2 Replies Latest reply: Dec 11, 2010 10:53 PM by BalletMom RSS

    Slow Playback in LMS

    BalletMom Community Member

      I use Captivate 5 for Mac. I am teaching a course in Blackboard CE8 (what used to be called WebCT) that uses a lot of Captivate presentations. Originally we did them as SCORM, but there were a number of issues, so we re-did them as just regular SWF/HTML, no SCORM reporting, quizzes using the quiz tool of the LMS rather than art of the Captivate presenation. Now students are all able to access the presentations, but some do not have the patience to wait for the playback to start. I recently timed it at a 5-minute wait for a 12-slide 15-minute presentation to begin. All files are in the content manager (file storage system) of the course. The presentations were all created from imported PowerPoint, with audio recorded in PowerPoint or Captivate. The presentations are from 6 to 25 slides long.

       

      What suggestions do people have for improving playback?

        • 1. Re: Slow Playback in LMS
          RodWard CommunityMVP

          From your description it sounds like the heaviest part of your presentation is likely to be your audio file.

          12-15 slides isn't a lot of filesize, but 15 minutes of audio could mean your students need to download about 10 megs or more.

           

          What quality settings do you have your audio set for output?  Is it higher than 64bit?

          What preloader settings are you using?  Have you tried using a 25% preloader?  This would mean that students begin seeing content after only downloading 2 or 3 meg of the total.

           

          If download times are still prohibitively high you'll need to establish the actual bandwidgth your students have.  It's not going to be as high as you might think because it will be shared.   For this task I recommend a software tool called Charles:  http://www.charlesproxy.com/download/

           

          It's shareware. Get a student complaining about slow downloads to install this and then watch what happens when they try to access the course. Charles will tell you exactly what the download speed was.

          • 2. Re: Slow Playback in LMS
            BalletMom Community Member

            Thanks, those are all good things to think about. The audio is definitely huge. We are going for a little higher quality, a bitrate of 96, but I can take it down and see if students notice a difference. The preload is 100%. I will see what kind of a trade-off I can get between faster starts and not having pauses in playback.