How to use '.on' events when using .exec?

[rzfzr]

Hello,
I wrote all my code using

const video = youtube(url...
video.on('error',...  
video.on('data',...

Now I'm migrating to .exec because as somebody figured out I also notice much much longer download times when specifying the video format inside the constructor, when compared to .exec
But the .on gave errors
Of course error, end, complete all resolve into the exec's callback, allright, but there is no info for when download starts and data for progress checking.
I had a lot of logic inside info....
Thanks for the help