https://bugs.kde.org/show_bug.cgi?id=513536
Rob Emery <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] Status|CONFIRMED |NEEDSINFO Resolution|--- |WORKSFORME --- Comment #37 from Rob Emery <[email protected]> --- (In reply to TSUKUMO Akito from comment #0) > Summary: > KDE Connect Bluetooth backend causes audio crackling/stuttering in Bluetooth > headset (A2DP) under PipeWire > > Description: > After updating to KDE Connect 25.12.0-1 on EndeavourOS (Arch Linux-based, > KDE Plasma 6.5.4), enabling the Bluetooth backend in KDE Connect settings > causes severe audio crackling and stuttering when playing audio through a > Bluetooth headset (Sony WH-1000XM4) using A2DP profile with AAC codec in > PipeWire. The same issue occurs with the two previous versions, 25.11.80 and > 25.11.90. > > The issue did not occur with the previous version (KDE Connect 25.08.3-2). > Downgrading to 25.08.3-2 resolves the problem completely while keeping the > Bluetooth backend enabled. > > Symptoms: > - Audio starts normally for a few seconds, then crackling persists for an > extended period (cycle of normal → heavy crackling → normal). > - The issue occurs only when the Bluetooth backend is enabled in KDE Connect > settings (Backends → Bluetooth checked). > - Disabling the Bluetooth backend immediately resolves the crackling (audio > becomes stable, though other KDE Connect features over Wi-Fi remain > functional). > - Switching to SBC codec reduces crackling but degrades sound quality > significantly. > - No issues with HSP/HFP profiles (mono, low quality). > > Workaround: > - Disabling the Bluetooth backend in KDE Connect GUI (Settings > Backends > > uncheck Bluetooth) or setting disabled_providers=BluetoothLinkProvider in > ~/.config/kdeconnect/config fully resolves the issue while keeping the > latest KDE Connect version. > - Downgrading KDE Connect to 25.08.3-2 allows using the Bluetooth backend > without issues. > > This behavior resembles Bug 415976 (KDE Connect increasing Bluetooth buffer > size leading to laggy sound in PulseAudio), but occurs in a modern PipeWire > environment. It appears the Bluetooth backend interferes with PipeWire's > Bluetooth audio buffering or scheduling. > > Steps to Reproduce: > 1. Update to KDE Connect 25.12.0-1 on EndeavourOS/Arch Linux with PipeWire. > 2. Pair a Bluetooth headset (e.g., Sony WH-1000XM4) and set A2DP Sink with > AAC codec. > 3. Open KDE Connect settings → Backends → Enable Bluetooth. > 4. Play audio (e.g., music or video). > 5. Observe crackling after a few seconds. > 6. Disable Bluetooth backend → Crackling stops immediately. > > Environment: > - OS: EndeavourOS (up to date as of December 2025) > - KDE Plasma Version: 6.5.4 > - KDE Frameworks Version: 6.21.0 > - Qt Version: 6.10.1 > - KDE Connect: 25.12.0-1 > - Audio server: PipeWire (with WirePlumber) > - Bluetooth headset: Sony WH-1000XM4 (firmware up to date) > - Codec: AAC (default/high priority) > > Additional Information: > - No relevant errors in journalctl for PipeWire/WirePlumber/Bluetooth during > the issue. > - Tested multiple buffer/quantum adjustments in PipeWire – no effect when > Bluetooth backend is enabled. > - Issue started after KDE Applications update to 25.12.0. > > This significantly impacts usability for users relying on high-quality > Bluetooth audio. A fix to prevent the Bluetooth backend from interfering > with A2DP audio buffering would be appreciated. Thanks for the report, although I am unable to reproduce using the AAC profile on my tumbleweed laptop using a realtek bluetooth 5.3 dongle (Bus 003 Device 002: ID 0bda:a729 Realtek Semiconductor Corp. Bluetooth 5.3 Radio). `bluetoothctl show` shows `Version: 0x0a (10)` for me and not experiencing any lag/crackling listening to music using AAC profile on my SoundPeat T3's? I'm wondering if it's linked to a slightly tighter bandwidth window on older versions. I know that I can't use AAC on my old Bluetooth 4.2 laptop at all, it'll basically never sync at all. Can you confirm the version of bluetooth that you're seeing the issue with? -- You are receiving this mail because: You are watching all bug changes.
