error with pillow: decoder not avaliable

Mark Lawrence breamoreboy at yahoo.co.uk
Thu Jul 2 09:42:44 CEST 2015


On 02/07/2015 08:29, telmo bacile wrote:
> Hi list, im new in this list.
> Im trying to run a python code that was made originally with pil using pillow,
>
> The problem is that i get this error:
>
> IOError: decoder jpeg not available

> Any idea why this code is not working with pillow?
>
> import math
> from PIL import Image
> imageFile = 'test.jpg'
> im = Image.open(imageFile)
> rgbHistogram = im.histogram()
> print 'Snannon Entropy for Red, Green, Blue:'
> for rgb in range(3):
>      totalPixels = sum(rgbHistogram[rgb * 256 : (rgb + 1) * 256])
>      ent = 0.0
>      for col in range(rgb * 256, (rgb + 1) * 256):
>          freq = float(rgbHistogram[col]) / totalPixels
>          if freq > 0:
>              ent = ent + freq * math.log(freq, 2)
>      ent = -ent
>      print ent
>

Searching for "python pil ioerror decoder jpeg not available" on google 
gives 3,930 results of which this is the first
http://stackoverflow.com/questions/8915296/python-image-library-fails-with-message-decoder-jpeg-not-available-pil

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence



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