SUNScholar/Media Filters/5.X

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PLEASE NOTE:

  • The media filters have changed by incorporating the use of ImageMagick and Ghostscript. See the link below for details about enabling media filters.
https://wiki.duraspace.org/display/DSDOC5x/ImageMagick+Media+Filters
  • After a while we noticed our server load increasing radically when doing the nightly media-filter jobs.
  • We isolated the problem to the "Branded Preview JPEG" filter.
  • This filter has been disabled as these branded previews are not important to us.

Step 1 - Install the Ubuntu software packages

Type the following: 

sudo apt-get install imagemagick ghostscript

Step 2 - Configuration

Check the value for thumbnail.maxwidth and that it corresponds to the size you want for preview images for the UI.

Edit the "dspace.cfg" file. 

nano $HOME/source/dspace/config/dspace.cfg

Search for the following and modify. 

# maximum width and height of generated thumbnails
thumbnail.maxwidth  = 160
thumbnail.maxheight = 160

Filters

Enable filters as follows: 

#Names of the enabled MediaFilter or FormatFilter plugins
filter.plugins = PDF Text Extractor, HTML Text Extractor, Word Text Extractor, \
                 PowerPoint Text Extractor, \
                 Branded Preview JPEG, \
                 ImageMagick Image Thumbnail, ImageMagick PDF Thumbnail

Names

Assign names for filters as follows: 

#Assign 'human-understandable' names to each filter
plugin.named.org.dspace.app.mediafilter.FormatFilter = \
  org.dspace.app.mediafilter.PDFFilter = PDF Text Extractor, \
  org.dspace.app.mediafilter.HTMLFilter = HTML Text Extractor, \
  org.dspace.app.mediafilter.WordFilter = Word Text Extractor, \
  org.dspace.app.mediafilter.PowerPointFilter = PowerPoint Text Extractor, \
  org.dspace.app.mediafilter.BrandedPreviewJPEGFilter = Branded Preview JPEG, \
  org.dspace.app.mediafilter.ImageMagickImageThumbnailFilter = ImageMagick Image Thumbnail, \
  org.dspace.app.mediafilter.ImageMagickPdfThumbnailFilter = ImageMagick PDF Thumbnail

Input Formats

Assign MIME file types to media filters as follows: 

#Configure each filter's input format(s)
filter.org.dspace.app.mediafilter.PDFFilter.inputFormats = Adobe PDF
filter.org.dspace.app.mediafilter.HTMLFilter.inputFormats = HTML, Text
filter.org.dspace.app.mediafilter.WordFilter.inputFormats = Microsoft Word
filter.org.dspace.app.mediafilter.PowerPointFilter.inputFormats = Microsoft Powerpoint, Microsoft Powerpoint XML
filter.org.dspace.app.mediafilter.BrandedPreviewJPEGFilter.inputFormats = BMP, GIF, JPEG, image/png
filter.org.dspace.app.mediafilter.ImageMagickImageThumbnailFilter.inputFormats = BMP, GIF, image/png, JPG, TIFF, JPEG, JPEG 2000
filter.org.dspace.app.mediafilter.ImageMagickPdfThumbnailFilter.inputFormats = Adobe PDF

Permissions

Configure media filter permissions. Search for "filter.org.dspace.app.mediafilter.publicPermission" and modify as follows: 

#Publicly accessible thumbnails of restricted content.
#List the MediaFilter name's that would get publicly accessible permissions
#Any media filters not listed will instead inherit the permissions of the parent bitstream
filter.org.dspace.app.mediafilter.publicPermission = BrandedPreviewJPEGFilter, ImageMagickImageThumbnailFilter, ImageMagickPdfThumbnailFilter

Step 3 - Rebuild DSpace

Step 4 - Test the media filers

Type the following to test. Select an item that has pdf files attached and use it as replacement for "123456789/29097". 

$HOME/bin/dspace filter-media -v -i 123456789/29097

Step 5 - Create new thumbnails

The script is configured to do 1000 items at a time only. This saves on memory and CPU time. Therefore on a large system you may need to run the script several times. Also make sure that the dspace user has full read/write access to all items in the asset store folders. 

$HOME/bin/dspace filter-media -v -f -m 1000 -p "ImageMagick PDF Thumbnail"

$HOME/bin/dspace filter-media -v -f -m 1000 -p "ImageMagick Image Thumbnail"

Step 6 - Add a daily admin task

See: http://wiki.lib.sun.ac.za/index.php/SUNScholar/Daily_Admin. Check the "filter-media" options!

References

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