"OK... make your project clearer. Presumably you want to synchronise fader movements to an audio playback.."
^ yes 100% correct. I would like to start with one fader to get the programming started and eventually move on to many more faders.
"Does the audio source have a timecode embedded in it ? Like the old SMPTE track of a muti-track tape machine?"
To make things easier I would like to assume it is an old tape machine. I say this because obviously these old consoles that linked to tape machines are still in use by many people.
"If so you have to find what that code is and synchronise to it. There's nothing magic about SMPTE. Look it up!"
I listened to this and tried. it's in the previous post.
"If not you have to synchronise your audio playback and fader movements - perhaps by starting them together and doing your own timing within the arduino. And for editing, go to a pre-defined point eg 34.45 seconds into the track .... not so easy if the audio and timing are disconnected, as you may have to go back to the beginning to get the sychronisation accurate - pain in the neck if a CD stream, much easier if it's a file. That's eg a PC job - no arduino can handle files that big. Arguably the whole job would be better handled with a PC rather than involve an arduino. I bet there are applications you can buy to do this."
I don't think we will have to do this since previous LTC will be available.
I need to add that usually in professional videography the LTC is in the metadata on the audio file, in this cause I think since the sounds are usually recorded into the DAW, the timecode is made by the software and then linked to the entire session. Before starting any modern recording session with even mildly professional software you need to choose a bit depth and sample rate. I generally use 32 bit float for bit depth and 192kHz for my sample rate. I'm purely guessing that my MOTU AD/DA that handles the bit depth and sample rate generates the oldschool LTC no matter what sample rate or bit depth I choose. I might be able to confirm this with the product support team.
"What is your audio source? can you go back/ forward a specific time? To a specific point?"
Yes to all of this question. My audio source is from the MOTU HD 192 as far as the fader movements should be concerned and the LTC will sync with it.