During a voip call, the volume (the audio I hear, not the volume bar) keeps going up and down. This strange phenomenon is most noticeable when the android volume bar is under ~3/4 from maximum. The variation diminishes when I set the volume bar above ~3/4 from maximum. I observe this behavior, when I use my Teracube. When I use my Moto E5 Play with the manufacturer’s Android, I do not have this problem.
I tested using both Linphone and Jami. They both have that issue in Teracube.
I don’t know if this has anything to do with this problem but the Linphone shows that in Teracube, the input/output audio devices are AAudio, while in Moto E5 Play they are OpenSLES.
What should I do to fix the fluctuating volume?
Where should I look to gain more understanding about this issue?
I really couldn’t say at this point. There are literally dozens upon dozens of VoIP troubleshooting articles out there covering everything from mobile to PBX stuff.
Lots of good info with a lot to consider and check (bandwidth, latency, router QoS, firewalls, VPNs, codecs, etc).
As far as the input/output audio devices, not sure that’s a factor. Linphone is on all my devices. The two Motos (G5 Plus and G5s Plus) only offer openSLES or the deprecated ANDROID SND. The other three devices, including the Teracube, default to AAudio but can be changed. I guess you could change it to match your Moto to see if it helps.
I have not actually tested call quality because I have no one to call.
Guess I’ll take the phones to work and have my coworkers help me test.
Anyway, the fluctuating volume may fall under the jitter category issue. Though usually descibed as broken or intermittent audio, one article did mention volume going up and down as a symptom.
Both my Teracube and my Moto E5 Play were tested using the same network, the same Linphone version, the same voip server. I test with, without vpn. The voip service support asked me to change codec in Linphone, but it did not solve the problem.
I thought it was a Linphone problem, but when I tested with Jami and the builtin android sip, I also had the same problem.
Here is what I did to reproduce the problem on Teracube:
Test 1
Do: Open Linphone
Do: Call echo test, (voip.ms is 4443)
Do: Set android volume to maximum with the hardware buttons
Do: Wait for the recorded voice to finish spelling the instructions if any
Do: Say AAAAAAAAA for as long as you can.
Result: The AAAAA is echoed back clearly audible with minimal clipping but very acceptable
Test 2
Do: Open Linphone
Do: Call echo test, (voip.ms is 4443)
Do: Set android volume to between 1/2 and 3/4 with the hardware buttons
Do: Wait for the recorded voice to finish spelling the instructions if any
Do: Say AAAAAAAAA for as long as you can.
Result: The AAAAAAAA is echoed back clearly audible for 2-3 seconds and then the volume (auditory) of the AAAAAAA becomes very low.
Do: Stop saying AAAAAAAA.
Do: Say AAAAAAAAA for as long as you can.
Result: The AAAAAAAA is echoed back clearly audible for 2-3 seconds and then the volume (auditory) of the AAAAAAA becomes very low.
Did a test myself with a few devices and the Teracube.
I don’t know what to make of the volume drop. I’ll do the long vowel test back and forth. The other devices will exhibit a slight drop but still workable. On the T2e the volume drops quickly and almost inaudible.
Also noticed it only happens with (not so) long connected notes. Recited the alphabet, both quickly and slowly. No problem with volume. If I sort of sing the alphabet with connected notes then the volume will drop. Deeee Eeeee F without a glottal stop is when the volume just goes almost silent.
Even the ole “Rain In Spain” will come out differently depending on if I use distinct words or lazy connecting words.
But then nothing is consistent. The volume drop didn’t seem so severe between two Android 11 devices as between 11 (T2e) and the others (Android 7, 8, 10)
I seriously don’t have a clue as to why the Teracube behaves this way or to what can be done to fix it.
I was wondering if the problem also occurs when using Teracube with their stock firmware. If it is still a problem with the stock firmware, we can seek help upstream.
I am not familiar with the inner workings of android and its boot process so I am hesitant to flash their stock firmware for the purpose of a test.
Any updates on this? I’m having the same problem when I make calls through the Signal app. Is there anything I can try to fix this? Is there any expectation that this bug will be fixed? What would be a reasonable timeframe to expect? Thank you!