Using FLV video with alpha and audio

Nov 26, 2012

When inserting an swf animation with audio and an alpha channel, the audio has an "echo" as if there were 2 audio tracks running at the same time.  I cannot figure out where I can fix this.  There are no other audio tracks running.  This is only apparent when previewing or publishing.

5 Replies
Christine Hendrickson

Good morning Manny. Welcome to E-Learning Heroes!

First, you might want to make sure that the presentation name doesn't contain any special characters. You should also ensure that the publish path does not contain special characters. In certain cases a presentation whose title contains accents or special characters will create two published output folders and the audio will overlap.

Are you using PowerPoint 2007, by any chance? If you are using PowerPoint 2007, you may also need to verify that the text boxes and other objects on the affected slide(s) are not named with special characters.

Here's how: 

1. Open your presentation in PowerPoint 2007, and navigate to the slide where this issue occurs or begins. 
2. Select the Home tab on the PowerPoint toolbar (ribbon). 
3. Click on the Select drop-down list (in the Editing group), and choose Selection Pane. 
4. In the Selection Pane, double-click the names of the shapes that contain special characters (e.g., accent marks, asterisks, quotation marks, etc.), and rename them with alpha-numeric characters only. 
5. Save your presentation, and republish it. 

Note that PowerPoint versions prior to 2007 do not include the Selection Pane feature. 

If this issue persists, create a new folder on your desktop, and republish your presentation to the new folder. Sometimes, when you republish projects to the same folder over and over, the contents do not update properly.

If you've checked all of the information I listed above and your audio still sounds like it has an echo, please let us know. Thanks!

Manny Wrobel

I have checked everything over as you have suggested above.  It appears that the audio problems start when we try to stop and/or start the slide using the "start/pause-backward/forward" control buttons.  If you pause the slide using the controls, the audio will continue to play (in Preview mode) but the animation stops.  When the slide is stopped and then started again from the beginning, the echo happens.  It's as if there are 2 separate media players going at the same time.  I have also checked the Articulate audio editor to make sure there are no audio files on the timeline in there.

Christine Hendrickson

Hi Manny,

Thanks for getting back to me. Would you mind submitting a support case, so we can take a closer look at what's happening with the audio? If you can, please create a Presenter Package and include it in your case. This will give our tech team access to the files, which will remain confidential, and we'll be able to test the audio and see what's causing the echo. You can also refer to this forum thread in your case, so our support team can see what steps you've already taken to troubleshoot the issue.

Also, if you do create a case, please share the case number with me. I'd like to follow the progress and update this thread when we find a resolution, just in case any other community members experience the same problem. 

Thanks, Manny!

I hope you have a great evening.

Christine Hendrickson

Hi Manny,

Thanks for the info! I'll keep an eye on the progress of the case. If you're away for an extended amount of time, all you need to do is reply to the case email and it will re-open. It will remain on file and update with any information you send through that case email.

I hope you have a great holiday, enjoy!

Thanks again,


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