Instantaneous Frequency from a certain IMF code

Hello everyone,

I want to use the instantaneous frequency distribustions as a feature for audio classification. I have seen the entries for extracting the IF in MATLAb, but my problem is that I do not know how to compute and use the IFs to generate my feature vector. To be more specific, I need the instantaneous frequencies from the 3rd IMF of my audio file. and I do not know how I can determine that I only want IFs from the 3rd IMF.

Thanks in advance