I got a nice email after my last entry on the various ways that vendors handle display of PowerPoint slides in their web conferencing products. They asked for a bit more detail on the subject and examples of pitfalls.
I just happen to have a convenient example at hand. I'm going to be kind and not mention the vendor with this very specific and convoluted bug. They are one of the big names in the industry. This vendor happens to have two ways to upload and convert PowerPoint files for display in a web meeting. One way converts the slides to a proprietary internal format that retains animations and slide transitions. The second method does a conversion to static graphic images.
I had a PowerPoint 2003 file that used some Autoshapes on certain slides. An Autoshape in PowerPoint is a predefined graphic element that you can resize and color. Rectangles and circles are some of the simplest Autoshapes. But there are asymmetric autoshapes like block arrows, flowchart symbols, smiley faces, stars, and much more.
On some of my slides I had placed an Autoshape, filled it with color, copied it to a new location on the slide, and used the Draw->Flip function in PowerPoint to turn the copy around. This is a convenient way to "bookend" shapes around some central text. Difficult to understand in writing, easy when you see it:
I found that after I uploaded the slides to my meeting room, some (but not all) of my flipped autoshapes had reverted to their original orientation instead of the flipped way they showed up when viewed in the PowerPoint application.
After going back and forth with Tech Support for a while and trying out a lot of test cases, we found that their conversion algorithm to the proprietary internal format didn't properly recognize the flip transformation on a shape if that shape was filled with a textured fill, an image fill, or a gradient color fill. Empty or solid color fills converted properly. Using their secondary conversion method to a static image format overcame these problems and everything converted correctly (but of course I lost all my animations).
Here's a test slide inside PowerPoint. The only difference between each set of four images is the type of fill that was used on the original shape:
And here is the same slide after uploading and conversion inside the vendor's meeting space. Note that only the solid color fill converted correctly:
This is the kind of thing that can drive you crazy at first. It seems like some of your slides work inside the web conferencing product and others don't! And if you forget which type of upload/conversion you did, you can really go nuts trying to recreate the problem.
The vendor with this bug is working on fixing it for a new release. As you can see, the requirements for reproducing the incorrect behavior are very specific and it's not surprising that it slipped through their own Q&A process. The point here is not to condemn the vendor (which is why I'm protecting their identity), but to show you how doing your own testing during your vendor selection and comparison period can save you headaches later on. Use the trial period most of them give you to see how they do with your fanciest slide presentation. And if you want to borrow my torture test file, just ask!