diff --git a/removeads.py b/removeads.py
index a8f4e86..b8722d4 100755
--- a/removeads.py
+++ b/removeads.py
@@ -356,10 +356,11 @@ def extractPictures(inputFile, begin, nbFrames, width=640, height=480):
     # "P6\nWIDTH HEIGHT\n255\n"
     headerLen=2+1+ceil(log(width, 10))+1+ceil(log(height, 10))+1+3+1
     logger.debug('Header length: %d' % headerLen)
-    length = (width*height*3+headerLen)*nbFrames
+    imageLength = width*height*3+headerLen
+    length = imageLength*nbFrames
     logger.debug("Estimated length: %d" % length)
     
-    pg = trange(length)
+    pg = trange(nbFrames)
     images = bytes()
     with Popen(['ffmpeg', '-loglevel', 'quiet' ,'-y', '-ss', '%s'%begin, '-i', '/proc/self/fd/%d' % infd, '-s', '%dx%d'%(width, height), '-vframes', '%d'%nbFrames, '-c:v', 'ppm', '-f', 'image2pipe', '/proc/self/fd/%d' % fdw ], stdout=PIPE, close_fds=False) as ffmpeg:
         while ffmpeg.poll() == None:
@@ -367,11 +368,11 @@ def extractPictures(inputFile, begin, nbFrames, width=640, height=480):
             # fds, _, _ = select([fdr, ffmpeg.stdout], [], [], .1)
             fds, _, _ = select([fdr], [], [], .1)
             if fdr in fds:
-                buf = os.read(fdr, 1000000)
+                buf = os.read(fdr, imageLength)
                 # print("Read %d bytes of image. ffmpeg finished: %s" % (len(buf), ffmpeg.poll()))
                 if len(buf) == 0:
                     break
-                pg.update(len(buf))
+                pg.update(len(buf)/imageLength)
                 images=images+buf
             if ffmpeg.stdout in fds:
                 for line in TextIOWrapper(ffmpeg.stdout, encoding="utf-8"):
@@ -383,11 +384,11 @@ def extractPictures(inputFile, begin, nbFrames, width=640, height=480):
     while True:
         fd, _, _ = select([fdr], [], [], .1)
         if fd != []:
-            buf = os.read(fdr, 1000000)
+            buf = os.read(fdr, imageLength)
             # print("Read %d bytes of image" % len(buf))
             if len(buf) == 0:
                 break
-            pg.update(len(buf))
+            pg.update(len(buf)/imageLength)
             images=images+buf
         else:
             # Nothing more to read