Video thumbnailer won't work anymore

[jonathlela]

When using PIL to make a video thumbnail, the following exception is raised :

AttributeError: 'module' object has no attribute 'frombytes'

This issue was fixed in #5321 (see ​5b8e0b2a63194d53da2ce434e867fc5eab1b60b4)

However, #5375 reintroduces the error (see ​6e38fec80ebaadc3b3cfdc912f40cc4e8bb9b31cc)

[ayleph]

Well that's weird. 8 months ago we get reports that frombytes is deprecated in favor of fromstring, and 5 weeks ago we get reports that fromstring is deprecated in favor of frombytes. I myself confirmed that Pillow==3.0.0 failed when fromstring was used.

What version of PIL are you using?

[jonathlela]

I dont know about pillow, but :

>>> import Image
>>> Image.version

gives me :

'1.1.7'

My guess is that mediagoblin with python 2 uses system wide PIL library which doesn't have frombytes and with python 3 uses downloaded pillow (because original PIL doesn't work with pyton 3) which aliased fromstring with frombytes and deprecated fromstring in its last releases.

[ayleph]

I'm using Python2 with Pillow==3.0.0. frombytes works for me, but fromstring causes an error. If I try to import Image in my mediagoblin virtual environment as you did, I get an error.

(mediagoblin) ~/mediagoblin $ python2
Python 2.7.11 (default, Dec  6 2015, 15:43:46)
[GCC 5.2.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import Image
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named Image

What is the output of pip freeze in your environment?

(mediagoblin)~/mediagoblin $ pip freeze | grep -i pil
Pillow==3.0.0

[ayleph]

I just noticed an interesting import call in the video transcoder code. Maybe this is causing the inconsistent behaviour between users. The code wants to default to PIL.Image, but may fallback to Image. I don't know what provides Image.

try:
    from PIL import Image
except ImportError:
    import Image

Here's how that plays out in my mediagoblin environment.

(mediagoblin-dev)mediagoblin@goblinrefuge ~/mediagoblin-dev $ python2
Python 2.7.11 (default, Dec  6 2015, 15:43:46)
[GCC 5.2.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import PIL.Image
>>> 
>>> PIL.Image.frombytes('RGB', (640, 480), 'buffer')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/srv/mediagoblin/mediagoblin-dev/lib/python2.7/site-packages/PIL/Image.py", line 2047, in frombytes
    im.frombytes(data, decoder_name, args)
  File "/srv/mediagoblin/mediagoblin-dev/lib/python2.7/site-packages/PIL/Image.py", line 731, in frombytes
    raise ValueError("not enough image data")
ValueError: not enough image data
>>> 
>>> PIL.Image.fromstring('RGB', (640, 480), 'buffer')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/srv/mediagoblin/mediagoblin-dev/lib/python2.7/site-packages/PIL/Image.py", line 2053, in fromstring
    "Please call frombytes() instead.")
Exception: fromstring() has been removed. Please call frombytes() instead.
>>> 
>>> import Image
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named Image

[ayleph]

I can confirm that the same behaviour is exhibited in Pillow=3.1.0, which is the latest available on ​PyPI.

And to confirm that my mediagoblin environment is using my local Pillow install instead of some system PIL package, I removed Pillow.

(mediagoblin)~/mediagoblin-dev $ pip uninstall pillow
...
Proceed (y/n)? y
  Successfully uninstalled Pillow
(mediagoblin)~/mediagoblin-dev $ python2
Python 2.7.11 (default, Dec  6 2015, 15:43:46)
[GCC 5.2.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import PIL.Image
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named PIL.Image

I recommend that you download pillow and use it instead of whatever system PIL library you have.

[jonathlela]

I agree with this solution.

However, this is not what is stated in the documentation :

​http://mediagoblin.readthedocs.org/en/stable/siteadmin/deploying.html

The documentation says to install PIL (with link to the old PIL). Pillow is never mentionned whatsoever.

As the PIL versionning seems very confusing, maybe PIL should not be mentionned in this page, and the installation process should download and install pillow by itself (if it's possible).

[Christopher Allan Webber]

See also #651. I think we can switch to Pillow pretty safely now, right?

[Ben Sturmfels]

Closing this issue, as we settled on Pillow some time back.