JP2 to AVIF Converter
Convert JP2 to AVIF in your browser. JP2 files usually come from libraries and digital archives, medical (DICOM) and satellite imaging, and digital cinema packages; AVIF is the better fit for maximum compression on modern websites. You get an AVIF encoded with libavif (AV1) compiled to WebAssembly, at the quality you choose. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
JP2 expected · other image formats also work
How to use JP2 to AVIF
- 1
Add your JP2 files: drop them here, choose them, or paste from the clipboard.
- 2
Set the quality. AVIF quality numbers run lower than JPEG: around 55 to 65 already looks excellent. Encoding is slow on phones.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .avif files one at a time or together as a ZIP.
Why use Aback Images for jp2 to avif
Where the AVIF goes next
AVIF opens in Chrome, Edge, Firefox, Safari 16 and later, Windows 11 Photos, macOS Preview and recent editors.
AVIF next to JP2
A lossy AVIF usually comes out far smaller than the JP2, which stores wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones.
The first lossy pass
The JP2 holds up to 16 bits per channel is common, more is possible with nothing discarded yet. This conversion is the first lossy encode these pixels see, and hard edges and flat colour show it first.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
JP2 vs AVIF
What changes from JP2 to AVIF
Encoding: the JP2 uses wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones; AVIF uses lossy or lossless AV1 intra-frame coding, and the download is an AVIF encoded with libavif (AV1) compiled to WebAssembly, at the quality you choose.
Bit depth: up to 16 bits per channel is common, more is possible in the JP2; AVIF allows 8, 10 or 12 bits per channel, and the AVIF written here has 8 bits per channel. 12 and 16-bit JPEG 2000 files are reduced to 8 bits per channel.
Colour: sRGB, greyscale, YCC or a space described by an ICC profile in the JP2; AVIF supports YUV 4:4:4 or 4:2:0 with BT.709, Display P3 or BT.2020 primaries, HDR curves possible, written here as 8-bit sRGB.
Transparency: the JP2 stores it as an extra component flagged as opacity; the AVIF keeps it as an auxiliary AV1 image stored beside the colour image.
Metadata: the JP2 can carry XML, ICC and resolution boxes; AVIF can carry EXIF, XMP and ICC stored as HEIF items, but nothing is copied across.
About JP2
JPEG 2000 is a wavelet-based format that can be truly lossless or lossy, handles very high bit depths and huge images, and is used where long-term fidelity matters: archives, medicine, satellites and digital cinema.
A .jp2 file is a box structure: a 12-byte signature box, an 'ftyp' box, a 'jp2h' header box with the size and colour specification, then the 'jp2c' box holding the codestream, which begins with FF 4F FF 51.
JP2 files usually come from libraries and digital archives, medical (DICOM) and satellite imaging, and digital cinema packages.
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.
When converting JP2 to AVIF makes sense
AVIF is the better choice for maximum compression on modern websites, while JP2 suits archival masters and specialist imaging.
AVIF strengths: Often 50% smaller than JPEG; Excellent at low quality settings; Transparency, HDR and 10/12-bit colour. Drawbacks to weigh: Slow to encode, especially on phones; Not supported by some older software; Can smooth away fine texture at low quality.
Limitations
- A JPEG 2000 file may be a lossless master or a lossy derivative; the file does not tell you which at a glance, so keep the original either way.
- Archival scans can be tens of thousands of pixels across, and decoding them needs a lot of memory on a phone.
- AVIF encoding is CPU-heavy, so large images and big batches take noticeably longer than JPG or WebP, especially on phones.
- Some older apps and operating systems cannot open AVIF yet; keep a JPG copy if you share the file widely.
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Frequently asked questions
Does converting JP2 to AVIF lose quality?
AVIF is lossy, so detail the eye barely notices is discarded to save space. 12 and 16-bit JPEG 2000 files are reduced to 8 bits per channel.
Is transparency kept in the AVIF?
Yes. JP2 stores it as an extra component flagged as opacity, and the AVIF is written with an alpha channel, so transparent areas stay transparent.
What quality should I choose for AVIF?
AVIF quality numbers run lower than JPEG: around 55 to 65 already looks excellent. Lower values give much smaller files with gentle softening. Encoding is CPU-heavy, so large batches take a while on phones.
Which apps open AVIF files?
Chrome, Edge, Firefox, Safari 16 and later, Windows 11 Photos, macOS Preview and recent editors. It opens in Chrome 85+, Edge, Firefox 93+ and Safari 16+.
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.