load/unload a pulseaudio module-remap-sink on OBS start/exit.

obs-pulse-remap-sink.lua

function script_description()
    return [[
        <h2>obs-pulse-remap v1</h2>
        <p>Load a module-remap-sink on pulseaudio when OBS starts, and unload it when OBS exits.</p>
        <p>Useful for when you want OBS to capture the audio of only one program.</p>
        <p>Author: ghesy <ehsan at disroot dot org></p>
    ]]
end

local modules = {}

function script_load()
    p = io.popen("pactl load-module module-remap-sink sink_name=OBSSink sink_properties=device.description=OBSSink", "r")
    for m in p:lines() do
        if tonumber(m) then
            table.insert(modules, m)
        end
    end
end

function script_unload()
    for _, m in ipairs(modules) do
        os.execute("pactl unload-module " .. m)
    end
end