Well it's not very complex but it's not as easy to set up as a regular beat meter either. If you can't stand looking at some math or few lines of somewhat-code, feel free to skip over this :)
In short it goes like this:
This is what the meter composition looks like:
It's made of big (middle) indicator that grows according to beats audio and small indicators that move (or rather - appear to move).
The key to all this is the ability to convert audio to numeric values (keyframes) and then tie it to specific layer property such as scale (for the middle one that grows) or opacity for the small ones (more on this later). To do that, all you need to do is to select the beat audio (without music) and go to Animation->Keyframe Assistant->Convert Audio to Keyframes (or rightclick the beat audio and find Keyframe Assistant there). This will cause a new layer to appear which has a keyframe in each time frame with a value that literally corresponds to how loud the beat audio is at that moment. It'll look something like this:
Depending on how loud you exported the beats those values will be higher or lower. For me they're in range of about 0-20. At this point all you need to do is tie this to some value of a layer. For example - i want the middle indicator to go to 130% scale when there's a beat and then go back down to 100%. The way you tie some layer property to a value is using
expressions. To tie a layer property to another value you Alt+leftclick on the stopwatch next to the property. This will open up expression editor where you type in your expression:
In case of the scale changes from 100 to 130 when the beat happens, the expression is the following:
https://pastebin.com/pxYTTY4D
The first line retrieves the value from the keyframed audio layer (in my case - "BPMTool Audio Keyframes") and assigns it to variable v. Next line takes that value and linearily converts it from range 0-10 (I assume that audio above value of 10 is a valid beat) and converts it to range 100-130. Last line assigns the result value to x and y scale. That way we get the middle indicator pulsing accordingly to beats.
You repeat the process with the small ones except this time you tie it to opacity. The effect we want to achieve is the dot appearing for a single frame when there's a beat and disappearing after that until the next beat happens. However, it's not as simple as in the previous case, because if you simply applied the formula above (in range 0-100%) to opacity, you'd get your dot appearing and then slowly fading. The reason for that is that the beat audio doesn't instantly go up above given falue (in my case - 10) and then instantly goes to 0. Instead, it slowly fades. Therefore the expression in this case is as follows:
https://pastebin.com/Lrv1TJ0q
It looks at given audio frame value and the one before. If current is above threshold and previous is not (meaning we're just at the start of the beat) it sets the opacity to 100, otherwise it's 0. If it sounds a bit confusing to you - it's fine, just copy paste it, it works.
At this point we have a single small beat blinking for one frame every time a new beat happens.
What can you do with that though? Well, all that's left is setting them in a row one next to another and shifting them in time by one frame. It'll look something like this (I've disabled the opacity expression in the screenshot so that you can see exactly what I mean):
As you can see, there's multiple duplicates of the same layer (which inside has the opacity set to mentioned expression) that are shifted in time by 1 frame - make sure it's 1 frame, otherwise it'll be blinking. At the same time, the layers are also separated in x position (first layer on the screenshot being the right-most one). The further apart you put them, the faster they'll appear to move. The effect should be the following - at given time when a beat happens, one layer blinks (opacity set to 100%) while others remain at 0%. Next frame that layer has its opacity set to 0 and next one (which is 1 frame later in time) appears. This gives an illusion of moving beats, while in fact all they do is appear and disappear.
At this point you're done. Just put all together: small and big beat comps, add music with beats audio, add video, captions and all the good stuff.
As I've said, it's not as easy. But you asked, so in case you're motivated, you should know how to do it now :)
