diff --git a/src/emu/stream.c b/src/emu/stream.c
index a3a31bb..2d6e3dc 100644
--- a/src/emu/stream.c
+++ b/src/emu/stream.c
@@ -47,13 +47,13 @@ load_stream_fd(struct stream *stream, int fd)
 {
 	struct stat st;
 	if (fstat(fd, &st) < 0) {
-		perror("fstat failed");
+		err("fstat failed:");
 		return -1;
 	}
 
 	/* Error because it doesn't have the header */
 	if (st.st_size == 0) {
-		err("load_stream_fd: stream %s is empty\n", stream->path);
+		err("stream %s is empty", stream->path);
 		return -1;
 	}
 
@@ -61,7 +61,7 @@ load_stream_fd(struct stream *stream, int fd)
 	stream->buf = mmap(NULL, st.st_size, prot, MAP_PRIVATE, fd, 0);
 
 	if (stream->buf == MAP_FAILED) {
-		perror("mmap failed");
+		err("mmap failed:");
 		return -1;
 	}
 
@@ -73,10 +73,10 @@ load_stream_fd(struct stream *stream, int fd)
 int
 stream_load(struct stream *stream, const char *tracedir, const char *relpath)
 {
-	int fd;
+	memset(stream, 0, sizeof(struct stream));
 
 	if (snprintf(stream->path, PATH_MAX, "%s/%s", tracedir, relpath) >= PATH_MAX) {
-		err("stream_load: path too long: %s/%s\n", tracedir, relpath);
+		err("path too long: %s/%s", tracedir, relpath);
 		return -1;
 	}
 
@@ -84,25 +84,26 @@ stream_load(struct stream *stream, const char *tracedir, const char *relpath)
 	path_remove_trailing(stream->path);
 
 	if (snprintf(stream->relpath, PATH_MAX, "%s", relpath) >= PATH_MAX) {
-		err("stream_load: path too long: %s\n", relpath);
+		err("path too long: %s", relpath);
 		return -1;
 	}
 
-	dbg("stream_load: loading %s\n", stream->relpath);
+	dbg("loading %s", stream->relpath);
 
+	int fd;
 	if ((fd = open(stream->path, O_RDWR)) == -1) {
-		err("stream_load: open failed: %s\n", stream->path);
+		err("open %s failed:", stream->path);
 		return -1;
 	}
 
 	if (load_stream_fd(stream, fd) != 0) {
-		err("stream_load: load_stream_fd failed for stream '%s'\n",
+		err("load_stream_fd failed for stream '%s'",
 				stream->path);
 		return -1;
 	}
 
 	if (check_stream_header(stream) != 0) {
-		err("stream_load: stream '%s' has bad header\n",
+		err("stream '%s' has bad header",
 				stream->path);
 		return -1;
 	}
@@ -113,17 +114,17 @@ stream_load(struct stream *stream, const char *tracedir, const char *relpath)
 	if (stream->offset < stream->size) {
 		stream->active = 1;
 	} else if (stream->offset == stream->size) {
-		err("warning: stream '%s' has zero events\n", stream->relpath);
+		err("warning: stream '%s' has zero events", stream->relpath);
 		stream->active = 0;
 	} else {
-		err("stream_load: impossible, offset %ld bigger than size %ld\n",
+		err("impossible, offset %ld bigger than size %ld",
 				stream->offset, stream->size);
 		return -1;
 	}
 
 	/* No need to keep the fd open */
 	if (close(fd)) {
-		perror("close failed");
+		err("close failed:");
 		return -1;
 	}
 
@@ -146,13 +147,13 @@ int
 stream_clkoff_set(struct stream *stream, int64_t clkoff)
 {
 	if (stream->cur_ev) {
-		die("stream_clkoff_set: cannot set clokoff in started stream '%s'\n",
+		die("cannot set clokoff in started stream '%s'",
 				stream->relpath);
 		return -1;
 	}
 
 	if (stream->clock_offset != 0) {
-		err("stream_clkoff_set: stream '%s' already has a clock offset\n",
+		err("stream '%s' already has a clock offset",
 				stream->relpath);
 		return -1;
 	}
@@ -184,7 +185,7 @@ int
 stream_step(struct stream *stream)
 {
 	if (!stream->active) {
-		err("stream_step: stream is inactive, cannot step\n");
+		err("stream is inactive, cannot step");
 		return -1;
 	}
 
@@ -194,7 +195,7 @@ stream_step(struct stream *stream)
 
 		/* It cannot pass the size, otherwise we are reading garbage */
 		if (stream->offset > stream->size) {
-			err("stream_step: stream offset %ld exceeds size %ld\n",
+			err("stream offset %ld exceeds size %ld",
 					stream->offset, stream->size);
 			return -1;
 		}
@@ -211,21 +212,25 @@ stream_step(struct stream *stream)
 
 	/* Ensure the event fits */
 	if (stream->offset + ovni_ev_size(stream->cur_ev) > stream->size) {
-		err("stream_step: stream '%s' ends with incomplete event\n",
+		err("stream '%s' ends with incomplete event",
 				stream->relpath);
 		return -1;
 	}
 
-	/* Ensure the clock grows monotonically */
 	int64_t clock = stream_evclock(stream, stream->cur_ev);
-	if (clock < stream->lastclock) {
-		err("clock goes backwards %ld -> %ld in stream '%s' at offset %ld\n",
-				stream->lastclock,
-				clock,
-				stream->relpath,
-				stream->offset);
-		return -1;
+
+	/* Ensure the clock grows monotonically if unsorted flag not set */
+	if (stream->unsorted == 0) {
+		if (clock < stream->lastclock) {
+			err("clock goes backwards %ld -> %ld in stream '%s' at offset %ld",
+					stream->lastclock,
+					clock,
+					stream->relpath,
+					stream->offset);
+			return -1;
+		}
 	}
+
 	stream->lastclock = clock;
 
 	return 0;
@@ -241,3 +246,9 @@ stream_progress(struct stream *stream)
 	double prog = (double) uoffset / (double) stream->usize;
 	return prog;
 }
+
+void
+stream_allow_unsorted(struct stream *stream)
+{
+	stream->unsorted = 1;
+}
diff --git a/src/emu/stream.h b/src/emu/stream.h
index 4a0a7da..3c7717b 100644
--- a/src/emu/stream.h
+++ b/src/emu/stream.h
@@ -21,6 +21,7 @@ struct stream {
 	int64_t offset;
 
 	int active;
+	int unsorted;
 
 	double progress;
 
@@ -46,6 +47,7 @@ int stream_step(struct stream *stream);
 struct ovni_ev *stream_ev(struct stream *stream);
 int64_t stream_evclock(struct stream *stream, struct ovni_ev *ev);
 int64_t stream_lastclock(struct stream *stream);
+void stream_allow_unsorted(struct stream *stream);
 
 void stream_data_set(struct stream *stream, void *data);
 void *stream_data_get(struct stream *stream);