vo=gpu-next does not work properly with geometry on extended monitor

[Zemax27]

mpv Information

mpv v0.40.0-dev-g0a53407a4 Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Oct 11 2025 08:36:30
libplacebo version: v7.351.0
FFmpeg version: 8.0
FFmpeg library versions:
   libavcodec      62.11.100
   libavdevice     62.1.100
   libavfilter     11.4.100
   libavformat     62.3.100
   libavutil       60.8.100
   libswresample   6.1.100
   libswscale      9.1.100

Other Information

- macOS version: macOS 26.0.1 (25A362)
- Source of mpv: bundle (from https://nightly.link/mpv-player/mpv/workflows/build/master)

Reproduction Steps

I'm using a multi-monitor configuration in MacOS where the main display is a MacBookPro built-in display and the external monitor is an Apple XDRpro connected through thunderbolt (used as Extended display).

Opening mpv.app bundle from terminal with:
open -n mpv.app --args --hidpi-window-scale=no --geometry=1804x3284+0+0 --screen=1 --vo=gpu-next VIDEO_FILE.EXT

places the mpv window at wrong coordinates that depends on screens/window resolution and arrangements.
--hidpi-window-scale=no or yes makes no difference

Expected Behavior

Opening mpv.app bundle from terminal with:
open -n mpv.app --args --hidpi-window-scale=no --geometry=1804x3284+0+0 --screen=1 --vo=libmpv VIDEO_FILE.EXT

places the mpv window correctly to the target monitor coordinate.

--vo=libmpv does it as expected !

Actual Behavior

--vo=gpu-next places the mpv window at wrong coordinates that depends on screens/window resolution and arrangements.
NOTE:
using a relatively small window size, e.g. --geometry=200x355+0+0, places the window correctly at 0:0

Log File

Log file when using the gpu-next (buggy geometry behavior)

gpu-next.txt

Log file when using the libmpv (correct geometry behavior)

libmpv.txt

Sample Files

No response

I carefully read all instruction and confirm that I did the following:

• I tested with the latest mpv version to validate that the issue is not already fixed.
• I provided all required information including system and mpv version.
• I produced the log file with the exact same set of files, parameters, and conditions used in "Reproduction Steps", with the addition of --log-file=output.txt.
• I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• I attached the full, untruncated log file.
• I attached the backtrace in the case of a crash.

[Akemi]

places the mpv window at wrong coordinates is an inadequate description for the problem. what is exactly wrong? what exactly is your expected right behaviour? provide some screenshots.

[Zemax27]

@Akemi yes, sorry. I provide here few screenshots.
When using libmpv, the mpv window is correctly placed on screen=1 at 0:0
This is the expected behavior:

When using gpu-next, the mpv window is placed on the main display
This is the wrong behavior:

The misplacement depends on the window size and/or display resolution. For example setting --geometry=512x910 with libmpv.
Correct and expected behavior:

While setting --geometry=512x910 with gpu-next.
Unexpected behavior:

I hope it can help to better identify the issue

[Akemi]

yeah that's much better, thank you. did this start with macOS 26 or was this the case on older macOS versions too?

[edit]
also how does your monitor arrangement look like in the settings, are they on top of each other or next to each other? was wondering because of the screenshot.

[Zemax27]

@Akemi
I don't know if this is the case on older macOS versions because I'm trying to use the geometry configuration for the first time with the already up-to-date macOS version. I was previously using it in Windows OS where it works flawlessly.
The monitor arrangement looks exactly as you see in the screenshots (they are on top of each other) but the issue occurs also if I change the configuration to a side by side geometry (monitors next to each other)

[Akemi]

should be fixed with #16940. one of the windows builds is broken atm so no comment with the test builds. you can get them on the PR build summary https://github.com/mpv-player/mpv/actions/runs/18630605149?pr=16940.