diff --git a/sndiod/abuf.c b/sndiod/abuf.c
index 7068312..bd8cc54 100644
--- a/sndiod/abuf.c
+++ b/sndiod/abuf.c
@@ -43,11 +43,10 @@ abuf_log(struct abuf *buf)
 #endif
 
 void
-abuf_init(struct abuf *buf, unsigned int len, unsigned int bpf)
+abuf_init(struct abuf *buf, unsigned int len)
 {
-	buf->data = xmalloc((size_t)len * bpf);
+	buf->data = xmalloc(len);
 	buf->len = len;
-	buf->bpf = bpf;
 	buf->used = 0;
 	buf->start = 0;
 }
@@ -80,7 +79,7 @@ abuf_rgetblk(struct abuf *buf, int *rsize)
 	if (count > buf->used)
 		count = buf->used;
 	*rsize = count;
-	return buf->data + buf->start * buf->bpf;
+	return buf->data + buf->start;
 }
 
 /*
@@ -136,5 +135,5 @@ abuf_wgetblk(struct abuf *buf, int *rsize)
 	if (count > avail)
 		count = avail;
 	*rsize = count;
-	return buf->data + end * buf->bpf;
+	return buf->data + end;
 }
diff --git a/sndiod/abuf.h b/sndiod/abuf.h
index b89acff..84b67ee 100644
--- a/sndiod/abuf.h
+++ b/sndiod/abuf.h
@@ -18,14 +18,13 @@
 #define ABUF_H
 
 struct abuf {
-	int bpf;	/* bytes per frames */
 	int start;	/* offset (frames) where stored data starts */
 	int used;	/* frames stored in the buffer */
 	int len;	/* total size of the buffer (frames) */
 	unsigned char *data;
 };
 
-void abuf_init(struct abuf *, unsigned int, unsigned int);
+void abuf_init(struct abuf *, unsigned int);
 void abuf_done(struct abuf *);
 void abuf_log(struct abuf *);
 unsigned char *abuf_rgetblk(struct abuf *, int *);
diff --git a/sndiod/dev.c b/sndiod/dev.c
index 51c6b7c..76cb046 100644
--- a/sndiod/dev.c
+++ b/sndiod/dev.c
@@ -481,14 +481,14 @@ dev_midi_exit(void *arg)
 void
 slot_mix_drop(struct slot *s)
 {
-	while (s->mix.drop > 0 && s->mix.buf.used >= s->round) {
+	while (s->mix.drop > 0 && s->mix.buf.used >= s->round * s->mix.bpf) {
 #ifdef DEBUG
 		if (log_level >= 4) {
 			slot_log(s);
 			log_puts(": dropped a play block\n");
 		}
 #endif
-		abuf_rdiscard(&s->mix.buf, s->round);
+		abuf_rdiscard(&s->mix.buf, s->round * s->mix.bpf);
 		s->mix.drop--;
 	}
 }
@@ -501,7 +501,7 @@ slot_sub_sil(struct slot *s)
 
 	while (s->sub.silence > 0) {
 		data = abuf_wgetblk(&s->sub.buf, &count);
-		if (count < s->round)
+		if (count < s->round * s->sub.bpf)
 			break;
 #ifdef DEBUG
 		if (log_level >= 4) {
@@ -512,8 +512,8 @@ slot_sub_sil(struct slot *s)
 		if (s->sub.encbuf)
 			enc_sil_do(&s->sub.enc, data, s->round);
 		else
-			memset(data, 0, s->round * s->sub.buf.bpf);
-		abuf_wcommit(&s->sub.buf, s->round);
+			memset(data, 0, s->round * s->sub.bpf);
+		abuf_wcommit(&s->sub.buf, s->round * s->sub.bpf);
 		s->sub.silence--;
 	}
 }
@@ -594,20 +594,18 @@ dev_mix_badd(struct dev *d, struct slot *s)
 	odata = DEV_PBUF(d);
 	idata = (adata_t *)abuf_rgetblk(&s->mix.buf, &icount);
 #ifdef DEBUG
-	if (icount < s->round && s->pstate != SLOT_STOP) {
+	if (icount < s->round * s->mix.bpf) {
 		slot_log(s);
 		log_puts(": not enough data to mix (");
 		log_putu(icount);
 		log_puts(" of ");
-		log_putu(d->round);
+		log_putu(d->round * s->mix.bpf);
 		log_puts(")\n");
 		panic();
 	}
 #endif
-	if (icount > s->round)
-		icount = s->round;
-	play_filt_dec(s, idata, odata, icount);
-	abuf_rdiscard(&s->mix.buf, icount);
+	play_filt_dec(s, idata, odata, s->round);
+	abuf_rdiscard(&s->mix.buf, s->round * s->mix.bpf);
 }
 
 void
@@ -649,7 +647,12 @@ dev_mix_cycle(struct dev *d)
 			ps = &s->next;
 			continue;
 		}
-		if (s->pstate == SLOT_STOP && s->mix.buf.used == 0) {
+		if (s->mix.buf.used < s->round * s->mix.bpf &&
+		    s->pstate == SLOT_STOP) {
+			/*
+			 * partial blocks are zero-filled by socket
+			 * layer
+			 */
 			s->pstate = SLOT_INIT;
 			abuf_done(&s->mix.buf);
 			if (s->mix.decbuf)
@@ -660,7 +663,8 @@ dev_mix_cycle(struct dev *d)
 			*ps = s->next;
 			continue;
 		}
-		if (s->mix.buf.used < s->round && !(s->pstate == SLOT_STOP)) {
+		if (s->mix.buf.used < s->round * s->mix.bpf && 
+		    !(s->pstate == SLOT_STOP)) {
 			if (s->xrun == XRUN_IGNORE) {
 				if (s->mode & MODE_RECMASK)
 					s->sub.silence--;
@@ -803,13 +807,13 @@ dev_sub_bcopy(struct dev *d, struct slot *s)
 	idata = (s->mode & MODE_MON) ? DEV_PBUF(d) : d->rbuf;
 	odata = (adata_t *)abuf_wgetblk(&s->sub.buf, &ocount);
 #ifdef DEBUG
-	if (ocount < s->round) {
+	if (ocount < s->round * s->sub.bpf) {
 		log_puts("dev_sub_bcopy: not enough space\n");
 		panic();
 	}
 #endif
 	ocount = rec_filt_enc(s, idata, odata, d->round);
-	abuf_wcommit(&s->sub.buf, ocount);
+	abuf_wcommit(&s->sub.buf, ocount * s->sub.bpf);
 }
 
 void
@@ -837,7 +841,7 @@ dev_sub_cycle(struct dev *d)
 			ps = &s->next;
 			continue;
 		}
-		if (s->sub.buf.len - s->sub.buf.used < s->round) {
+		if (s->sub.buf.len - s->sub.buf.used < s->round * s->sub.bpf) {
 			if (s->xrun == XRUN_IGNORE) {
 				if (s->mode & MODE_PLAY)
 					s->mix.drop--;
@@ -1812,8 +1816,9 @@ slot_start(struct slot *s)
 			log_puts("\n");
 		}
 #endif
-		abuf_init(&s->mix.buf, bufsz,
-		    s->par.bps * (s->mix.slot_cmax - s->mix.slot_cmin + 1));
+		s->mix.bpf = s->par.bps * 
+		    (s->mix.slot_cmax - s->mix.slot_cmin + 1);
+		abuf_init(&s->mix.buf, bufsz * s->mix.bpf);
 	}
 	if (s->mode & MODE_RECMASK) {
 #ifdef DEBUG
@@ -1826,8 +1831,9 @@ slot_start(struct slot *s)
 			log_puts("\n");
 	}
 #endif
-		abuf_init(&s->sub.buf, bufsz,
-		    s->par.bps * (s->sub.slot_cmax - s->sub.slot_cmin + 1));
+		s->sub.bpf = s->par.bps * 
+		    (s->sub.slot_cmax - s->sub.slot_cmin + 1);
+		abuf_init(&s->sub.buf, bufsz * s->sub.bpf);
 	}
 	s->mix.weight = MIDI_TO_ADATA(MIDI_MAXCTL);
 #ifdef DEBUG
diff --git a/sndiod/dev.h b/sndiod/dev.h
index a5d9471..a2bbb0e 100644
--- a/sndiod/dev.h
+++ b/sndiod/dev.h
@@ -53,6 +53,7 @@ struct slot {
 		unsigned int vol;		/* volume within the vol */
 		int drop;			/* to drop on next read */
 		struct abuf buf;		/* socket side buffer */
+		int bpf;			/* byte per frame */
 		int slot_cmin, slot_cmax;	/* slot source chans */
 		int dev_cmin, dev_cmax;		/* device destination chans */
 		struct cmap cmap;		/* channel mapper state */
@@ -65,6 +66,7 @@ struct slot {
 	struct {
 		int silence;			/* to add on next write */
 		struct abuf buf;		/* socket side buffer */
+		int bpf;			/* byte per frame */
 		int slot_cmin, slot_cmax;	/* slot destination chans */
 		int dev_cmin, dev_cmax;		/* device source chans */
 		struct cmap cmap;		/* channel mapper state */
diff --git a/sndiod/midi.c b/sndiod/midi.c
index 1218084..922ded0 100644
--- a/sndiod/midi.c
+++ b/sndiod/midi.c
@@ -130,10 +130,10 @@ midi_new(struct midiops *ops, void *arg, int mode)
 	 * to client input
 	 */
 	if (ep->mode & MODE_MIDIOUT) {
-		abuf_init(&ep->ibuf, MIDI_BUFSZ, 1);
+		abuf_init(&ep->ibuf, MIDI_BUFSZ);
 	}
 	if (ep->mode & MODE_MIDIIN) {
-		abuf_init(&ep->obuf, MIDI_BUFSZ, 1);
+		abuf_init(&ep->obuf, MIDI_BUFSZ);
 	}
 	return ep;
 }
diff --git a/sndiod/sock.c b/sndiod/sock.c
index 076e580..ee64d67 100644
--- a/sndiod/sock.c
+++ b/sndiod/sock.c
@@ -184,7 +184,7 @@ sock_slot_flush(void *arg)
 	struct sock *f = arg;
 	struct slot *s = f->slot;
 
-	f->wmax += s->round * s->sub.buf.bpf;
+	f->wmax += s->round * s->sub.bpf;
 #ifdef DEBUG
 	if (log_level >= 4) {
 		sock_log(f);
@@ -527,7 +527,7 @@ sock_rdata(struct sock *f)
 	 * XXX: this can happen in MIDIOUT mode, since we dont
 	 *	have flow control
 	 */
-	if (count * buf->bpf < f->rtodo) {
+	if (count < f->rtodo) {
 		sock_log(f);
 		log_puts(": data read buffer overrun\n");
 		panic();
@@ -545,7 +545,7 @@ sock_rdata(struct sock *f)
 	 * XXX: commit data earlier, don't sacrify a full block in case
 	 * of xrun
 	 */
-	abuf_wcommit(buf, f->rsize / buf->bpf);
+	abuf_wcommit(buf, f->rsize);
 	f->rtodo = 0;
 #ifdef DEBUG
 	if (log_level >= 4) {
@@ -611,7 +611,7 @@ sock_wdata(struct sock *f)
 		return 0;
 	}
 	if (f->pstate != SOCK_STOP) {
-		abuf_rdiscard(buf, f->wsize / buf->bpf);
+		abuf_rdiscard(buf, f->wsize);
 		if (f->slot)
 			slot_read(f->slot);
 	}
@@ -960,6 +960,7 @@ sock_execmsg(struct sock *f)
 	struct slot *s = f->slot;
 	struct amsg *m = &f->rmsg;
 	unsigned int size, ctl;
+	unsigned char *data;
 
 	switch (ntohl(m->cmd)) {
 	case AMSG_DATA:
@@ -991,7 +992,7 @@ sock_execmsg(struct sock *f)
 			return 0;
 		}
 		size = ntohl(m->u.data.size);
-		if (s != NULL && size % s->mix.buf.bpf != 0) {
+		if (s != NULL && size % s->mix.bpf != 0) {
 #ifdef DEBUG
 			if (log_level >= 1) {
 				sock_log(f);
@@ -1020,7 +1021,7 @@ sock_execmsg(struct sock *f)
 		if (s != NULL) {
 			f->ralign -= size;
 			if (f->ralign == 0)
-				f->ralign = s->round * s->mix.buf.bpf;
+				f->ralign = s->round * s->mix.bpf;
 		}
 		if (f->rtodo > f->rmax) {
 #ifdef DEBUG
@@ -1071,11 +1072,11 @@ sock_execmsg(struct sock *f)
 		if (s->mode & MODE_PLAY) {
 			f->fillpending = -(int)s->dev->bufsz *
 			    (int)s->round / (int)s->dev->round;
-			f->ralign = s->round * s->mix.buf.bpf;
-			f->rmax = SLOT_BUFSZ(s) * s->mix.buf.bpf;
+			f->ralign = s->round * s->mix.bpf;
+			f->rmax = SLOT_BUFSZ(s) * s->mix.bpf;
 		}
 		if (s->mode & MODE_RECMASK) {
-			f->walign = s->round * s->sub.buf.bpf;
+			f->walign = s->round * s->sub.bpf;
 			f->wmax = 0;
 		}
 		f->pstate = SOCK_START;
@@ -1129,7 +1130,20 @@ sock_execmsg(struct sock *f)
 		f->pstate = SOCK_STOP;
 		f->rstate = SOCK_RMSG;
 		f->rtodo = sizeof(struct amsg);
-		slot_stop(s);
+		if (s->mode & MODE_PLAY) {
+			data = abuf_wgetblk(&s->mix.buf, &size);
+#ifdef DEBUG
+			if (size < f->ralign) {
+				sock_log(f);
+				log_puts(": unaligned stop\n");
+				panic();
+			}
+#endif
+			memset(data, 0, f->ralign);
+			abuf_wcommit(&s->mix.buf, f->ralign);
+			f->ralign = 0;
+		}
+		slot_stop(s);		
 		break;
 	case AMSG_SETPAR:
 #ifdef DEBUG
@@ -1357,7 +1371,7 @@ sock_buildmsg(struct sock *f)
 		f->wmsg.u.ts.delta = htonl(f->fillpending);
 		size = f->fillpending;
 		if (f->slot)
-			size *= f->slot->mix.buf.bpf;
+			size *= f->slot->mix.bpf;
 		f->rmax += size;
 		f->wtodo = sizeof(struct amsg);
 		f->wstate = SOCK_WMSG;
@@ -1404,7 +1418,8 @@ sock_buildmsg(struct sock *f)
 	 * If data available, build a DATA message.
 	 */
 	if (f->slot != NULL && f->slot->sub.buf.used > 0 && f->wmax > 0) {
-		size = f->slot->sub.buf.used * f->slot->sub.buf.bpf;
+		/* XXX: round to bpf */
+		size = f->slot->sub.buf.used;
 		if (size > AMSG_DATAMAX)
 			size = AMSG_DATAMAX;
 		if (size > f->walign)
@@ -1421,7 +1436,7 @@ sock_buildmsg(struct sock *f)
 		f->walign -= size;
 		f->wmax -= size;
 		if (f->walign == 0)
-			f->walign = f->slot->round * f->slot->sub.buf.bpf;
+			f->walign = f->slot->round * f->slot->sub.bpf;
 #ifdef DEBUG
 		if (log_level >= 4) {
 			sock_log(f);