CONVERT
HDR → AVIF
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Fast, secure HDR to AVIF conversion. No registration required.
Here is the short version — HDR is a raster image format with its own balance of compression, colour depth, and software support. Hence the need for AVIF. Turn a HDR image into a AVIF in seconds. The two formats share the same raster DNA so the visible quality is very close; what changes is how the file is packaged, which matters for browsers, editors and CMS uploaders. KaijuConverter runs the conversion server-side and deletes both files within two hours. Context: HDR is a raster image format with its own balance of compression, colour depth, and software support. AVIF is the AV1-based next-gen image codec, extremely efficient with full HDR and alpha support.
Radiance HDR Image
Source formatHDR (Radiance) stores high dynamic range images for realistic lighting in 3D rendering.
AVIF Image
Target formatAVIF is a next-generation image format based on the AV1 video codec. It offers significantly better compression than JPEG and WebP while maintaining excellent visual quality, including HDR and wide color gamut support.
Why convert HDR to AVIF
The real reason to move from HDR to AVIF is almost never picture quality — both raster formats store essentially the same pixels. It is about the tools downstream: which editors open the file natively, which CMSes upload it without transcoding, which social platforms accept it. Picking AVIF solves those edge cases at the cost of a short conversion step.
HOW TO CONVERT
HDR → AVIF
Provide the HDR
Click or drag to upload. We accept a single HDR file per job, with an optional queue of additional images for batch mode.
Encode to AVIF
The conversion decodes the HDR, resolves the colour space to sRGB and writes the AVIF container around the pixel data.
Save the AVIF
The download is streamed back over HTTPS. If you uploaded multiple files, a ZIP with all AVIF outputs is produced instead.
Common Use Cases
Share across platforms
Send AVIF files to anyone without worrying about whether they have the right software for HDR.
Embed in documents
Drop AVIF output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
AVIF often produces smaller files than HDR for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
HDR vs AVIF — Strengths and limitations
What each format does best, and where it falls short.
HDR Strengths
- True floating-point dynamic range in 32 bits per pixel.
- Simple format — easy to parse and generate.
- Standard for environment maps and lighting probes in 3D.
- 30+ years of continuous use in architectural rendering.
Limitations
- No compression — files are larger than OpenEXR or AVIF for equivalent quality.
- Only one channel set (RGB) — no alpha, no multi-layer like EXR.
- Not a web format.
AVIF Strengths
- Best-in-class compression efficiency — 30-50% smaller than JPEG for the same quality.
- Royalty-free and patent-unencumbered (unlike HEIC).
- Supports alpha transparency, HDR, wide gamut (BT.2020), and up to 12-bit color.
- Progressive decoding: a blurry preview appears while the file is still downloading.
- Supported in all major browsers since late 2022 — no polyfills needed.
Limitations
- Encoding is CPU-expensive — an AVIF export can take 10-30× longer than JPEG.
- Older software (pre-2022) cannot open AVIF without plugins.
- Email clients still largely ignore it — stick to JPEG for attachments.
HDR vs AVIF — Technical specifications
Side-by-side comparison of the technical details.
HDR
- MIME type
- image/vnd.radiance
- Extensions
- .hdr, .pic
- Encoding
- RGBE (shared 8-bit exponent)
- Dynamic range
- ~76 orders of magnitude
- Creator
- Greg Ward, Radiance renderer (1991)
AVIF
- MIME type
- image/avif
- Container
- HEIF (ISOBMFF)
- Codec
- AV1 (intra-only)
- Max dimensions
- 65 536 × 65 536 px
- Color depth
- Up to 12-bit per channel
- Color spaces
- sRGB, Display-P3, BT.2020, arbitrary ICC
| Specification | HDR | AVIF |
|---|---|---|
| MIME type | image/vnd.radiance | image/avif |
| Extensions | .hdr, .pic | — |
| Encoding | RGBE (shared 8-bit exponent) | — |
| Dynamic range | ~76 orders of magnitude | — |
| Creator | Greg Ward, Radiance renderer (1991) | — |
| Container | — | HEIF (ISOBMFF) |
| Codec | — | AV1 (intra-only) |
| Max dimensions | — | 65 536 × 65 536 px |
| Color depth | — | Up to 12-bit per channel |
| Color spaces | — | sRGB, Display-P3, BT.2020, arbitrary ICC |
HDR vs AVIF — Typical file sizes
Approximate file sizes for common scenarios.
HDR
- 2K environment map 15-35 MB
- 4K environment map 60-130 MB
- 8K HDRI 250-500 MB
AVIF
- Thumbnail (400px) 10-30 KB
- Web photo (1920px) 80-300 KB
- 4K photo (3840px) 300 KB - 1.2 MB
- Lossless copy of 24MP photo 8-15 MB
Quality & Compatibility
HDR-to-AVIF conversion does not change the visible content. Quality is capped by the HDR decode; re-encoding a lossy source at high quality cannot recover detail that was already discarded. For archival masters, keep the original HDR alongside the AVIF copy.
Tips for Best Results
- Large HDR files may look identical to small AVIF files for photographic content; pick quality based on end use, not headline megapixels.
- For print, export AVIF at 300 DPI minimum and check that the colour profile embedded matches the print shop specification.
- Batch-convert related HDR images in one pass so they share identical encoder settings and look consistent side-by-side.
Frequently Asked Questions
It depends on the codecs involved. If both HDR and AVIF are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If AVIF is lossless (PNG, TIFF, BMP) the output keeps every pixel of the decoded HDR exactly, but cannot recover detail that HDR had already compressed away.
Often yes, especially when AVIF is lossless. HDR tuned for efficient web delivery will usually produce smaller files than AVIF's default settings. If file size matters, drop the quality in Advanced or pick a more compressed target format instead.
KaijuConverter uploads over HTTPS, processes the image in an isolated container and deletes both the source and the output within two hours. No account is required, file contents are never logged, and we do not use uploads to train any model. For confidential material, the paid plan includes a data-processing agreement.
Related comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
AVIF Image Format: AV1-Powered Next-Generation Compression
Complete guide to AVIF image format: AV1 intra-frame compression, HEIF container, HDR and wide color gamut support, avifenc/ffmpeg encoding, browser compatibility, and comparison with WebP/JPEG/HEIC.
Read guideOpenEXR: High Dynamic Range & 16-Bit Float HDR Imaging
Complete guide to OpenEXR: 16-bit float color depth, HDR imaging, alpha channels, multi-layer compositing, and professional VFX workflows.
Read guideAVIF: AV1 Image Format & Next-Generation Compression
Complete guide to AVIF image format: AV1 codec, 50% better compression than JPEG, HDR support, color gamut, and browser compatibility.
Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.