NAudio.Vorbis

NAudio.Vorbis is a convenience wrapper that lets you play and read Ogg Vorbis files with NAudio, using NVorbis to do the decoding.

Requirements

NAudio.Vorbis	Requires
3.x	NAudio 3, .NET 9
1.5.0	NAudio 2, .NET Standard 2.0

NAudio 3 dropped .NET Framework and .NET Standard 2.0 and changed the Read signatures on IWaveProvider and ISampleProvider to take a Span<T>, so NAudio.Vorbis 3.0 is a clean break. If you are still on NAudio 2, stay on NAudio.Vorbis 1.5.0.

Playing a file

VorbisWaveReader is a WaveStream, so it plugs into any NAudio output device:

using NAudio.Vorbis;
using NAudio.Wave;

using var reader = new VorbisWaveReader("path/to/file.ogg");
using var player = new WasapiPlayerBuilder().Build();

player.Init(reader);
player.Play();

// wait here until playback stops or should stop

WasapiPlayer comes from the NAudio.Wasapi package. Any other NAudio output works the same way — WaveOut from NAudio.WinMM, or AlsaOut from NAudio.Alsa on Linux.

Reading samples

VorbisWaveReader also implements ISampleProvider, so it drops straight into a sample pipeline:

using NAudio.Wave.SampleProviders;

using var reader = new VorbisWaveReader("path/to/file.ogg");
var mixer = new MixingSampleProvider(new[] { (ISampleProvider)reader });

Or convert to a WAV file:

using var reader = new VorbisWaveReader("path/to/file.ogg");
WaveFileWriter.CreateWaveFile("output.wav", reader);

VorbisSampleProvider is the layer underneath, and exposes the things VorbisWaveReader deliberately hides — the end-of-stream event, and switching between the logical streams of a chained file.

Seeking

VorbisWaveReader supports seeking when the underlying stream does. Positions are in bytes and should be a multiple of WaveFormat.BlockAlign:

reader.CurrentTime = TimeSpan.FromSeconds(30);

A source that cannot seek (a network or pipe stream) still decodes; only Position and Length are unavailable.

Known NVorbis limitations

Decoding is NVorbis's job, and the current stable release (0.10.5) has bugs we cannot work around from here. All three are fixed in the NVorbis 1.0.0 line, which is still a prerelease — a stable package should not depend on one, so releases stay on 0.10.5 until NVorbis 1.0 ships.

• Seeking into the final page can throw InvalidDataException: GranulePos mismatch when the last page's granule position does not line up with the packets on it — the ordinary shape of an encoder's trailing partial page (NVorbis#39)
• Seeking back to the start does not always land on the first sample. The position reads back as 0, but decoding can resume elsewhere in the file
• A forward-only source can still hang on a file whose granule positions understate its contents. For seekable sources this is handled — reads are clamped to what the stream has left — but with no length to clamp to there is nothing to be done here (NVorbis#40, #16)

To try a build against the NVorbis 1.0 prerelease:

dotnet build -p:NVorbisVersion=1.0.0-rc.2

The release workflow takes the same value, so preview packages on the NVorbis 1.0 prerelease can be published without changing the repo default.

Strong naming

The assembly is strong-named from 3.0 onwards, as NAudio and NLayer are; 1.5.0 and earlier were not, so the assembly identity changes with this release. The key is checked in at the repo root: for open-source strong naming the private half is not a secret — it establishes assembly identity, it does not protect anything — and a key nobody can build with would be worse than none.

NVorbis is not strong-named, in any version, so the build suppresses CS8002 for that reference. .NET Framework refused to load an unsigned reference from a signed assembly, but .NET Core and later dropped strong-name verification, so on net9.0 it has no effect.

Building

dotnet build NAudio.Vorbis.slnx
dotnet test NAudio.Vorbis.slnx

The solution is in the XML .slnx format, so it needs the .NET 9.0.200 SDK or later; global.json pins that floor and rolls forward to newer SDKs.

TestApp is a WinForms harness (Windows only) for playing a file by hand and dragging a position bar around, which is the most practical way to exercise seeking. It reports failed seeks in its status line rather than crashing, so you can see which files misbehave.

The test corpus in NAudio.Vorbis.Tests/TestFiles is generated from synthesised tones rather than taken from any recording; NAudio.Vorbis.Tests/tools has the script that regenerates it.

Releasing

build.yml builds and tests every push and pull request, and separately builds against the NVorbis 1.0 prerelease. release.yml publishes to NuGet:

• Final release — set VersionPrefix in Directory.Build.props, rename the ### Unreleased section of RELEASE_NOTES.md to ### <version> (date), then push a matching v* tag. The workflow refuses to cut a final release against a prerelease NVorbis
• Preview — run the workflow manually from master. It publishes <VersionPrefix>-preview.<run number>, or the label you pass in milestone. Pass nvorbis_version to build the preview against a different NVorbis

Publishing uses NuGet trusted publishing (OIDC), so there is no API key to rotate; the NUGET_USER repository variable names the NuGet.org account.

Licence

MIT.