Playback hangs when loadfile input command is used from script

mpv Information

mpv v0.40.0-61-g44816ef8f Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Apr 13 2025 13:53:36
libplacebo version: v7.350.0 (v7.349.0-65-g2bd627f8)
FFmpeg version: N-119224-gbf327ac676
FFmpeg library versions:
   libavcodec      62.0.101
   libavdevice     62.0.100
   libavfilter     11.0.100
   libavformat     62.0.100
   libavutil       60.1.100
   libswresample   6.0.100
   libswscale      9.0.100

Other Information

- Linux version: Ubuntu 24
- GPU Model: NVIDIA GT 1030
- Window Manager and Version: Gnome X11
- Source of mpv: mpv-build current master
- Latest known working version: v0.39

Reproduction Steps

When I call loadfile from script from key binding, the video file opens, but it doesn't play, it hangs at position 0, the play/pause button indicates it's playing, nothing happens when pressing the button, it starts playing when the seek bar is clicked.

It works correctly when I call loadfile from the console.

The logic of the code is to cycle pause if the playlist isn't empty, if the playlist is empty, a defined video folder is loaded.

It worked with v0.39.

The code:

mp.register_script_message("cycle-pause", function ()
    local count = mp.get_property_number("playlist-count")

    if count > 0 then
        mp.command("cycle pause")
    else
        if is_windows then
            mp.command("loadfile 'E:\\Video\\YouTube'")
        else
            mp.command("loadfile '/mnt/Media/Video/YouTube'")
        end
    end
end)

Expected Behavior

Video file plays.

Actual Behavior

Video playback hangs.

Log File

mpv-log.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.

Start by reproducing the issue with the shown Lua script-message callback and loadfile command, then inspect the script-message and loadfile entry points while comparing v0.39 with v0.40. Use the attached log to trace why playback remains at position 0; done means the file begins playing from the key binding without clicking the seek bar.