diff --git a/lib/formats/csv.c b/lib/formats/csv.c
index 7d23554dd..b21e8b09b 100644
--- a/lib/formats/csv.c
+++ b/lib/formats/csv.c
@@ -36,20 +36,26 @@ static size_t csv_sprint_single(struct io *io, char *buf, size_t len, const stru
 	size_t off = 0;
 	struct signal *sig;
 
-	if (io->flags & SAMPLE_HAS_TS_ORIGIN)
-		off += snprintf(buf + off, len - off, "%ld%c%09ld", smp->ts.origin.tv_sec, io->separator, smp->ts.origin.tv_nsec);
-	else
-		off += snprintf(buf + off, len - off, "nan%cnan", io->separator);
+	if (io->flags & SAMPLE_HAS_TS_ORIGIN) {
+		if (io->flags & SAMPLE_HAS_TS_ORIGIN)
+			off += snprintf(buf + off, len - off, "%ld%c%09ld", smp->ts.origin.tv_sec, io->separator, smp->ts.origin.tv_nsec);
+		else
+			off += snprintf(buf + off, len - off, "nan%cnan", io->separator);
+	}
 
-	if (io->flags & SAMPLE_HAS_TS_RECEIVED)
-		off += snprintf(buf + off, len - off, "%c%.09f", io->separator, time_delta(&smp->ts.origin, &smp->ts.received));
-	else
-		off += snprintf(buf + off, len - off, "%cnan", io->separator);
+	if (io->flags & SAMPLE_HAS_OFFSET) {
+		if (smp->flags & SAMPLE_HAS_TS_RECEIVED)
+			off += snprintf(buf + off, len - off, "%c%.09f", io->separator, time_delta(&smp->ts.origin, &smp->ts.received));
+		else
+			off += snprintf(buf + off, len - off, "%cnan", io->separator);
+	}
 
-	if (io->flags & SAMPLE_HAS_SEQUENCE)
-		off += snprintf(buf + off, len - off, "%c%" PRIu64, io->separator, smp->sequence);
-	else
-		off += snprintf(buf + off, len - off, "%cnan", io->separator);
+	if (io->flags & SAMPLE_HAS_SEQUENCE) {
+		if (smp->flags & SAMPLE_HAS_SEQUENCE)
+			off += snprintf(buf + off, len - off, "%c%" PRIu64, io->separator, smp->sequence);
+		else
+			off += snprintf(buf + off, len - off, "%cnan", io->separator);
+	}
 
 	if (io->flags & SAMPLE_HAS_DATA) {
 		for (int i = 0; i < smp->length; i++) {
@@ -177,18 +183,31 @@ void csv_header(struct io *io, const struct sample *smp)
 {
 	FILE *f = io_stream_output(io);
 
-	fprintf(f, "# secs%cnsecs%coffset%csequence", io->separator, io->separator, io->separator);
+	fprintf(f, "# ");
+	if (io->flags & SAMPLE_HAS_TS_ORIGIN)
+		fprintf(f, "secs%cnsecs%c", io->separator, io->separator);
 
-	for (int i = 0; i < smp->length; i++) {
-		struct signal *sig = (struct signal *) list_at(smp->signals, i);
+	if (io->flags & SAMPLE_HAS_OFFSET)
+		fprintf(f, "offset%c", io->separator);
 
-		if (sig->name)
-			fprintf(f, "%c%s", io->separator, sig->name);
-		else
-			fprintf(f, "%csignal%d", io->separator, i);
+	if (io->flags & SAMPLE_HAS_SEQUENCE)
+		fprintf(f, "sequence%c", io->separator);
 
-		if (sig->unit)
-			fprintf(f, "[%s]", sig->unit);
+	if (io->flags & SAMPLE_HAS_DATA) {
+		for (int i = 0; i < smp->length; i++) {
+			struct signal *sig = (struct signal *) list_at(smp->signals, i);
+
+			if (sig->name)
+				fprintf(f, "%s", sig->name);
+			else
+				fprintf(f, "signal%d", i);
+
+			if (sig->unit)
+				fprintf(f, "[%s]", sig->unit);
+
+			if (i+1 < smp->length)
+				fprintf(f, "%c", io->separator);
+		}
 	}
 
 	fprintf(f, "%c", io->delimiter);
diff --git a/lib/formats/json.c b/lib/formats/json.c
index bb60663e7..8edb89b44 100644
--- a/lib/formats/json.c
+++ b/lib/formats/json.c
@@ -50,14 +50,14 @@ static enum signal_type json_detect_format(json_t *val)
 	}
 }
 
-static json_t * json_pack_timestamps(struct sample *smp)
+static json_t * json_pack_timestamps(struct io *io, struct sample *smp)
 {
 	json_t *json_ts = json_object();
 
-	if (smp->flags & SAMPLE_HAS_TS_ORIGIN)
+	if (io->flags & smp->flags & SAMPLE_HAS_TS_ORIGIN)
 		json_object_set(json_ts, "origin", json_pack("[ I, I ]", smp->ts.origin.tv_sec, smp->ts.origin.tv_nsec));
 
-	if (smp->flags & SAMPLE_HAS_TS_RECEIVED)
+	if (io->flags & smp->flags & SAMPLE_HAS_TS_RECEIVED)
 		json_object_set(json_ts, "received", json_pack("[ I, I ]", smp->ts.received.tv_sec, smp->ts.received.tv_nsec));
 
 	return json_ts;
@@ -98,15 +98,15 @@ static int json_pack_sample(struct io *io, json_t **j, struct sample *smp)
 	json_t *json_smp;
 	json_error_t err;
 
-	json_smp = json_pack_ex(&err, 0, "{ s: o }", "ts", json_pack_timestamps(smp));
+	json_smp = json_pack_ex(&err, 0, "{ s: o }", "ts", json_pack_timestamps(io, smp));
 
-	if (smp->flags & SAMPLE_HAS_SEQUENCE) {
+	if (io->flags & smp->flags & SAMPLE_HAS_SEQUENCE) {
 		json_t *json_sequence = json_integer(smp->sequence);
 
 		json_object_set(json_smp, "sequence", json_sequence);
 	}
 
-	if (smp->flags & SAMPLE_HAS_DATA) {
+	if (io->flags & smp->flags & SAMPLE_HAS_DATA) {
 		json_t *json_data = json_array();
 
 		for (int i = 0; i < smp->length; i++) {
diff --git a/lib/formats/protobuf.c b/lib/formats/protobuf.c
index d0324ae9a..5e6a11521 100644
--- a/lib/formats/protobuf.c
+++ b/lib/formats/protobuf.c
@@ -68,12 +68,12 @@ int protobuf_sprint(struct io *io, char *buf, size_t len, size_t *wbytes, struct
 
 		pb_smp->type = VILLAS__NODE__SAMPLE__TYPE__DATA;
 
-		if (smp->flags & SAMPLE_HAS_SEQUENCE) {
+		if (io->flags & smp->flags & SAMPLE_HAS_SEQUENCE) {
 			pb_smp->has_sequence = 1;
 			pb_smp->sequence = smp->sequence;
 		}
 
-		if (smp->flags & SAMPLE_HAS_TS_ORIGIN) {
+		if (io->flags & smp->flags & SAMPLE_HAS_TS_ORIGIN) {
 			pb_smp->timestamp = alloc(sizeof(Villas__Node__Timestamp));
 			villas__node__timestamp__init(pb_smp->timestamp);
 
diff --git a/lib/formats/villas_human.c b/lib/formats/villas_human.c
index e7d71d201..76a863f1f 100644
--- a/lib/formats/villas_human.c
+++ b/lib/formats/villas_human.c
@@ -38,15 +38,23 @@ static size_t villas_human_sprint_single(struct io *io, char *buf, size_t len, c
 	struct signal *sig;
 
 	if (io->flags & SAMPLE_HAS_TS_ORIGIN) {
-		off += snprintf(buf + off, len - off, "%llu", (unsigned long long) smp->ts.origin.tv_sec);
-		off += snprintf(buf + off, len - off, ".%09llu", (unsigned long long) smp->ts.origin.tv_nsec);
+		if (smp->flags & SAMPLE_HAS_TS_ORIGIN) {
+			off += snprintf(buf + off, len - off, "%llu", (unsigned long long) smp->ts.origin.tv_sec);
+			off += snprintf(buf + off, len - off, ".%09llu", (unsigned long long) smp->ts.origin.tv_nsec);
+		}
+		else
+			off += snprintf(buf + off, len - off, "nan.nan");
 	}
 
-	if (io->flags & SAMPLE_HAS_TS_RECEIVED)
-		off += snprintf(buf + off, len - off, "%+e", time_delta(&smp->ts.origin, &smp->ts.received));
+	if (io->flags & SAMPLE_HAS_OFFSET) {
+		if (smp->flags & SAMPLE_HAS_TS_RECEIVED)
+			off += snprintf(buf + off, len - off, "%+e", time_delta(&smp->ts.origin, &smp->ts.received));
+	}
 
-	if (io->flags & SAMPLE_HAS_SEQUENCE)
-		off += snprintf(buf + off, len - off, "(%" PRIu64 ")", smp->sequence);
+	if (io->flags & SAMPLE_HAS_SEQUENCE) {
+		if (io->flags & SAMPLE_HAS_SEQUENCE)
+			off += snprintf(buf + off, len - off, "(%" PRIu64 ")", smp->sequence);
+	}
 
 	if (io->flags & SAMPLE_HAS_DATA) {
 		for (int i = 0; i < smp->length; i++) {
@@ -207,18 +215,29 @@ void villas_human_header(struct io *io, const struct sample *smp)
 {
 	FILE *f = io_stream_output(io);
 
-	fprintf(f, "# %-20s", "seconds.nanoseconds+offset(sequence)");
+	fprintf(f, "# ");
 
-	for (int i = 0; i < smp->length; i++) {
-		struct signal *sig = (struct signal *) list_at(smp->signals, i);
+	if (io->flags & SAMPLE_HAS_TS_ORIGIN)
+		fprintf(f, "seconds.nanoseconds");
 
-		if (sig->name)
-			fprintf(f, "%c%s", io->separator, sig->name);
-		else
-			fprintf(f, "%csignal%d", io->separator, i);
+	if (io->flags & SAMPLE_HAS_OFFSET)
+		fprintf(f, "+offset");
 
-		if (sig->unit)
-			fprintf(f, "[%s]", sig->unit);
+	if (io->flags & SAMPLE_HAS_SEQUENCE)
+		fprintf(f, "(sequence)");
+
+	if (io->flags & SAMPLE_HAS_DATA) {
+		for (int i = 0; i < smp->length; i++) {
+			struct signal *sig = (struct signal *) list_at(smp->signals, i);
+
+			if (sig->name)
+				fprintf(f, "%c%s", io->separator, sig->name);
+			else
+				fprintf(f, "%csignal%d", io->separator, i);
+
+			if (sig->unit)
+				fprintf(f, "[%s]", sig->unit);
+		}
 	}
 
 	fprintf(f, "%c", io->delimiter);