If you are getting zeros, the most probably cause is it's the library for the IR. Reinstall or update the library. Sometimes you have to reinstall more than one time. That should work.
About media keys, the keyboard library doesn't have media keys functionality, so you need to use another one. This one worked for me: https://github.com/NicoHood/HID
After you install this library, you have to change your code. The code for pressing media keys is different. You have to use Consumer.write, for example, Consumer.write(MEDIA_VOLUME_UP) for volume up. You can find the name of every key here: https://github.com/NicoHood/HID/wiki/Consumer-API
For normal keys, just use Keyboard.write(). If you want, I can send you the code I made to do this.
