nb_celp.c

SPeex语音压缩算法的静态连接库和源代码

   } else {
      st->relative_quality = -1;
   }

   if (st->encode_submode)
   {
#ifdef EPIC_48K
   if (!st->lbr_48k) {
#endif

   /* First, transmit a zero for narrowband */
   speex_bits_pack(bits, 0, 1);

   /* Transmit the sub-mode we use for this frame */
   speex_bits_pack(bits, st->submodeID, NB_SUBMODE_BITS);

#ifdef EPIC_48K
   }
#endif
   }

   /* If null mode (no transmission), just set a couple things to zero*/
   if (st->submodes[st->submodeID] == NULL)
   {
      for (i=0;i<st->frameSize;i++)
         st->exc[i]=st->exc2[i]=st->sw[i]=VERY_SMALL;

      for (i=0;i<st->lpcSize;i++)
         st->mem_sw[i]=0;
      st->first=1;
      st->bounded_pitch = 1;

      /* Final signal synthesis from excitation */
      iir_mem2(st->exc, st->interp_qlpc, st->frame, st->frameSize, st->lpcSize, st->mem_sp);

      for (i=0;i<st->frameSize;i++)
         in[i]=st->frame[i];

      return 0;

   }

   /* LSP Quantization */
   if (st->first)
   {
      for (i=0;i<st->lpcSize;i++)
         st->old_lsp[i] = st->lsp[i];
   }


   /*Quantize LSPs*/
#if 1 /*0 for unquantized*/
   SUBMODE(lsp_quant)(st->lsp, st->qlsp, st->lpcSize, bits);
#else
   for (i=0;i<st->lpcSize;i++)
     st->qlsp[i]=st->lsp[i];
#endif

#ifdef EPIC_48K
   if (st->lbr_48k) {
      speex_bits_pack(bits, pitch_half[0]-st->min_pitch, 7);
      speex_bits_pack(bits, pitch_half[1]-pitch_half[0]+1, 2);
      
      {
         int quant = (int)floor(.5+7.4*GAIN_SCALING_1*ol_pitch_coef);
         if (quant>7)
            quant=7;
         if (quant<0)
            quant=0;
         ol_pitch_id=quant;
         speex_bits_pack(bits, quant, 3);
         ol_pitch_coef=GAIN_SCALING*0.13514*quant;
         
      }
      {
         int qe = (int)(floor(.5+2.1*log(ol_gain*1.0/SIG_SCALING)))-2;
         if (qe<0)
            qe=0;
         if (qe>15)
            qe=15;
         ol_gain = exp((qe+2)/2.1)*SIG_SCALING;
         speex_bits_pack(bits, qe, 4);
      }

   } else {
#endif

   /*If we use low bit-rate pitch mode, transmit open-loop pitch*/
   if (SUBMODE(lbr_pitch)!=-1)
   {
      speex_bits_pack(bits, ol_pitch-st->min_pitch, 7);
   } 

   if (SUBMODE(forced_pitch_gain))
   {
      int quant;
      quant = (int)floor(.5+15*ol_pitch_coef*GAIN_SCALING_1);
      if (quant>15)
         quant=15;
      if (quant<0)
         quant=0;
      speex_bits_pack(bits, quant, 4);
      ol_pitch_coef=GAIN_SCALING*0.066667*quant;
   }
   
   
   /*Quantize and transmit open-loop excitation gain*/
#ifdef FIXED_POINT
   {
      int qe = scal_quant32(ol_gain, ol_gain_table, 32);
      /*ol_gain = exp(qe/3.5)*SIG_SCALING;*/
      ol_gain = MULT16_32_Q15(28406,ol_gain_table[qe]);
      speex_bits_pack(bits, qe, 5);
   }
#else
   {
      int qe = (int)(floor(.5+3.5*log(ol_gain*1.0/SIG_SCALING)));
      if (qe<0)
         qe=0;
      if (qe>31)
         qe=31;
      ol_gain = exp(qe/3.5)*SIG_SCALING;
      speex_bits_pack(bits, qe, 5);
   }
#endif


#ifdef EPIC_48K
   }
#endif


   /* Special case for first frame */
   if (st->first)
   {
      for (i=0;i<st->lpcSize;i++)
         st->old_qlsp[i] = st->qlsp[i];
   }

   /* Filter response */
   res = PUSH(stack, st->subframeSize, spx_sig_t);
   /* Target signal */
   target = PUSH(stack, st->subframeSize, spx_sig_t);
   syn_resp = PUSH(stack, st->subframeSize, spx_sig_t);
   mem = PUSH(stack, st->lpcSize, spx_mem_t);
   orig = PUSH(stack, st->frameSize, spx_sig_t);
   for (i=0;i<st->frameSize;i++)
      orig[i]=st->frame[i];

   /* Loop on sub-frames */
   for (sub=0;sub<st->nbSubframes;sub++)
   {
      int   offset;
      spx_sig_t *sp, *sw, *exc, *exc2;
      int pitch;

#ifdef EPIC_48K
      if (st->lbr_48k)
      {
         if (sub*2 < st->nbSubframes)
            ol_pitch = pitch_half[0];
         else
            ol_pitch = pitch_half[1];
      }
#endif

      /* Offset relative to start of frame */
      offset = st->subframeSize*sub;
      /* Original signal */
      sp=st->frame+offset;
      /* Excitation */
      exc=st->exc+offset;
      /* Weighted signal */
      sw=st->sw+offset;

      exc2=st->exc2+offset;


      /* LSP interpolation (quantized and unquantized) */
      lsp_interpolate(st->old_lsp, st->lsp, st->interp_lsp, st->lpcSize, sub, st->nbSubframes);
      lsp_interpolate(st->old_qlsp, st->qlsp, st->interp_qlsp, st->lpcSize, sub, st->nbSubframes);

      /* Make sure the filters are stable */
      lsp_enforce_margin(st->interp_lsp, st->lpcSize, LSP_MARGIN);
      lsp_enforce_margin(st->interp_qlsp, st->lpcSize, LSP_MARGIN);

      /* Compute interpolated LPCs (quantized and unquantized) */
      lsp_to_lpc(st->interp_lsp, st->interp_lpc, st->lpcSize,stack);

      lsp_to_lpc(st->interp_qlsp, st->interp_qlpc, st->lpcSize, stack);

      /* Compute analysis filter gain at w=pi (for use in SB-CELP) */
      {
         spx_word32_t pi_g=st->interp_qlpc[0];
         for (i=1;i<=st->lpcSize;i+=2)
         {
            pi_g += -st->interp_qlpc[i] +  st->interp_qlpc[i+1];
         }
         st->pi_gain[sub] = pi_g;
      }


      /* Compute bandwidth-expanded (unquantized) LPCs for perceptual weighting */
      bw_lpc(st->gamma1, st->interp_lpc, st->bw_lpc1, st->lpcSize);
      if (st->gamma2>=0)
         bw_lpc(st->gamma2, st->interp_lpc, st->bw_lpc2, st->lpcSize);
      else
      {
         st->bw_lpc2[0]=1;
         for (i=1;i<=st->lpcSize;i++)
            st->bw_lpc2[i]=0;
      }

      /* Compute impulse response of A(z/g1) / ( A(z)*A(z/g2) )*/
      for (i=0;i<st->subframeSize;i++)
         exc[i]=VERY_SMALL;
      exc[0]=SIG_SCALING;
      syn_percep_zero(exc, st->interp_qlpc, st->bw_lpc1, st->bw_lpc2, syn_resp, st->subframeSize, st->lpcSize, stack);

      /* Reset excitation */
      for (i=0;i<st->subframeSize;i++)
         exc[i]=VERY_SMALL;
      for (i=0;i<st->subframeSize;i++)
         exc2[i]=VERY_SMALL;

      /* Compute zero response of A(z/g1) / ( A(z/g2) * A(z) ) */
      for (i=0;i<st->lpcSize;i++)
         mem[i]=st->mem_sp[i];
      iir_mem2(exc, st->interp_qlpc, exc, st->subframeSize, st->lpcSize, mem);
      
      for (i=0;i<st->lpcSize;i++)
         mem[i]=st->mem_sw[i];
      filter_mem2(exc, st->bw_lpc1, st->bw_lpc2, res, st->subframeSize, st->lpcSize, mem);
      
      /* Compute weighted signal */
      for (i=0;i<st->lpcSize;i++)
         mem[i]=st->mem_sw[i];
      filter_mem2(sp, st->bw_lpc1, st->bw_lpc2, sw, st->subframeSize, st->lpcSize, mem);
      
      /* Compute target signal */
      for (i=0;i<st->subframeSize;i++)
         target[i]=sw[i]-res[i];

      for (i=0;i<st->subframeSize;i++)
         exc[i]=exc2[i]=0;

      /* If we have a long-term predictor (otherwise, something's wrong) */
      if (SUBMODE(ltp_quant))
      {
         int pit_min, pit_max;
         /* Long-term prediction */
         if (SUBMODE(lbr_pitch) != -1)
         {
            /* Low bit-rate pitch handling */
            int margin;
            margin = SUBMODE(lbr_pitch);
            if (margin)
            {
               if (ol_pitch < st->min_pitch+margin-1)
                  ol_pitch=st->min_pitch+margin-1;
               if (ol_pitch > st->max_pitch-margin)
                  ol_pitch=st->max_pitch-margin;
               pit_min = ol_pitch-margin+1;
               pit_max = ol_pitch+margin;
            } else {
               pit_min=pit_max=ol_pitch;
            }
         } else {
            pit_min = st->min_pitch;
            pit_max = st->max_pitch;
         }
         
         /* Force pitch to use only the current frame if needed */
         if (st->bounded_pitch && pit_max>offset)
            pit_max=offset;

#ifdef EPIC_48K
         if (st->lbr_48k)
         {
            pitch = SUBMODE(ltp_quant)(target, sw, st->interp_qlpc, st->bw_lpc1, st->bw_lpc2,
                                       exc, SUBMODE(ltp_params), pit_min, pit_max, ol_pitch_coef,
                                       st->lpcSize, st->subframeSize, bits, stack, 
                                       exc2, syn_resp, st->complexity, ol_pitch_id);
         } else {
#endif

         /* Perform pitch search */
         pitch = SUBMODE(ltp_quant)(target, sw, st->interp_qlpc, st->bw_lpc1, st->bw_lpc2,
                                    exc, SUBMODE(ltp_params), pit_min, pit_max, ol_pitch_coef,
                                    st->lpcSize, st->subframeSize, bits, stack, 
                                    exc2, syn_resp, st->complexity, 0);
#ifdef EPIC_48K
         }
#endif

         st->pitch[sub]=pitch;
      } else {
         speex_error ("No pitch prediction, what's wrong");
      }

      /* Update target for adaptive codebook contribution */
      syn_percep_zero(exc, st->interp_qlpc, st->bw_lpc1, st->bw_lpc2, res, st->subframeSize, st->lpcSize, stack);
      for (i=0;i<st->subframeSize;i++)
         target[i]=SATURATE(SUB32(target[i],res[i]),805306368);


      /* Quantization of innovation */
      {
         spx_sig_t *innov;
         spx_word32_t ener=0;
         spx_word16_t fine_gain;

         innov = st->innov+sub*st->subframeSize;
         for (i=0;i<st->subframeSize;i++)
            innov[i]=0;
         
         residue_percep_zero(target, st->interp_qlpc, st->bw_lpc1, st->bw_lpc2, st->buf2, st->subframeSize, st->lpcSize, stack);

         ener = SHL(compute_rms(st->buf2, st->subframeSize),SIG_SHIFT);

         /*for (i=0;i<st->subframeSize;i++)
            printf ("%f\n", st->buf2[i]/ener);
         */
         
         /*FIXME: Should use DIV32_16 and make sure result fits in 16 bits */
#ifdef FIXED_POINT
         {
            spx_word32_t f = DIV32(ener,PSHR(ol_gain,SIG_SHIFT));
            if (f<32768)
               fine_gain = f;
            else
               fine_gain = 32767;
         }
#else
         fine_gain = DIV32_16(ener,PSHR(ol_gain,SIG_SHIFT));
#endif
         /* Calculate gain correction for the sub-frame (if any) */
         if (SUBMODE(have_subframe_gain)) 
         {
            int qe;
            if (SUBMODE(have_subframe_gain)==3)
            {
               qe = scal_quant(fine_gain, exc_gain_quant_scal3_bound, 8);
               speex_bits_pack(bits, qe, 3);
               ener=MULT16_32_Q14(exc_gain_quant_scal3[qe],ol_gain);
            } else {
               qe = scal_quant(fine_gain, exc_gain_quant_scal1_bound, 2);
               speex_bits_pack(bits, qe, 1);
               ener=MULT16_32_Q14(exc_gain_quant_scal1[qe],ol_gain);               
            }
         } else {
            ener=ol_gain;
         }

         /*printf ("%f %f\n", ener, ol_gain);*/

         /* Normalize innovation */
         signal_div(target, target, ener, st->subframeSize);

         /* Quantize innovation */
         if (SUBMODE(innovation_quant))
         {
            /* Codebook search */
            SUBMODE(innovation_quant)(target, st->interp_qlpc, st->bw_lpc1, st->bw_lpc2, 
                                      SUBMODE(innovation_params), st->lpcSize, st->subframeSize, 
                                      innov, syn_resp, bits, stack, st->complexity);
            
            /* De-normalize innovation and update excitation */
            signal_mul(innov, innov, ener, st->subframeSize);

            for (i=0;i<st->subframeSize;i++)
               exc[i] += innov[i];
         } else {
            speex_error("No fixed codebook");
         }

         /* In some (rare) modes, we do a second search (more bits) to reduce noise even more */
         if (SUBMODE(double_codebook)) {
            char *tmp_stack=stack;
            spx_sig_t *innov2 = PUSH(tmp_stack, st->subframeSize, spx_sig_t);
            for (i=0;i<st->subframeSize;i++)
               innov2[i]=0;
            for (i=0;i<st->subframeSize;i++)
               target[i]*=2.2;
            SUBMODE(innovation_quant)(target, st->interp_qlpc, st->bw_lpc1, st->bw_lpc2, 
                                      SUBMODE(innovation_params), st->lpcSize, st->subframeSize, 
                                      innov2, syn_resp, bits, tmp_stack, st->complexity);
            signal_mul(innov2, innov2, ener*(1/2.2), st->subframeSize);
            for (i=0;i<st->subframeSize;i++)
               exc[i] += innov2[i];
         }

         signal_mul(target, target, ener, st->subframeSize);
      }

      /*Keep the previous memory*/
      for (i=0;i<st->lpcSize;i++)
         mem[i]=st->mem_sp[i];
      /* Final signal synthesis from excitation */
      iir_mem2(exc, st->interp_qlpc, sp, st->subframeSize, st->lpcSize, st->mem_sp);

      /* Compute weighted signal again, from synthesized speech (not sure it's the right thing) */
      filter_mem2(sp, st->bw_lpc1, st->bw_lpc2, sw, st->subframeSize, st->lpcSize, st->mem_sw);
      for (i=0;i<st->subframeSize;i++)
         exc2[i]=exc[i];
   }

   /* Store the LSPs for interpolation in the next frame */
   if (st->submodeID>=1)
   {
      for (i=0;i<st->lpcSize;i++)
         st->old_lsp[i] = st->lsp[i];
      for (i=0;i<st->lpcSize;i++)
         st->old_qlsp[i] = st->qlsp[i];
   }

   if (st->submodeID==1)
   {
      if (st->dtx_count)
         speex_bits_pack(bits, 15, 4);
      else
         speex_bits_pack(bits, 0, 4);
   }

   /* The next frame will not be the first (Duh!) */
   st->first = 0;

   if (0) {
      float ener=0, err=0;
      float snr;
      for (i=0;i<st->frameSize;i++)
      {
         ener+=st->frame[i]*st->frame[i];
         err += (st->frame[i]-orig[i])*(st->frame[i]-orig[i]);
      }
      snr = 10*log10((ener+1)/(err+1));
      /*printf ("%f %f %f\n", snr, ener, err);*/
   }

   /* Replace input by synthesized speech */
   for (i=0;i<st->frameSize;i++)
   {
      spx_word32_t sig = PSHR(st->frame[i],SIG_SHIFT);
      if (sig>32767)
         sig = 32767;
      if (sig<-32767)
         sig = -32767;
     in[i]=sig;
   }

   if (SUBMODE(innovation_quant) == noise_codebook_quant || st->submodeID==0)
      st->bounded_pitch = 1;
   else
      st->bounded_pitch = 0;

   return 1;
}


void *nb_decoder_init(const SpeexMode *m)
{
   DecState *st;
   const SpeexNBMode *mode;
   int i;

   mode=(SpeexNBMode*)m->mode;
   st = (DecState *)speex_alloc(sizeof(DecState)+4000*sizeof(spx_sig_t));
   st->mode=m;

   st->stack = ((char*)st) + sizeof(DecState);

   st->encode_submode = 1;
#ifdef EPIC_48K
   st->lbr_48k=mode->lbr48k;
#endif

   st->first=1;
   /* Codec parameters, should eventually have several "modes"*/
   st->frameSize = mode->frameSize;
   st->windowSize = st->frameSize*3/2;
   st->nbSubframes=mode->frameSize/mode->subframeSize;
   st->subframeSize=mode->subframeSize;
   st->lpcSize = mode->lpcSize;