Base64 to AVIF
Paste a Base64 string or a data:image/avif;base64, URI below and click Decode Base64 to AVIF. The decoder checks the file signature, shows a preview and lets you download the result as a real .avif file.
How to convert Base64 to AVIF online
- Paste the Base64 value into the input box. Data URIs, whitespace and line breaks are handled automatically.
- Press Decode Base64 to AVIF.
- Check the preview and the detected file type, dimensions and size.
- Click Download to save the .avif file.
Important notes about the decoder
- The decoder detects the real file type from the decoded bytes (magic number). If your string is not actually AVIF, you will see the real type and can still download it.
- Invalid characters are reported instead of silently producing a broken file. If decoding fails, try the Base64 repair tool.
- Nothing is uploaded: the data is decoded locally by your browser, so even confidential documents stay on your device.
About AVIF
AVIF stores images compressed with the AV1 video codec inside a HEIF container. It offers excellent quality at very small sizes, often beating WebP by another 20% or more.
AVIF is supported by all major browsers released since 2024. If file size is your main concern when embedding images as Base64, AVIF is currently the most efficient choice.
| Developed | 2019, Alliance for Open Media |
|---|---|
| Compression | Lossy and lossless (AV1) |
| Transparency | Yes |
| HDR / wide gamut | Yes |
| File signature | ....ftypavif |
Frequently asked questions
How do I convert Base64 to AVIF?
Paste the Base64 string into the box above and click "Decode Base64 to AVIF". You can preview the result and download it as a .avif file.
Why is my Base64 AVIF not displaying?
Usually the string is truncated, contains URL-safe characters, or was double-encoded. The decoder reports the exact problem; the Base64 repair tool can fix most of them automatically.
Do I need to remove the data URI prefix?
No. The decoder strips "data:...;base64," automatically and uses the MIME type from it as a hint.
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