Synchronisation Led and song

[patator100]

Hello

i have successfully managed to play 2 mp3 files (spiffs storage) successively combined with LEDs movements (multithread). Unfortunately, the opening and closing of these 800ms long file is too slow for my application. After hours and hours of search, I have no idea on how to speed up the closing/opening of the files without having issues. I m currently using delay(100) in my code to be able to play both file successfully without any cutting but then synchronization with my backward and forward movement of my leds is off.

any idea ?
Thanks