DWA compression in OpenEXR 2.2
OpenEXR 2.2 was just released, and it features a new lossy codec created by Karl Rasche of DreamWorks Animation. Simply called DWA , it applies techniques common in lossy image compression like the discrete cosine transform and Huffman coding , but it uses them to great effect. If you can accept a little loss in your HDR images, DWA can shrink them to a fraction of their lossless size. Like other DCT compression formats such as JPEG, DWA lets you set the amount of compression you want, so you can find a balance between loss and file size that best suits your particular task. This is a first for OpenEXR, or any other HDR format to my knowledge. The DWA Compression Level parameter is a floating point number, with higher values leading to more loss and smaller files. The default Compression Level setting is 45.0, which creates a visually lossless image that is often less than half the size of its truly lossless Piz counterpart. In my tests, boosting that value to 100.0 still had no vis...