monitor (1920x1080) and first set the size to 724x540 I expected that it could be scaled with a factor of 2.0 exactly, but it did not.
Using WinUAE 4.2.1 64 bit. D3D11, Automatic Scaling and Aspect Ratio Correction 16:9 are enabled, but that's not the point. I noticed that on all native screens I get an additional gray scanline on the bottom which is also counted for computing the scaling factor. So when I set the PAL overscan height to 270 lines, the display gets finally 271 (542 interlaced) lines and the scaling factors are 1.989637 and 1.992620. That sometimes causes bad looking text characters, for example. Code:
Display Size: 724x540 Offset: 6x18 First: 35 Last: 305 MinV: 31 MaxV: 313 Min: 26 POS (0 0 1920 1080) - (0 0 960 540)[960,540] (-112 18) S=1920*1080 B=752*574 8 -1 2 2 -> -736.000000 576.000000 768.000000 -572.000000 2.000000 2.000000 Display Size: 724x540 Offset: 2x18 First: 35 Last: 305 MinV: 34 MaxV: 312 Min: 26 POS (0 0 1920 1080) - (0 0 960 540)[960,540] (-116 18) S=1920*1080 B=752*574 12 -1 2 2 -> -728.000000 576.000000 776.000000 -572.000000 2.000000 2.000000 SNDRATE 312.5*227.0*50.000282=3546895.024776 PAL mode lace V=50.0003Hz H=15625.0879Hz (227x312+1) IDX=10 (PAL) D=0 RTG=0/0 Display Size: 724x542 Offset: 2x18 First: 35 Last: 306 MinV: 34 MaxV: 313 Min: 26 POS (0 0 1920 1080) - (0 0 965 542)[965,542] (-118 18) S=1920*1080 B=752*574 11 -2 2 2 -> -726.217590 575.867126 769.989624 -567.896667 1.989637 1.992620 With an overscan height of only 269 the display size is really 724x540 and the scaling works correctly with 2.0. Code:
Display Size: 724x538 Offset: 6x18 First: 35 Last: 304 MinV: 31 MaxV: 313 Min: 26 POS (0 0 1920 1080) - (0 0 956 538)[956,538] (-110 18) S=1920*1080 B=752*574 8 0 2 2 -> -739.079529 576.133789 771.213379 -576.133789 2.008368 2.007435 Display Size: 724x538 Offset: 2x18 First: 35 Last: 304 MinV: 34 MaxV: 312 Min: 26 POS (0 0 1920 1080) - (0 0 956 538)[956,538] (-114 18) S=1920*1080 B=752*574 12 0 2 2 -> -731.046021 576.133789 779.246887 -576.133789 2.008368 2.007435 SNDRATE 312.5*227.0*50.000282=3546895.024776 PAL mode lace V=50.0003Hz H=15625.0879Hz (227x312+1) IDX=10 (PAL) D=0 RTG=0/0 Display Size: 724x540 Offset: 2x18 First: 35 Last: 305 MinV: 34 MaxV: 313 Min: 26 POS (0 0 1920 1080) - (0 0 960 540)[960,540] (-116 18) S=1920*1080 B=752*574 12 -1 2 2 -> -728.000000 576.000000 776.000000 -572.000000 2.000000 2.000000 There always appears this additional gray line at the bottom, except for the case that I move the display rectangle down in the overscan settings, which makes 270 lines with a correct scaling possible, but the lowest interlaced line doesn't appear and the last but one is flickering. (Disable utilities like BlackBorder.) Is this gray bottom line a chipset feature or caused by WinUAE (even v3.0.0 shows it)? Is it required to display this line and send it to the graphics card? |
11 September 2019, 19:43 | #2 |
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Location: Hämeenlinna/Finland
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It is correct. Interlaced modes always have odd number of lines and due to some odd chipset feature, last line (interlaced or not) is always blank and drawn in background color. (Except if A1000!)
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11 September 2019, 19:48 | #3 |
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But could you make an option in WinUAE to suppress it on the display and not to send it to the graphics card?
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11 September 2019, 20:11 | #4 |
WinUAE developer
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Location: Hämeenlinna/Finland
Age: 49
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Not going to happen. Line is there in hardware level and it is normal scanline like any other scanline and it can have background color changes. PAL or NTSC mode is not a programmed mode where number of scanlines can change.
Why not just set manual 2x scale and move the display so that last line is not visible? Or at least automatic integer scale so that there is no scaling artifacts. |
11 September 2019, 20:13 | #5 |
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How does this work?
1. Display > Native: Fullscreen, 1920x1080 2. Host > Filter > Null Filter and 2x scaling? I have a 1920x1080 monitor and here it looks fine with no extra line. If you change resolution of the monitor, you're in the hands of the monitor scaling chip. Last edited by Photon; 11 September 2019 at 22:52. |
11 September 2019, 21:21 | #6 | |
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Ok, I can live with it, but an option would have been nice.
Quote:
@Photon Can you post a "Display" and "Filter" screenshot or your config file, please. Thx. |
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