On 6/26/17, David Rowe <da...@rowetel.com> wrote: > I'm currently using a 2D DCT approach (bit like JPG) to code a version > of the spectrum. VQ could also be used. > > We don't really need to reg-generate the upper 4kHz as it doesn't take > many bits to encode it faithfully (perhaps 20% more than the first > 4kHz). The log(f) response of the ear means there isn't much info there > we can actually perceive.
You might try a non-linear scaling prior to the 2D DCT. Squish and stretch it as you would if making a log-normal graph. That is, so that your spectrum plot shows octaves with equal spacing, such that you could line it up with a musical keyboard. A transform of that nature lets you handle the higher frequencies with an appropriate level of detail. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
