diff --git a/demux/demux_subreader.c b/demux/demux_subreader.c
index e95ffda976..f422441b0b 100644
--- a/demux/demux_subreader.c
+++ b/demux/demux_subreader.c
@@ -1500,6 +1500,7 @@ static int d_check_file(struct demuxer *demuxer)
 
     p->sh = new_sh_stream(demuxer, STREAM_SUB);
     p->sh->codec = sd->codec;
+    p->sh->sub->frame_based = !sd->sub_uses_time;
 
     add_sub_data(demuxer, sd);
     subdata_free(sd);
diff --git a/demux/stheader.h b/demux/stheader.h
index 14418accb0..37bdbcc568 100644
--- a/demux/stheader.h
+++ b/demux/stheader.h
@@ -163,6 +163,7 @@ typedef struct sh_sub {
     SH_COMMON
     unsigned char *extradata;   // extra header data passed from demuxer
     int extradata_len;
+    int frame_based;            // timestamps are frame-based
     struct ass_track *track;    // loaded by libass
     struct dec_sub *dec_sub;    // decoder context
 } sh_sub_t;
diff --git a/sub/dec_sub.c b/sub/dec_sub.c
index dd1168d0ad..54f3c1ebfe 100644
--- a/sub/dec_sub.c
+++ b/sub/dec_sub.c
@@ -275,6 +275,10 @@ bool sub_read_all_packets(struct dec_sub *sub, struct sh_sub *sh)
         MP_TARRAY_APPEND(tmp, subs.packets, subs.num_packets, pkt);
     }
 
+    // 23.976 FPS is used as default timebase for frame based formats
+    if (sub->video_fps && sh->frame_based)
+        multiply_timings(&subs, sub->video_fps / 23.976);
+
     if (opts->sub_fps && sub->video_fps)
         multiply_timings(&subs, opts->sub_fps / sub->video_fps);