QOI to EXR Converter
Convert QOI to EXR in your browser. QOI files usually come from game engines, emulators and tools that want lossless images without a PNG library; EXR is the better fit for visual effects, compositing and 3D render output. You get a ZIP-compressed OpenEXR with 16-bit half-float channels, 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
QOI expected · other image formats also work
How to use QOI to EXR
- 1
Add your QOI files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the EXR is written losslessly. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .exr files one at a time or together as a ZIP.
Why use Aback Images for qoi to exr
Where the EXR goes next
EXR opens in Nuke, Blender, Houdini, After Effects, DaVinci Resolve, Photoshop, Krita and OpenImageIO.
EXR next to QOI
Both sides are lossless, so the size depends on how well the EXR encoder handles this picture compared with the QOI's lossless, byte-aligned run, index, difference and literal codes.
Written without a lossy pass
The EXR is written losslessly, so the pixels decoded from the QOI arrive unchanged.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
QOI vs EXR
What changes from QOI to EXR
Encoding: the QOI uses lossless, byte-aligned run, index, difference and literal codes; EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file, and the download is a ZIP-compressed OpenEXR with 16-bit half-float channels, the 8-bit sRGB values converted to linear light.
Bit depth: 8 bits per channel in the QOI; EXR allows 16-bit half or 32-bit floating point per channel, and the EXR written here has 16-bit half float per channel.
Colour: RGB or RGBA, tagged sRGB or linear in the QOI; EXR supports scene-linear RGB, often ACEScg or linear Rec.709, written here as linear-light RGB.
Transparency: the QOI stores it as a full 8-bit alpha channel; the EXR keeps it as an A channel stored like any other channel.
Metadata: the QOI can carry none: a 14-byte header holds only size, channels and colour space; EXR can carry named header attributes such as chromaticities, timecode and camera data, but nothing is copied across.
About QOI
QOI is a modern lossless format that encodes 20-50 times faster than PNG with similar file sizes. It is popular in games and tools that value speed and simplicity.
A QOI file is a 14-byte header ('qoif', width, height, channels, colour space), a stream of chunks that each encode a run, an index into 64 recently seen colours, a small difference from the previous pixel or a literal value, and an 8-byte end marker.
QOI files usually come from game engines, emulators and tools that want lossless images without a PNG library.
About EXR
OpenEXR is the high dynamic range format of film visual effects. It stores half or full floating-point channels in linear light, plus any extra render passes, and is the working format of compositing pipelines.
An EXR starts with the magic number 76 2F 31 01 and a version field, then a header of named, typed attributes (channels, compression, dataWindow, displayWindow) and a table of offsets to scanline or tile blocks.
When converting QOI to EXR makes sense
EXR is the better choice for visual effects, compositing and 3D render output, while QOI suits fast lossless storage in games and tools.
EXR strengths: True high dynamic range in linear light; Any number of channels and render passes; Lossless compression options. Drawbacks to weigh: Needs tone mapping to look right on a normal screen; Very large files; No browser or phone support.
Limitations
- QOI is lossless, so the pixels you get out are exactly the ones that went in.
- No range is added: the EXR holds the 8-bit picture in linear light, and nothing in it is brighter than the original white.
- Compositing and 3D software read the EXR as linear light, the convention for the format, so it displays correctly there.
- The file holds colour and, when the image has transparency, an alpha channel; there are no extra render passes.
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Frequently asked questions
Does converting QOI to EXR lose quality?
EXR is written losslessly, so the pixels are stored exactly as decoded.
Is transparency kept in the EXR?
Yes. QOI stores it as a full 8-bit alpha channel, and the EXR is written with an alpha channel, so transparent areas stay transparent.
Does saving as EXR add dynamic range?
No. The values come from an 8-bit image, converted to linear light so compositing software displays them correctly, but nothing brighter than the original white is invented. The file is ready to use as a plate or texture in an EXR pipeline.
Which apps open EXR files?
Nuke, Blender, Houdini, After Effects, DaVinci Resolve, Photoshop, Krita and OpenImageIO. 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.