AVIF to HDR Converter
Convert AVIF to HDR in your browser. AVIF files usually come from image CDNs, modern web build pipelines and some recent phones; HDR is the better fit for 3D lighting and environment maps. You get a Radiance RGBE (.hdr) file, with the 8-bit sRGB values converted to linear light. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
AVIF expected · other image formats also work
How to use AVIF to HDR
- 1
Add your AVIF files: drop them here, choose them, or paste from the clipboard.
- 2
Pick the colour that replaces transparent areas, since HDR has none.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .hdr files one at a time or together as a ZIP.
Why use Aback Images for avif to hdr
Where the HDR goes next
HDR opens in Blender, Photoshop, Houdini, Unreal Engine, Unity and Affinity Photo.
HDR next to AVIF
The HDR keeps the decoded pixels without lossy compression, so expect it to be larger than the AVIF.
No new artefacts
AVIF is already lossy, since it stores lossy or lossless AV1 intra-frame coding; the HDR keeps the decoded pixels losslessly, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
AVIF vs HDR
What changes from AVIF to HDR
Encoding: the AVIF uses lossy or lossless AV1 intra-frame coding; HDR uses run-length encoded RGBE scanlines, and the download is a Radiance RGBE (.hdr) file, with the 8-bit sRGB values converted to linear light.
Bit depth: 8, 10 or 12 bits per channel in the AVIF; HDR allows an 8-bit mantissa per channel sharing an 8-bit exponent (RGBE), 32 bits per pixel, and the HDR written here has RGBE, 32 bits per pixel. 10 and 12-bit AVIFs, including HDR ones, are decoded to 8 bits per channel.
Colour: YUV 4:4:4 or 4:2:0 with BT.709, Display P3 or BT.2020 primaries, HDR curves possible in the AVIF; HDR supports linear RGB (or XYZ in the XYZE variant), written here as linear-light RGB.
Transparency: the AVIF stores it as an auxiliary AV1 image stored beside the colour image; the HDR has none, so transparent areas are filled with the colour you choose.
Animation: an AV1 image sequence under the 'avis' brand; the HDR holds one image, so only the first frame is converted.
Metadata: the AVIF can carry EXIF, XMP and ICC stored as HEIF items; HDR can carry a text header with FORMAT, EXPOSURE and optional comments, but nothing is copied across.
About AVIF
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 files usually come from image CDNs, modern web build pipelines and some recent phones.
About HDR
Radiance .hdr stores high dynamic range light values, widely used for 3D environment maps and HDRI lighting.
A Radiance file starts with '#?RADIANCE' (or '#?RGBE'), text lines such as FORMAT=32-bit_rle_rgbe and EXPOSURE, a blank line, a resolution line like '-Y 2048 +X 4096', then the scanlines.
When converting AVIF to HDR makes sense
HDR is the better choice for 3D lighting and environment maps, while AVIF suits maximum compression on modern websites.
HDR strengths: True high dynamic range; Standard for HDRI environment maps. Drawbacks to weigh: Needs tone mapping to view on normal screens.
Limitations
- Almost any other format needs more bytes than AVIF for the same picture, so expect the file to grow.
- HDR and wide-gamut AVIFs are mapped to standard sRGB on decode, so very bright highlights can look flatter than on an HDR screen.
- No range is added: the HDR holds the 8-bit picture in linear light, and nothing in it is brighter than the original white.
- 3D software treats the file as linear light, so an ordinary photo used as an environment map may need its exposure raised to light a scene well.
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Frequently asked questions
Does converting AVIF to HDR lose quality?
HDR is written losslessly, so the pixels are stored exactly as decoded. Artefacts already in the AVIF stay, but nothing new is lost. 10 and 12-bit AVIFs, including HDR ones, are decoded to 8 bits per channel.
What happens to transparency when converting AVIF to HDR?
AVIF stores transparency as an auxiliary AV1 image stored beside the colour image. HDR has no alpha channel, so transparent pixels are composited onto a solid colour, white unless you pick another. To keep transparency, convert to PNG, WebP or AVIF instead.
Will my animated AVIF stay animated?
No. HDR holds a single image, so only the first frame is kept. Convert to animated WebP, APNG or GIF to keep the motion, or export every frame with the GIF Frame Extractor.
Does saving as HDR make a real HDRI?
No. A real HDRI is merged from several exposures. This file holds an 8-bit image in linear light, so 3D software reads it correctly, but it has no more range than the source.
Which apps open HDR files?
Blender, Photoshop, Houdini, Unreal Engine, Unity and Affinity Photo. It does not open in web browsers.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.