Jitter / stuttering when on audio calls via Linux signal-desktop-beta | follow up to issue #5819

[charmingcamo]

Using a supported version?

• I have searched searched open and closed issues for duplicates.
• I am using Signal-Desktop as provided by the Signal team, not a 3rd-party package.

Overall summary

Please Note: This is not a package / build issue! I know Arch Linux is not officially supported, but I still wanted to get this out there and provide logs, help testing and get to the bottom of this to help other users.
I apologize in advance, if this is an inappropriate place to report this.
This seems similar to #5819 which went cold.

Description of the issue

• When making audio calls to other people via the Signal-Desktop app on Linux, I'm experiencing audio stutter and glitches. It sounds like a poor network connection / insufficient bandwidth.
• When using voice messages, there is no issue. Even when they are several minutes long.
• When I call back the the same person from my Android smartphone over the same connection, the problem is gone immediately. Tested with multiple people, different smartphones in different locations.
• I tested this without any active VPN or applications that could compromise bandwidth.
• I do not have the option "Always relay calls" enabled.
• I have not tested video calls in Signal (desktop). In this post, I only refer to audio calls.

Last time stamp on Signal-Desktop when the issue happened: April, 4th 2024, 11:05
-> I called the same person back via my smartphone over Signal one minute later (11:06) and had no issue.
I attached the link for debug log from Android also.

Full Debug Log (Linux desktop app)

Signal_debuglog.txt

Setup

Internet bandwidth is about 300MBit/s download, 50MBit/s upload
Arch Linux, 6.6.24-1-lts
Gnome Desktop + Wayland
Memory: 64GB
AMD Ryzen 7 7040 Series

Steps to reproduce

1. Call a contact over the Signal-Desktop app or receive a call over the Signal-Desktop app on Linux.
2. Listen back to the called party: Jitter / stutter will occur.

Expected result

Clear audio communication without interruptions, given a there is a stable and fast internet connection.

Actual result

Jitter and stutter when the called party speaks as if the connection wasn't stable or too slow (although speed tests say otherwise).

Screenshots

No response

Signal version

7.5.0 beta1

Operating system

Arch Linux (6.6.24-lts)

Version of Signal on your phone

7.3.0

Link to debug log

https://debuglogs.org/android/7.3.0/dc1e53e9d608609e488d1dd67b1df9feac6937c05453f4668e3d0490d84d8aa8

[trevor-signal]

Hi @charmingcamo, thanks for the report and sorry for this issue. It looks like on Desktop we're seeing 20-50% packet loss on incoming audio which would explain the poor quality. From the Android logs it looks like the calls were connected over a cellular network -- do you mind double-checking for us that both devices were connected to the same network?

[charmingcamo]

Hi @trevor-signal ,

my apologies for the delay on my end; I've fallen ill and it's been quite a few rough days.

Anyways, yes I can confirm that this was in the same network, because I've used the hot spot of my phone (5G network) for the laptop which I used to make the first call. I disabled the VPN for both calls to ensure, this is not a factor.

I can perform more tests with other connections (and especially WiFi and/or Ethernet) at the end of this week or beginning of the next week. I will post updates here, as soon as I have news.

Cheers