1. Oasis works with TV and Airpods
1) If you use TV optical output, then the TV volume setting is FIXED, your can neither increase it nor lower it via TV remote control. And also you can't adjust the volume by volume's button on Oasis. Airpods doesn't have volume button. So the volume can not adjust.
2) If you use TV AUX/3.5mm output, you can adjust the volume either via TV remote control or short press Oasis +/- button.
3). If you use TV RCA OUTPUT, then you may or may not use the TV remote control to adjust the volume, it depends on your TV. Some TV support this function, while some TV does not. You can adjust the volume either via short press Oasis +/- button.
2.Oasis works with PC and Airpods
If you use PC AUX/3.5mm output, you can adjust the volume either on PC or short press Oasis +/- button.