dcraw.js

Convert RAW camera images using JavaScript (supported on Node.js and your Browser)

This project is a port of dcraw.c using Emscripten.

Install:

Node.js

npm install dcraw

Browser

htmlCopy
<script src="https://cdn.jsdelivr.net/npm/dcraw"></script>

Usage

Read a RAW image file into a buffer (or Uint8Array in the browser, see browser example here)

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const fs = require('fs');
const buf = fs.readFileSync('./example.CR2');

Get Image Metadata

Parse the file for metadata

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const dcraw = require('dcraw');
dcraw(buf, { verbose: true, identify: true });

Result

>   Filename: raw_buf
    Timestamp: Thu Sep 21 07:17:42 2017
    Camera: Canon EOS 20D
    Owner: unknown
    ISO speed: 3200
    Shutter: 252.0 sec
    Aperture: f/inf
    Focal length: 0.0 mm
    Embedded ICC profile: no
    Number of raw images: 1
    Thumb size:  1536 x 1024
    Full size:   3596 x 2360
    Image size:  3522 x 2348
    Output size: 3522 x 2348
    Raw colors: 3
    Filter pattern: RG/GB
    Daylight multipliers: 2.098645 0.930145 1.180146
    Camera multipliers: 1021.000000 1015.000000 1018.000000 1015.000000

Convert to TIFF

Convert to TIFF file, and save to disk

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const tiffFile = dcraw(buf, { exportAsTiff: true });
fs.writeFileSync('example.tiff', tiffFile)

Options

You may use the same options that dcraw supports by providing the flags directly, or you may use the following human friendly versions.

Example

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// The following dcraw command, can be written two ways using dcraw.js
// dcraw -T -4 -E <filename>

// Both of these do the same thing
dcraw(buf, { T: true, 4: true, E: true });
dcraw(buf, { exportAsTiff: true, use16BitLinearMode: true, useExportMode: true });

Options List

Option	Type	Description
verbose	boolean	Print verbose messages
identify	boolean	Identify files without decoding them (use with '-v' to identify files and show metadata)
extractThumbnail	boolean	Extract embedded thumbnail image
useCameraWhiteBalance	boolean	Use camera white balance, if possible
useAverageWhiteBalance	boolean	Average the whole image for white balance
whiteBalanceBox	x y w h	Average a grey box for white balance
useCustomWhiteBalance	r g b g	Set custom white balance
useEmbeddedColorMatrix	boolean	Use/don't use an embedded color matrix
correctChromaticAberration	r b	Correct chromatic aberration
deadPixelFile	buffer	Fix the dead pixels listed in this file
darkFrameFile	buffer	Subtract dark frame (16-bit raw PGM)
setDarknessLevel	num	Set the darkness level
setSaturationLevel	num	Set the saturation level
setWaveletThreshold	num	Set threshold for wavelet denoising
setHighlightMode	[0-9]	Highlight mode (0=clip, 1=unclip, 2=blend, 3+=rebuild)
setFlipMode	[0-7]	Flip image (0=none, 3=180, 5=90CCW, 6=90CW)
setColorSpace	[0-6]	Output colorspace (raw,sRGB,Adobe,Wide,ProPhoto,XYZ,ACES)
setICCFromFile	buffer	Apply output ICC profile from file
setICCFromCamera	buffer	Apply camera ICC profile from file or "embed"
useDocumentMode	boolean	Document mode (no color, no interpolation, no debayer)
useRawMode	boolean	Document mode without scaling (totally raw)
useExportMode	boolean	Document mode without cropping
setNoStretchMode	boolean	Don't stretch or rotate raw pixels
setNoAutoBrightnessMode	boolean	Don't automatically brighten the image
setBrightnessLevel	num	Adjust brightness (default = 1.0)
setCustomGammaCurve	p ts	Set custom gamma curve (default = 2.222 4.5)
setInterpolationQuality	[0-3]	Set the interpolation quality
setHalfSizeMode	boolean	Half-size color image (twice as fast as "-q 0")
setFourColorMode	boolean	Interpolate RGGB as four colors
setMedianFilter	num	Apply a 3x3 median filter to R-G and B-G
setImageCount	[0..N-1]	Select one raw image or "all" from each file
use16BitMode	boolean	Write 16-bit instead of 8-bit
use16BitLinearMode	boolean	Linear 16-bit, same as "-6 -W -g 1 1"
exportAsTiff	boolean	Write TIFF instead of PPM

Browser Example

You'll need to do a little bit of work to get a file buffer on the browser. There is a full example available here.

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var reader = new FileReader();

reader.onload = function (e) {
    // Get the image file as a buffer
    var buf = new Uint8Array(e.currentTarget.result);

    // Get the RAW metadata
    const metadata = dcraw(buf, { verbose: true, identify: true });
};

reader.readAsArrayBuffer(file);