Feature request - Volume control

[Cascasbah]

I have noticed that there is no way to control audio in and audio out volumes on the goggles.

The feature would be useful to record good audio, especially when using external mics, and to review footage directly on the goggles.

Additionally, when using the goggles via HDMI, it can be useful to control audio levels.

[ligenxxxx]

range 0~31

[xer271]

I messed with the Line In settings a bit today. I found that the amixer cset numid=15,iface=MIXER,name='MIC2 boost AMP gain control' setting was the amp control for line in (default value of 4, range of [0,7]), and amixer cset numid=1,iface=MIXER,name='AIF1 ADC timeslot 0 volume' controlled the line in volume (default value of 160, range of [0,255].
For my mic (BY-M110), mic positioning, and voice, I had the best results with the following:
Minimum amp gain that was still enabled, as having it completely off made the snr worse, but with it higher I could make the audio clip quite easily even with the volume turned down.
amixer cset numid=15,iface=MIXER,name='MIC2 boost AMP gain control' 1
And then setting the mic volume as high as I could without clipping.
amixer cset numid=1,iface=MIXER,name='AIF1 ADC timeslot 0 volume' 155

Here are the results:
adjusting amp gain from default of 4 down to 0:

adjusting volume in increments of 5 from 160 to 140 (with gain of 1):

I think it would be quite useful if we could have a setting in the "Record Option" menu page for setting both the gain and volume for line in. Just volume would also be fine if you wanted to keep it simpler, I was able to get alright results only reducing volume, but not as good as with also reducing gain.

[xer271]

I now have results of testing my settings at an actual race:

with default settings (amp gain = 4, adc volume = 160):

with amp gain = 1, adc volume = 155:

For reference, the spikes at the beginning of both files are me yelling "ready" to the race director with goggles already down, the lower volume background noise at the beginning of each file is mostly the goggle fans, and the higher volume background noise is multiple quads in a gym. For the first file the very short spikes on the first are from sticks hitting the endpoints and flipping switches. For the second file the longer spikes are from me talking mid race, with the very short ones being from my sticks and switches.

Unfortunately I forgot to talk at a regular volume during the one pack I flew with default settings, but with my specific mic it normally clips/peaks when I speak at all above a normal, non-drone race, conversational volume.

These settings won't be correct for everyone's mic but hopefully the results show how useful this feature would be.