Graphical Diff of PowerPoint Presentations

Question

I made a powerpoint presentation which I sent to my boss who made changes to the format so it matched presentation policy. I am just curious as to what he changed and was wondering if there was a tool to find all the differences between two PowerPoint Presentations and highlight them.

Answer 1

If you have a graphics program that can subtract images or do a layer with a subtraction blend mode, use that. Photoshop or Paint Shop Pro are two examples, and the GIMP probably works too.

Unfortunately it doesn't work directly with Powerpoint files, you have to save each page as a graphic file.

Answer 2

You can easily compare whole pdf files.

For this simply export both presentations as pdf-files. Now you can compare both pdf files with any pdf comparison tool.

I would suggest diffpdf (free, open source, Windows, Linux, Mac). For more information see http://www.qtrac.eu/diffpdf.html. Other tools are listed here: How to compare the differences between two PDF files on Windows?

Answer 3

Check out DiffDoc, that might give you what you need.

Answer 4

Modern tools make this surprisingly easy, if both files have the same play length:

1. In PowerPoint 2013, say File > Export > Create a Video for each version of the presentation. (PP2010 can do this, too.)

2. Open one of them in Photoshop CS6 or higher. It will appear on a layer, in a video group.

3. In the Layers panel, add another group from the panel menu.

4. In the Timeline, click the little filmstrip icon and say Add Media, which will let you select the second presentation's video file. It will get added to the layer group you just created.

   By using two separate groups instead of putting both video files into the same group, you can stack them on the timeline so they play simultaneously. Video files within the same group play one after another, which isn't what we want.

5. Back in the Layers panel, change the upper video group's blend mode from Normal to Difference. This subtracts its pixel values from that of the lower group.

6. Play the video directly from the timeline. If it stays black the whole way through, the two presentations are identical. Where they differ, you will get a kind of reverse image of the differences.

You can do substantially the same thing in After Effects, and probably in a lot of video editing packages.

I chose this way because Photoshop is commonly found in a lot of the same places PowerPoint is, and it shows off the video editing features that recently (CS6) made their way from the Extended version of Photoshop ($$$) to the regular version ($$).