AV1 Image File Format
Convert AVIF images to JPG, PNG, or WebP directly in your browser — no upload, no server, no quality loss beyond the format transition. FileDex decodes AV1 locally and re-encodes to your chosen format in seconds, keeping your images private.
This format is not currently supported for conversion in FileDex.
Common questions
Is AVIF better than WebP for web images?
AVIF achieves 20-30% smaller files than WebP at equivalent visual quality and supports 10/12-bit HDR, wide color gamut, and film grain synthesis. The trade-off is slower encoding speed and slightly less browser support. For most web use cases, AVIF is the better choice when browser coverage is acceptable.
Why are AVIF files slow to encode compared to JPEG?
AV1 encoding uses advanced prediction, transform selection, and rate-distortion optimization that require significantly more computation than JPEG DCT. A typical 12-megapixel image takes 2-10 seconds to encode in AVIF at medium speed versus milliseconds for JPEG. Hardware AV1 encoders are emerging to address this.
Can I use AVIF on my website right now?
Yes. Chrome, Firefox, Safari 16+, and Edge all support AVIF. Use the HTML picture element with AVIF as the preferred source and JPEG/WebP as fallbacks: the browser automatically selects the best supported format. CDNs like Cloudflare and Fastly can serve AVIF automatically via content negotiation.
Does AVIF support transparency and animation?
Yes. AVIF supports full alpha channel transparency in both lossy and lossless modes, plus animation via AVIF sequences (avis brand). Animated AVIF produces significantly smaller files than animated GIF or WebP with better color depth and quality.
Is AVIF royalty-free?
Yes. AVIF uses the AV1 codec developed by the Alliance for Open Media under a royalty-free patent license. Unlike HEIC (which requires HEVC licensing from MPEG LA), AVIF can be used freely in open-source and commercial projects without patent fees.
What makes .AVIF special
What is an AVIF file?
AVIF (AV1 Image File Format) is a royalty-free image format ratified in 2019 by the Alliance for Open Media. It uses the AV1 video codec in intra-frame mode for image compression, stored within an ISO BMFF (HEIF) container. AVIF achieves approximately 50% smaller file sizes than JPEG and 20-30% smaller than WebP at equivalent visual quality.
Continue reading — full technical deep dive
How to open AVIF files
- Chrome 85+ (2020) — Native support
- Firefox 93+ (2021) — Native support
- Safari 16+ (2022) — Native support
- Windows 10/11 — Install AV1 Video Extensions from Microsoft Store
- Adobe Photoshop 2022+ — Native support
- GIMP 2.10.32+ — Native support via libavif
Technical specifications
| Property | Value |
|---|---|
| Compression | AV1 intra-frame (lossy and lossless) |
| Bit Depth | 8-bit, 10-bit, 12-bit |
| Color Spaces | sRGB, Display P3, Rec. 2020, HDR10, PQ, HLG |
| Transparency | Full alpha channel support |
| Animation | Supported (AVIS sequences) |
| Container | ISO BMFF (HEIF variant) |
| Max Dimensions | 65,536 x 65,536 pixels (AV1 level 6.3) |
| Licensing | Royalty-free (AOM patent license) |
Common use cases
- Web delivery: Best-in-class compression for images served via CDN with picture element fallbacks
- HDR photography: Native 10/12-bit depth with PQ and HLG transfer functions
- App assets: Smaller image bundles for mobile and progressive web applications
- Archival: Lossless mode provides efficient long-term storage with modern compression
.AVIF compared to alternatives
| Formats | Criteria | Winner |
|---|---|---|
| .AVIF vs .JPG | Compression efficiency AVIF AV1 achieves approximately 50% file size reduction over JPEG at equivalent SSIM quality. AV1 uses larger variable-size blocks, directional intra prediction, and advanced entropy coding that far exceed JPEG's 8x8 DCT approach. | AVIF wins |
| .AVIF vs .WEBP | Compression and HDR support AVIF achieves 20-30% better compression than WebP VP8 lossy. AVIF supports 10/12-bit HDR with PQ and HLG transfer functions, wide gamut (BT.2020), and film grain synthesis — none of which WebP offers. | AVIF wins |
| .AVIF vs .HEIC | Licensing and adoption AVIF is fully royalty-free under the AOM patent license. HEIC requires HEVC patent licensing through MPEG LA and Access Advance. Compression quality is comparable, but AVIF's open licensing drives broader adoption. | AVIF wins |
| .AVIF vs .PNG | File size for photographic content AVIF lossy produces files 30-100x smaller than PNG for photographs. AVIF also supports lossless mode, though PNG lossless is more efficient for synthetic graphics with large flat color areas. | AVIF wins |
Technical reference
- MIME Type
image/avif- Developer
- Alliance for Open Media
- Year Introduced
- 2019
- Open Standard
- Yes — View specification
Binary Structure
AVIF uses the ISO Base Media File Format (ISOBMFF / ISO 14496-12) container, the same box-based structure as MP4, MOV, and HEIC. The file opens with an ftyp box declaring the 'avif' brand. Image data is stored as AV1 intra-frame (keyframe-only) bitstream in the mdat box. The meta box contains iloc (item location), iprp (item properties including color profile and codec configuration), and pitm (primary item) boxes. AVIF sequence files use the 'avis' brand and contain a moov box with track structure for animated content.
| Offset | Length | Field | Example | Description |
|---|---|---|---|---|
0x00 | 4 bytes | Box size | 00 00 00 1C | Size of the ftyp box in bytes (big-endian uint32). Typically 28 bytes for AVIF. |
0x04 | 4 bytes | Box type | 66 74 79 70 | ASCII 'ftyp' — file type box, always the first box in ISOBMFF files. |
0x08 | 4 bytes | Major brand | 61 76 69 66 | ASCII 'avif' for still image, 'avis' for image sequence/animation. |
0x0C | 4 bytes | Minor version | 00 00 00 00 | Version of the brand specification. Typically 0. |
0x10 | variable | Compatible brands | 61 76 69 66 6D 69 66 31 | List of compatible brands (avif, mif1, miaf) for reader compatibility detection. |
variable | variable | meta box | 6D 65 74 61 | Contains pitm (primary item), iloc (item locations), iprp (item properties with av1C codec config), and optional iref (item references). |
variable | variable | mdat box | 6D 64 61 74 | Media data box containing AV1 intra-frame compressed image bitstream. |
Attack Vectors
- AV1 decoder heap overflow — crafted AV1 bitstream can trigger memory corruption in decoder implementations (dav1d, libaom)
- ISOBMFF box parsing integer overflow — deeply nested or oversized boxes can cause allocation errors in container parsers
- Color profile injection — malicious ICC profile embedded in AVIF can exploit ICC parser vulnerabilities in downstream applications
Mitigation: FileDex decodes AVIF in the browser sandbox via the native Canvas API. Browser AV1 decoders (dav1d in Chrome/Firefox) receive regular security patches. No server upload occurs.