Escalating RX latency

setup: server = 1.65 on ubuntu 22 , client = 1.64 on pop-os 22.04
rx codec: opus 1ch — tx codec: LPCM 1ch 16bit

I see in the status bar at the bottom of wfview client that the RX latency stays at about 120 to 140ms and then after 3 or 4 minutes of using the client it creeps up to 500, then 1000 and then stays roughly at 3300ms and never recovers.

I had pings going between client and server and they stay about 2ms to 6ms. always.

Whats causing the increasing latency? If i click “Disconnect from radio” on the client and then “Connect to Radio” then the problem goes away for awhile but might reappear after 5 to 10 mins

PS: The Shuttle Pro V2 is working great!! thank you

I have personally not seen the rise in latency issue, although it has been reported here before.

Have you tried the Opus codec, and also, have you tried each of the three audio systems (RT, QT, and Port)? Remember to disconnect, change the audio parameters, and then re-connect.

Also what do you have your latency sliders set to in the user interface?

de W6EL

“Have you tried the Opus…”

Yes, I have Opus 1ch for the RX, and LPCM 1ch 16bit for the TX codec

Sliders: RX Latency: 110ms TX Latency : 130ms

Which of the three audio systems are you using? You may wish to vary both the server side and the client side (server side interacts with the radio’s USB audio source).

BTW what is the radio model?

de W6EL

Why are you using Opus for RX and LPCM for TX? I would use Opus for both.

The different audio systems are the most important. I would use Qt if possible on both server and client, but try PA and RT to see if that makes any difference.


Creeping latency is also an indication that the server just can’t keep up, what server hardware are you using?

Elliott: I’m using pulse. rig is IC7300

Phil see below
server : Dell Precision M4400 laptop
client: Dell XPS 13 laptop


Please try RT Audio and Qt Audio, on both client and server sides. Make sure to disconnect from the server before changing both sides.

Also as Phil mentioned, use the same codec for both Tx and Rx. Sometimes Opus is higher CPU usage, but on the other hand, Opus is much more tolerant of network glitches.

I would also set your sample rate to 16 khz, but you can try higher and lower.

de W6EL

I have it stabilized sort of. On the client I’m using PortAudio and the LPCM codecs for both TX and RX.
Latency stays around 250ms which is borderline OK. It can and sometimes does exceed 500ms. At which point I just disconnect and reconnect client and that usually fixes it.

I’ve had similar issues as I posted on below link.
I cured it by running Qtaudio in both ends. Now it stays on 120mS, give or take 10mS, all the time.
I run Windows 11 on a decent PC. i3/i5. Dont remember what generation. But about 7 years old.

Latency build up over hours and days - Bugs - wfview