Powerpoint, audio, and packaging…

This is a post about how to take conference audio and add it to a powerpoint presentation to give you a self-contained package you can give out. It took me a while to figure out how to do this effectively, so I’m hoping this will help others.

But, since I’m all about the story, there’s a bit of background first. If you just want to understand the mechanics of how to do it, scroll down until you see “Mechanics”.

Earlier this year I did a presentation (with Lowell Meyer) for the Microsoft Connected Health Conference, entitled “Practical HealthVault: Challenges and Opportunities”.

The goal of the deck was to cover the things that are different and/or confusing about HealthVault – the things that we’ve answered over and over in the past couple of years. We wanted to come out with something that we could give to people who were new to HealthVault (anybody from the technical side, be they developer or manager) and therefore make our lives easier. And – which will come as no surprise to those who have seen me speak – I was interested in the adulation of my fans.

In both writing and presenting, I’m a big fan of progressive revelation, where you start simple and build things up. For this talk, that meant a lot of custom animations in powerpoint. A *lot* of custom animations in powerpoint. Five of my slides have more custom animation steps than will fit in the custom animation box on the side.

We had a company doing video production for the conference, and a few weeks after our presentation (which was a lot of fun – I always forget how much I enjoy presenting), the video showed up.

It consists of a lot of mostly-dark shots of us presenting, cutting back and forth with the slides. If they happen to be showing the slides when the animation happens, things generally work okay, but at times they showed the design view. And the resolution is what you get with video, which isn’t great.

What I want is a narrated presentation, so I set out to do that.


1. Pulling the audio off of the video

For this I used AoA Audio Extractor, which gave me 155 MB MP3 file.

2. Editing the audio

For editing the audio, I used Audacity, which is pretty darn nice. My one caveat is that with the version I have, you can’t perform any operations on the audio if the audio is paused. So, you have to hit “stop” on the transport controls and then do a trim/cut/export/whatever.

If you just took that whole audio track and put it on a powerpoint presentation, it would work fine at the beginning but would get out of sync on some machines. To prevent this from happening, we need to use per-slide audio.

It’s also true that working with a 90-minute track is not a lot of fun, so breaking it up will help in that realm as well.

I started by going though the audio track and putting labels on all of the slide breaks. This support is there to break albums up into songs, but it works very well for this as well. I had the presentation open on another monitor so I could reference it during the audio. Name the labels “Slide<x>”, where <x> is the number of the slide. Make sure to put one at the beginning for the start of the presentation.

Once you have the labels, you choose “File->Export multiple”, and it creates individual .wav files for each slide.

At that point I walked through all the slides and did some judicious editing. This is a bottomless pit of time consumption if you let it, so I tried to just pull out the things that were distracting where it was simple to do so. I also highly recommend adding 5 seconds of silence at the end of each slide’s audio – I didn’t do this initially and had to go back and re-edit all of them.

3. Conversion to lossy format

Audicity gave me files in .wav format, which are a bit wasteful in size. I download Lame and converted them into .mp3s. You can use the encoder of your choice (the list of formats that PP supports is here); I used lame because it’s what my home system runs on and is very simple to use from the command-line.

4. Adding the audio to your presentation

The following steps are all manual – if you have powerpoint 2010 (which has a macro recorder) and/or want to write some macros, you may be able to automate it. I just suffered doing it by hand in PP 2007.

  1. Select the slide
  2. Pick the insert tab
  3. Click on the sound icon
  4. Pick the appropriate audio file for the slide.
  5. Choose “automatic” when it asks you if it should start playing automatically.
  6. Drag the sound icon someplace that isn’t too annoying.
  7. In the custom-animation tab, drag the audio to the top of the list
  8. Right click on the audio, choose “Timing”, and then set “repeat” to “until end of slide”. If you don’t do this, the audio will only play until you hit the spacebar to start your animation.
  9. Repeat this 4000 times for the rest of your slides.

At this point, you should be able to start the slideshow and have your audio start playing.

5. Recording the animation timings

For some reason that is not apparent to me, powerpoint calls this “rehearsing” the timings. And by default, it only supports it for the whole presentation, and there’s no (obvious) way to do it for a single slide.

However, my mad search-fu led to a workaround. When you rehearse the timings, it only does it for the slides that are visible, so you can hide all the slides but one and rehearse the timings only for that slide.

Here’s the progression:

  1. Hide all the slides
  2. Unhide the one you want to record the timings for.
  3. On the slideshow page, make sure “use rehearsed timings” is not checked.
  4. Choose “rehearse timings”
  5. Listen to your audio and hit the spacebar at the appropriate point to run the animation.
  6. When your audio is done, wait a couple of seconds and hit pause on the rehearse controls, then close the window.
  7. PP should ask you if you want to save the timings. You do.
  8. Repeat for each slide.

You may find that you need to slightly modify your animations – some of mine seemed to change the “1” elements to “0” elements so they showed up too early. I think this happened when I added the audio to the slides.

The 5 seconds of silence is critical here. If not, you get to step 6, and your audio will start to repeat.

We had a few slides with 2 minutes of presentation and 10 minutes of questions. If you have this, stop the recording when the animation is done, and accept the timings. Then go to the Animations tab – on the right side you will see “advance slide automatically after” and a time. Look at the length of the audio for that slide (any player will tell you that), and set the value to 2 seconds shorter than that. That will put the advance right in the middle of the silent section you added.

6. Polish

At this point, you may need to polish the animation on certain slides. You may have to go back and redo some audio.

7. Publish

At this point you will want to publish the presentation. My plan is to just use PP’s publish to folder functionality, though there are also ways to publish to video if you are willing to deal with the loss in resolution. Publish to HD video might be worthwhile, but it would be pretty big, and right now the publish to folder is about 80MB in size.