diff --git a/video2x/decoder.py b/video2x/decoder.py
index 1941548..ef8d7ce 100755
--- a/video2x/decoder.py
+++ b/video2x/decoder.py
@@ -104,16 +104,13 @@ class VideoDecoder(threading.Thread):
                     "RGB", (self.input_width, self.input_height), buffer
                 )
 
-                # if this is the first frame
-                # there wouldn't be a "previous image"
-                if previous_image is not None:
-                    self.processing_queue.put(
-                        (
-                            frame_index,
-                            (previous_image, image),
-                            self.processing_settings,
-                        )
+                self.processing_queue.put(
+                    (
+                        frame_index,
+                        (previous_image, image),
+                        self.processing_settings,
                     )
+                )
                 previous_image = image
 
                 frame_index += 1
diff --git a/video2x/interpolator.py b/video2x/interpolator.py
index 41232b3..035a8fb 100755
--- a/video2x/interpolator.py
+++ b/video2x/interpolator.py
@@ -56,6 +56,11 @@ class Interpolator(multiprocessing.Process):
                     time.sleep(0.1)
                     continue
 
+                # if image0 is None, image1 is the first frame
+                # skip this round
+                if image0 is None:
+                    continue
+
                 difference = ImageChops.difference(image0, image1)
                 difference_stat = ImageStat.Stat(difference)
                 difference_ratio = (
diff --git a/video2x/upscaler.py b/video2x/upscaler.py
index ab78646..bd10208 100755
--- a/video2x/upscaler.py
+++ b/video2x/upscaler.py
@@ -74,11 +74,15 @@ class Upscaler(multiprocessing.Process):
                     time.sleep(0.1)
                     continue
 
-                difference = ImageChops.difference(image0, image1)
-                difference_stat = ImageStat.Stat(difference)
-                difference_ratio = (
-                    sum(difference_stat.mean) / (len(difference_stat.mean) * 255) * 100
-                )
+                difference_ratio = -1
+                if image0 is not None:
+                    difference = ImageChops.difference(image0, image1)
+                    difference_stat = ImageStat.Stat(difference)
+                    difference_ratio = (
+                        sum(difference_stat.mean)
+                        / (len(difference_stat.mean) * 255)
+                        * 100
+                    )
 
                 # if the difference is lower than threshold
                 # process the interpolation
@@ -150,8 +154,9 @@ class Upscaler(multiprocessing.Process):
                 else:
 
                     # make sure the previous frame has been processed
-                    while self.processed_frames[frame_index - 1] is None:
-                        time.sleep(0.1)
+                    if frame_index > 0:
+                        while self.processed_frames[frame_index - 1] is None:
+                            time.sleep(0.1)
 
                     # make the current image the same as the previous result
                     self.processed_frames[frame_index] = self.processed_frames[
diff --git a/video2x/video2x.py b/video2x/video2x.py
index af2bfa1..f52cbf8 100755
--- a/video2x/video2x.py
+++ b/video2x/video2x.py
@@ -378,8 +378,8 @@ def parse_arguments() -> argparse.Namespace:
         "-t",
         "--threshold",
         type=float,
-        help="if the % difference between two adjacent frames exceeds this value, two images are deemed the same",
-        default=0.1,
+        help="if the % difference between two adjacent frames exceeds this value, two images are deemed the same; 0 is off",
+        default=0,
     )
 
     # interpolator arguments
@@ -400,7 +400,7 @@ def parse_arguments() -> argparse.Namespace:
         "-t",
         "--threshold",
         type=float,
-        help="if the % difference between two adjacent frames exceeds this value, no interpolation will be performed",
+        help="if the % difference between two adjacent frames exceeds this value, no interpolation will be performed; 0 is off",
         default=10,
     )