JP2 to CR2 Converter
Convert JP2 to CR2 in your browser. You download a Linear DNG (.dng), not a .cr2: only a Canon camera can create a genuine CR2, and every editor that opens CR2 also opens DNG. 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 CR2
- 1
Add your JP2 files: drop them here, choose them, or paste from the clipboard.
- 2
Pick the colour that replaces transparent areas, since DNG has none.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .dng files one at a time or together as a ZIP.
Why use Aback Images for jp2 to cr2
Where a CR2 would go
CR2 files are opened by Canon Digital Photo Professional, Lightroom, Photoshop Camera Raw, Capture One and darktable, and every one of them opens the DNG too.
DNG next to JP2
The DNG is written uncompressed, so expect it to be several times larger than the JP2, which stores wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones.
Written without a lossy pass
The DNG is written uncompressed, so the pixels decoded from the JP2 arrive unchanged, apart from precision beyond 8 bits per channel.
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 CR2
What changes from JP2 to CR2
Encoding: the JP2 uses wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones; CR2 uses lossless JPEG-compressed sensor data, cut into vertical slices, and the download is a Linear DNG: demosaiced 8-bit RGB with the colour matrices raw editors need.
Bit depth: up to 16 bits per channel is common, more is possible in the JP2; CR2 allows 12 or 14 bits per channel, and the DNG written here has 8 bits per channel, linearised. 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; CR2 supports camera RGB from a Bayer mosaic, with the Picture Style recorded in the maker notes, written here as 8-bit sRGB.
Transparency: the JP2 stores it as an extra component flagged as opacity; the DNG has none, so transparent areas are filled with the colour you choose.
Metadata: the JP2 can carry XML, ICC and resolution boxes; CR2 can carry EXIF, Canon maker notes (Picture Style, lens, focus points) and the embedded previews, 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 CR2
CR2 is the raw format of Canon EOS cameras from 2004 until CR3 replaced it in 2018. It holds the sensor's 12 or 14-bit readings, losslessly compressed, plus a large JPEG preview rendered with the camera's Picture Style.
CR2 is TIFF-based: the TIFF header is followed by the letters 'CR' and version 2.0, then four image directories: a large JPEG preview with the EXIF block, a 160×120 thumbnail, a small uncompressed RGB image, and the sensor data as lossless JPEG cut into vertical slices.
CR2 files come from Canon EOS DSLRs made from 2004 to 2018, such as the 5D Mark II and III, 6D, 7D and the Rebel series.
When converting JP2 to CR2 makes sense
Forms and workflows that ask for CR2 usually feed a raw editor, and each of those opens DNG as well, so the DNG can take the CR2's place. Keep the JP2 if you only need to view or share the picture.
What CR2 offers when it comes straight from the camera: Large embedded JPEG rendered with the camera's Picture Style; Lossless 12 or 14-bit sensor data; Widely supported after fourteen years of Canon DSLRs. Its drawbacks: Replaced by CR3 in 2018, so current Canon bodies no longer write it; 20 to 50 MB per photo; Sliced lossless JPEG data that only raw decoders can read.
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.
- The DNG holds the decoded 8-bit pixels, so it adds no dynamic range or detail beyond the JP2.
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Frequently asked questions
Why do I get a .dng file instead of a .cr2?
A real CR2 is written by Canon cameras and holds the sensor's own readings (12 or 14 bits per channel, stored as lossless JPEG-compressed sensor data, cut into vertical slices) along with EXIF, Canon maker notes (Picture Style, lens, focus points) and the embedded previews. A JP2 holds no sensor data, so no software outside the camera can create a genuine CR2. The Linear DNG you get instead is Adobe's open raw format, and every editor that opens CR2 files opens it with the same raw controls. It holds decoded pixels, so it adds no quality or dynamic range.
Does converting JP2 to CR2 lose quality?
DNG is written uncompressed, so the pixels are stored exactly as decoded. 12 and 16-bit JPEG 2000 files are reduced to 8 bits per channel.
What happens to transparency when converting JP2 to CR2?
JP2 stores transparency as an extra component flagged as opacity. DNG 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.
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.