Imazen.WebP — .NET Bindings for libwebp

Encode, decode, and animate WebP images from .NET. Supports both System.Drawing.Bitmap and raw pixel buffer APIs for cross-platform use.

Features

• Encode & Decode — lossy, lossless, and advanced config encoding; decode to Bitmap or raw byte arrays
• Animation — decode animated WebP to individual frames; encode frames into animated WebP
• Cross-Platform — raw buffer APIs (WebPEncoder, WebPDecoder) work everywhere without System.Drawing
• 7 Platform Runtimes — native libwebp binaries for win-x64, win-x86, win-arm64, linux-x64, linux-arm64, osx-x64, osx-arm64
• Multi-Framework — targets net472, net48, netstandard2.0, and net8.0
• Advanced Config — fluent WebPEncoderConfig builder for quality, method, lossless presets, near-lossless, alpha quality, sharp YUV, and more
• Probing — WebPInfo retrieves dimensions, alpha, animation, and format without full decoding

Quick Start

Install

dotnet add package Imazen.WebP.AllPlatforms

Or install only the runtime you need (see Packages below).

Encode a Bitmap

using Imazen.WebP;

var encoder = new SimpleEncoder();
using var bitmap = new Bitmap("input.png");
using var stream = File.Create("output.webp");

// Lossy encoding (quality 0–100), or -1 for lossless
encoder.Encode(bitmap, stream, 80);

Decode a Bitmap

using Imazen.WebP;

var decoder = new SimpleDecoder();
byte[] webpBytes = File.ReadAllBytes("image.webp");
using Bitmap bitmap = decoder.DecodeFromBytes(webpBytes, webpBytes.LongLength);

Decode to Raw Pixels (Cross-Platform)

using Imazen.WebP;

byte[] webpBytes = File.ReadAllBytes("image.webp");
byte[] pixels = WebPDecoder.Decode(webpBytes, out int width, out int height, WebPPixelFormat.Rgba);
// pixels is now width * height * 4 bytes of RGBA data

Encode from Raw Pixels (Cross-Platform)

using Imazen.WebP;

byte[] encoded = WebPEncoder.Encode(rgbaPixels, width, height, width * 4, WebPPixelFormat.Rgba, quality: 80);
File.WriteAllBytes("output.webp", encoded);

Advanced Encoding Config

using Imazen.WebP;

var config = new WebPEncoderConfig()
    .SetQuality(85)
    .SetMethod(6)           // Slowest, best compression
    .SetSharpYuv()          // Better color fidelity
    .SetSnsStrength(50)
    .SetFilterStrength(20);

var encoder = new SimpleEncoder();
using var bitmap = new Bitmap("input.png");
using var stream = File.Create("output.webp");
encoder.Encode(bitmap, stream, config);

Decode Animation

using Imazen.WebP;

byte[] animatedWebP = File.ReadAllBytes("animation.webp");
using var decoder = new AnimDecoder(animatedWebP);
Console.WriteLine($"{decoder.Info.FrameCount} frames, {decoder.Info.Width}x{decoder.Info.Height}");

foreach (var frame in decoder.DecodeAllFrames())
{
    // frame.Pixels = BGRA byte array for the full canvas
    // frame.TimestampMs, frame.DurationMs
}

Encode Animation

using Imazen.WebP;

using var encoder = new AnimEncoder(width, height, loopCount: 0);
encoder.AddFrame(frame1Bgra, timestampMs: 0, quality: 80);
encoder.AddFrame(frame2Bgra, timestampMs: 100, quality: 80);
encoder.AddFrame(frame3Bgra, timestampMs: 200, quality: 80);

byte[] animatedWebP = encoder.Assemble();
File.WriteAllBytes("animation.webp", animatedWebP);

Probe Image Info

using Imazen.WebP;

byte[] data = File.ReadAllBytes("image.webp");
var info = WebPInfo.GetImageInfo(data);
Console.WriteLine($"{info.Width}x{info.Height}, alpha={info.HasAlpha}, animated={info.HasAnimation}");

Packages

Package	Description
Imazen.WebP	Managed bindings (requires a runtime package)
Imazen.WebP.AllPlatforms	Managed bindings + all 7 native runtimes
Imazen.WebP.NativeRuntime.win-x64	Windows x64 native libraries
Imazen.WebP.NativeRuntime.win-x86	Windows x86 native libraries
Imazen.WebP.NativeRuntime.win-arm64	Windows ARM64 native libraries
Imazen.WebP.NativeRuntime.linux-x64	Linux x64 native libraries
Imazen.WebP.NativeRuntime.linux-arm64	Linux ARM64 native libraries
Imazen.WebP.NativeRuntime.osx-x64	macOS x64 native libraries
Imazen.WebP.NativeRuntime.osx-arm64	macOS ARM64 (Apple Silicon) native libraries

Platform Support

OS	Architecture	.NET Framework 4.7.2+	.NET Standard 2.0	.NET 8+
Windows	x64	Yes	Yes	Yes
Windows	x86	Yes	Yes	Yes
Windows	ARM64	Yes (.NET 4.8.1+)	Yes	Yes
Linux	x64	—	Yes	Yes
Linux	ARM64	—	Yes	Yes
macOS	x64	—	Yes	Yes
macOS	ARM64	—	Yes	Yes

API Reference

Full API documentation is available at imazen.github.io/libwebp-net.

License

MIT — Copyright 2012–2026 Imazen LLC