GIF to AVIF Converter

Encoding: the GIF uses lossless LZW over a palette of at most 256 colours; AVIF uses lossy or lossless AV1 intra-frame coding, and the download is an AVIF encoded with libavif (AV1) compiled to WebAssembly, at the quality you choose.

Bit depth: 8 bits per pixel, as indexes into a palette in the GIF; AVIF allows 8, 10 or 12 bits per channel, and the AVIF written here has 8 bits per channel.

Colour: an indexed palette of up to 256 colours per frame in the GIF; AVIF supports YUV 4:4:4 or 4:2:0 with BT.709, Display P3 or BT.2020 primaries, HDR curves possible, written here as 8-bit sRGB.

Transparency: the GIF stores it as one palette entry marked transparent, so each pixel is either fully shown or fully hidden; the AVIF keeps it as an auxiliary AV1 image stored beside the colour image.

Animation: image blocks with their own delay and disposal method, looped by the NETSCAPE2.0 extension; the AVIF holds one image, so only the first frame is converted.

Metadata: the GIF can carry comment and application extension blocks, but no EXIF; AVIF can carry EXIF, XMP and ICC stored as HEIF items, but nothing is copied across.

GIF is the classic animated image format. It is limited to 256 colours per frame and 1-bit transparency, so photos look grainy and files are large, but it plays everywhere.

A GIF starts with 'GIF89a' (or the older 87a), a logical screen descriptor and an optional global colour table, then image blocks, each preceded by a graphic control extension that sets its delay and transparent colour.

GIF files usually come from reaction clips, memes, old websites and screen recordings.

AVIF uses the AV1 video codec for still images. It is the most efficient widely supported format, often half the size of JPEG, with HDR, wide colour and transparency, but encoding is slow.

An AVIF is a HEIF file, the same ISO base media boxes as MP4, with the brand 'avif'. The picture is an AV1 key frame stored as an image item, and its size, colour and pixel layout are item properties.

AVIF is the better choice for maximum compression on modern websites, while GIF suits short animations and reactions that must play everywhere.

AVIF strengths: Often 50% smaller than JPEG; Excellent at low quality settings; Transparency, HDR and 10/12-bit colour. Drawbacks to weigh: Slow to encode, especially on phones; Not supported by some older software; Can smooth away fine texture at low quality.