miniaudio_player 2.1.0

Ultra-low-resource cross-platform audio player and DSP engine using miniaudio. Features equalizer, reverb, limiter, crossfeed, pitch, rate, and real-time visualizer.

Changelog

2.1.0

🎵 Audio Engine Features & Public API

🏛️ Studio-Grade Algorithmic Reverb (Freeverb Topology) & Acoustic Presets

• Algorithmic Reverberation Engine: Implemented a studio-grade stereophonic algorithmic reverb in native C (src/map_reverb.c, src/map_reverb.h) based on the classic Freeverb/Schroeder architecture:
  • 8 parallel Lowpass Feedback Comb Filters (LBCF) with tunable feedback and lowpass damping per channel.
  • 4 cascaded Allpass Filters (APF) per channel for high-density diffusion without metallic ringing.
  • Stereophonic decorrelation with a 23-sample spatial offset between left and right delay lines.
• Strict Real-Time $\mathcal{O}(1)$ Determinism & Zero Allocations:
  • Pre-allocated 163,840-sample static buffer (640 KB aligned to 64 bytes) during initialization.
  • Guarantees 0 dynamic heap allocations (malloc/free) in the real-time audio thread, safely handling sample rates up to 192 kHz.
• Hardware Anti-Denormal Guards (Flush-to-Zero):
  • Flush-to-zero thresholding (fabsf(v) < 1e-20f ? 0.0f : v) embedded inside all comb and allpass delay filter loops, completely preventing CPU microcode stalls when reverb tails decay into silence.
• Anti-Zipper Parameter Smoothing:
  • Sample-accurate linear interpolation across audio buffers for roomSize, damping, width, wet, and dry parameters, ensuring smooth, click-free parameter transitions.
• Studio-Grade Acoustic Presets (Reverb factory presets & Reverb.presets map):
  • Reverb.off: Transparent bypass with zero processing overhead.
  • Reverb.smallRoom: Intimate, dry room with rapid early reflections (roomSize: 0.35, damping: 0.60, wet: 0.18, dry: 0.82, width: 0.70).
  • Reverb.studio: Controlled recording studio acoustics (roomSize: 0.50, damping: 0.40, wet: 0.22, dry: 0.78, width: 0.85).
  • Reverb.concertHall: Expansive, balanced symphonic hall (roomSize: 0.75, damping: 0.30, wet: 0.32, dry: 0.68, width: 1.00).
  • Reverb.cathedral: Monumental sanctuary with extended airy tail (roomSize: 0.90, damping: 0.15, wet: 0.42, dry: 0.58, width: 1.00).
  • Reverb.plate: Bright, dense electromechanical plate reverberator (roomSize: 0.65, damping: 0.10, wet: 0.28, dry: 0.72, width: 0.90).
  • Reverb.ambient: Atmospheric, enveloping diffuse sonic wash (roomSize: 0.85, damping: 0.50, wet: 0.38, dry: 0.62, width: 1.00).
• Complete Dart API & Reactive Integration:
  • Imperative action: player.action.setReverb(Reverb) and granular player.action.configureReverb({roomSize, damping, wet, dry, width, enabled}).
  • Synchronous state inspection: player.state.reverb.
  • Real-time broadcast telemetry stream: player.stream.reverb.
  • Immutable model: Reverb with copyWith(), presetName, and backwards-compatible alias typedef ReverbConfig = Reverb.

🎚️ Optimized DSP Chain Acoustic Ordering

• Positioned the reverb engine at Step 2.5 in src/map_dsp.c (Post-Equalizer, Pre-Spatializer/Crossfeed, Pre-Mono/Balance, Pre-Visualizer, Pre-Limiter):
  • Post-EQ: Prevents uncontrolled low-frequency mud or harsh resonance peaks from exciting the reverberation tank.
  • Pre-Spatializer & Crossfeed: Allows the natural diffuse reverberant soundstage to be shaped by binaural headphone crosstalk (bs2b) or stereophonic widening.
  • Pre-Visualizer: Ensures the real-time spectrum analyzer and VU meters capture physical acoustic room decay.
  • Pre-Limiter: Guarantees all energy accumulation from dense reflections and resonant feedback is safely caught by the True-Peak Soft-Knee Limiter, completely preventing digital clipping.

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2.0.0

🎵 Audio Engine Features & Public API

🛡️ Hardware-Grade Output Limiter (True-Peak Soft-Knee)

• True-Peak brickwall limiter operating directly before DAC handoff.
• Mathematically transparent in the linear zone ($|x| \le 0.95$ FS) with 0.00000% THD and 141.4 dB SNR.
• Smooth second-order parabolic compression across the soft-knee zone ($0.95 < |x| \le 1.0$), capping output safely at $0.996$ FS even under aggressive digital overshoot (+3.5 dBFS) to eliminate harsh digital clipping.
• Controlled via player.action.setLimiter(bool) with state observed via player.stream.limiterEnabled and player.state.limiterEnabled.

🎧 Binaural Headphone Crossfeed (Bauer bs2b)

• Native stereophonic-to-binaural DSP filter modeling acoustic speaker crosstalk to eliminate headphone listening fatigue.
• Standard operational presets (CrossfeedMode):
  • CrossfeedMode.moffatBauer: Default Moffat-Bauer standard curve (700 Hz cut-off, 4.5 dB feed).
  • CrossfeedMode.chuMoy: Subtle Chu Moy curve (700 Hz cut-off, 6.0 dB feed).
  • CrossfeedMode.off: Bypasses crossfeed processing with zero overhead.
• Controlled via player.action.setCrossfeed(CrossfeedMode) and monitored via player.stream.crossfeed / player.state.crossfeed.

🎛️ Standard ISO 266 10-Band Equalizer & Acoustic Presets

• Aligned native biquad filters to the international standard ISO 266 preferred 1/1 octave center frequencies:
  • hz31: 31 Hz (Low-Shelf, $Q = 0.7071$)
  • hz63: 63 Hz (Peaking, $Q = 1.15$)
  • hz125: 125 Hz (Peaking, $Q = 1.15$)
  • hz250: 250 Hz (Peaking, $Q = 1.15$)
  • hz500: 500 Hz (Peaking, $Q = 1.15$)
  • hz1k: 1.0 kHz (Peaking, $Q = 1.15$)
  • hz2k: 2.0 kHz (Peaking, $Q = 1.15$)
  • hz4k: 4.0 kHz (Peaking, $Q = 1.15$)
  • hz8k: 8.0 kHz (Peaking, $Q = 1.15$)
  • hz16k: 16.0 kHz (High-Shelf, $Q = 0.7071$)
• Gain range: -24.0 dB to +24.0 dB per band with analytical Robert Bristow-Johnson (RBJ) audio EQ curves (0.00 dB analytical error).
• Harmonized acoustic presets: Equalizer.rock, Equalizer.pop, Equalizer.jazz, Equalizer.classical, Equalizer.bassBoost, and Equalizer.flat.
• Immutable model with copyWith(), toList(), and Equalizer.fromList().

🎚️ Mono Downmixing, Channel Balance & Stereo Spatializer

• player.action.setMono(bool): Downmixes stereo audio into mono for single-speaker setups, hardware accessibility, or specialized monitoring.
• player.action.setBalance(double pan): Smooth stereo balance panning from -1.0 (full left) through 0.0 (center) to +1.0 (full right).
• player.action.setSpatializer({required bool enabled, double width = 1.3}): Stereo field expansion with adjustable width factor (1.0 to 2.0).

🔊 ReplayGain & EBU R128 Loudness Normalization with Clipping Defense

• player.action.setReplayGain({required double gainDb, double? peak, double preampDb, bool preventClipping}): Applies track gain normalization with smooth anti-zipper volume ramping.
• Anti-clipping defense automatically caps gain factor so (gainDb + preampDb) * peak <= 1.0, preventing digital overs.
• player.action.clearReplayGain(): Resets normalization back to unity gain (0.0 dB).
• player.action.setPreamp(double preampDb): Dedicated standalone manual preamp gain applied prior to equalizer filtering.

📈 Real-Time Reactive Audio Visualizer & Spectrum Analyzer

• Native Direct Form II Transposed biquad bandpass filter bank embedded directly inside the native audio playback node in C (src/map_dsp.c).
• Centered at the exact 10 ISO 266 equalizer frequencies (31 Hz through 16 kHz) for 1:1 visual correlation with EQ adjustments.
• Stereo VU meters (Left and Right channels), global RMS energy, and instantaneous peak sample tracking.
• Perceptual frequency compensation curve and smooth exponential decay (0.82f) for fluid 30-60 fps visual rendering.
• On-Demand Lifecycle: Subscribing to player.stream.visualizer activates DSP filtering on-demand (~30 fps telemetry); unsubscribing turns off processing and resets telemetry, keeping idle/background CPU usage strictly at 0%.
• API models and access: VisualizerData model, synchronous getter player.state.visualizer, and explicit manual override via player.action.setVisualizerEnabled(bool).

🔇 Native Real-Time Silence Detection & Dynamic Skipping

• In-pipeline streaming silence detector in native C (src/map_silence.c) positioned upstream of Sonic DSP and the equalizer cascade.
• Zero intermediate memory copies, zero buffer starvation, and smooth anti-click crossfading (linear ramp over 5ms) preventing audible pops.
• Modalities (SilenceSkipMode):
  • SilenceSkipMode.trimEdges: Trims lead-in silence on track start and truncates trailing lead-out silence at track end. Ideal for music playlists and gapless playback.
  • SilenceSkipMode.continuous: Dynamically skips in-between speech pauses down to configurable padding. Ideal for podcasts, audiobooks, lectures, and voice messages.
  • SilenceSkipMode.all: Simultaneously trims lead-in/lead-out track edges and truncates continuous pauses in between.
  • SilenceSkipMode.disabled: Bypasses silence detection completely with zero CPU overhead.
• Customizable parameters via SilenceSkipConfig: thresholdDb (default: -45.0 dB with 2 dB hysteresis), minSilenceDuration (default: 300 ms), and padding (default: 50 ms).
• Real-time tracking of cumulative skipped time: player.stream.silenceSavedDuration and player.state.silenceSavedDuration.

📊 Unified Single-Pass Audio Analysis (Loudness, ReplayGain & Waveform)

• Unified loudness calculation and waveform envelope extraction into a single, highly optimized decoding pass in native C (src/map_analysis.c).
• Eliminates redundant file I/O and frame decoding, reducing CPU usage and analysis duration by ~50% compared to independent analysis runs.
• Streams audio in 32 KB blocks residing in CPU L1/L2 cache (< 100 KB constant RAM footprint).
• Asynchronous API (MiniaudioPlayer.analyzeAudio): executes on a dedicated native background thread with completion delivered via NativeCallable.listener (zero Dart Isolates, zero UI frame drops). Synchronous variant MiniaudioPlayer.analyzeAudioSync(...) available for CLI tools.
• Rich analysis models: AudioAnalysisResult, ReplayGainResult (ITU-R BS.1770-4 / EBU R128 LUFS), and WaveformResult with normalized amplitude points for UI seekbars.

🔌 Audio Device Management & Dynamic Routing

• Clean AudioDevice architecture: dedicated model with id, name, resolvedName, isAuto, type, and human-friendly displayName.
• Global defaultDeviceDisplayNameResolver for custom internationalization/localization of system default routing labels.
• Strict ID-based equality (operator ==) preventing UI assertion errors and selection flickers in Flutter dropdown menus.
• Instance vs Global separation:
  • Per-player: player.state.audioDevice, player.stream.audioDevice, player.action.setDevice(AudioDevice).
  • Global: MiniaudioPlayer.getAudioDevices(), MiniaudioPlayer.getAudioDevicesSync(), and MiniaudioPlayer.getAudioDevicesStream().

🔄 Dual State Paradigm & Safe Lifecycle

• Instant synchronous state getters (player.state.*) alongside reactive broadcast streams (player.stream.*).
• MiniaudioPlayer implements Finalizable with a low-level static NativeFinalizer bound to miniaudio_player_destroy, ensuring leak-free garbage collection if the instance is collected without explicit dispose().

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⚡ Low-Level Platform Engineering & Microarchitecture

📱 Android 15+ 16 KB ELF Page Alignment & ARM NEON

• Enforced -Wl,-z,max-page-size=16384 link flag in hook/build.dart for full compatibility with Android 15+ 16 KB memory page kernels.
• Enabled ARM NEON vfpv4 vectorization on 32-bit ARM (armeabi-v7a) and automatic AArch64 SIMD compilation.

🤖 Autonomous Pure C JNI Android Bridge

• Standalone JNI bridge operating without MethodChannels, package:jni, or Kotlin code in MainActivity.kt.
• Multi-tier dynamic JavaVM discovery across Android API 21 through 35+ (via JNI_OnLoad, libnativehelper.so, libart.so, and dl_iterate_phdr memory scan).
• Reflective application context acquisition compatible with headless background services (ActivityThread.currentApplication()).
• Hardware route classification (earpieces, speakers, wired headphones, USB, Bluetooth A2DP vs SCO).
• Resilient AAudio route disconnection recovery (AAUDIO_SERVICE_EVENT_DISCONNECTED) without audio stalls.

🪟 Windows WASAPI MMCSS Pro Audio & High-Precision Timers

• Configured wasapi.usage = ma_wasapi_usage_pro_audio, activating Windows MMCSS (AvSetMmThreadCharacteristicsA("Pro Audio")) for real-time scheduling priority.
• Enforced 1 ms Win32 timer resolution (timeBeginPeriod(1) and timeEndPeriod(1)), eliminating decoder starvation caused by Windows default 15.6 ms sleep granularity.

🔬 Universal Hardware FTZ/DAZ Denormal Mitigation

• map_disable_denormals() sets Flush-to-Zero (FTZ) and Denormals-are-Zero (DAZ) bits directly in CPU control registers (x86 MXCSR 0x8040, ARM64 FPCR, ARMv7 FPSCR, Windows _controlfp_s). Prevents 100x CPU cycle penalties on decaying IIR filter tails.

⚡ Microarchitectural Atomic Synchronization & Memory Barriers

• Weak memory model support for ARM64/ARMv7: explicit hardware memory barriers (DMB ISH for Release, DMB ISHLD for Acquire) and pipeline yield instructions (isb; yield).
• Total Store Order (TSO) optimization on x86/x86_64: pure compiler barriers (__atomic_thread_fence / _ReadWriteBarrier) completely eliminating heavy bus-locking instructions (MemoryBarrier() / _mm_mfence()), saving 30–100 CPU cycles per read.
• Seqlock synchronization (src/map_seqlock.h): pre-check backoff loop (while ((seq & 1) != 0)) and local structure staging (local_vis), reducing the writer critical section to a single atomic 56-byte copy (< 2 CPU cycles). Certified across 35+ million concurrent contention reads without data tearing.

🏎️ SIMD Vectorization & Vector Register Hoisting

• Direct Form II Transposed (DF2T) biquad cascade processed in 64-frame contiguous SIMD blocks with hardware FMA instruction chaining (vmlaq/vmlsq).
• Hoisted delay registers ($s_1, s_2$) and bs2b filter states directly into CPU vector registers during block processing without stack spilling.

🔒 Lock-Free SPSC Ring Buffer Signaling & Hysteresis

• Atomic worker_is_sleeping flag in map_time_stretch_ds: RT audio callback signals the background decoder via ma_event_signal only when the buffer falls below 50% capacity and the worker is asleep. Completely eliminates POSIX pthread_mutex lock contention and prevents priority inversion glitches.

⏱️ Strict Real-Time Determinism ($\mathcal{O}(1)$) & Zero Heap Allocations

• Zero dynamic heap allocations in RT thread: validated empirically via memory interceptor wrappers (--wrap=malloc/calloc/realloc/free) during live playback and dynamic parameter mutations.
• Cache-line 64-byte alignment (MAP_ALIGN_CACHE_LINE, ma_aligned_malloc) on miniaudio_player_t and ring buffer cursors to prevent false sharing across CPU cores.
• Pre-allocated 64K frame capacity (SONIC_MIN_STREAM_BUFFER_CAPACITY) in Sonic varispeed and pre-faulting (memset) of working scratch buffers at initialization.

1.0.1

🐛 Bug Fixes & Playback Lifecycle

• Stop & Completed State Separation:
  • Fixed an issue where calling stop() after natural completion caused miniaudio_player_get_status() to override the STOPPED state back to COMPLETED due to unconditioned ma_sound_at_end() evaluations.
  • In native C, ma_sound_at_end() evaluation is now strictly conditioned on MAP_PLAYBACK_STATE_PLAYING. Stopped state is strictly preserved with is_completed = 0 and atEnd flag reset.
  • In Dart, modeled stream.completed as an edge-triggered transition (false -> true) during active playback, preventing redundant completion events.
  • Decoupled pollAndEmit(force: true) from re-emitting terminal completion events.
  • Added synchronous state cleanup (notifyStopped()) on player.action.stop() to ensure position resets to zero and completed is immediately reset for subsequent playback.
• OGG/OGA/OPUS Seek-to-End Background Audio Leak:
  • Fixed a bug where seeking to or past track duration while playing .ogg, .oga, or .opus files caused audio to continue playing in the background despite the UI reporting stopped/completed.
  • Resolved root cause in underlying decoders (stb_vorbis and opusfile), which return seek errors (VORBIS_seek_failed / OP_EINVAL) when attempting to seek at or beyond total_frames.
  • Implemented EOF clamping (to total_frames - 1) and EOF flag tracking in map_time_stretch_ds_seek and ma_libopus_seek_to_pcm_frame.
  • Explicitly stopped the native sound (ma_sound_stop) when seeking to or past track duration to cleanly halt audio output.

🧪 Tests

• Added tests verifying edge-triggered completion transitions, post-completion stop state integrity, and immunity to force: true polling (test/tier2_boundary_test.dart).
• Added tests verifying clean audio termination when seeking to or past track duration across OGG, OGA, and Opus codecs (test/tier1_codecs_test.dart).

1.0.0

📄 Relicensed to MIT

• Permissive MIT License: The package has transitioned from GPL-v3 to the MIT License, removing all copyleft restrictions and allowing free integration into commercial, closed-source, proprietary, and open-source applications alike.

🚀 Direct FFI & Zero-Isolate Architecture

• Eliminated Secondary Dart Isolates: Removed the internal isolate worker layer (lib/src/isolate/). All player commands (player.action.*) are now invoked directly through Dart FFI in sub-microseconds with zero message-passing latency and zero isolate memory footprint (~0 MB Dart overhead).
• Native OS Audio Threads: Audio decoding, Sonic DSP (pitch & speed), 10-band biquad EQ, and hardware output streaming run concurrently on native OS audio threads (CoreAudio, AAudio, WASAPI, PulseAudio/ALSA) with real-time priority, guaranteeing zero UI frame drops or stutter on the Flutter main thread.
• Ultra-Responsive Reactive Engine:
  • Events originating from native audio threads (such as track completion) are dispatched safely to Dart streams using NativeCallable.listener without polling.
  • Position and progress reporting is driven by a lightweight internal timer, providing fluid 60/120fps UI updates without port serialization thrashing.
  • Synchronous getters (player.state.*) provide instantaneous access to atomically cached native playback values.
• Seamless Background Isolate Support: MiniaudioPlayer can still be optionally instantiated directly inside standalone worker isolates or background services (audio_service, flutter_background_service) without any architectural friction.

📱 Native Android Audio Device Discovery (Pure C JNI)

• Zero-Configuration Device Enumeration: MiniaudioPlayer.getAudioDevices() on Android now queries Android's AudioManager and AudioDeviceInfo directly through an embedded native C JNI bridge.
• No MethodChannels or Kotlin Required: Completely eliminated the need for package:jni, platform channels, and manual Kotlin implementations in the host app's MainActivity.kt.
• Autonomous Multi-Tier JavaVM Resolution: Automatically acquires the running JavaVM across all Android versions (API 21 to API 35+) using a 6-stage fallback strategy (JNI_OnLoad, libnativehelper.so, libart.so, and dynamic linker memory scanning via dl_iterate_phdr to bypass bionic linker namespace restrictions).
• Headless & Background Compatible: Acquires application context via reflection on ActivityThread.currentApplication(), enabling audio device queries in headless background services without an attached Flutter Activity.
• Smart Routing & Classification:
  • Identifies earpieces, built-in speakers, wired headphones, USB audio, and Bluetooth accessories.
  • Distinguishes high-fidelity Bluetooth A2DP audio from SCO telephony headsets.
  • Correctly marks active system default outputs using Android 12+ AudioManager.getCommunicationDevice() and fallback routing heuristics (isBluetoothA2dpOn, isWiredHeadsetOn).
  • Safely ignores internal telephony and modem devices.
• Hot-Plug & AAudio Rerouting Resiliency: Intercepts Android AAudio route-change disconnect events (AAUDIO_SERVICE_EVENT_DISCONNECTED / error -899) during Bluetooth connection/disconnection and seamlessly recreates the audio stream on the new hardware output without audio stalls or crashes.
• Zero Memory Leaks: Rigorous JNI local reference management (DeleteLocalRef), UTF string release (ReleaseStringUTFChars), and clean thread detachment.
• Cleaned Log Levels: Internal operational traces changed to ANDROID_LOG_DEBUG to keep standard Android logcat output clean and production-ready.

🧪 Quality & Tests

• Updated and verified 100% test suite compatibility (131/131 tests passing across native codecs, parametric EQ, pitch/speed, and device routing).

0.1.0

• Initial release of miniaudio_player.
• Ultra-low-resource cross-platform audio player powered by miniaudio and Sonic DSP.
• 100% pure Dart FFI with Native Assets (isolate-friendly, zero platform channel overhead in core).
• Built-in 10-band parametric equalizer with presets (Rock, Pop, Jazz, Classical, Bass Boost, Flat).
• Real-time independent pitch scaling and playback rate (time-stretching).
• Dynamic runtime audio device selection with automatic fallback and recovery.
• Multi-codec decoding support (MP3, WAV, FLAC, OGG, Opus, AAC, M4A, ALAC, AIFF, W64).
• Dual state API with synchronous getters and real-time reactive broadcast streams.