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A pure-Kotlin AV1 / AVIF decoder for Kotlin Multiplatform.

• Still AVIF images and AVIS image sequences (every frame, in presentation order).
• Grid-derived images (dimg) with cell composition and edge trimming.
• Auxiliary images: alpha (including the legacy alpha layout without ispe) and depth.
• Gain maps with metadata parsing and tone mapping.
• Color: nclx CICP conversion (BT.601/709/2020, FCC, SMPTE 240M, YCgCo, identity), ICC profile, Exif and XMP metadata passthrough.
• Sample formats: 8 / 10 / 12-bit, monochrome, 4:2:0, 4:2:2 and 4:4:4.
• AV1 tools: loop filter, CDEF, loop restoration, intra/inter prediction, warped motion, OBMC, palette, intra block copy, film grain synthesis.
• Item transforms: irot, imir, clap.

Add the dependency to your build.gradle.kts:

implementation("io.github.zf1234d:kavif-kmp:<version>")

import org.glavo.avif.AvifImage

val image = AvifImage.read(bytes)
val frame = image.firstFrame()

val width = frame.width()
val height = frame.height()

// 8-bit packed, non-premultiplied ARGB in 0xAARRGGBB.
val argb: IntArray = frame.intPixels()

// 16-bit packed, non-premultiplied ARGB in 0xAAAA_RRRR_GGGG_BBBB.
val argb16: LongArray = frame.longPixels()

intPixels() and longPixels() are interchangeable. An 8-bit frame expands each channel to 16-bit on longPixels(); a 16-bit frame reduces each channel to 8-bit with rounding on intPixels().

val frames = AvifImage.read(bytes).frames() // every frame, in presentation order

val info = image.info()

val alphaPresent = info.alphaPresent()
val colorInfo = info.colorInfo()   // CICP primaries / transfer / matrix, or null
val iccProfile = info.iccProfile()
val exif = info.exif()
val xmp = info.xmp()

Provides Bitmap helpers. Decoding is CPU-bound; call it off the main thread.

import io.github.zf1234d.avif.decodeBitmap
import io.github.zf1234d.avif.decodeBitmaps
import io.github.zf1234d.avif.toBitmap

val bitmap: Bitmap = decodeBitmap(bytes)              // first frame as a Bitmap
val bitmaps: List<Bitmap> = decodeBitmaps(bytes)      // every frame as a Bitmap
val frameBitmap: Bitmap = frame.toBitmap()            // any AvifFrame as a Bitmap

Bitmap is always 8-bit ARGB_8888; HDR (10/12-bit) content is rounded down. Use longPixels() if your pipeline needs full precision before tone mapping.

Requirements: JDK 17 or newer, and an Android SDK for the Android target.

# compile all targets and run all tests
./gradlew build

# JVM test suite only
./gradlew jvmTest

# Android AAR, JVM JAR, metadata
./gradlew assemble

# install to ~/.m2 for local testing
./gradlew publishToMavenLocal

Licensed under the Apache License 2.0. See LICENSE for details.

Some source files are derived from javif and remain under the Mozilla Public License 2.0, with the original copyright preserved in the file headers. See LICENSE-MPL for the license text.

This project (source code and documentation alike) was produced with AI assistance and reviewed and iteratively debugged by a human. AI-generated content may contain errors, omissions, outdated or misleading information; read the code and verify its behavior yourself before use.

javif by Glavo.

Referenced the decoding behavior of libavif.