diff --git a/lib/libsndio/sio.c b/lib/libsndio/sio.c
index 02e8a8dd176..5ec306a8126 100644
--- a/lib/libsndio/sio.c
+++ b/lib/libsndio/sio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sio.c,v 1.28 2026/01/22 09:24:26 ratchov Exp $	*/
+/*	$OpenBSD: sio.c,v 1.29 2026/03/10 06:23:44 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -112,6 +112,7 @@ sio_start(struct sio_hdl *hdl)
 		return 0;
 	}
 	hdl->cpos = 0;
+	hdl->cpending = 0;
 	hdl->rused = hdl->wused = 0;
 	if (!sio_getpar(hdl, &hdl->par))
 		return 0;
@@ -494,20 +495,24 @@ _sio_printpos(struct sio_hdl *hdl)
 		wdiff = wdiff - wround;
 	}
 	DPRINTF("%011lld: "
-	    "clk %+5lld%+5lld, wr %+5lld%+5lld rd: %+5lld%+5lld\n",
+	    "clk %+5lld%+5lld, wr %+5lld%+5lld rd: %+5lld%+5lld (cpending: %d)\n",
 	    1000000000LL * ts.tv_sec + ts.tv_nsec - hdl->start_nsec,
-	    cpos, cdiff, wpos, wdiff, rpos, rdiff);
+	    cpos, cdiff, wpos, wdiff, rpos, rdiff, hdl->cpending);
 }
 #endif
 
 void
 _sio_onmove_cb(struct sio_hdl *hdl, int delta)
 {
-	hdl->cpos += delta;
+	hdl->cpending += delta;
+	if (hdl->cpending <= 0)
+		return;
+
+	hdl->cpos += hdl->cpending;
 	if (hdl->mode & SIO_REC)
-		hdl->rused += delta * (hdl->par.bps * hdl->par.rchan);
+		hdl->rused += hdl->cpending * (hdl->par.bps * hdl->par.rchan);
 	if (hdl->mode & SIO_PLAY)
-		hdl->wused -= delta * (hdl->par.bps * hdl->par.pchan);
+		hdl->wused -= hdl->cpending * (hdl->par.bps * hdl->par.pchan);
 #ifdef DEBUG
 	if (_sndio_debug >= 3)
 		_sio_printpos(hdl);
@@ -518,7 +523,8 @@ _sio_onmove_cb(struct sio_hdl *hdl, int delta)
 	}
 #endif
 	if (hdl->move_cb)
-		hdl->move_cb(hdl->move_addr, delta);
+		hdl->move_cb(hdl->move_addr, hdl->cpending);
+	hdl->cpending = 0;
 	hdl->xrun = 0;
 }
 
diff --git a/lib/libsndio/sio_aucat.c b/lib/libsndio/sio_aucat.c
index 3745defe0a9..bca50f463bf 100644
--- a/lib/libsndio/sio_aucat.c
+++ b/lib/libsndio/sio_aucat.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sio_aucat.c,v 1.22 2026/01/22 09:24:26 ratchov Exp $	*/
+/*	$OpenBSD: sio_aucat.c,v 1.23 2026/03/10 06:23:44 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -38,7 +38,6 @@ struct sio_aucat_hdl {
 	unsigned int rbpf, wbpf;	/* read and write bytes-per-frame */
 	int events;			/* events the user requested */
 	unsigned int curvol, reqvol;	/* current and requested volume */
-	int delta;			/* some of received deltas */
 #define PSTATE_INIT	0
 #define PSTATE_RUN	1
 	int pstate;
@@ -107,13 +106,9 @@ sio_aucat_runmsg(struct sio_aucat_hdl *hdl)
 		break;
 	case AMSG_MOVE:
 		delta = ntohl(hdl->aucat.rmsg.u.ts.delta);
-		hdl->delta += delta;
-		DPRINTFN(3, "aucat: move(%d), delta = %d, maxwrite = %d\n",
-		    delta, hdl->delta, hdl->aucat.maxwrite);
-		if (hdl->delta >= 0) {
-			_sio_onmove_cb(&hdl->sio, hdl->delta);
-			hdl->delta = 0;
-		}
+		DPRINTFN(3, "aucat: move(%d), maxwrite = %d\n",
+		    delta, hdl->aucat.maxwrite);
+		_sio_onmove_cb(&hdl->sio, delta);
 		break;
 	case AMSG_XRUN:
 		DPRINTFN(3, "aucat: xrun\n");
@@ -195,7 +190,6 @@ sio_aucat_start(struct sio_hdl *sh)
 	hdl->rbpf = hdl->sio.par.bps * hdl->sio.par.rchan;
 	hdl->aucat.maxwrite = 0;
 	hdl->round = hdl->sio.par.round;
-	hdl->delta = 0;
 	DPRINTFN(2, "aucat: start, maxwrite = %d\n", hdl->aucat.maxwrite);
 
 	AMSG_INIT(&hdl->aucat.wmsg);
diff --git a/lib/libsndio/sio_priv.h b/lib/libsndio/sio_priv.h
index 206b7b2119d..8d711a493bf 100644
--- a/lib/libsndio/sio_priv.h
+++ b/lib/libsndio/sio_priv.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sio_priv.h,v 1.13 2026/01/22 09:24:26 ratchov Exp $	*/
+/*	$OpenBSD: sio_priv.h,v 1.14 2026/03/10 06:23:44 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -41,6 +41,7 @@ struct sio_hdl {
 	int rused;			/* bytes used in read buffer */
 	int wused;			/* bytes used in write buffer */
 	int xrun;			/* xrun reported */
+	int cpending;			/* clock ticks not reported yet */
 	long long cpos;			/* clock since start */
 	struct sio_par par;
 #ifdef DEBUG
diff --git a/lib/libsndio/sio_sun.c b/lib/libsndio/sio_sun.c
index 11b6efbe1dc..10bfc5cb413 100644
--- a/lib/libsndio/sio_sun.c
+++ b/lib/libsndio/sio_sun.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sio_sun.c,v 1.33 2026/01/22 09:24:26 ratchov Exp $	*/
+/*	$OpenBSD: sio_sun.c,v 1.34 2026/03/10 06:23:44 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -617,17 +617,15 @@ sio_sun_xrun(struct sio_sun_hdl *hdl)
 			 */
 			cmove += hdl->sio.par.round;
 		}
-		hdl->idelta = -cmove;
 	}
 
-	if (hdl->sio.mode & SIO_PLAY) {
+	if (hdl->sio.mode & SIO_PLAY)
 		hdl->sio.wsil = hdl->sio.wused + cmove * hdl->obpf;
-		hdl->odelta = -cmove;
-	}
 
 	DPRINTFN(1, "%s: cmove = %d, wsil = %d, rdrop = %d\n", __func__,
 	    cmove, hdl->sio.wsil, hdl->sio.rdrop);
 
+	_sio_onmove_cb(&hdl->sio, -cmove);
 	return 1;
 }
 
@@ -690,12 +688,11 @@ sio_sun_revents(struct sio_hdl *sh, struct pollfd *pfd)
 		 */
 		delta = hdl->odelta > hdl->idelta ? hdl->odelta : hdl->idelta;
 	}
-	if (delta > 0) {
-		_sio_onmove_cb(&hdl->sio, delta);
-		if (hdl->sio.mode & SIO_PLAY)
-			hdl->odelta -= delta;
-		if (hdl->sio.mode & SIO_REC)
-			hdl->idelta -= delta;
-	}
+	_sio_onmove_cb(&hdl->sio, delta);
+	if (hdl->sio.mode & SIO_PLAY)
+		hdl->odelta -= delta;
+	if (hdl->sio.mode & SIO_REC)
+		hdl->idelta -= delta;
+
 	return revents;
 }