Using Streaming MP3 for PowerPoint Narration

Use Internet Explorer 5 or higher to view embedded Windows Media Video tutorials linked from this page.

One of the problems that arise when people narrate PowerPoints and post them online is that they often either forget or don't know how to compress their audio. This can be a big problem, since by default, PowerPoint records audio at CD quality in a non-streaming format. This can make for unreasonable upload and download times.

I've created a simple 5-slide PowerPoint presentation. It is the introdutory section of a hypothetical tutorial using screenshots and narrative text. Your assignment is to record and embed MP3 narration into the presentation, then save and upload it in html format. The MP3 audio will stream automatically from the LRS and COE servers.


1. Download the PowerPoint file.

Right click this link and choose "Save Target As" or "Save Link As" from the popup menu. Save the file "LaunchWord.ppt" to your hard drive.

If you're on a Mac, hold down the mouse button on this link until a popup menu appears. Choose "Save Target As" or "Save Link As" from the popup menu. Save the file "LaunchWord.ppt" to your hard drive.

Internet Explorer
Nestscape Navigator

 

2. Record Five Narrative Audio Files & Convert to MP3

A big apology to the Mac folks for my delay on a supplemental tutorial. I've posted a QuickTime for Mac-specific info here.

a. Launch Sound Recorder.

If you're on a Mac, follow this alternative tutorial to for recording your voice to AIFF format on your computer.

b. Prepare Sound Recorder to record sound at 44.100kHz, 16 bit, Mono. (Here's how.)

c. Practice recording and playing back your voice.
You should adjust your microphone volume settings until you have a good range of motion in the volume meter, as you see in the animation to the right.

d. Once you have adjusted your volume settings, delete any test audio you've recorded. To do that, move the position slider all the way to the left. From the 'Edit' menu, select 'Delete after current position'. You should now be able to record onto a "blank slate".

e. To begin recording, click the Record button. Speak the narrative text for slide 1:
"In this module, you will learn to use Microsoft Word’s Envelope wizard to address and print envelopes." When finished, click the stop button.

f. When you are satisfied that the narration quality is good enough, convert it to MP3 format at 24kBits/sec, 22,050 Hz, Mono. (Here's how.) (Note: If you don't have the MPEG Layer 3 codec available in Sound Recorder, you'll have to install the latest version of Windows Media Player. Sorry about that.)

g. Continue using Sound Recorder to make a total of 5 mp3 files. Remember, each time you record a new file, record in high quality PCM format as described in step 2B. Then convert to low quality MP3 as described in step 2f.

File Name Narrative Text
slide01.mp3 In this module, you will learn to use Microsoft Word’s Envelope wizard to address and print envelopes.
slide02.mp3 To begin, you will need to launch Microsoft Word if it is not already running.
slide03.mp3 From the File menu, select New.
slide04.mp3 At the top of New Documents dialog box, select the Letters & Faxes tab.
slide05.mp3 Select the Envelope Wizard icon, and click the OK button.

h. Upload the 5 mp3 files to your student account.

 

3. Create five M3U metafiles to prepare MP3s for streaming.

What's a metafile, and why do I need one?

A metafile sets up streaming for your media file. If you were to provide a link directly from your Web page to your media file, when a user clicked the link, the media would download in its entirety before it started to play. That's the way the Web and Web browsers were designed to work in the first place.

Since you want your media to start playing before the entire file has downloaded, you don't link directly to the media file. Rather, you link to it indirectly through a metafile. A metafile is just a text file that contains the full URL of the media file that you want to stream. Follow the instructions below to create five metafiles for each of your MP3 files.

a. Launch Notepad (as can be seen in the graphic below).

 

b. In Notepad, type the full URL for your first MP3 file that you have already uploaded to your student account. For example, if I had uploaded my first MP3 file into a folder named "narration" in my student account, I would type the following into Notepad.

If I were a CTER 3 student with a LRS account:


If I were a CTER 4 student with a College of Education account:

 

c. Save the Notepad metafile as slide01.m3u in the same folder with your PowerPoint.

 

d. Repeat this process so that you create a total of 5 m3u metafiles in Notepad.
(Quick Tip Demo)

 

 

4. Embed Five M3U Metafiles as Sound Objects in PowerPoint File

 

Follow these instructions.

If you have trouble embedding the M3U files, here are three possible solutions:

  1. Problem: M3U files don't show up in folder after publishing to HTML.
  2. Problem: PowerPoint won't let you insert M3U.
  3. Problem: Absolute path in M3U - Slow connection to Internet.

 

 

5. Save the PowerPoint as html and upload it to your student account.

 

Follow these instructions.

 

 

6. View your PowerPoint with streaming MP3 audio.

 

The final product should look and sound like this (use Internet Explorer):

http://students.ed.uiuc.edu/bertelsn/narration/LaunchWord.htm