I have libreelec alpha 7.90 on my odroid-C2 with the odroid bluetooth dongle connected to my Bluetooth headset. When it sends audio to the headset I hear a lot of background noise/static as if the gain was up too high. But my headset doesn't have a gain control or A/V buttons for remote volume control. If I lower the volume using KODI or pulseaudio's command line tool, it doesn't lower the background noise, it just lowers the volume of sounds that come from KODI.
I tried a couple headsets and they all have this issue. I also tried connecting my headsets to my android phone to see if I get the same problem with android, and my findings were interesting. Initially when connected, the background noise was there, however when I adjusted the volume on my phone, the noise faded to acceptable levels.
I believe the problem is in how the volume is being controlled, or more specifically, in what part of the process the volume is controlled. It seems Android controls the volume at the end-point in the headset, whereas KODI/Pulseaudio only controls the volume of the stream mix going into the Bluetooth connection, putting the actual headset device at maximum volume all the time.I don't really know where to look to fix this. I tried messing around with bluetoothctl to no avail.
Does anyone know of a way to fix this (by using libreelec to control the volume of the actual headset)?
