Philippe Bossut (Merov Linden) wrote: > KDU is flat out 3 times faster to decode than OpenJPEG. The ratio is > consistent throughout the whole session. >
Until OpenJPEG v2, this 3x factor is simply due to the fact that KDU is able to pull metadata without any decode on any resolution level. The API for v1.x didn't have a call to extract just the header like the v2 of the API does. Therefore, at least up to 2x of that that 3x factor can be accounted for in time wasted to decode resolution levels when it didn't need to in order to just get metadata out of the header. Also, the default compile options on the OpenJPEG library does not have tree-vectorization optimization turned on. Without tree-vectorization, only a few picked areas of the code get SSE optimization. With tree-vectorization, the compiler will vectorize as much as it can as the code is written in a way to enable such tree-vectorization. Do note that tree-vectorization is not on by default because not everybody compiles with GCC, and MSVS did not support tree-vectorization. As for the metadata only mentioned above, that is fixed in OpenJPEG v2. _______________________________________________ Policies and (un)subscribe information available here: http://wiki.secondlife.com/wiki/SLDev Please read the policies before posting to keep unmoderated posting privileges
