Codecs

The cornnerstoneWADOImageLoader uses the following third party libraries to decode the various ways DICOM images are compressed:

1. OpenJPEG.js for JPEG2000 images. Based on the OpenJPEG library

2. OHIF/image-JPEG2000 For JPEG2000 Images. Based on the PDF.js library

3. CharLS.js for JPEG-LS images. Based on the CharLS library

4. JPEGLossless Decoder JS for JPEG Lossless images.

5. JPEG Lossy for JPEG Lossy images. Based on notmasteryet with changes contributed by gSquared

6. pako.js for deflate based images.

JPEG2000

The OpenJPEG based codec is the default codec for JPEG2000 images. This codec is the default because the OpenJPEG library is in wide use, activily supported and believed to be able to decode most of if not all JPEG2000 images found in medical imaging. The PDF.js library is not recommended as it has known issues that nobody is fixing and not actively supported. The performance of the PDF.js library may be better on some browsers or with some types of images, here are some benchmarks:

Images from ftp://medical.nema.org/MEDICAL/Dicom/DataSets/WG04/compsamples_j2k.tar

iMac Retina 5k Late 2014 4GHz Intel Core i7 Chrome 50.0.2661.102 (64 bit)

Image	OpenJPEG	PDF.js
NM1_J2KR	233 ms	103 ms
CT1_J2KR	424 ms	147 ms
RG1_J2KR	6058 ms	2311 ms
MG1_J2KR	19312 ms	7380 ms

iMac Retina 5k Late 2014 4GHz Intel Core i7 FireFox 46.0.1

Image	OpenJPEG	PDF.js
NM1_J2KR	240 ms	102 ms
CT1_J2KR	185 ms	91 ms
RG1_J2KR	3445 ms	1594 ms
MG1_J2KR	10295 ms	14207 ms

iMac Retina 5k Late 2014 4GHz Intel Core i7 Safari 9.1.1

Image	OpenJPEG	PDF.js
NM1_J2KR	64 ms	56 ms
CT1_J2KR	115 ms	94 ms
RG1_J2KR	2367 ms	1567 ms
MG1_J2KR	6496 ms	18547 ms