Screen capture stops working after $HOURS

[2e0byo]

At some point (4h < point < 24h) after booting the system, screen capture fails: obs for instance shows

info: [pipewire] Asking for desktop
info: [pipewire] desktop selected, setting up screencast
info: [pipewire] Server version: 0.3.84
info: [pipewire] Library version: 0.3.84
info: [pipewire] Header version: 0.3.84
info: [pipewire] Created stream 0x562bfd558800
info: [pipewire] Stream 0x562bfd558800 state: "connecting" (error: none)
info: [pipewire] Playing stream 0x562bfd558800
info: [pipewire] Stream 0x562bfd558800 state: "paused" (error: none)
info: [pipewire] Stream 0x562bfd558800 state: "error" (error: no more input formats)
error: [pipewire] Error id:2 seq:10 res:-32 (Unknown error -32): no more input

I've traced this down to xdg-desktop-portal-hyprland by restarting services until it worked again. Logs from before restart:

Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy] SHAREDATA returned selection 0
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy] Start:
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_125/obs3
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_125/obs1
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy]  | appid:
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy]  | parent_window:
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [ERR] [screencopy] Couldn't obtain a format from dma
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy] New session:
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_118/webrtc_53953641
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_118/webrtc_session903947359
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy]  | appid:
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy] SelectSources:
Nov 18 18:05:01 digory xdg-desktop-portal-hyprland[2852]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_118/webrtc908602552

Logs from after, with successful screen capture

ov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] SHAREDATA returned selection 0
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] Start:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_162/obs3
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_162/obs1
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | appid:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | parent_window:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [pw] Building modifiers for dma
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] Sharing initialized
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] New session:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_168/obs1
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_168/obs1
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | appid:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] SelectSources:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_168/obs2
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_168/obs1
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | appid:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] option cursor_mode to 2
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] option persist_mode to 2
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] unused option multiple
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] unused option types
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] restore data invalid / missing, prompting
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] execAndGet: WAYLAND_DISPLAY=wayland-1 QT_QPA_PLATFORM="wayland" XCURSOR_SIZE=24 HYPRLAND_IN>
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [sc] Selection: /screen:DP-4
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] SHAREDATA returned selection 0
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] Start:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_168/obs3
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_168/obs1
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | appid:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | parent_window:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [pw] Building modifiers for dma
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] Sharing initialized
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [pw] Building modifiers for dma
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [pw] Building modifiers for dma
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy/pipewire] Out of buffers
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] New session:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_174/obs1
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_174/obs1
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | appid:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] SelectSources:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_174/obs2
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_174/obs1
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | appid:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] option cursor_mode to 2
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] option persist_mode to 2
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] unused option multiple
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] unused option types
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] restore data invalid / missing, prompting
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] execAndGet: WAYLAND_DISPLAY=wayland-1 QT_QPA_PLATFORM="wayland" XCURSOR_SIZE=24 HYPRLAND_IN>
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [sc] Selection: /screen:DP-4
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] SHAREDATA returned selection 0
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy] Start:
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/request/1_174/obs3
Nov 18 18:31:00 digory xdg-desktop-portal-hyprland[556063]: [LOG] [screencopy]  | /org/freedesktop/portal/desktop/session/1_174/obs1

I've realised I'm on a slightly outdated commit, so I'll rebuild (arch, xdg-desktop-portal-hyprland-git) and see if this goes away, but it's been happening for at least a month.

How do I debug further? If it just failed I'd run in gdb, but I don't want to do that for hours on end until the problem emerges.