On Wed, 2007-08-01 at 10:45 -0700, Gregory Alan Hildstrom wrote: > I got 32-bit true lossless j2kaudio transcoding working today. I compared it > against wavpack and > wavpack seems far superior in terms of speed and compression for 32-bit > floating point data. I > created the test files with audacity, which only uses float values from +1 to > -1, so I am not sure > if it actually uses the full 32-bits, but it is still good enough for a > meaningful test. > > Here are the compressed size % for the worst case that I tested: > 32bWN.wav 44.1kHz/32b/10ch > 60sec 10 channels of white noise > 105840152B > j2kaudio 91.06 > wavpack 82.32 > tar czf (gzip) 92.29 > tar cjf (bz2) 93.24 > > The full test tables are here: > http://geocities.com/hildstrom/projects/j2kaudio/ > > Are there any wav/audio programs out there that use the full float range of > 3.4e+/-38? It seems to > me that this larger range would use more of the 32 bits.
all of them :) the idea is that 0 ... +1 maps to the nominal range of the D/A converter (-inf dB ... 0dbFS), leaving the rest of the range to span larger and smaller values without clipping. as fons explained recently, you could agree on a different convention for this, and say that 0 ... 2^23-1 mapped to the physical range, but you don't gain anything in so doing. --p _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev
