5 Replies Latest reply on Jan 14, 2011 6:25 AM by RodWard

    Are there potential downsides to using the largest 1024x768 project dimension?

    videodan7

      I've got a general question about how project dimensions and file sizes affect playback of published Captivate modules.

       

      I've developed a module using Captivate 5 at 800x600 with no problems except that, for some users, the standard definition videos in the module freeze or do not play properly. Now, I'm developing new modules that will be using a lot of HD video. So, I'd like to use the extra screen real estate available with a 1024x768 project size. Does the larger size have a negative impact on users ability to access and playback modules? Is there an amount of total video in a project that could "choke" user's systems?

       

      More generally, I know modules with lots of video are dependent on reliable broadband connections but I'm unclear on any limitations I should place on the design of modules within Captivate to limit playback problems. I don't expect to be able to completely eliminate playback issues but I'd like guidance on what I can do from a design standpoint to make sure the problems aren't accentuated on my end - thanks,

        • 1. Re: Are there potential downsides to using the largest 1024x768 project dimension?
          Captiv8r Adobe Community Professional & MVP

          Hi there

           

          Generally speaking the larger the project dimensions the larger the size of the file that sits on the server and the longer it will take to download to the viewer.

           

          As for video, it is my understanding that it always exists outside the Captivate project and is delivered when needed. So from the perspective of video impacting Captivate, there may be a *PERCEIVED* issue (because the video doesn't play back cleanly) but it's not really related to Captivate.

           

          I could be mistaken on this but it is my own understanding that HD really refers more to the aspect ratio of video than overall dimensions. I have a small pocket camcorder that records in HD. There are two sizes. I can record in 720p and 1080p. That means that I get 720 pixels across or 1,080 pixels across. As you are referring to using 1024, that means that even that size won't truly accommodate your HD clip if it has been created in 1080p. And if you stick with 800x600 your typical 720p should easily fit within that area.

           

          I'm sure others will chime in with more observations and suggestions.

           

          Cheers... Rick

           

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          • 2. Re: Are there potential downsides to using the largest 1024x768 project dimension?
            videodan7 Level 1

            Thanks Rick,

             

            It sounds as if I should stay with 800x600 to avoid increasing playback issues?

             

            The source videos are actually output at 1920x1080 from my edit system. I understand that I will need to encode the HD clips to a smaller size to fit into the module no matter what project dimensions I choose. It's not only the video dimensions but the file size that is being significantly reduced while encoding. But, a larger project dimension will accommodate a larger video file particularly if the aspect ratio is closer to HD and not the 4:3 ratio of an 800x600 Captivate project. But I'm not clear on whether going bigger with both the Captivate project dimensions and the embedded flash videos will create more playback problems for users.

             

            I wasn't aware that Captivate didn't load video until its needed. I've been finding it virtually impossible to troubleshoot playback issues since there are so many variables that affect performance on the user end. I just want to find an approach that maximizes quality while being realistic about the data load I can expect to work with most of my audience - thanks,

             

            Dan

            • 3. Re: Are there potential downsides to using the largest 1024x768 project dimension?
              RodWard Adobe Community Professional & MVP

              So if you're considering going to a larger screen size for your Captivate movies, see here for more information about how to work out the right screen size: http://www.infosemantics.com.au/node/20  Bottom line is that if you're working with 1024x768 you need to set your Captivate movie to something underneath this to allow for all the browser chrome and toolbars etc.

               

              Going with a bigger video screen area will definitely have an impact on your end-user's abilities to view the content without buffering.

               

              Remember this phrase: BANDWIDTH IS EVERYTHING!!

               

              If you already have some users experiencing issues with playback of video and you're only using  a relatively small amount of video then that should be a warning to you.  Unless your target audience is currently in the process of upgrading all their bandwidth, you can expect more issues by going larger.

               

              Think of internetn bandwidth as if it were the water pipes coming into your home.  You can only get a finite amount of water to flow out of those pipes every minute because there are two limitations:  A) the physical dimensions of the pipe, and B) the water pressure. If you want more water, and you cannot change the water pressure, you have to put in bigger pipes.

               

              With most Captivate movies using text, some animation, a certain amount of graphics, and audio voiceover MP3 quality set to around 64kbps, your user will need to be able to download around 1 megabyte per minute of playing time to avoid any stop/start buffering.  As soon as you add video the picture changes.  But it changes wildly depending on the size of the video format, and the quality (related to the compression) of the video.  Good quality video in even a relatively small screen size could require at least 10 times as much bandwidth as the Captivate movie.

               

              You can easily see how much bandwidth the video will consume by dividing the length in seconds by the filesize.  So if the video plays for one minute and is 10 megabytes in size, your audience will need to have enough bandwidth to download 10 meg per minute.  You may think that sounds quite doable, because your company has a 100megabit network.  But you'll need to consider that this bandwidth is not typically all available for video.  It will be shared among many systems, and typically the IT department will have a fixed limit on the amount that can be used for video files (called 'filtering').

               

              So the bottom line here is that before you go too far down this path you should really be doing some extensive testing to determine exactly what you can get away with. Otherwise you and your clients could be very disappointed with the results.

              • 4. Re: Are there potential downsides to using the largest 1024x768 project dimension?
                videodan7 Level 1

                Thanks Rod,

                 

                I think I'd better stick with 800x600 and encode the HD video to a size appropriate for those dimensions.

                 

                I saw a Widget for Captivate on Adobe Exchange that is designed to link to YouTube videos. I've had good experiences in terms of video quality and playback using YouTube. Have you or anyone reading this post had experience with that option. The prospect of linking to YouTube is attractive to me. It would seem to potentially solve the video streaming issues.

                 

                Dan

                • 5. Re: Are there potential downsides to using the largest 1024x768 project dimension?
                  RodWard Adobe Community Professional & MVP

                  I've not used the YouTube video option so far.  I mainly create courses for corporate clients and all of them have strict limits on employees accessing YouTube.  The reason should be fairly obvious.  Some people would eat up all the company bandwidth and never do any work.  So using YouTube to deliver elearning hasn't been an option for me.

                   

                  Your mileage may differ.