Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-02-10, 05:17

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by James-F

in DOSBox Development

in DOSBox Development

He's talking about "sharp bilinear": https://github.com/rsn8887/Sharp-Bilinear-Shaders Yep. This is exactly what a "big integer prescale then interpolation" does, and exactly what I am asking for. "sharp-bilinear-simple" This shader does an automatic optimum integer prescale (2x, 3x, 4x etc.), …

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-02-09, 13:25

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by James-F

in DOSBox Development

in DOSBox Development

jmarsh wrote on 2020-02-09, 12:11: An integer upscale to the closest resolution equal to or larger than the output resolution, followed by bilinear filtering. +1000

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-02-09, 08:00

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by James-F

in DOSBox Development

in DOSBox Development

Latest ECE editions removed Scale 4x-6x and Ant_222's scalers. with a 1080p and a 12oop displays all 320x240 and all 640x480 need to be scaled to 1280x960 (with a 1440p display these games will be scaled to 1920x1440) I want to use bilinear filtering that is intentional and important to maintain …

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-02-08, 11:22

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by James-F

in DOSBox Development

in DOSBox Development

320x200 or 320x240 scales perfectly to 1600x1200 so no interpolation is used,, forcing 2x or 3x is no longer integer of 1600x1200 and it interpolates the image. I'm not sure dosbox is doing that, but rather my gpu,, need confirmation. The point of all my commotion is to make the pixels sharper yet …

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-02-08, 09:17

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by James-F

in DOSBox Development

in DOSBox Development

I see there is some new magic going on with the official scaler. Using scaler=none and opengl, at certain resolution bilinear filtering is applied but on others not. Easiest to test with Quake that can switch all resolutions on the fly. 320x200, 320x240, 800x600 there is no bilinear filtering,, but …

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-01-29, 15:12

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by James-F

in DOSBox Development

in DOSBox Development

Yeah, YP, consider helping or even merging with Dosbox-staging. Github is very convenient for such project with multiple patches.

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-01-29, 12:02

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by James-F

in DOSBox Development

in DOSBox Development

Sorry, I meant Opus. My .cue files has .OGG though as file type.

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-01-29, 11:34

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by James-F

in DOSBox Development

in DOSBox Development

The PC Speaker emulation in current SVN is shit. No Nuked OPL3 support in official SVN. The lack of support of .ogg and other audio formats for .cue is very limiting (my entire DOSBox CD library is in .OGG). Maximum scaling of x3 is still blurry since vertical 200 x 3=600, we need something closer …

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2020-01-24, 07:36

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by James-F

in DOSBox Development

in DOSBox Development

I really don't like thinking about the discontinuation of ECE edition.... that sucks. :'(

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 15:38

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by James-F

in DOSBox Development

in DOSBox Development

gdjacobs wrote on 2020-01-09, 14:54: although It can be implemented in integer with a LUT for the sinc function. This is exactly what Qbix is trying to do,, WinFilter can export C or VHDL code. If everything goes smoothly, DOSBox will have awesome SB16 filtering emulation.

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 13:47

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by James-F

in DOSBox Development

in DOSBox Development

I'm talking to Qbix about it, dosbox has linear interpolation as Resampling and it results in lowpass filtering an some aliasing with lower sampling rates like most games. But, the good news is it looks very similar to what the SB2.0 is already doing, and the SBPro just adds a filter on top of that. …

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 13:25

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by James-F

in DOSBox Development

in DOSBox Development

I'm using a DAW with VST plugins to capture DOBox response, it stays in the digital domain on the same computer. Sorry, you realize I'm not new at this , right?

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 13:06

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by James-F

in DOSBox Development

in DOSBox Development

That's Doom chainsaw gun captured with frequency analyzer. Other smaples I use is White Noise which is flat when viewed in a frequency analyzer without filtering. I'm not going to get into details, that would take hours, you can click my signature and do a little research.

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 10:43

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by James-F

in DOSBox Development

in DOSBox Development

I am a purist myself, and have a big-ish collection of old SB cards. In my opinion lowpass filtering is a huge part of a proper DOS experience, and painfully missing part of DOSBox, call me a nagger. :) hmm.. looks like DOSBox already does 1st order lowpass filtering similar to SB2.0. How can that …

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 08:32

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by James-F

in DOSBox Development

in DOSBox Development

@appiah4 Yes, it is for PCM (SBPro2 and PCem) but the measurement process is exactly the same for OPL, I even attached a AT2 file for that.

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 08:27

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by James-F

in DOSBox Development

in DOSBox Development

For starters, any filter is much better than no filter, and I'm sure no one will complain about it not being SB16 accurate. 😀 And yes, SBPro2 2nd order sounds better for dos games than a brickwall filter.

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 08:22

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by James-F

in DOSBox Development

in DOSBox Development

Why incorrect? A 2nd order filter like everything prior to SB16 is a ton better than no filter at all, and imo sounds better than the sb16 brickwall filtering. You can implement SB16 filtering if you can read the game PCM sampling rate.

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 08:18

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by James-F

in DOSBox Development

in DOSBox Development

@Qbix SB16 is much harder to implement hence PCem uses this 2nd order LPF for SB16 too, it sounds good. The SB16 will change its filter depending on the sampling rate of the PCM source it is playing (each game is different),, see first post. For 11kHz sample rate PCM it will cut everything above 5. …

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Re: DOSBox Sound Blaster emulation (Lowpass Filtering)

Posted on 2020-01-09, 08:13

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by James-F

in DOSBox Development

in DOSBox Development

Yes I can. :smiley: Same for OPL3 lowpass, use Adlib Tracker 2 player called adt2play.exe to play the noise.a2m file and capture with spectrum analyzer. https://www.vogons.org/viewtopic.php?p=815309#p815309 It's only a matter if any developer has a few spare minutes to implement this. I'll do the …

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Re: Lets improve DOSBox Sound Blaster emulation

Posted on 2020-01-09, 08:07

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by James-F

in DOSBox Development

in DOSBox Development

Filtering is applied only to PCM audio,, OPL is unfiltered (sb16) or slightly filtered (sbpro2) on the real sound cards. Hence, we don't want filtering on the global output of DOSBox. We could have separate filters for OPL and PCM which will produce super accurate results. Any dosbox dev here has …

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