mpvnet can't open videos with long path, while mpv.exe can

[bmacho]

Describe the bug
mpvnet fails to open videos with long PATH from command line/another program.

To Reproduce

I have this longname

$longname = "Big.Back.Bunny.Test.File.With.A.Very.Long.Name.That.Ensures.Total.Path.Length.Exceeds.Windows.Limit.Players.Fail.Debugging.Headache.2025.Edition.UltraHD.x265.DTS.TrueHD"

And videos $longname/Bunny.mp4 (a working case) and $longname/$longname.mp4.

In powershell

~Downloads/mpv.net-v7.1.1.3-beta-portable-x64/mpvnet.exe $longname/Bunny.mp4
# works
~Downloads/mpv.net-v7.1.1.3-beta-portable-x64/mpvnet.exe $longname/$longname.mp4
# does not work

while with mpv.exe they work

mpv.exe $longname/Bunny.mp4
# works
mpv.exe $longname/$longname.mp4
# works

Additional context

1. mpv.net version latest beta
2. Windows version latest windows 10

[bmacho]

The videos work when started from File Explorer, because it truncates the path. But they don't work when started from another program, for example, a torrent client.

Workaround for users: ChatGPT gave me the following script

@echo off
rem Mpvnet wrapper
rem Turns long file path to 8.3 path format

set MPVNET_PATH=mpvnet.exe

rem To check if the file path is too long
rem Slice it from 257
set "ARG=%~1"
set EMPTY_IF_ARG_SHORT=%ARG:~257, 99999%

if "%EMPTY_IF_ARG_SHORT%"=="" (
	rem No need to shorten the path
	"%MPVNET_PATH%" "%~1"
) else (
	rem Shorten the path
	"%MPVNET_PATH%" "%~s1"
)

Save this as mpvnet_wrapper.bat and set it to open your videos instead of mpvnet.