Technical advices for setting up multimedia materia

The CASUS system saves the multimedia data in the form in which you import it into the program. This means that your pictures and movies are not automatically compressed. The reason for this is that only you as the author can decide if the substantial information of the multimedia data should be kept or not. The more fluently the data appears on the screen the more fun it is to study with CASUS. Loading a 100 kb image from the database only takes about one second. It is not possible to upload images bigger than 2 MB or movies of more than 10 MB! In order to reach a compromise between the quality of the picture and the time taken to load it, we have put together some advices based on our experience. We would be pleased to hear any comments or suggestions of yours on this subject.

Already when recording the data, you can be aware of compression compatibility. In general:

  • Choose a background which is as uniform as possible
  • Make sure you have good lighting and avoid a back light
  • Pay attention to the display window
  • Choose the best available recording quality

Especially for movies:

  • Use a tripod
  • Achieve the optimal sound quality (be aware of background noises, choose a high quality microphone)

Generally the finished product is not as good as that seen on the camera screen. It would be ideal to test and optimize the whole productive procedure in CASUS just once from the recording to the presentation.

Images

We assume that you can use some pictures from your store of slides. Experience has shown us though, that it is necessary to renew the illustrations from the patient in the case (original findings to histology, technical tests etc.). It is easiest to make new slides, which can then be further used by means of a slide scanner. Digital cameras are now cheaper to buy than before, and they save the need to scan the pictures. When adapting pictures (re-scaling, cutting out details,…), we recommend for example Adobe Photoshop®

  • Compression: When setting up pictures please be aware of their size. Picture files should not be bigger than 150 kb, so as not to unnecessarily overload the network and to keep the loading time down to a minimum. JPEG, gif or png are the accepted file types. As a rule it should be sufficient to choose the quality level 8 to 10. Avoid “calculating the picture bigger”. We recommend that you save a safety copy of the picture in its original form, in order to be able to make out cuts at a later date.
  • Appropriate formats are:
    • 320×240: small size when the picture should not be able to be enlarged
    • 640×480 Pixel, standard size on multimedia cards (without text or question), respectively a size which can be enlarged using the magnifying glass symbol.

      By using these sizes, you will maintain the best quality for your pictures.

Videos

Video sequences can be recorded in any available format, preferably with a digital camera. The size of the film should be made compatible to the capabilities of the server and network. But playing time of more than 2 minutes per card should be avoided due to motivation reasons.

To play videos and audio sequences Apple Quick Time Version 4 or higher is neccessary. You can download Apple Quick Time for free from Apple.

Some clues:

  • A movie which was 150 MB, should be maximum 1 MB after compression!
  • The ideal size for movies of 30-80 MB: 300-500 kb (it is possible!)
  • Never forget how long it takes to play a movie of 300 kb with a 56k modem!
  • Super-ideal: 10 second movie, 20 MB original size, 180 KB compressed (it works!).

Sound

E.g. auscultation sounds should be made available in a digital form as far as possible (sound storage medium). Format and Compression: Same as for movies.

Text

Text can be written outside of the CASUS authoring system. You can then incorporate the written text into the intended fields in the editor with copy and paste. Problems can occur when using special characters. The most reliable procedure is to type the text directly into the authoring system.


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