diff --git a/README.md b/README.md
index 27cbefb..c138ed3 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ $ ./generator --help
 Video Thumbnail Generator
 
 Usage:
-  ./generator <video> <interval> <width> <height> <columns> <output>
+  ./generator <video> <interval> <width> <height> <columns> <output> [<parallelism>]
   ./generator (-h | --help)
   ./generator --version
 
@@ -45,17 +45,33 @@ Options:
   <height>        Height of each thumbnail.
   <columns>       Total number of thumbnails per line.
   <output>        Output.
+  [<parallelism>]   Number of files to process in parallel
 ```
 
 ## Example
+**Single file**
 ```shell
-$ ./generator videos/27467_1_milkbots_wg_720p.mp4 2 126 73 10 thumbnails.jpg
-Extracting 5 frames
-  [####################################]  100%
-Frames extracted.
+$ ./generator samples/sample.mp4 60 300 200 2 output/sample.mp4.png
+[sample.mp4] Extracting frame 1/3
+[sample.mp4] Extracting frame 2/3
+[sample.mp4] Extracting frame 3/3
+[sample.mp4.png] Savedacted.
 Saved!
 ```
 
+**Directory**
+```shell
+$ ./generator samples/ 60 300 200 2 output/
+[sample copy.mp4] Extracting frame 1/3
+[sample.mp4] Extracting frame 1/3
+[sample copy.mp4] Extracting frame 2/3
+[sample.mp4] Extracting frame 2/3
+[sample copy.mp4] Extracting frame 3/3
+[sample.mp4] Extracting frame 3/3
+[sample copy.mp4.png] Saved
+[sample.mp4.png] Saved
+```
+
 ![image](https://cloud.githubusercontent.com/assets/244265/11234316/b42913a6-8d94-11e5-865a-128ea8d801f7.png)
 
 
diff --git a/generator b/generator
index 2f70ed6..6e0f5d1 100755
--- a/generator
+++ b/generator
@@ -3,99 +3,198 @@
 """Video Thumbnail Generator
 
 Usage:
-  ./generator <video> <interval> <width> <height> <columns> <output>
+  ./generator <video> <interval> <width> <height> <columns> <output> [<parallelism>]
   ./generator (-h | --help)
   ./generator --version
 
 Options:
-  -h --help     Show this screen.
-  --version     Show version.
+  -h --help       Show this screen.
+  --version       Show version.
   <video>         Video filepath.
   <interval>      Interval em seconds between frames.
   <width>         Width of each thumbnail.
   <height>        Height of each thumbnail.
   <columns>       Total number of thumbnails per line.
   <output>        Output.
+  [<parallelism>] Number of files to process in parallel.
 """
 
 from docopt import docopt
 from moviepy.editor import VideoFileClip
 from PIL import Image
 from click import progressbar
-import glob, os, random, shutil, math, tempfile
+from collections import namedtuple
+from multiprocessing import cpu_count, Queue, Process
+import glob
+import os
+import random
+import shutil
+import math
+import tempfile
+import sys
 
 
 TMP_FRAMES_PATH = tempfile.mkdtemp()
 
-def generate_video_thumbnail(args):
-    videoFileClip = VideoFileClip(args['<video>'])
+
+def generate_video_thumbnails(args):
+    input_path = args['<video>']
     interval = int(args['<interval>'])
     size = (int(args['<width>']), int(args['<height>']))
-    outputPrefix = get_output_prefix()
-    generate_frames(videoFileClip, interval, outputPrefix, size)
-
     columns = int(args['<columns>'])
-    output = args['<output>']
-    generate_sprite_from_frames(outputPrefix, columns, size, output)
+    output_path = args['<output>']
+    parallelism = args.get('[<parallelism>]', cpu_count()*2-1)
 
-def generate_frames(videoFileClip, interval, outputPrefix, size):
-    print("Extracting", int(videoFileClip.duration / interval), "frames")
-    frameCount = 0
-    with progressbar(range(0, int(videoFileClip.duration), interval)) as items:
-        for i in items:
-            extract_frame(videoFileClip, i, outputPrefix, size, frameCount)
-            frameCount += 1
-    print("Frames extracted.")
+    work_queue = Queue()
+    work_units = 0
 
-def extract_frame(videoFileClip, moment, outputPrefix, size, frameCount):
-    output = outputPrefix + ("%05d.png" % frameCount)
-    videoFileClip.save_frame(output, t=int(moment))
+    if os.path.isdir(input_path):
+        # Ensure output path is also directory
+        if not os.path.isdir(output_path):
+            print(
+                "If input path is directory then "
+                "output path must be directory"
+            )
+            sys.exit(1)
+
+        # Strip seperator so contructing output is uniform
+        output_path = output_path.rstrip(os.sep)
+
+        # Add all files in directory for processing
+        for file_name in os.listdir(input_path):
+            file_path = os.path.join(input_path, file_name)
+            if os.path.isfile(file_path):
+                # Construct output path for thumbnail using
+                # the video files filename
+                single_output_path = os.path.join(
+                    output_path, os.path.basename(file_path) + ".png"
+                )
+
+                work_queue.put((file_path, single_output_path,
+                                interval, size, columns,))
+                work_units += 1
+    else:
+        work_queue.put((input_path, output_path, interval, size, columns,))
+        work_units += 1
+
+    # Limit the number of parallel jobs if lower number of files
+    parallelism = min(int(parallelism), work_units)
+
+    # Start worker processes
+    processes = []
+    for i in range(parallelism):
+        p = Process(target=worker, args=(work_queue,))
+        p.start()
+        processes.append(p)
+
+    # Block until all processes complete
+    for p in processes:
+        p.join()
+
+
+def worker(queue):
+    while True:
+        try:
+            work_unit = queue.get(False)
+
+            # If no work unit then quit
+            if not work_unit:
+                break
+        # Handle exception when no more items in queue
+        except:
+            break
+
+        input_file, output_file, interval, size, columns = work_unit
+
+        file_name = os.path.basename(input_file)
+
+        # Skip over any thumbnails that exist already
+        if os.path.exists(output_file):
+            print("[{file_name}] Already exists, skipping".format(
+                file_name=file_name))
+            continue
+
+        try:
+            video_file_clip = VideoFileClip(input_file)
+            output_prefix = get_output_prefix()
+            generate_frames(file_name, video_file_clip,
+                            interval, output_prefix, size)
+            generate_sprite_from_frames(output_prefix, columns,
+                                        size, output_file)
+        except:
+            print("[{file_name}] Error occurred with file".format(
+                file_name=file_name))
+
+
+def generate_frames(file_name, video_file_clip, interval, output_prefix, size):
+    duration = video_file_clip.duration
+    frame_count = 0
+    total_frames = int(duration / interval)
+    for i in range(0, int(duration), interval):
+        print("[{file_name}] Extracting frame {current}/{total}".
+              format(file_name=file_name, current=frame_count+1,
+                     total=total_frames+1))
+        extract_frame(video_file_clip, i, output_prefix, size, frame_count)
+        frame_count += 1
+
+
+def extract_frame(video_file_clip, moment, output_prefix, size, frame_count):
+    output = output_prefix + ("%05d.png" % frame_count)
+    video_file_clip.save_frame(output, t=int(moment))
     resize_frame(output, size)
 
+
 def resize_frame(filename, size):
     image = Image.open(filename)
     image = image.resize(size, Image.ANTIALIAS)
     image.save(filename)
 
-def generate_sprite_from_frames(framesPath, columns, size, output):
-    framesMap = sorted(glob.glob(framesPath + "*.png"))
 
-    masterWidth = size[0] * columns
-    masterHeight = size[1] * int(math.ceil(float(len(framesMap)) / columns))
+def generate_sprite_from_frames(frames_path, columns, size, output):
+    frames_map = sorted(glob.glob(frames_path + "*.png"))
+
+    master_width = size[0] * columns
+    master_height = size[1] * int(math.ceil(float(len(frames_map)) / columns))
 
     line, column, mode = 0, 0, 'RGBA'
 
     try:
-        finalImage = Image.new(mode=mode, size=(masterWidth, masterHeight), color=(0,0,0,0))
-        finalImage.save(output)
+        final_image = Image.new(
+            mode=mode,
+            size=(master_width, master_height),
+            color=(0, 0, 0, 0)
+        )
+        final_image.save(output)
     except IOError:
         mode = 'RGB'
-        finalImage = Image.new(mode=mode, size=(masterWidth, masterHeight))
+        final_image = Image.new(mode=mode, size=(master_width, master_height))
 
-    for filename in framesMap:
-        with Image.open(filename) as image:              
+    for filename in frames_map:
+        with Image.open(filename) as image:
 
-            locationX = size[0] * column
-            locationY = size[1] * line
+            location_x = size[0] * column
+            location_y = size[1] * line
 
-            finalImage.paste(image, (locationX, locationY))
+            final_image.paste(image, (location_x, location_y))
 
             column += 1
-            
+
             if column == columns:
                 line += 1
                 column = 0
 
-    finalImage.save(output)
-    shutil.rmtree(TMP_FRAMES_PATH, ignore_errors=True)
-    print("Saved!")
+    final_image.save(output)
+    shutil.rmtree(frames_path, ignore_errors=True)
+    output_file = os.path.basename(output)
+    print("[{output_file}] Saved".format(output_file=output_file))
+
 
 def get_output_prefix():
     if not os.path.exists(TMP_FRAMES_PATH):
         os.makedirs(TMP_FRAMES_PATH)
     return TMP_FRAMES_PATH + os.sep + ("%032x_" % random.getrandbits(128))
 
+
 if __name__ == "__main__":
     arguments = docopt(__doc__, version='0.0.2')
-    generate_video_thumbnail(arguments)
-
+    generate_video_thumbnails(arguments)