https://bugs.kde.org/show_bug.cgi?id=513536
--- Comment #39 from Martin <[email protected]> --- (In reply to Rob Emery from comment #37) > (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? For me it is Bluetooth 4.2 -- You are receiving this mail because: You are watching all bug changes.
