Dosbox Pure: No video synchronization?

Hi there,

On my GNU/Linux KMS/DRM LibRetro/RetroArch setup (using latest stable RetroArch, and using latest GIT code to build the cores), cores show the trademark RetroArch video synchronization that results on totally smooth scrolls in games.

All, except Dosbox Pure: As with previous Dosbox LR core, this core is not synchronizing video emulation with the host video frequency, resulting on hiccups/desync once in a while. So, what is the mistery with DOS emulators on RetroArch? Is it not possible to synchronize them as with the rest of the cores? I have changed the max audio skew to 0.50 (that would be more than sufficient for 70Hz vs 60Hz differences) but still, the core is not synchronizing and scrolls in DOS games like Super Frog and Pinball Dreams are poor.

Dosbox Pure indeed doesn’t have the same sync capabilities as the dosbox-svncore(?) core. If you need rock-solid sync, I’d suggest that one instead.

EDIT: I believe it’s dosbox-core that has the good-good sync: https://github.com/libretro/dosbox-core

Oh, thanks as always, @hunterk

Seems like I am not the only one who noticed this:

Anyway, dosbox-svn seems to be outdated. So it seems I am one again out of luck, no updated dosbox core with proper video sync.

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Yeah I feel your pain! I was hoping the author of dosbox pure would just copy and paste the vsync code of dosbox SVN into his core. Dosbox SVN has perfect vsync on android (jazz jackrabbit is a sight to behold in this core). It might be the same way on Windows. Sadly it’s hard to enjoy dosbox SVN on Android because of the lack of a hideaway on-screen keyboard that you should be able to swipe between on-screen gamepad and keyboard. Dosbox pure does have on-screen keyboard but I think it’s missing on-screen gamepad and has broken vsync. If dosbox pure ever incorporates dosbox SVN vsync and on-screen gamepad for Android, it will be the undisputed king of dosbox.

@magichost: Do you mean the code on this repository allows perfect host rate synchronization?

Yes! Dosbox-svn external timing option interfaces with retroarch frontend v-sync timing perfectly so you can get perfect v-sync.

Dosbox Pure and Dosbox Core are the currently maintained cores. So use one of those, if possible. Dosbox SVN is only there if it’s not possible to use Core or Pure.

Oh, so we have an unmantained core that synchronizes video correctly and two maintained cores that dont.

Nice. I think I’ll stick to FPGAs for DOS games then.

Dosbox-core is a direct continuation of dosbox-svn and thus has video sync.

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