When encoding (or re-encoding) MP3 files to use with the slideshow, there are two settings which will come up: the sample rate and the bitrate.    The Flash Player has inherent limitations which must be followed to ensure that the audio plays correctly.    The most common issue is with the sample rate.    The preferred sample rate is 44100 Hz, but 96000, 22050 and 11025 Hz are all supported.    Failing to use a supported sample rate will result in the audio playing back at a distorted speed, often described as "chipmunks."

You can use any bitrate for the MP3 as long as it is constant; variable bitrates are not supported.    A lower bitrate corresponds to smaller file size and faster download times, but reduces quality.    A higher bitrate produces higher quality, but takes longer to load.    The best bitrate depends on your situation and the type of audio you're using.

If you need to convert your audio to MP3 format or re-encode it, we recommend a freeware program called Switch.  It can be downloaded for free from: http://www.nch.com.au/switch/ .    Switch is compatible with both Mac and Windows.