I have the same use case/requirement and have taken also your example (as well as the original source of your example) and facing the same problem. Only the second input GPIO 12 is working.
I also have not yet understdood what need to be implemented twice to measure two frequencies.
I found this ...

Hi, very good code, thanks a lot.
I have the same question as it was asked around 3 times but I have not found an answer/response to that questions: I also need to measure two frequencies at the same time. Is it possible to use two input pins or what need to be doubled or is it possible at all? A ...

I'm also looking for a precise frequency measurement of a digital IO for up to 10kHz with an accuracy below 1Hz. Could you share your final solution? BTW I need also to calculate the standard deviation of the pulses. Not sure if a simple HW pulse counter is sufficient then or if I anyhow need to ...

I'm using a very similar code already in Arduino Studio. It should more or less work 1:1. Main function code needs to go to setup().

I have another very important question to the experts here:
I need a sine wave which shall sweep from 400Hz to 10kHz with 1Hz steps. The cosine works almost nicely ...

will the 3.3.x API also been available for Arduino Studio and when can we expect it?
I also have this issue and I'm working with Arduino Studio.

I need a high precison sine tone sweep generator (200 to 8000Hz at least) and I found a working solution using the CW generator.
I used this source: https://github.com/krzychb/dac-cosine
Now I found your hint, that I should not go the the internal DAC directly but via the I2S.
That is axcatly ...

I have also purchased 4 ESP32 audio boards (LyraT and ESP31-A1S Audio Kits from AI) with the idea to have local speech recognition for at least 20 commands.
Unfortunatly we get only a hadnfull useless Chineese Words. So it is totally useless outside China.
It would only makes sense if a handfull ...