Production builds should not include debug assertions. ALSA's assert()
calls cause aborts when internal invariants are violated, even for
recoverable error conditions.
The crash occurred when snd_pcm_close() was called with a NULL pointer,
triggering assertion failure at pcm.c:779 instead of graceful error
handling.
Stack trace:
pcm.c:779: snd_pcm_close: Assertion `pcm' failed
SIGABRT in jetkvm_audio_capture_init()
Adding -DNDEBUG disables all assert() calls in ALSA, Opus, and SpeexDSP
libraries for production robustness.
We use direct hw: device access with SpeexDSP for resampling, so the
ALSA plugin layer (plug) and rate conversion plugin are not needed.
This reduces library size while maintaining all required functionality.
Replace ALSA plugin layer resampling with libspeexdsp for improved audio
quality and reliability. This implementation uses direct hardware access
(hw:) instead of ALSA plugins (plughw:) and handles sample rate conversion
with SpeexDSP's high-quality sinc-based resampler.
Key changes:
- Add libspeexdsp 1.2.1 with ARM NEON optimizations to build dependencies
- Switch from plughw: to hw: device access for lower latency
- Implement conditional resampling (only when hardware rate ≠ 48kHz)
- Use SPEEX_RESAMPLER_QUALITY_DESKTOP for high-quality interpolation
- Add automatic audio dependency building in dev_deploy.sh
Quality improvements:
- Fix race condition in resampler cleanup with mutex protection
- Fix memory leak on resampler re-initialization
- Add buffer overflow validation (3840 frame limit for 192kHz)
- Improve error logging for resampling, encoding, and ALSA configuration
- Simplify code structure while maintaining all functionality
Technical details:
- Hardware negotiates actual sample rate (e.g., HDMI may vary)
- SpeexDSP converts hardware rate → 48kHz for Opus encoding
- USB Audio Gadget hardcoded to 48kHz (no resampling overhead)
- Static buffer allocation for zero allocation in hot path
- WebRTC requires 48kHz RTP clock rate per RFC 7587
Changes the audio subsystem from hw: (direct hardware access) to plughw:
(plugin layer with rate conversion) to enable configurable sample rates.
Changes:
- Update ALSA build to include plug,rate,linear,copy plugins
- Change device names from hw: to plughw: in C and Go code
- Remove 48kHz hardcoding for HDMI audio output
- Keep USB at 48kHz since hardware is fixed at that rate
- Update all comments to reflect plughw usage
Technical details:
- hw: devices bypass all ALSA plugins and require exact hardware rate match
- plughw: devices enable the ALSA plugin layer for automatic rate conversion
- Hardware still receives at native rate (48kHz), resampling happens in userspace
- HDMI can now use 8k/12k/16k/24k/48kHz, USB remains at 48kHz
- NEON-optimized resampling provides good performance on Cortex-A7
Requires rebuilding ALSA library with updated plugin configuration.
- Replace helper function in getAudioConfig with explicit validation
- Consolidate audio default application in LoadConfig
- Streamline relay retry logic with inline conditions
- Extract closeFile and openHidFile helpers in USB gadget
- Simplify setPendingInputTrack pointer handling
- Improve error handling clarity in startAudio and updateUsbRelatedConfig
- Clean up processInputPacket mutex usage
Integrated latest dev branch changes including:
- Native process refactoring with gRPC architecture
- OTA update system refactor with new component-based updates
- Updated build system and dependencies
- UI improvements and bug fixes
Post-merge fixes applied:
- Remove duplicate OTA RPC function declarations (now in ota.go)
- Fix GetDefaultEDID reference to use native.DefaultEDID constant
- Fix IsUpdatePending to use otaState.IsUpdatePending() method
- Add missing OTA RPC handler registrations for new update system
All audio functionality from feat/audio-support preserved.
All dev branch functionality preserved.
- Resolved conflicts in .gitignore, ActionBar, UsbDeviceSetting, and devices.$id.tsx
- Added audio-related translations to all language files:
- action_bar_audio
- usb_device_enable_audio_title
- usb_device_enable_audio_description
- usb_device_keyboard_mouse_mass_storage_and_audio
- Updated UI components to use localization messages
- Added separate USB preset for keyboard/mouse/storage without audio
- Kept OPUS_STEREO_PARAMS import from audio branch
- Preserved AudioPopover component from audio branch
Alex P
Aveline
Alex
Marc Brooks
Alex Goodkind
Techno Tim
Brandon Tuttle