diff options
Diffstat (limited to 'third_party/ilbc/FrameClassify.c')
-rw-r--r-- | third_party/ilbc/FrameClassify.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/third_party/ilbc/FrameClassify.c b/third_party/ilbc/FrameClassify.c new file mode 100644 index 00000000..80d72d91 --- /dev/null +++ b/third_party/ilbc/FrameClassify.c @@ -0,0 +1,114 @@ + + /****************************************************************** + + iLBC Speech Coder ANSI-C Source Code + + FrameClassify.c + + Copyright (C) The Internet Society (2004). + All Rights Reserved. + + ******************************************************************/ + + #include "iLBC_define.h" + + /*---------------------------------------------------------------* + * Classification of subframes to localize start state + *--------------------------------------------------------------*/ + + int FrameClassify( /* index to the max-energy sub-frame */ + iLBC_Enc_Inst_t *iLBCenc_inst, + /* (i/o) the encoder state structure */ + float *residual /* (i) lpc residual signal */ + ) { + float max_ssqEn, fssqEn[NSUB_MAX], bssqEn[NSUB_MAX], *pp; + int n, l, max_ssqEn_n; + const float ssqEn_win[NSUB_MAX-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_MAX*sizeof(float)); + memset(bssqEn, 0, NSUB_MAX*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<iLBCenc_inst->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=iLBCenc_inst->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 */ + + if (iLBCenc_inst->mode==20) l=1; + else l=0; + + max_ssqEn=(fssqEn[0]+bssqEn[1])*ssqEn_win[l]; + max_ssqEn_n=1; + for (n=2; n<iLBCenc_inst->nsub; n++) { + + + + + + + l++; + if ((fssqEn[n-1]+bssqEn[n])*ssqEn_win[l] > max_ssqEn) { + max_ssqEn=(fssqEn[n-1]+bssqEn[n]) * + ssqEn_win[l]; + max_ssqEn_n=n; + } + } + + return max_ssqEn_n; + } + |