Setting time_pos too early makes it stick

[pmcgaley]

Setting time_pos too early appears to succeed but it doesn't actually seek. Playback proceeds from the start of the file, I can observe the property and get correct values that way, but reading player.time_pos is stuck at whatever value I initially set it to.

I thought calling wait_for_property('seekable') before setting time_pos had solved this for me, but in fact I've since seen it happen once even when I make that call.

from mpv import MPV

player = MPV()

def on_time_pos(name, value):
    print(f"time: {value} vs {player.time_pos}")

player.observe_property('time-pos', on_time_pos)

player.play("file.m4b")

# here's where I now call player.wait_for_property('seekable')

player.time_pos = 1.23

player.wait_for_playback()

$ python mpvtest.py 
time: None vs 1.23
time: 0.0 vs 1.23
time: 0.043594991793650784 vs 1.23
time: 0.09264593575283447 vs 1.23
time: 0.1746740883537415 vs 1.23
...

Raspberry Pi OS Trixie
mpv 0.40.0-3+deb13u1
python-mpv 1.0.8
Python 3.13.5

[jaseg]

Hi there, thank you for the report. This is very likely to be a bug in libmpv itself, not in python-mpv. The time-pos value just gets passed to libmpv by python-mpv without any further processing.

I was able to reproduce the behavior you observe on mpv v0.41.0. I'd suggest you ask the folks over at the core mpv project about this, since I think it's unlikely we can do anything about it here.