Compression methods

There are 3 general types of lossless compression built into OpenEXR, with two different methods of Zip compressing. For most images without a lot of grain, the two Zip compression methods seem to work best, while the PIZ compression algorithm is better suited to grainy images. The following options are available:


Disables all compression. Run Length Encoding (RLE)

This is a basic form of compression that is comparable to that used by standard Targa files. Zip (per scanline)

Zip style compression applied to individual scanlines. Zip (16 scanline blocks)

Zip style compression applied to blocks of 16 scanlines at time. This tends to be the most effective style of compression to use with rendered images that do not have film grain applied. PIZ (wavelet compression)

This uses a new combined wavelet / Huffman compression. This form of compression is quite effective when dealing with grainy images, and will often surpass any of the other options under grainy conditions. PXR24 (24 bit data conversion then zipped compression)

This form of compression from Pixar converts data to 24 bit then uses Zip compression. It is lossless for half and 32bit integer data and slightly lossy for 32bit float data. B44

This form of compression is lossy for half data and stores 32bit data uncompressed. B44A

An extension to B44 where areas of flat color are further compressed. Regular B44 compresses uniformly regardless of image content.


PIZ. PIX, ZIP, ZIPS and RLEについてはロスレス圧縮


Original DPX(Cineon) 1.19GB


1. Zip1 1.56GB

2. Zip16 1.46GB

3. PIZ 988.9MB

4. RLE 1.77GB

5. B44 798MB

6. None 1.78GB




No comments: