- Linux version: Fedora 41
- Kernel Version: 6.12.12
- Window Manager and Version: Gnome Wayland (mutter 47.5)

(gdb) bt
#0  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
#1  0x00007ffff4036183 in __pthread_kill_internal (threadid=<optimized out>, signo=6) at pthread_kill.c:78
#2  0x00007ffff3fdcf9e in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#3  0x00007ffff3fc4942 in __GI_abort () at abort.c:79
#4  0x00007ffff3fc485e in __assert_fail_base
    (fmt=0x7ffff4179cb0 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion@entry=0x55555579af0e "res.display_par", file=file@entry=0x55555579af01 "../sub/osd.c", line=line@entry=553, function=function@entry=0x555555820450 <__PRETTY_FUNCTION__.1.lto_priv.52> "osd_rescale_bitmaps") at assert.c:96
#5  0x00007ffff3fd50c7 in __assert_fail
    (assertion=0x55555579af0e "res.display_par", file=0x55555579af01 "../sub/osd.c", line=553, function=0x555555820450 <__PRETTY_FUNCTION__.1.lto_priv.52> "osd_rescale_bitmaps") at assert.c:105
#6  0x00005555556573cf in osd_rescale_bitmaps (imgs=0x7fffd37f5120, frame_w=1920, frame_h=1080, res=..., compensate_par=-1)
    at ../sub/osd.c:553
#7  0x00005555556609e8 in get_bitmaps (sd=0x555556838520, d=..., format=1, pts=164.37299999999999) at ../sub/sd_lavc.c:523
#8  0x000055555564e9b6 in sub_get_bitmaps (sub=0x5555578e6330, dim=..., format=1, pts=164.37299999999999) at ../sub/dec_sub.c:427
#9  0x00005555556568de in render_object
    (osd=0x555555957ff0, obj=0x555555958860, osdres=..., video_pts=164.37299999999999, sub_formats=0x555555820268 <mp_draw_sub_formats>) at ../sub/osd.c:329
#10 0x0000555555656c3c in osd_render
    (osd=0x555555957ff0, res=..., video_pts=164.37299999999999, draw_flags=0, formats=0x555555820268 <mp_draw_sub_formats>)
    at ../sub/osd.c:397
#11 0x000055555565705c in osd_draw_on_image_p
    (osd=0x555555957ff0, res=..., video_pts=164.37299999999999, draw_flags=0, pool=0x0, dest=0x7fffc0001e10) at ../sub/osd.c:468
#12 0x0000555555656ff0 in osd_draw_on_image
    (osd=0x555555957ff0, res=..., video_pts=164.37299999999999, draw_flags=0, dest=0x7fffc0001e10) at ../sub/osd.c:457
#13 0x00005555556ae932 in draw_frame (vo=0x5555559db200, frame=0x7fffc32ab200) at ../video/out/vo_kitty.c:284
#14 0x00005555556a656f in render_frame (vo=0x5555559db200) at ../video/out/vo.c:1010
#15 0x00005555556a6bb3 in vo_thread (ptr=0x5555559db200) at ../video/out/vo.c:1142
#16 0x00007ffff4034168 in start_thread (arg=<optimized out>) at pthread_create.c:448
#17 0x00007ffff40b814c in __GI___clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

(gdb) frame 9
#9  0x00005555556568de in render_object (osd=0x555555957ff0, obj=0x555555958860, osdres=..., video_pts=164.37299999999999, 
    sub_formats=0x555555820268 <mp_draw_sub_formats>) at ../sub/osd.c:329
329	           res = sub_get_bitmaps(obj->sub, obj->vo_res, format, video_pts);
(gdb) p *obj
$1 = {type = 0, is_sub = true, osd_changed = true, text = 0x5555559589a0 "", progbar_state = {type = -1, value = 0, stops = 0x0, 
    num_stops = 0}, sub = 0x5555578e6330, externals = 0x0, num_externals = 0, external2 = 0x0, vo_change_id = 2, vo_res = {w = 2160, 
    h = 1215, mt = 0, mb = 0, ml = 0, mr = 0, display_par = 0}, vo_had_output = false, changed = false, ass = {log = 0x0, 
    track = 0x0, render = 0x0, library = 0x0, res_x = 0, res_y = 0, changed = false, vo_res = {w = 0, h = 0, mt = 0, mb = 0, ml = 0, 
      mr = 0, display_par = 0}}, ass_packer = 0x0, copy_cache = 0x0, ass_imgs = 0x0}
(gdb) p format
$2 = 1

diff --git a/video/out/vo_kitty.c b/video/out/vo_kitty.c
index 2664df659f..e54fd684e3 100644
--- a/video/out/vo_kitty.c
+++ b/video/out/vo_kitty.c
@@ -280,7 +280,7 @@ static bool draw_frame(struct vo *vo, struct vo_frame *frame)
         mp_image_clear(p->frame, 0, 0, p->width, p->height);
     }
 
-    struct mp_osd_res res = { .w = p->width, .h = p->height };
+    struct mp_osd_res res = { .w = p->width, .h = p->height, .display_par=1.0 };
     osd_draw_on_image(vo->osd, res, mpi ? mpi->pts : 0, 0, p->frame);