SUNScholar/Media Filters/5.X

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  • The media filters have changed by incorporating the use of ImageMagick and Ghostscript. See the link below for details about enabling 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

Edit the "dspace.cfg" file.

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


Search for following and change to true: = true = true
webui.preview.enabled = true


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

Search for the following and modify.

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


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


Assign names for filters as follows:

#Assign 'human-understandable' names to each filter = \ = PDF Text Extractor, \ = HTML Text Extractor, \ = Word Text Extractor, \ = PowerPoint Text Extractor, \ = Branded Preview JPEG, \ = ImageMagick Image Thumbnail, \ = ImageMagick PDF Thumbnail

Input Formats

Assign MIME file types to media filters as follows:

#Configure each filter's input format(s) = Adobe PDF = HTML, Text = Microsoft Word = Microsoft Powerpoint, Microsoft Powerpoint XML = BMP, GIF, JPEG, image/png = BMP, GIF, image/png, JPG, TIFF, JPEG, JPEG 2000 = Adobe PDF


Configure media filter permissions. Search for "" 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 = BrandedPreviewJPEGFilter, ImageMagickImageThumbnailFilter, ImageMagickPdfThumbnailFilter

List Emphasis

Search for xmlui.theme.mirage.item-list.emphasis. There are two options available namely "metadata" or "file", select "file".

See example below.

### Settings for Item lists in Mirage theme ###
# What should the emphasis be in the display of item lists?
# Possible values : 'file', 'metadata'. If your repository is
# used mainly for scientific papers 'metadata' is probably the
# best way. If you have a lot of images and other files 'file'
# will be the best starting point
# (metdata is the default value if this option is not specified)
xmlui.theme.mirage.item-list.emphasis = file

Save the "dspace.cfg" file and exit nano.

NANO Editor Help
CTL+O = Save the file and then press Enter
CTL+X = Exit "nano"
CTL+K = Delete line
CTL+U = Undelete line
CTL+W = Search for %%string%%
CTL+\ = Search for %%string%% and replace with $$string$$
CTL+C = Show line numbers

More info =

Step 4 - Rebuild DSpace

Step 5 - 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 6 - 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 7 - Add a daily admin task

See: Check the "filter-media" options!