NAudio 3 is a major release. The single `NAudio` assembly is now split into focused, independently usable packages; the minimum target framework moves to `net9.0`; the core is cross-platform and Native-AOT compatible; and several large new subsystems — a cross-platform effects suite, a software sampler, VST 3 hosting, and ALSA and libsndfile backends — join the library. **Upgrading from NAudio 2?** [Migrating from NAudio 2 to NAudio 3](Docs/MigratingFromNAudio2.md) walks through every breaking change with before/after code. Most apps need only re-target to `net9.0`, rename `WaveOutEvent` to `WaveOut`, and adjust custom providers to the new `Span<T>` `Read` signature. #### Packages and platform * Minimum target framework is now `net9.0` — legacy .NET Framework and .NET Standard 2.0 support is dropped * `NAudio` is now a set of focused packages: `NAudio.Core`, `NAudio.Midi`, `NAudio.WinMM`, `NAudio.Wasapi`, `NAudio.Asio`, `NAudio.Dmo`, `NAudio.WinForms`, plus the new `NAudio.Effects` (shipped in `NAudio.Core`), `NAudio.Sampler`, `NAudio.Vst3`, `NAudio.Alsa` and `NAudio.SoundFile`. The `NAudio` meta-package still pulls the Windows stack together, so existing consumers see no change. See `Docs/Architecture/NAudio3AssemblyLayoutPlan.md` * `NAudio.Core`, `NAudio.Midi`, `NAudio.Wasapi`, `NAudio.Dmo`, `NAudio.Sampler`, `NAudio.SoundFile` and `NAudio.Alsa` are Native-AOT compatible (`IsAotCompatible=true`), enforced in CI by `NAudioAotSmokeTest` * `NAudio.Wasapi` targets plain `net9.0` (Windows-only at runtime via `[SupportedOSPlatform("windows")]`), so cross-platform apps can reference it and build on Linux/macOS without `EnableWindowsTargeting`. The WinRT MIDI backend moved to `NAudio.Midi`, which now dual-targets `net9.0;net9.0-windows10.0.19041.0` (#1384) * The `NAudio.Uap` package is removed — use `WasapiPlayerBuilder` / `WasapiRecorderBuilder` * Packages ship with SourceLink, `.snupkg` symbol packages and an embedded SPDX SBOM #### New capabilities Each new subsystem has its own tutorial or README; only the headline is listed here. * **Audio effects** — a cross-platform `NAudio.Effects` framework: `IAudioEffect` / `EffectSampleProvider` / `EffectChain` with click-free bypass, dry/wet mix and an optional parameter model, plus a broad effect set (EQ and filtering, dynamics, saturation/lo-fi, delay and modulation, reverb including FFT convolution, pitch shifting, and voice-comms AGC/noise suppression). See [Docs/AudioEffects.md](Docs/AudioEffects.md) * **Modern WASAPI** — high-level `WasapiPlayer` / `WasapiRecorder`, built via `WasapiPlayerBuilder` / `WasapiRecorderBuilder`: `IAudioClient3` low latency, MMCSS thread priority, `IAsyncDisposable`, zero-copy buffers, per-process loopback capture, automatic stream routing that follows the default endpoint (#942), acoustic-echo-cancellation reference control (#1223), communications mode, raw mode (#476), and resample-free bit-depth/channel adaptation in exclusive and low-latency modes. See [Docs/WasapiPlayer.md](Docs/WasapiPlayer.md) and [Docs/WasapiRecorder.md](Docs/WasapiRecorder.md) * **Modern ASIO** — a new `AsioDevice` replacing `AsioOut`: explicit playback/recording/duplex modes, non-contiguous channels, per-channel `Span<float>` callbacks, driver-reset recovery and per-buffer timing. `AsioOut` is preserved as a facade. See [Docs/AsioMigration.md](Docs/AsioMigration.md) * **Cross-platform audio files** — new `NAudio.SoundFile` package: read and write WAV/AIFF/FLAC/Ogg-Vorbis/Opus/MP3 via a system libsndfile on Windows, Linux and macOS (the first cross-platform FLAC/Vorbis/Opus *encoder* in NAudio). See [Docs/CrossPlatformAudioFilesWithSoundFile.md](Docs/CrossPlatformAudioFilesWithSoundFile.md) (#1289) * **Linux audio** — new `NAudio.Alsa` package: `AlsaOut` (`IWavePlayer`) and `AlsaIn` (`IWaveIn`) plus `AlsaDeviceEnumerator`, backed by `libasound`. See [Docs/PlayAudioFileLinuxAlsa.md](Docs/PlayAudioFileLinuxAlsa.md) and [Docs/RecordAudioFileLinuxAlsa.md](Docs/RecordAudioFileLinuxAlsa.md) (#1182) * **VST 3 hosting** — new `NAudio.Vst3` package (Windows-only): discover, load and host VST 3 effects and instruments, with parameters, state and `.vstpreset` presets, native editor windows, program lists/units, latency compensation, and live/offline MIDI-file playback through the shared MIDI pipeline. See the `NAudio.Vst3` README and `Docs/Architecture/Vst3Hosting.md`. VST is a registered trademark of Steinberg Media Technologies GmbH * **Software sampler** — new `NAudio.Sampler` package: polyphonic, cross-platform playback of SoundFont (`.sf2`) and SFZ instruments and single-sample instruments, rendered as an `ISampleProvider` (SF2 modulator engine, DAHDSR envelopes, LFOs, modulated filters, reverb/chorus sends, voice stealing, choke groups). See [Docs/Sampler.md](Docs/Sampler.md) * **Event-based device notifications** — `MMDeviceEnumerator.CreateNotificationClient()` returns an `MMDeviceNotificationClient` exposing `DeviceStateChanged`, `DeviceAdded`, `DeviceRemoved`, `DefaultDeviceChanged` and `PropertyValueChanged` as ordinary events, so callers no longer implement a COM interface or manage CCW lifetime (#1395) * **MIDI** — `NAudio.Midi`'s portable leg is now cross-platform; new WinRT `WinRTMidiIn` / `WinRTMidiOut` and backend-agnostic `IMidiInput` / `IMidiOutput`; and a new `IMidiInstrument` seam (`MidiFileSequence` / `SequencedMidiPlayer` / `OfflineMidiRenderer` / `LiveMidiInstrument`) giving an end-to-end MIDI-file → audio pipeline that drives the sampler or a hosted VST 3 instrument. `MidiFile` also reads RIFF-RMID (`.rmi`) files (#1236) and `MidiFile.Export` gains a `Stream` overload, thanks to @MaKiPL (#499) * **Sequencing** — a portable `NAudio.Sequencing` namespace in `NAudio.Core` (tempo and time-signature maps, transport, `EventTimeline`, swing, and a sample-accurate per-buffer dispatcher) underpinning MIDI-file playback and the sampler. See `Docs/Architecture/Sequencing.md` * **Live capture mixing** — new `NAudio.Extras` helpers `CaptureMixerInput` and `RealtimeCaptureMixer` capture and live-mix several sources with different sample rates and channel counts (e.g. microphone + system loopback) into one wall-clock-paced stream. See [Docs/MixMicrophoneAndSystemAudio.md](Docs/MixMicrophoneAndSystemAudio.md) (#761) * **Reading audio from streams** — `AudioFileReader` and `CachedSound` gain `Stream` constructors, detecting WAV/AIFF from the contents and delegating anything else to Media Foundation, so embedded or in-memory audio plays without a temp file (#927, #963). `StreamMediaFoundationReader` also gains optional `contentType` / `originName` hints and Ogg container sniffing (#952) * **WAV chunk model** — `WaveFileReader.Chunks` with an `IWaveChunkInterpreter<T>` extension point and built-in interpreters for cue lists, BWF `bext` (`BroadcastExtension`, now read *and* write, with v2 loudness) and LIST/INFO (`InfoMetadata`); `WaveFileWriter` gains `AddCue`, `WriteCueList`, `WriteBroadcastExtension`, arbitrary `AddChunk` and RF64 promotion via `WaveFileWriterOptions` (#1013) * **Latency reporting** — new `IWaveLatency` interface in `NAudio.Core` exposing `AverageLatency` / `CurrentLatency` for A/V sync and drift detection, implemented across the playback and capture classes (#601) * **Sample providers and DSP** — new `ChannelMixerSampleProvider` with ready-made `ChannelMixMatrix` routings, thanks to @antiduh (#982); a new `FftProcessor`; `Span<T>` overloads across the codec/DSP surface; reusable building blocks (`EnvelopeFollower`, `DelayLine`, `Lfo`, `Oversampler`, `LinkwitzRileyCrossover`, `PartitionedConvolver`, …); plus improvements to `SmbPitchShiftingSampleProvider` (#922), `AdsrSampleProvider` (#671) and `FadeInOutSampleProvider` (#1136) * **WaveFormatExtensible** — new constructors for SubFormat, valid-bits-per-sample and channel mask, readable `ValidBitsPerSample` / `ChannelMask`, and a `[Flags] Speakers` enum for building channel masks (#1325) * **WASAPI sessions and devices** — `AudioSessionControl.SetDuckingPreference(bool)` (#760); `WasapiPlayer` / `WasapiRecorder` expose `DeviceId` and `DeviceFriendlyName` for the active endpoint (#681) #### Breaking changes The full upgrade walkthrough — every breaking change with before/after code — is in **[Migrating from NAudio 2 to NAudio 3](Docs/MigratingFromNAudio2.md)**. The highest-impact changes: * Minimum target framework is now `net9.0` (legacy .NET Framework / .NET Standard 2.0 dropped) * `IWaveProvider.Read` / `ISampleProvider.Read` now take a single `Span<byte>` / `Span<float>` (was buffer/offset/count) — callers migrate via `source.Read(buffer.AsSpan(offset, count))`; implementations override the span method * `WaveOutEvent` is renamed to `WaveOut` and `WaveInEvent` to `WaveIn` (the old names remain as `[Obsolete]` subclasses). `WaveOut` / `WaveIn` now default to event-driven callbacks; the window-based variants are `WaveOutWindow` / `WaveInWindow` in `NAudio.WinForms`, and `WaveCallbackInfo` / `WaveCallbackStrategy` are removed * `WaveOut.DesiredLatency` is replaced by `BufferMilliseconds`, which sizes each individual buffer rather than the total across all of them. `WaveIn`'s default record format changes from 8 kHz mono to 44.1 kHz stereo * `WasapiOut`, `WasapiCapture` and `WasapiLoopbackCapture` are `[Obsolete]` in favour of `WasapiPlayer` / `WasapiRecorder` (the legacy types still ship and work); `WasapiOut`'s embedded exclusive-mode resampler was removed, though it now adapts bit depth and channels, so only a sample-rate mismatch requires upstream resampling * The low-level `IMMNotificationClient` interface and `MMDeviceEnumerator.RegisterEndpointNotificationCallback` / `UnregisterEndpointNotificationCallback` are now internal — use `CreateNotificationClient()` and its events. The raw Core Audio and Media Foundation COM interfaces are likewise internal, and `PropertyStoreProperty.Value` is now `object` rather than `PropVariant` * Some types moved package or namespace as part of the split — classic Windows MIDI I/O and `winmm` types to `NAudio.WinMM`; the DMO/DirectSound types into the new `NAudio.Dmo` package; plus smaller moves (`AudioVolumeLevel`, `CaptureState`, `DmoMp3FrameDecompressor`). Meta-package consumers are unaffected * Removed seven members that were already `[Obsolete]` throughout NAudio 2, each with a direct replacement on the same class: `WaveFileWriter.WriteData` (both overloads → `Write` / `WriteSamples`), `WaveFileReader.TryReadFloat` (→ `ReadNextSampleFrame`, which doesn't drop channels on stereo), `AcmStream.Convert(int)` (→ the overload returning `sourceBytesConverted`), `WaveFormatConversionStream.SourceToDest` / `DestToSource` (unreliable estimates with no replacement — use `Position` / `Length`), and `AsioAudioAvailableEventArgs.GetAsInterleavedSamples()` (→ the overload taking a reusable array, avoiding an allocation per ASIO callback). `AsioOut.Volume` is kept despite its obsolete notice — it's an `IWavePlayer` interface member * `AudioMediaSubtypes` moved from the `NAudio.Dmo` namespace to `NAudio.Wave`. It ships in `NAudio.Core`, so cross-platform code previously needed `using NAudio.Dmo;` to name the media subtype GUIDs even on Linux without the DMO package; it now sits alongside `WaveFormatExtensible` * `SimpleCompressorStream`, `ImpulseResponseConvolution` and `NAudio.Extras.Equalizer` were removed — superseded by `NAudio.Effects` (`CompressorEffect`, `ConvolutionReverbEffect`, `Equalizer`) * `CueWaveFileReader`, `CueWaveFileWriter`, `BwfWriter` and `BextChunkInfo` were removed, along with `WaveFileReader.ExtraChunks` / `GetChunkData` — the unified chunk model on `WaveFileReader.Chunks` and `WaveFileWriter` replaces them * `MixingWaveProvider32` was removed — it was an untested float-only mixer that offered nothing over `MixingSampleProvider`. `ImaAdpcmWaveFormat` was removed — it was a non-functional stub used nowhere * `WaveFileWriter` / `AiffFileWriter` no longer dispose a caller-supplied stream, matching the readers' ownership rule; only the filename constructor owns and closes the file. `IgnoreDisposeStream` is no longer needed when writing to a stream you want to keep (#1040) * Finalizers were removed from `MediaFoundationTransform`, `MediaFoundationEncoder` and `MediaBuffer`, and `MediaType` is now `IDisposable` — call `Dispose()` * Core Audio, Media Foundation and DMO errors now throw `CoreAudioException` / `MediaFoundationException`, both subclasses of `COMException`, so existing `catch (COMException)` keeps working #### Notable bug fixes The sampler, effects and WASAPI subsystems also saw extensive correctness work during development. The full per-PR list is on the GitHub Release; the fixes most likely to affect existing NAudio 2 code are: * `WaveFileWriter.WriteSample` / `WriteSamples`: fixed 32-bit `WaveFormatExtensible` output writing near-silence or corrupt data — both paths ignored the declared SubFormat (#651) * `ToSampleProvider()` now handles `WAVE_FORMAT_EXTENSIBLE` PCM and IEEE float sources (e.g. multichannel or >16-bit WAV) instead of throwing `Unsupported source encoding` (#639); `AudioFileReader` no longer routes such WAVs through an unnecessary ACM conversion stream * `WaveFileReader` / `AiffFileReader`: malformed headers declaring `BlockAlign=0` throw `InvalidDataException` from the constructor rather than `DivideByZeroException` later (#1254); an oversized `data` chunk length is clamped to the bytes actually present (#1090); an oversized `fmt` `cbSize` no longer throws (#482) * `AiffFileReader` / `AiffFileWriter`: 8-bit PCM is now read and written as signed two's-complement per the AIFF spec, fixing DC-shifted/garbled playback (#1178) * `BlockAlignReductionStream.Read`: a read larger than the 4-second internal buffer no longer silently truncates the stream — e.g. converting a non-PCM WAV via `AudioFileReader` (#1022) * `WaveOut`: fixed a race where stopping or disposing faster than the buffer latency could throw a `NullReferenceException` via `PlaybackStopped` (#804); `DirectSoundOut`: fixed a startup race that could collapse playback immediately (#759) * `WasapiRecorder`, `WasapiCapture` and `WasapiLoopbackCapture`: a capture device removed mid-recording no longer crashes the process — `RecordingStopped` always fires with the originating exception (#672). Silent packets no longer leak the uninitialised WASAPI buffer as a burst of stale audio * Fixed an access violation that could crash the process when an endpoint notification fired after `RegisterEndpointNotificationCallback` — Windows does not AddRef the client, so the CCW was being collected (#1394) * `AudioClient.Dispose` is now idempotent and safe against concurrent disposal (#1183); `MMDevice.Dispose` releases the property store deterministically (#1145); `AudioSessionControl` supports multiple event clients without leaking (#1263); `AudioEndpointVolume.OnVolumeNotification` reports the correct channel (#351) * `AcmInterop`: serialised all `msacm32` P/Invokes process-wide, fixing process-killing access violations under concurrent ACM use * `ResamplerDmoStream`: fixed an infinite loop on `Read` after seeking and the loss of the resampler tail at end-of-stream (#607, #608); `LoopStream.Read` no longer spins at 100% CPU when the source can't satisfy a read (#1338) * `FastFourierTransform.FFT`: fixed drifting high-frequency bins at large FFT sizes by carrying the twiddle-factor recurrence in double precision (#520) * `WdlResampler`: backported upstream Cockos WDL fixes, including reinterleaving on channel-count change and denormal flushing in the IIR feedback path (#800) * `WaveViewer`: fixed rendering upside-down (#801, #818) and now renders any source format via `ToSampleProvider()` (#564) * `Mp3FileReader`: fixed false sample-rate-change errors near end of file, and more robust frame parsing against album art and trailing metadata; `MidiFile` preserves running status across meta events * `WaveFormat.Serialize`: PCM formats now write the canonical 16-byte `fmt ` chunk (#934, #1098) * Hardened Media Foundation and DMO interop against COM ref leaks on error paths (#1293) #### Demos and tooling * `NAudioDemo` and `NAudioWpfDemo` were substantially reworked against the new APIs, including a rebuilt WASAPI Recorder panel driven by `WasapiRecorderBuilder`, transport/volume/position controls across the playback panels, and a Graphic EQ panel on `NAudio.Effects` * The network chat demo is now UDP-only with a bounded jitter buffer and Opus codecs (via `Concentus`, replacing the vendored NSpeex binary), and gained a [tutorial](Docs/NetworkChatDemo.md) * The documentation site (tutorials plus a generated API reference) is published to GitHub Pages from `Docs/` and the source XML comments. Every package's `projectUrl` and README now point at it; nuget.org still links the GitHub repo via the package's `repository` metadata