alan
b93327dc26
The daemon now requests the Bluetooth headset profile itself (pactl set-card-profile) the moment a take starts, instead of waiting for WirePlumber to notice the stream and run its switch timer. The microphone link comes up 0.15-0.18 s after the key instead of 0.21-0.27 s; WirePlumber still restores A2DP when the stream goes away. First real audio is now at 0.82-0.86 s, which is the headset's own floor. When the plugin is updated while the daemon runs, the daemon sees its source change, exits with code 4 once idle, and the shell service relaunches it without counting that as a crash. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Xoc9DJCViR7dg9eKzzAcfQ
55 lines
2.9 KiB
Markdown
55 lines
2.9 KiB
Markdown
# How we cut Bluetooth microphone startup time
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Measured on a Sony WH-1000XM5 over an Intel AX210, PipeWire 1.6.8, WirePlumber
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0.5.17, kernel 7.2.3. Times are after the dictation key press.
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| | before | after |
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|---|---|---|
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| mic link (eSCO) up | 0.7–1.0 s, sometimes never | 0.15–0.18 s |
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| first real audio at the daemon | 1.5–1.7 s, or never | 0.82–0.86 s |
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| "Listening" in the bar | 2.1 s on a timer, even with no audio | 0.86–0.94 s, only on real audio |
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"After" is with the daemon recording straight from `bluez_input.<addr>`; via
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`camera-effects-mic` add ~0.25 s (its 250 ms poll and processing).
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## What changed
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| Change | Where it lives | Gain |
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|---|---|---|
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| Daemon indicator: green on real audio only (RMS > 0.0005 or three consecutive non-silent chunks), no timer | `daemon/sttd.py` | the bar cannot claim to listen to a dead mic |
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| Daemon asks for the headset profile itself at capture start (`pactl set-card-profile`), before WirePlumber notices the stream | `daemon/sttd.py` | link up ~0.1 s sooner (0.21–0.27 s → 0.15–0.18 s); WirePlumber still restores A2DP |
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| Record from `bluez_input.<addr>` instead of `camera-effects-mic` | `~/.config/speech-to-text/config.json` | ~0.25 s sooner, no noise suppression on dictation |
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| WirePlumber profile-switch timeout 500 ms → 50 ms | `~/.local/share/wireplumber/scripts/device/autoswitch-bluetooth-profile.lua` | link up ~0.45 s sooner |
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| A2DP auto-connect rule narrowed to the XM5 | `~/.config/wireplumber/wireplumber.conf.d/bluetooth-a2dp-autoconnect.conf` | no 5 s pages of absent devices at login |
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| btusb driver patch `0002` | `/usr/lib/modules/<kernel>/updates/btusb.ko` | mic link no longer comes up silent when a page overlaps it |
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| PipeWire bluez5 patches `0001` + `0003` | `~/.local/lib/spa-0.2/bluez5/` via `SPA_PLUGIN_DIR` drop-ins | no stale-error dead takes; back-to-back takes work |
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Only the first two rows are part of this repo. The rest are machine-level and are
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described, with patches and measurements, in [HANDOFF.md](HANDOFF.md).
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## Why ~0.85 s is the floor
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```
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key press
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0.00 s ─┬─ daemon asks for the headset profile, starts pw-record
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│
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0.07 s ─┼─ eSCO connect() reaches the kernel
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│ headset leaves sniff mode, radio sets up the link
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0.16 s ─┼─ eSCO link up
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│
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│ headset sends encoded digital silence while its own
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│ mic path starts and mSBC syncs: ~0.6 s
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│ (measured at the decoder; Linux cannot shorten it)
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│
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0.80 s ─┼─ first non-zero samples leave the headset
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│ decode + 50 ms chunking
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0.85 s ─┴─ first real audio reaches the daemon
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```
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Nothing measurable is left on the Linux side.
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The headset's silence after link-up and the eSCO setup are hardware. Words
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spoken in the first ~0.9 s are lost unless the microphone is already in
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hands-free mode, which drops playback to mono, so it is off by default
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(`warmMic`).
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