Editing OpenEXR (section)

==Compression methods==
There are three 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:<ref>{{Cite web |url=http://www.openexr.com/TechnicalIntroduction.pdf#%5B%7B%22num%22%3A47%2C%22gen%22%3A0%7D%2C%7B%22name%22%3A%22XYZ%22%7D%2C69%2C437%2C0%5D |title=Technical Introduction to OpenEXR |access-date=2006-02-23 |archive-url=https://web.archive.org/web/20110717152538/http://www.openexr.com/TechnicalIntroduction.pdf#%5B%7B%22num%22%3A47%2C%22gen%22%3A0%7D%2C%7B%22name%22%3A%22XYZ%22%7D%2C69%2C437%2C0%5D |archive-date=2011-07-17 }}</ref>

; None: Disables all compression.
; [[Run-length encoding|Run Length Encoding (RLE)]]: This is a basic form of compression that is comparable to that used by standard [[Truevision TGA|Targa]] files.
; Zip (per scanline): [[deflate]] compression with [[zlib#Encapsulation|zlib wrapper]] applied to individual [[scanline]]s (not based on the [[ZIP file format]] despite its name).
; Zip (16 scanline blocks): deflate 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 lossless method uses a new combined wavelet / [[Huffman coding|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 deflate compression): This form of compression from [[Pixar Animation Studios]] converts 32-bit floats to 24 bits then uses deflate compression. It is lossless for half and 32-bit integer data and slightly lossy for 32-bit float data.
; B44: This form of compression is lossy for half data and stores 32-bit data uncompressed. It maintains a fixed compression size of either 2.28:1 or 4.57:1 and is designed for realtime playback. B44 compresses uniformly regardless of image content. <ref>{{Cite web |url=http://www.openexr.com/TechnicalIntroduction.pdf |title=Technical Introduction to OpenEXR |access-date=2006-02-23 |archive-url=https://web.archive.org/web/20110717152538/http://www.openexr.com/TechnicalIntroduction.pdf |archive-date=2011-07-17 |url-status=dead }}</ref>
; B44A: An extension to B44 where areas of flat color are further compressed, such as alpha channels.
; DWAA: JPEG-like lossy compression format contributed by [[DreamWorks Animation]]. Compresses 32 scanlines together.<ref name="OpenEXR 2.2"/>
; DWAB: Same as DWAA, but compresses blocks of 256 scanlines.