[Product-Developers] Re: Capture still image from video/automatically assign P4A file image

Tom Gross itconsense at gmail.com
Wed Sep 23 06:51:26 UTC 2009

Hi Brayton,

  p4a-video uses the File-content-type, which again uses OFS.File as
content-class. If you want to access the raw-data use:




If you need a file-like object, you have to do:

stream = StringIO(str(atfileobject.getFile()))


Brayton Osgood wrote:
> I'm trying to extend P4A Video to automatically generate the file images
> that can be added to each video via the edit panel of any IVideoEnhanced
> content. Ideally, the result will be an adapter (I think) that responds
> to the IVideoEnhanced interface.
> Right now I'm running into trouble capturing an image from a video file
> once it's stored in Plone. I've tried calling ffmpeg as a subprocess,
> but I get an I/O error (see below):
>>>> image = subprocess.Popen('ffmpeg -i moviefile -ss 1 -an -vframes 1
> -f image2 thumb%2d.jpg', shell=True, stdin=subprocess.PIPE,
> stdout=subprocess.PIPE, stderr=subprocess.STDOUT, close_fds=True)
>>>> print image.stdout.read()
> FFmpeg version SVN-rUNKNOWN, Copyright (c) 2000-2007 Fabrice Bellard, et
> al.
>   configuration: --enable-gpl --enable-pp --enable-swscaler
> --enable-pthreads --enable-libvorbis --enable-libtheora --enable-libogg
> --     enable-libgsm --enable-dc1394 --disable-debug --enable-shared
> --prefix=/usr
>   libavutil version: 1d.49.3.0
>   libavcodec version: 1d.51.38.0
>   libavformat version: 1d.51.10.0
>   built on Mar 16 2009 21:19:49, gcc: 4.2.4 (Ubuntu 4.2.4-1ubuntu3)
> moviefile: I/O error occured
> Usually that means that input file is truncated and/or corrupted.
> I've tried doing this where 'moviefile' is an <ATFile at
> /Plone/Members/brayt/jumping2.mov> object, a <p4a.video _ATCTFileVideo>
> object (applying the IVideo interface to the ATFile), and even the
> binary data (passed by moviefile.getData()). Each case gives me the same
> error.
> I suspect this is because ffmpeg expects to receive certain file types,
> and Plone files are somehow wrapped so they aren't recognized. I guess
> my question may boil down to how do I access (and do something useful
> with) the data in a file that's not normally read by Plone? I suspect
> that the indexing of PDFs behaves similarly to what I'm hoping to do,
> but I haven't quite figured out how that works.
> Any help would be greatly appreciated!
> Thanks much,
> Brayton

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