I like to embed a lot of videos in my iBooks Author projects. These videos can often push the size of my iBooks up to an unacceptable size. One way I get around this is to create YouTube widgets in a program like Hype or using a web service like Bookry. However, this means students must have in internet connection to view the videos. Requiring the internet can sometimes be a problem which is why I like to try to include full videos when possible.
Magic Move Transition to move a cursor from one location on the screen to another, or to highlight a a particular item. Then all I need is a voice over.
Currently audio files will not autoplay on the iPad, but videos will. So in-order to add a voiceover I need to add in a video. Now this seems like it might be a bit counter productive as I was trying to not add a video in the first place. The video I make for this is tiny, consisting of only a solid background and recorded audio. I make these using Quicktime. Simply select "New Screen Recording" from the "File" menu and then drag a rectangle over a plain white portion of your screen when prompted. I discussed using a video for a voiceover in my video on Tara Maynard's Interactive Math Practice Widget.
You can see some examples of my finished video replacements in an iBook on using Google Drive in education I made for my school last summer. The content is slightly outdated now, but you can still see how I used Keynote to replace screencasts. In this iBook I didn't use a single video nor HTML5 widget.
I should note that videos playing in a Keynote widget will not have video controls, so there is no way to pause them nor replay them. With this in mind I'd recommend adding linked buttons to replay a slide as well as buttons to go forward or back as needed. The replay button was not something I added to the Keynotes in my book, but I will in the future.
I wouldn't replace all of my screencast videos but I will be using Keynote more and more in the future to replace videos. One of the things I like about replacing videos with Keynote is you can easily have playback require student input to progress. This is important for two reasons. First is the student is more likely to pay attention if they have to click to continue and secondarily the passes can give time for reflection or note taking.