How can I manage the size of media-based feedback files?

This article provides best practice guidance and considerations when uploading media-based feedback (e.g. audio or video/screencast feedback) files to the Grade Centre in Blackboard either as attached files or for streaming via Medial.

For an overview of non-media based files (e.g. Word and PowerPoint), please read the article on managing large files aimed specifically as guidance for students.

Files that exceed 250MB cannot be attached to Blackboard. Media-based files of any size up to 2GB can be uploaded as streaming media via the Medial server.

The size of existing files can be checked by:

1. PC – hovering the mouse over the name of a file to see the size of the file or rightclicking on the file and choosing Properties.

2. Mac – clicking on a file and press the Command button + i simultaneously.

This is particularly important when returning choosing options for returning media-based feedback electronically via the Blackboard Grade Centre. Some useful guidance is provided to help you make your audio and screencast/video feedback files manageable.

Audio feedback

Audio feedback commonly takes the form of a digital audio file created using a voice recorder or software such as Audacity (which is available on all SHU Managed Desktop PCs,but is also freely downloadable) and then uploaded to the Blackboard Grade Centre either as an attached file or streaming via Medial. To help keep your audio feedback files manageable:

  • Create/export your recordings as MP3 files. This will make the file sizes smaller and easier to deliver. As a rule of thumb 128Kbps are generally acceptable.
  • Create/export your recordings as mono files. This will halve the file size of a stereo file which is not necessary for these types of recordings.
  • Focus on the quality of the feedback as opposed to the quality of the recording. The recording should be coherent and pleasant to listen to.
  • Keep the feedback succinct. About five to six minutes is usually sufficient to record the key issues you want to comment on.
  • Due to its limited size, your HomeDrive (F:) may not be suitable for storing large numbers of audio files during creation or transfer to Blackboard. Refer to the IS&T guidance on the most appropriate locations to store files.
  • A 5 minute MP3 audio recorded at 128Kbps uses around 4.7mb of file space.

Screencast feedback

Screencast feedback (moving image and audio together) commonly takes the form of a video file created using screencasting software such as Screencast-O-Matic (for which the University has licences, but also freely available to create videos up to 15 minutes in length) and then uploaded to the Blackboard Grade Centre. To help keep your video files manageable:

  • Create/export your recordings as MP4 files. This will make the files smaller and easier to deliver.
  • Due to its limited size, your HomeDrive (F:) may not be suitable for storing large numbers of video files during creation or transfer to Blackboard. Refer to the IS&T guidance on the most appropriate locations to store files.
  • A 5 minute MP4 video recorded at ‘normal’ quality uses around 8.7mb of file space.
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