diff --git a/streaming/core.py b/streaming/core.py
index 8ef7b59..40e48a8 100644
--- a/streaming/core.py
+++ b/streaming/core.py
@@ -182,7 +182,7 @@ class Torrent(object):
             logger.debug('Calling read again to get the real number')
             return self.can_read(from_byte)
         else:
-            return ((last_available_piece - needed_piece) * self.piece_length) + rest + self.piece_length
+            return ((last_available_piece - needed_piece) * self.piece_length) + self.piece_length - rest
 
     def is_idle(self):
         return not self.readers and self.last_activity + TORRENT_CLEANUP_INTERVAL < datetime.now()
diff --git a/streaming/torrentfile.py b/streaming/torrentfile.py
index 6429612..ee3b103 100644
--- a/streaming/torrentfile.py
+++ b/streaming/torrentfile.py
@@ -50,6 +50,9 @@ class DelugeTorrentInput(InputBase.find_plugin('file')):
         if self.can_read_to <= tell or self.can_read_to is None:
             self.can_read_to = self.torrent.can_read(self.offset + tell) + tell
 
+            if self._open_file:
+                self._open_file.seek(tell)
+
         real_num = min(num, self.can_read_to - tell)
         if num != real_num:
             logger.info('The real number we can read to is %s and not %s at position %s' % (real_num, num, tell))