Can libavif Encode Animated AVIF?

This article examines the capabilities of the libavif library regarding animated AVIF sequences. It provides a direct answer on whether libavif supports animation encoding, explains the underlying technical process, and details how developers and command-line users can create animated AVIF files.

Yes, libavif Encodes Animated AVIF

The official reference library libavif fully supports encoding animated AVIF sequences. AVIF (AV1 Image File Format) supports both static images and image sequences (animations) using the AV1 video compression standard inside an ISOBMFF (ISO Base Media File Format) container. Because libavif is designed to be a complete implementation of the AVIF specification, it includes the APIs and tools necessary to compile multiple image frames into a single, highly compressed animated AVIF file.

How libavif Handles Animation Encoding

To encode an animation, libavif packages a sequence of individual image frames and writes them as an AV1 video track inside the container. This process yields significantly better compression than animated GIFs or WebP, as it leverages AV1’s advanced inter-frame compression techniques (predicting changes between frames rather than saving each frame individually).

The library handles animation through two primary methods:

1. Command-Line Encoding with avifenc

For general users and automated scripts, libavif includes a command-line utility called avifenc. This tool can create animated AVIFs using two different approaches: * From a Video File: You can pass a standard video file (such as an MP4 or WebM) directly to avifenc. The tool will decode the video and re-encode it as an animated AVIF sequence. * From an Image Sequence: You can input a series of numbered still images (like PNGs or JPEGs) along with a specified frame duration to stitch them into a seamless animation.

2. The Developer API

For software developers integrating libavif into their applications, the C library provides a dedicated API for sequence encoding. The workflow generally follows these steps: 1. Initialize an encoder instance (avifEncoder). 2. Set the container properties, such as the width, height, pixel format, and frame rate. 3. Call avifEncoderAddImage() repeatedly for each frame in the sequence, specifying the duration for which each frame should be displayed. 4. Call avifEncoderFinish() to write the metadata and finalize the animated container.

By utilizing these tools and APIs, libavif serves as a highly efficient engine for generating animated web graphics that outperform older animation formats in both visual quality and file size.