CASUS saves multimedia data in the form in which it is imported. This means that images and videos are not automatically compressed. The reason for this is that only you, the author, can decide whether the substantial information from the multimedia data should be kept or not. The better the data appears on the screen, the more fun it is to study using CASUS. Loading a 100kb image from the database only takes about one second. It is not possible to upload images that are bigger than 2MB or videos that are bigger than 10MB! In order to reach a compromise between the quality of the image and the time it takes to load, we have put together some advice based on our experience. If you have any comments or suggestions, we would be more than happy to include these on this advice page.

Compression compatibility can be determined while you are recording. In general:

• Choose a simple, uniform background
• Make sure you have good lighting and try to avoid back lighting
• Pay attention to the display window
• Choose the best available recording quality

More specifically for videos:

• Use a tripod
• Try to achieve optimal sound quality (avoid background noises, choose a high quality microphone, etc.)

Generally speaking, the finished product is never as good as what you see on the screen. Ideally, you should test and optimize the entire productive procedure, from recording to presenting, in CASUS.

Experience has shown us that it may be necessary to renew certain patient or lab images (original findings to histology, technical tests, etc.). You can do so by making new slides, which can then be used by a slide scanner. It is also possible to take digital pictures and to edit these accordingly (re-scale, cut, crop, etc.). We recommend using Adobe Photoshop® to edit digital pictures.

• Compression: When uploading images please be aware of their size. Image files should not exceed 150kb, so as not to overload the server and to keep loading time down to a minimum. JPEG, gif or png are accepted image file types. As a rule, it should be sufficient to choose a quality level between 8 and 10. Please avoid the function “calculating the picture bigger”. We recommend that you save a back-up copy of the original image, in order to be able to re-use it again.

• Appropriate formats are:
  • 320×240 Pixel: Small image, which is not meant to be enlarged
  • 640×480 Pixel: Standard size image on multimedia cards (without text or questions) and which can be enlarged using the magnifying glass icon.
    
    By using these sizes, you will maintain the best quality for your images.

Video sequences can be recorded in any available format, preferably using a digital camera. The size of the video file should be compatible with the capabilities of the server and network. Video playing time should be kept under two minutes, to avoid a decrease in motivation and attention among players.

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

More tips:

• A 150MB video should have a maximum of 1MB after compression
• The ideal size for video files that are 30-80MB is 300-500kb (it is possible!)
• As a reference, keep in mind how long it takes to play a 300kb video with a 56k modem
• Ideal: 10 second movie, 20MB original size, 180kb compressed (it works!)

Auscultation sounds, for example, should be made available in digital form (sound storage medium). The same format and compression rules for videos also apply for sound files.

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