Hi all! I have some question about "scfsi". I made an additional routine called after final iteration of iteration_loop, in quantize.c. This routine calculate how many bits are demanded to store the scalefactor. And as it uses the scfsi, scalefac_scale, and preflag(preemphasis), the efficiency of bit allocation will be improved. See my latest snapshot 1115 or 1115-2, like http://www.isoternet.org/~tominaga/lame-beta/lame-1115-2.tar.bz2. I will merge this code into current LAME, but before the merging, I wanna the answer of the below questions.... Q1 Is this allowed that set the preflag of gr=0 different from that of gr=1, and use the scfsi on the scalefactor band that preemphasis is effected on. And if it is allowed, how to scalefactor determin ? example) preflag[gr = 0] = 1, preflag[gr = 1] = 0, scfsi = 0001 <- does the MP3 standard allow this stuation ? and scalefactor[gr = 0] = stored (..... 1) + pretab effect (..... 2) = 3 then scalefactor[gr = 1] = 1 or 3 <- which one is used ? Q2 Same as Q1 for not preflag but scalefac_scale. Q3 in the dist10 code, preemphasis(preflag) is used when the all of upper 4 scalefactor bands are distorted. but when enabling preflag, it amplify the upper 10 bands. I think it is wasting the bits... there is a comment in the dist 10 code before the enabling preflag, saying "see if we should use the preemphasis". Does the MP3 standard says that we *must* enable the preemphasis when the all of upper 4 scalefactor bands are distorted ? Or is it only the recomendation ? TIA. --- Takehiro TOMINAGA // may the source be with you ! -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
