Hi,
My code that controls the speed of the video can also work with audio. Attached is a version of the code, where I changed out the JavaScript call of document.querySelectorAll('video') to document.querySelectorAll('audio') in the control buttons, and this seemed to work.
Like before, you have to sum up ALL the audio bits in the entire Storyline file, then set the variable "numberOfVideos" (I didn't change the name but you can if you want - probably "numberOfAudios" might make sense if you don't mind a little grammatical ugliness) to that summed number. For example, if you have 15 slides, all with a single audio layer, you need to set this number to 15. [It's really a constant & never changes value — Storyline doesn't allow for constants per se, nor arrays (grrrrr.)]
This isn't as nice as Matt's code using GSAP, but it does have the benefit of being a little more universal. I'm just wary of Articulate perhaps dropping GSAP like they did jQuery.
This code will still make the Seek bar fall out of sync with the audio playback, but perhaps you could use the play media triggers, and not use the player timeline. It all kind of depends if you really want to tie the audio to the slide timeline. If that's not a big deal, you could drop the Seek bar, use the Play Media trigger, and then put up an animated GIF (see attached) in the corner to inform the view that an indeterminate-length audio bit is playing back - then make it disappear when the audio is done playing. This approach is a little less intrusive IMO if you have a long audio monolog, which we have unfortunately many times in our courses.
HTH,
Mark