diff options
Diffstat (limited to 'codecs/ilbc/FrameClassify.c')
-rwxr-xr-x | codecs/ilbc/FrameClassify.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/codecs/ilbc/FrameClassify.c b/codecs/ilbc/FrameClassify.c new file mode 100755 index 000000000..61ede133b --- /dev/null +++ b/codecs/ilbc/FrameClassify.c @@ -0,0 +1,100 @@ + +/****************************************************************** + + iLBC Speech Coder ANSI-C Source Code + + FrameClassify.c + + Copyright (c) 2001, + Global IP Sound AB. + All rights reserved. + +******************************************************************/ + +#include "iLBC_define.h" + +/*----------------------------------------------------------------* + * Classification of subframes to localize start state + *---------------------------------------------------------------*/ + +int FrameClassify( /* index to the max-energy sub frame */ + float *residual /* (i) lpc residual signal */ +){ + float max_ssqEn, fssqEn[NSUB], bssqEn[NSUB], *pp; + int n, l, max_ssqEn_n; + const float ssqEn_win[NSUB-1]={(float)0.8,(float)0.9, + (float)1.0,(float)0.9,(float)0.8}; + const float sampEn_win[5]={(float)1.0/(float)6.0, + (float)2.0/(float)6.0, (float)3.0/(float)6.0, + (float)4.0/(float)6.0, (float)5.0/(float)6.0}; + + /* init the front and back energies to zero */ + + memset(fssqEn, 0, NSUB*sizeof(float)); + memset(bssqEn, 0, NSUB*sizeof(float)); + + /* Calculate front of first seqence */ + + n=0; + pp=residual; + for(l=0;l<5;l++){ + fssqEn[n] += sampEn_win[l] * (*pp) * (*pp); + pp++; + } + for(l=5;l<SUBL;l++){ + fssqEn[n] += (*pp) * (*pp); + pp++; + } + + /* Calculate front and back of all middle sequences */ + + for(n=1;n<NSUB-1;n++) { + pp=residual+n*SUBL; + for(l=0;l<5;l++){ + fssqEn[n] += sampEn_win[l] * (*pp) * (*pp); + bssqEn[n] += (*pp) * (*pp); + pp++; + } + for(l=5;l<SUBL-5;l++){ + fssqEn[n] += (*pp) * (*pp); + bssqEn[n] += (*pp) * (*pp); + pp++; + } + for(l=SUBL-5;l<SUBL;l++){ + fssqEn[n] += (*pp) * (*pp); + bssqEn[n] += sampEn_win[SUBL-l-1] * (*pp) * (*pp); + pp++; + } + } + + /* Calculate back of last seqence */ + + n=NSUB-1; + pp=residual+n*SUBL; + for(l=0;l<SUBL-5;l++){ + bssqEn[n] += (*pp) * (*pp); + pp++; + } + for(l=SUBL-5;l<SUBL;l++){ + bssqEn[n] += sampEn_win[SUBL-l-1] * (*pp) * (*pp); + pp++; + } + + /* find the index to the weighted 80 sample with + most energy */ + + max_ssqEn=(fssqEn[0]+bssqEn[1])*ssqEn_win[0]; + max_ssqEn_n=1; + for (n=2;n<NSUB;n++) { + + if ((fssqEn[n-1]+bssqEn[n])*ssqEn_win[n-1] > max_ssqEn) { + max_ssqEn=(fssqEn[n-1]+bssqEn[n]) * + ssqEn_win[n-1]; + max_ssqEn_n=n; + } + } + + return max_ssqEn_n; +} + + |