--- /dev/null
+/*
+ * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
+ * Universitaet Berlin. See the accompanying file "COPYRIGHT" for
+ * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <assert.h>
+
+#include "gsm610_priv.h"
+
+/* 4.2.13 .. 4.2.17 RPE ENCODING SECTION
+ */
+
+/* 4.2.13 */
+
+static void Weighting_filter (
+ register word * e, /* signal [-5..0.39.44] IN */
+ word * x /* signal [0..39] OUT */
+)
+/*
+ * The coefficients of the weighting filter are stored in a table
+ * (see table 4.4). The following scaling is used:
+ *
+ * H[0..10] = integer( real_H[ 0..10] * 8192 );
+ */
+{
+ /* word wt[ 50 ]; */
+
+ register longword L_result;
+ register int k /* , i */ ;
+
+ /* Initialization of a temporary working array wt[0...49]
+ */
+
+ /* for (k = 0; k <= 4; k++) wt[k] = 0;
+ * for (k = 5; k <= 44; k++) wt[k] = *e++;
+ * for (k = 45; k <= 49; k++) wt[k] = 0;
+ *
+ * (e[-5..-1] and e[40..44] are allocated by the caller,
+ * are initially zero and are not written anywhere.)
+ */
+ e -= 5;
+
+ /* Compute the signal x[0..39]
+ */
+ for (k = 0; k <= 39; k++) {
+
+ L_result = 8192 >> 1;
+
+ /* for (i = 0; i <= 10; i++) {
+ * L_temp = GSM_L_MULT( wt[k+i], gsm_H[i] );
+ * L_result = GSM_L_ADD( L_result, L_temp );
+ * }
+ */
+
+#undef STEP
+#define STEP( i, H ) (e[ k + i ] * (longword)H)
+
+ /* Every one of these multiplications is done twice --
+ * but I don't see an elegant way to optimize this.
+ * Do you?
+ */
+
+#ifdef STUPID_COMPILER
+ L_result += STEP( 0, -134 ) ;
+ L_result += STEP( 1, -374 ) ;
+ /* + STEP( 2, 0 ) */
+ L_result += STEP( 3, 2054 ) ;
+ L_result += STEP( 4, 5741 ) ;
+ L_result += STEP( 5, 8192 ) ;
+ L_result += STEP( 6, 5741 ) ;
+ L_result += STEP( 7, 2054 ) ;
+ /* + STEP( 8, 0 ) */
+ L_result += STEP( 9, -374 ) ;
+ L_result += STEP( 10, -134 ) ;
+#else
+ L_result +=
+ STEP( 0, -134 )
+ + STEP( 1, -374 )
+ /* + STEP( 2, 0 ) */
+ + STEP( 3, 2054 )
+ + STEP( 4, 5741 )
+ + STEP( 5, 8192 )
+ + STEP( 6, 5741 )
+ + STEP( 7, 2054 )
+ /* + STEP( 8, 0 ) */
+ + STEP( 9, -374 )
+ + STEP(10, -134 )
+ ;
+#endif
+
+ /* L_result = GSM_L_ADD( L_result, L_result ); (* scaling(x2) *)
+ * L_result = GSM_L_ADD( L_result, L_result ); (* scaling(x4) *)
+ *
+ * x[k] = SASR( L_result, 16 );
+ */
+
+ /* 2 adds vs. >>16 => 14, minus one shift to compensate for
+ * those we lost when replacing L_MULT by '*'.
+ */
+
+ L_result = SASR_L( L_result, 13 );
+ x[k] = ( L_result < MIN_WORD ? MIN_WORD
+ : (L_result > MAX_WORD ? MAX_WORD : L_result ));
+ }
+}
+
+/* 4.2.14 */
+
+static void RPE_grid_selection (
+ word * x, /* [0..39] IN */
+ word * xM, /* [0..12] OUT */
+ word * Mc_out /* OUT */
+)
+/*
+ * The signal x[0..39] is used to select the RPE grid which is
+ * represented by Mc.
+ */
+{
+ /* register word temp1; */
+ register int /* m, */ i;
+ register longword L_result, L_temp;
+ longword EM; /* xxx should be L_EM? */
+ word Mc;
+
+ longword L_common_0_3;
+
+ EM = 0;
+ Mc = 0;
+
+ /* for (m = 0; m <= 3; m++) {
+ * L_result = 0;
+ *
+ *
+ * for (i = 0; i <= 12; i++) {
+ *
+ * temp1 = SASR_W( x[m + 3*i], 2 );
+ *
+ * assert(temp1 != MIN_WORD);
+ *
+ * L_temp = GSM_L_MULT( temp1, temp1 );
+ * L_result = GSM_L_ADD( L_temp, L_result );
+ * }
+ *
+ * if (L_result > EM) {
+ * Mc = m;
+ * EM = L_result;
+ * }
+ * }
+ */
+
+#undef STEP
+#define STEP( m, i ) L_temp = SASR_W( x[m + 3 * i], 2 ); \
+ L_result += L_temp * L_temp;
+
+ /* common part of 0 and 3 */
+
+ L_result = 0;
+ STEP( 0, 1 ); STEP( 0, 2 ); STEP( 0, 3 ); STEP( 0, 4 );
+ STEP( 0, 5 ); STEP( 0, 6 ); STEP( 0, 7 ); STEP( 0, 8 );
+ STEP( 0, 9 ); STEP( 0, 10); STEP( 0, 11); STEP( 0, 12);
+ L_common_0_3 = L_result;
+
+ /* i = 0 */
+
+ STEP( 0, 0 );
+ L_result <<= 1; /* implicit in L_MULT */
+ EM = L_result;
+
+ /* i = 1 */
+
+ L_result = 0;
+ STEP( 1, 0 );
+ STEP( 1, 1 ); STEP( 1, 2 ); STEP( 1, 3 ); STEP( 1, 4 );
+ STEP( 1, 5 ); STEP( 1, 6 ); STEP( 1, 7 ); STEP( 1, 8 );
+ STEP( 1, 9 ); STEP( 1, 10); STEP( 1, 11); STEP( 1, 12);
+ L_result <<= 1;
+ if (L_result > EM) {
+ Mc = 1;
+ EM = L_result;
+ }
+
+ /* i = 2 */
+
+ L_result = 0;
+ STEP( 2, 0 );
+ STEP( 2, 1 ); STEP( 2, 2 ); STEP( 2, 3 ); STEP( 2, 4 );
+ STEP( 2, 5 ); STEP( 2, 6 ); STEP( 2, 7 ); STEP( 2, 8 );
+ STEP( 2, 9 ); STEP( 2, 10); STEP( 2, 11); STEP( 2, 12);
+ L_result <<= 1;
+ if (L_result > EM) {
+ Mc = 2;
+ EM = L_result;
+ }
+
+ /* i = 3 */
+
+ L_result = L_common_0_3;
+ STEP( 3, 12 );
+ L_result <<= 1;
+ if (L_result > EM) {
+ Mc = 3;
+ EM = L_result;
+ }
+
+ /**/
+
+ /* Down-sampling by a factor 3 to get the selected xM[0..12]
+ * RPE sequence.
+ */
+ for (i = 0; i <= 12; i ++) xM[i] = x[Mc + 3*i];
+ *Mc_out = Mc;
+}
+
+/* 4.12.15 */
+
+static void APCM_quantization_xmaxc_to_exp_mant (
+ word xmaxc, /* IN */
+ word * expon_out, /* OUT */
+ word * mant_out ) /* OUT */
+{
+ word expon, mant;
+
+ /* Compute expononent and mantissa of the decoded version of xmaxc
+ */
+
+ expon = 0;
+ if (xmaxc > 15) expon = SASR_W(xmaxc, 3) - 1;
+ mant = xmaxc - (expon << 3);
+
+ if (mant == 0) {
+ expon = -4;
+ mant = 7;
+ }
+ else {
+ while (mant <= 7) {
+ mant = mant << 1 | 1;
+ expon--;
+ }
+ mant -= 8;
+ }
+
+ assert( expon >= -4 && expon <= 6 );
+ assert( mant >= 0 && mant <= 7 );
+
+ *expon_out = expon;
+ *mant_out = mant;
+}
+
+static void APCM_quantization (
+ word * xM, /* [0..12] IN */
+ word * xMc, /* [0..12] OUT */
+ word * mant_out, /* OUT */
+ word * expon_out, /* OUT */
+ word * xmaxc_out /* OUT */
+)
+{
+ int i, itest;
+
+ word xmax, xmaxc, temp, temp1, temp2;
+ word expon, mant;
+
+
+ /* Find the maximum absolute value xmax of xM[0..12].
+ */
+
+ xmax = 0;
+ for (i = 0; i <= 12; i++) {
+ temp = xM[i];
+ temp = GSM_ABS(temp);
+ if (temp > xmax) xmax = temp;
+ }
+
+ /* Qantizing and coding of xmax to get xmaxc.
+ */
+
+ expon = 0;
+ temp = SASR_W( xmax, 9 );
+ itest = 0;
+
+ for (i = 0; i <= 5; i++) {
+
+ itest |= (temp <= 0);
+ temp = SASR_W( temp, 1 );
+
+ assert(expon <= 5);
+ if (itest == 0) expon++; /* expon = add (expon, 1) */
+ }
+
+ assert(expon <= 6 && expon >= 0);
+ temp = expon + 5;
+
+ assert(temp <= 11 && temp >= 0);
+ xmaxc = gsm_add( SASR_W(xmax, temp), (word) (expon << 3) );
+
+ /* Quantizing and coding of the xM[0..12] RPE sequence
+ * to get the xMc[0..12]
+ */
+
+ APCM_quantization_xmaxc_to_exp_mant( xmaxc, &expon, &mant );
+
+ /* This computation uses the fact that the decoded version of xmaxc
+ * can be calculated by using the expononent and the mantissa part of
+ * xmaxc (logarithmic table).
+ * So, this method avoids any division and uses only a scaling
+ * of the RPE samples by a function of the expononent. A direct
+ * multiplication by the inverse of the mantissa (NRFAC[0..7]
+ * found in table 4.5) gives the 3 bit coded version xMc[0..12]
+ * of the RPE samples.
+ */
+
+
+ /* Direct computation of xMc[0..12] using table 4.5
+ */
+
+ assert( expon <= 4096 && expon >= -4096);
+ assert( mant >= 0 && mant <= 7 );
+
+ temp1 = 6 - expon; /* normalization by the expononent */
+ temp2 = gsm_NRFAC[ mant ]; /* inverse mantissa */
+
+ for (i = 0; i <= 12; i++) {
+
+ assert(temp1 >= 0 && temp1 < 16);
+
+ temp = xM[i] << temp1;
+ temp = GSM_MULT( temp, temp2 );
+ temp = SASR_W(temp, 12);
+ xMc[i] = temp + 4; /* see note below */
+ }
+
+ /* NOTE: This equation is used to make all the xMc[i] positive.
+ */
+
+ *mant_out = mant;
+ *expon_out = expon;
+ *xmaxc_out = xmaxc;
+}
+
+/* 4.2.16 */
+
+static void APCM_inverse_quantization (
+ register word * xMc, /* [0..12] IN */
+ word mant,
+ word expon,
+ register word * xMp) /* [0..12] OUT */
+/*
+ * This part is for decoding the RPE sequence of coded xMc[0..12]
+ * samples to obtain the xMp[0..12] array. Table 4.6 is used to get
+ * the mantissa of xmaxc (FAC[0..7]).
+ */
+{
+ int i;
+ word temp, temp1, temp2, temp3;
+
+ assert( mant >= 0 && mant <= 7 );
+
+ temp1 = gsm_FAC[ mant ]; /* see 4.2-15 for mant */
+ temp2 = gsm_sub( 6, expon ); /* see 4.2-15 for exp */
+ temp3 = gsm_asl( 1, gsm_sub( temp2, 1 ));
+
+ for (i = 13; i--;) {
+
+ assert( *xMc <= 7 && *xMc >= 0 ); /* 3 bit unsigned */
+
+ /* temp = gsm_sub( *xMc++ << 1, 7 ); */
+ temp = (*xMc++ << 1) - 7; /* restore sign */
+ assert( temp <= 7 && temp >= -7 ); /* 4 bit signed */
+
+ temp <<= 12; /* 16 bit signed */
+ temp = GSM_MULT_R( temp1, temp );
+ temp = GSM_ADD( temp, temp3 );
+ *xMp++ = gsm_asr( temp, temp2 );
+ }
+}
+
+/* 4.2.17 */
+
+static void RPE_grid_positioning (
+ word Mc, /* grid position IN */
+ register word * xMp, /* [0..12] IN */
+ register word * ep /* [0..39] OUT */
+)
+/*
+ * This procedure computes the reconstructed long term residual signal
+ * ep[0..39] for the LTP analysis filter. The inputs are the Mc
+ * which is the grid position selection and the xMp[0..12] decoded
+ * RPE samples which are upsampled by a factor of 3 by inserting zero
+ * values.
+ */
+{
+ int i = 13;
+
+ assert(0 <= Mc && Mc <= 3);
+
+ switch (Mc) {
+ case 3: *ep++ = 0;
+ case 2: do {
+ *ep++ = 0;
+ case 1: *ep++ = 0;
+ case 0: *ep++ = *xMp++;
+ } while (--i);
+ }
+ while (++Mc < 4) *ep++ = 0;
+
+ /*
+
+ int i, k;
+ for (k = 0; k <= 39; k++) ep[k] = 0;
+ for (i = 0; i <= 12; i++) {
+ ep[ Mc + (3*i) ] = xMp[i];
+ }
+ */
+}
+
+/* 4.2.18 */
+
+/* This procedure adds the reconstructed long term residual signal
+ * ep[0..39] to the estimated signal dpp[0..39] from the long term
+ * analysis filter to compute the reconstructed short term residual
+ * signal dp[-40..-1]; also the reconstructed short term residual
+ * array dp[-120..-41] is updated.
+ */
+
+#if 0 /* Has been inlined in code.c */
+void Gsm_Update_of_reconstructed_short_time_residual_signal (
+ word * dpp, /* [0...39] IN */
+ word * ep, /* [0...39] IN */
+ word * dp) /* [-120...-1] IN/OUT */
+{
+ int k;
+
+ for (k = 0; k <= 79; k++)
+ dp[ -120 + k ] = dp[ -80 + k ];
+
+ for (k = 0; k <= 39; k++)
+ dp[ -40 + k ] = gsm_add( ep[k], dpp[k] );
+}
+#endif /* Has been inlined in code.c */
+
+void Gsm_RPE_Encoding (
+ /*-struct gsm_state * S,-*/
+
+ word * e, /* -5..-1][0..39][40..44 IN/OUT */
+ word * xmaxc, /* OUT */
+ word * Mc, /* OUT */
+ word * xMc) /* [0..12] OUT */
+{
+ word x[40];
+ word xM[13], xMp[13];
+ word mant, expon;
+
+ Weighting_filter(e, x);
+ RPE_grid_selection(x, xM, Mc);
+
+ APCM_quantization( xM, xMc, &mant, &expon, xmaxc);
+ APCM_inverse_quantization( xMc, mant, expon, xMp);
+
+ RPE_grid_positioning( *Mc, xMp, e );
+
+}
+
+void Gsm_RPE_Decoding (
+ /*-struct gsm_state * S,-*/
+
+ word xmaxcr,
+ word Mcr,
+ word * xMcr, /* [0..12], 3 bits IN */
+ word * erp /* [0..39] OUT */
+)
+{
+ word expon, mant;
+ word xMp[ 13 ];
+
+ APCM_quantization_xmaxc_to_exp_mant( xmaxcr, &expon, &mant );
+ APCM_inverse_quantization( xMcr, mant, expon, xMp );
+ RPE_grid_positioning( Mcr, xMp, erp );
+
+}
projects / Faustine.git / blobdiff