diff --git a/oxtimelines/ffmpeg.py b/oxtimelines/ffmpeg.py
index c01515a..3a0fac2 100644
--- a/oxtimelines/ffmpeg.py
+++ b/oxtimelines/ffmpeg.py
@@ -13,7 +13,14 @@ import numpy as np
 import ox
 
 
-FFMPEG = 'ffmpeg'
+FFMPEG = None
+for cmd in ('ffmpeg', 'avconv'):
+    cmd = ox.file.cmd(cmd)
+    if subprocess.call(['which', cmd], stdout=subprocess.PIPE) == 0:
+        FFMPEG = cmd
+        break
+if not FFMPEG:
+    print("could not find ffmpeg, make sure its installed and available in PATH")
 FPS = 25
 
 class Video(object):
diff --git a/oxtimelines/timeline.py b/oxtimelines/timeline.py
index 5cef458..250c001 100644
--- a/oxtimelines/timeline.py
+++ b/oxtimelines/timeline.py
@@ -44,9 +44,10 @@ class Timelines():
         self.render_slitscan = 'slitscan' in modes
         if 'multiline' in modes:
             info = ox.avinfo(video_files[0])
+            self.render_multiline = info['video'][0]['width']
             self.output_h = sizes[0]
             sizes = [info['video'][0]['height']] + sizes[1:]
-            self.render_multiline = info['video'][0]['width']
+            self.render_multiline = True
             self._pool = ThreadPool(multiprocessing.cpu_count())
         else:
             self.render_multiline = False
@@ -459,7 +460,7 @@ class Timelines():
                         self.tile_path, line, 'slitscan', self.output_h, index, type
                     )
                     ox.makedirs(os.path.dirname(tile_file))
-                    width = self.large_tile_image[mode][line].size[0]
+                    width = self.large_tile_image[mode][line].size[1]
                     img = self.large_tile_image[mode][line]
                     if self.output_h != self.large_tile_image[mode][line].size[0]:
                         img = img.resize((width, self.output_h), Image.BICUBIC)