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

<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)

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

Get Image Metadata

Parse the file for metadata

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

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

// 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

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.

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);