Captivate Audio Output Settings Comparison – Part One – Encoding Bitrate

I’ve been wanting to do this for a few years but have never had the time. Goal: determine exactly what the optimal audio output settings in Captivate are for voiceover audio, which is 99% of the audio I use in Captivate (and I could care less if background/intro music is not fm quality!). I’m currently working on a project in which I really need to keep file size down, and after searching for a definitive audio settings comparison chart on this topic I couldn’t find one…so, here goes.

Comparison Details

While I’m no scientist, I think I adhered to a logical way of approaching this. I of course used the same machine to publish each clip, I used the same exact .cp file for each file (I simply went into the Publish window’s Audio settings and decreased the encoding bitrate, then double-clicked on the single text caption in the movie (residing on the first slide (of two) and set to display throughout project), and then published.

For the audio file, I used the same audio clip that I got from a public domain audio book website. I simply downloaded the full clip, in .ogg format, from the page above and then opened in Audacity to export the first 8 to 10 seconds of it. I exported to .wav format. I of course used the same exact audio file for each published output (again – I used the same exact .cp file repeatedly for each test).

Here are the results for you to compare with your ears:

And, the file sizes:

Captivate Audio Settings File Size Comparison

No, the 16 and 24 bit version filesizes being higher than the higher-quality ones is not a typo. At first I was so surprised that I went and re-checked and re-published. So basically from what I can see there is no point in ever going below 32kbps as you’re gaining filesize and losing quality.

Where I’ll Go From Here

Obviously encoding bitrate is just one of the 3 parameters that can be configured, with the other two being encoding frequency and encoding speed. I will be following this post with some new tests that compare those settings. Eventually, I hope to compile a definitive table and a final recommendation for exactly what settings in Captivate deliver the absolute best ‘value’ in terms of filesize-to-quality ratio. Keep in mind that I am concerned strictly with voiceover audio. I would assume that is what anyone else would care about when it comes to Captivate as well.

Please leave a comment if you have suggestions, or know of an unbiased, definitive comparison that perhaps I missed in my search, or if you have any tips for how I should approach the next batch of tests.

UPDATE: I’ve continued on with the testing. Here is a link to Part Two.