diff --git a/bin/oxtimelines b/bin/oxtimelines
index 3ef8f02..69c1701 100755
--- a/bin/oxtimelines
+++ b/bin/oxtimelines
@@ -42,6 +42,7 @@ tiles without having to decode the video again.
     parser.add_option('-s', '--sizes', dest='sizes', help='timeline size(s) (64 or 64,16)')
     parser.add_option('-w', '--wide', dest='wide', default=False, action='store_true', help='keep wide frames tiles')
     parser.add_option('-l', '--log', dest='log', default=False, action='store_true', help='log performance')
+    parser.add_option('-x', '--slit-position', dest='slit_position', default=None, action='store_true', help='slit scan position (default center frame)')
     (opts, args) = parser.parse_args()
 
     if None in (opts.modes, opts.sizes, opts.tiles) or not args:
@@ -54,4 +55,4 @@ tiles without having to decode the video again.
     opts.modes = [m.strip() for m in opts.modes.split(',')]
     opts.sizes = list(map(int, opts.sizes.split(',')))
 
-    oxtimelines.Timelines(opts.videos, opts.tiles, opts.cuts, opts.points, opts.modes, opts.sizes, opts.wide, opts.log).render()
+    oxtimelines.Timelines(opts.videos, opts.tiles, opts.cuts, opts.points, opts.modes, opts.sizes, opts.wide, opts.log, slit_positoin=opts.slit_position).render()
diff --git a/oxtimelines/timeline.py b/oxtimelines/timeline.py
index 0d347fe..39129cf 100644
--- a/oxtimelines/timeline.py
+++ b/oxtimelines/timeline.py
@@ -23,7 +23,8 @@ class Timelines():
 
     def __init__(
         self, video_files, tile_path, cuts_path,
-        points, modes, sizes, render_wide_tiles, log
+        points, modes, sizes, render_wide_tiles, log,
+        slit_position=None
     ):
 
         self.video_files = video_files
@@ -46,6 +47,11 @@ class Timelines():
         self.render_data = 'data' in modes
         self.render_video = len(modes) > 1 if self.render_audio else True
 
+        if slit_position:
+            self.frame_center = int(slit_position)
+        else:
+            self.frame_center = None
+
         if self.detect_cuts or self.render_cuts or self.render_keyframes:
             self.detect_cuts = True
             self.cuts = [0]
@@ -132,7 +138,8 @@ class Timelines():
             frame_size = self.videos[0].get_size()
             self.frame_w = frame_size[0]
             self.frame_ratio = frame_size[0] / frame_size[1]
-            self.frame_center = int(frame_size[0] / 2)
+            if self.frame_center is None:
+                self.frame_center = int(frame_size[0] / 2)
 
         self.large_tile_n = int(math.ceil(self.frame_n / self.large_tile_w))
         self.large_tile_last_w = self.frame_n % self.large_tile_w or self.large_tile_w