Integer Modelines for MiSTer / OSSC DEXX-Pro Lite
Please read all information provided in the repository thoroughly.
- Basic Information
- Using Non-Standard Video Modes To Produce Hybrid Scaling
- MiSTer Provided Scaling Methods
- MiSTer.ini Information Related To This Repository
- MiSTer.ini Recommended Settings
- OSSC DEXX-Pro Lite Add-On Provided Scaling Methods
- OSSC DEXX-Pro Lite Add-On Custom_Scaling.txt Information
- Integer Video Mode Calculation Examples
- Tools Utilized To Create Integer Video Modes
- Tools Utilized To Create New EDID Resolutions
- Console / Handheld Video Modes & Timings
- Arcade Video Modes & Timings
- Video Modes & Timings Templates
- Repository License
- Developer Support
Basic Information:
- Video Modes designed for monitors that upscale the provided resolution from the DE-10 Nano. This is known as Display Scaling; a hybrid scaling technique.
- Video Modes designed for LCD displays with a resolution of 1280x1024 and 5:4 aspect ratio; these video modes utilize step-integer scaling.
- Video Modes designed for 120 Hz capable displays; compatible with Black Frame Insertion (BFI) options from the DEXX-Pro or MiSTer framework (BFI for the DE-10 Nano is currently a work in progress).
- Preconfigured MiSTer.ini / custom_scaler.txt files containing sensibly-grouped sets of video modes and timings available for download with all necessary documentation corresponding to the provided video modes.
Using Non-Standard Video Modes To Produce Hybrid Scaling:
MiSTer integer-scales the content up to the full height of the provided video mode (defined as a perfect integer size of the original content), the display scales the largest integer image possible by non-integer scaling the provided resolution to the displays native vertical resolution. This fills the entire screen height. Non-integer scaling is minimized utilizing this method; thus, scaling imperfections are drastically reduced, becoming unperceivable to the human eye.
Cavaet:
Not all displays are compatible with non-standard video modes. Your display may not accept all or any of them. Displays supporting Variable Refresh Rate (VRR), Nvidia G-Sync, or AMD FreeSync are likely to be compatible.
MiSTer Provided Scaling Methods:
Integer scaling yields pixel-perfect upscaling, but also means the image is unable to fill the display's full height; known as vscale_mode=1. Step-integer scaling is available; scaling is done at 1/2 or 1/4 of the provided resolution; known as vscale_mode=2 and vscale_mode=3.
Non-integer scaling fills the displays height, but introduces scaling artifacts (uneven scanlines, "shimmering" during vertical scrolling, etc); known as vscale_mode=0.
MiSTer's "auto display scaling" yields similar results; the algorithm used for Coordinated Video Timings (CVT) is calculated different and video modes do not correspond to the native refresh rate from the provided content. The basis for "auto display scaling" is sourced from this repositories previous information. Visit MiSTerFPGA MKDocs for further information.
MiSTer.ini Information Related To This Repository:
The defaults for pre-configured MiSTer.ini files provided are:
video_mode=0 (720p)
vscale_mode=1 (Integer Scale Only)
vsync_adjust=1 (HDMI vsync refresh rate adjusted to match core)
The calculated video modes provided will also function with vsync_adjust=0 (retaining the native refresh rate) and vsync_adjust=2 (this will deviate from the native refresh rate); vscale_mode=0 and vsync_adjust=0 require extensive testing. End users will not experience issues when scaling (uneven scanlines, "shimmering" during vertical scrolling, etc) using the calculated modelines provided.
Due to the horizontal limitation of the DE-10 Nano's scaler and ADV7513, video modes exceeding the horizontal capability utilize -1x for the horizontal scale. This will not affect the aspect ratio on your displays that take advantage of the video mode provided. These are display dependent; nothing is a universal standard.
Integer-step scaled video modes are available for 1280x1024 LCD displays. Integer step-scaled video modes specify the vscale_mode in the pre-configured MiSTer.ini file. When utilitzing integer scaled video modes set the defaults in the OSD for pre-configured integer step-scaled MiSTer.ini files provided:
aspect ratio: full screen
custom_aspect_ratio:XX:XX
The custom aspect ratio is set for the contents Display Aspect Ratio (DAR); this is the correct aspect ratio for a modern display. When utilizing integer-step scaled video modes with aspect ratio: full screen in the MiSTer OSD, this properly displays the provided video mode for a 5:4 aspect ratio display (1280x1024).
Compatible with Variable Refresh Rate (VRR) settings supported by MiSTer. The default setting in the pre-configured MiSTer.ini files provided:
vrr_mode=0
vrr_freesync_min_framerate=46
vrr_freesync_max_framerate=120
End-Users need to select their vrr_mode as each display will be different. Visit MiSTerFPGA MKDocs for more information on VRR support and vsync_adjust.
MiSTer.ini Recommended Settings:
In-conjunction with the provided video modes and settings defined in the pre-configured MiSTer.ini files the following options are recommended; results may vary based on display type. These settings will result in vsync_adjust=2 keeping the native core timing based on the calculated video mode.
120Hz Capable Displays
vrr_mode=1
vrr_freesync_min_framerate=46
vrr_freesync_max_framerate=120
vsync_adjust=2
60Hz Capable Displays
vrr_mode=1
vrr_freesync_min_framerate=46
vrr_freesync_max_framerate=60
vsync_adjust=2
75Hz Capable Displays
vrr_mode=1
vrr_freesync_min_framerate=46
vrr_freesync_max_framerate=75
vsync_adjust=2
OSSC DEXX-Pro Lite Add-On Provided Scaling Methods:
- WIP; OSSC DEXX-Pro Lite Add-On being assembled by cyo.the.vile
OSSC DEXX-Pro Lite Add-On Custom_Scaling.txt Information:
- WIP; OSSC DEXX-Pro Lite Add-On being assembled by cyo.the.vile
Integer Video Mode Information
Integer Video Mode Calculation Examples:
Integer scaled modelines for HDMI displays are based off the vertical refresh rate (found by calculating the pixel clock, horizontal total, and vertical total) and visible resolution.
Integer scaled modelines for CRT displays are based off the vertical refresh rate (found by calculating the pixel clock, horizontal total, and vertical total), visible resolution and providing the total resolution.
Visible resolution plus horizontal and vertical blanking equal the horizontal and vertical total lines for the specified video modes.
Vertical Refresh Rate Formula |
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Coordinated Video Timings-Standard Blanking (CVT-Standard VESA-2013-3 v1.2) based off the calculated vertical refresh rate, utilizing negative sync polarity on the horizontal, positive sync polarity on the vertical, and the total resolution.
Total resolution is required for accurate modeline calculations based off the pixel clock. For this example, the horizontal total is 512 lines and the vertical total is 256 lines.
CVT-Standard Modeline Calculation (Manual) |
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Coordinated Video Timings-Reduced Blanking (CVT-RB; VESA-2013-3 v1.2) based off the calculated vertical refresh rate, utilizing positive sync polarity on the horizontal, negative sync polarity on the vertical, and the visible resolution.
The pixel clock for 4x integer scaling in the example below is exact (native refresh rate); in-line with reduced blanking standards lowering the overall pixel clock. It is not 1/4 rounded using an algorithm like "auto display scaling".
CVT-RB Modeline Calculation (4x Integer Scale) |
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Tools Utilized To Create Integer Video Modes:
- MiSTer modeline to video_mode conversion by morf77; this tool can be utilized to create video_modes for MiSTer by calculating modlines. There are several modeline tools available. This process is not used in the repository, but worth noting.
- Video Timings Calculator by Tom Verbeure; this tool can be used in-conjunction with the below. It does not provide a precise pixel clock without extensive knowledge about video mode timings.
- MiSTer video_mode to modeline conversion by morf77; this tool can be utilized for creating OSSC timing parameters based off of modeline information. This tool is invaluable, I cannot thank morf77 enough for implementing this request.
- MiSTer aspect ratio calculator by morf77 and kitrinx (algorithm code); this tool can be utilized to find Display Aspect Ratio (DAR) with information provided in this repository.
- Custom Resolution Utility (CRU) 1.5 by ToastyX; this tool is the primary resource for creating integer modelines. Many thanks to the developer; consider supporting their endeavors.
Tools Utilized To Create New EDID Resolutions:
- Dump EDID by NirSoft; quick tool for finding vendor specific information about your display.
- EDID Repository using the information above, locate your display in the
digitalhoused in this repository for proper EDID information. - EDID/DisplayID Writer by ToastyX; follow the instructions provided (USE AT YOUR OWN RISK). Used to create resolutions (i.e. 2048x1440, 1920x1440) that exceed the horizontal resolution of
2048; assists with EDID parsing.
Console / Handheld Video Modes & Timings
For MiSTer cores & the DEXX-Pro Lite Add-On
Arcade Video Modes & Timings
For MiSTer cores & the DEXX-Pro Lite Add-On
Video Modes & Timings Templates
For MiSTer cores & the DEXX-Pro Lite Add-On
License
This repository and project is licensed under the GNU General Public License v3.0. If you utilize the information elsewhere, reference the source repository and provide credit to the author(s).
Support
Please consider showing support for this and future projects on my Patreon. While it isn't necessary, it's greatly appreciated.