optimized pixel access with explicit load()

pysstv/color.py

@@ -11,12 +11,12 @@ class ColorSSTV(GrayscaleSSTV):
     def encode_line(self, line):
         cs = self.COLOR_SEQ
         msec_pixel = self.SCAN / self.WIDTH
-        image = self.image
+        image = self.image.load()
         for index in cs:
             for item in self.before_channel(index):
                 yield item
             for col in xrange(self.WIDTH):
-                pixel = image.getpixel((col, line))
+                pixel = image[col, line]
                 freq_pixel = byte_to_freq(pixel[index])
                 yield freq_pixel, msec_pixel
             for item in self.after_channel(index):

pysstv/grayscale.py

@@ -15,9 +15,9 @@ class GrayscaleSSTV(SSTV):
 
     def encode_line(self, line):
         msec_pixel = self.SCAN / self.WIDTH
-        image = self.image
+        image = self.image.load()
         for col in xrange(self.WIDTH):
-            pixel = image.getpixel((col, line))
+            pixel = image[col, line]
             freq_pixel = byte_to_freq(sum(pixel) / len(pixel))
             yield freq_pixel, msec_pixel