# HG changeset patch # User Mychaela Falconia # Date 1713056479 0 # Node ID 65d3304502bd940cdbeb261ba88f08a6ec15e663 # Parent 8821ffaa93a5549a50e6ecec7627a8363c9f99f9 libgsmfr2: integrate long_term.c from libgsm diff -r 8821ffaa93a5 -r 65d3304502bd libgsmfr2/Makefile --- a/libgsmfr2/Makefile Sun Apr 14 00:36:16 2024 +0000 +++ b/libgsmfr2/Makefile Sun Apr 14 01:01:19 2024 +0000 @@ -1,8 +1,8 @@ CC= gcc CFLAGS= -O2 -OBJS= add.o comfort_noise.o dec_main.o ed_state.o enc_main.o pack_frame.o \ - pack_frame2.o pp_bad.o pp_good.o pp_state.o prng.o sidclass.o \ - silence_frame.o unpack_frame.o unpack_frame2.o xmaxc_mean.o +OBJS= add.o comfort_noise.o dec_main.o ed_state.o enc_main.o long_term.o \ + pack_frame.o pack_frame2.o pp_bad.o pp_good.o pp_state.o prng.o \ + sidclass.o silence_frame.o unpack_frame.o unpack_frame2.o xmaxc_mean.o HDRS= ed_internal.h ed_state.h pp_internal.h pp_state.h tw_gsmfr.h typedef.h LIB= libgsmfr2.a diff -r 8821ffaa93a5 -r 65d3304502bd libgsmfr2/long_term.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libgsmfr2/long_term.c Sun Apr 14 01:01:19 2024 +0000 @@ -0,0 +1,266 @@ +/* + * This C source file has been adapted from TU-Berlin libgsm source, + * original notice follows: + * + * 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 +#include +#include "tw_gsmfr.h" +#include "typedef.h" +#include "ed_state.h" +#include "ed_internal.h" + +/* + * 4.2.11 .. 4.2.12 LONG TERM PREDICTOR (LTP) SECTION + */ + + +/* + * This module computes the LTP gain (bc) and the LTP lag (Nc) + * for the long term analysis filter. This is done by calculating a + * maximum of the cross-correlation function between the current + * sub-segment short term residual signal d[0..39] (output of + * the short term analysis filter; for simplification the index + * of this array begins at 0 and ends at 39 for each sub-segment of the + * RPE-LTP analysis) and the previous reconstructed short term + * residual signal dp[ -120 .. -1 ]. A dynamic scaling must be + * performed to avoid overflow. + */ + +static void Calculation_of_the_LTP_parameters ( + register word * d, /* [0..39] IN */ + register word * dp, /* [-120..-1] IN */ + word * bc_out, /* OUT */ + word * Nc_out /* OUT */ +) +{ + register int k, lambda; + word Nc, bc; + word wt[40]; + + longword L_max, L_power; + word R, S, dmax, scal; + register word temp; + + /* Search of the optimum scaling of d[0..39]. + */ + dmax = 0; + + for (k = 0; k <= 39; k++) { + temp = d[k]; + temp = GSM_ABS( temp ); + if (temp > dmax) dmax = temp; + } + + temp = 0; + if (dmax == 0) scal = 0; + else { + assert(dmax > 0); + temp = gsm_norm( (longword)dmax << 16 ); + } + + if (temp > 6) scal = 0; + else scal = 6 - temp; + + assert(scal >= 0); + + /* Initialization of a working array wt + */ + + for (k = 0; k <= 39; k++) wt[k] = SASR( d[k], scal ); + + /* Search for the maximum cross-correlation and coding of the LTP lag + */ + L_max = 0; + Nc = 40; /* index for the maximum cross-correlation */ + + for (lambda = 40; lambda <= 120; lambda++) { + +# undef STEP +# define STEP(k) (longword)wt[k] * dp[k - lambda] + + register longword L_result; + + L_result = STEP(0) ; L_result += STEP(1) ; + L_result += STEP(2) ; L_result += STEP(3) ; + L_result += STEP(4) ; L_result += STEP(5) ; + L_result += STEP(6) ; L_result += STEP(7) ; + L_result += STEP(8) ; L_result += STEP(9) ; + L_result += STEP(10) ; L_result += STEP(11) ; + L_result += STEP(12) ; L_result += STEP(13) ; + L_result += STEP(14) ; L_result += STEP(15) ; + L_result += STEP(16) ; L_result += STEP(17) ; + L_result += STEP(18) ; L_result += STEP(19) ; + L_result += STEP(20) ; L_result += STEP(21) ; + L_result += STEP(22) ; L_result += STEP(23) ; + L_result += STEP(24) ; L_result += STEP(25) ; + L_result += STEP(26) ; L_result += STEP(27) ; + L_result += STEP(28) ; L_result += STEP(29) ; + L_result += STEP(30) ; L_result += STEP(31) ; + L_result += STEP(32) ; L_result += STEP(33) ; + L_result += STEP(34) ; L_result += STEP(35) ; + L_result += STEP(36) ; L_result += STEP(37) ; + L_result += STEP(38) ; L_result += STEP(39) ; + + if (L_result > L_max) { + + Nc = lambda; + L_max = L_result; + } + } + + *Nc_out = Nc; + + L_max <<= 1; + + /* Rescaling of L_max + */ + assert(scal <= 100 && scal >= -100); + L_max = L_max >> (6 - scal); /* sub(6, scal) */ + + assert( Nc <= 120 && Nc >= 40); + + /* Compute the power of the reconstructed short term residual + * signal dp[..] + */ + L_power = 0; + for (k = 0; k <= 39; k++) { + + register longword L_temp; + + L_temp = SASR( dp[k - Nc], 3 ); + L_power += L_temp * L_temp; + } + L_power <<= 1; /* from L_MULT */ + + /* Normalization of L_max and L_power + */ + + if (L_max <= 0) { + *bc_out = 0; + return; + } + if (L_max >= L_power) { + *bc_out = 3; + return; + } + + temp = gsm_norm( L_power ); + + R = SASR( L_max << temp, 16 ); + S = SASR( L_power << temp, 16 ); + + /* Coding of the LTP gain + */ + + /* Table 4.3a must be used to obtain the level DLB[i] for the + * quantization of the LTP gain b to get the coded version bc. + */ + for (bc = 0; bc <= 2; bc++) if (R <= gsm_mult(S, gsm_DLB[bc])) break; + *bc_out = bc; +} + +/* 4.2.12 */ + +static void Long_term_analysis_filtering ( + word bc, /* IN */ + word Nc, /* IN */ + register word * dp, /* previous d [-120..-1] IN */ + register word * d, /* d [0..39] IN */ + register word * dpp, /* estimate [0..39] OUT */ + register word * e /* long term res. signal [0..39] OUT */ +) +/* + * In this part, we have to decode the bc parameter to compute + * the samples of the estimate dpp[0..39]. The decoding of bc needs the + * use of table 4.3b. The long term residual signal e[0..39] + * is then calculated to be fed to the RPE encoding section. + */ +{ + register int k; + register longword ltmp; + +# undef STEP +# define STEP(BP) \ + for (k = 0; k <= 39; k++) { \ + dpp[k] = GSM_MULT_R( BP, dp[k - Nc]); \ + e[k] = GSM_SUB( d[k], dpp[k] ); \ + } + + switch (bc) { + case 0: STEP( 3277 ); break; + case 1: STEP( 11469 ); break; + case 2: STEP( 21299 ); break; + case 3: STEP( 32767 ); break; + } +} + +void Gsm_Long_Term_Predictor ( /* 4x for 160 samples */ + struct gsmfr_0610_state * S, + + word * d, /* [0..39] residual signal IN */ + word * dp, /* [-120..-1] d' IN */ + + word * e, /* [0..39] OUT */ + word * dpp, /* [0..39] OUT */ + word * Nc, /* correlation lag OUT */ + word * bc /* gain factor OUT */ +) +{ + assert( d ); assert( dp ); assert( e ); + assert( dpp); assert( Nc ); assert( bc ); + + Calculation_of_the_LTP_parameters(d, dp, bc, Nc); + Long_term_analysis_filtering( *bc, *Nc, dp, d, dpp, e ); +} + +/* 4.3.2 */ +void Gsm_Long_Term_Synthesis_Filtering ( + struct gsmfr_0610_state * S, + + word Ncr, + word bcr, + register word * erp, /* [0..39] IN */ + register word * drp /* [-120..-1] IN, [-120..40] OUT */ +) +/* + * This procedure uses the bcr and Ncr parameter to realize the + * long term synthesis filtering. The decoding of bcr needs + * table 4.3b. + */ +{ + register longword ltmp; /* for ADD */ + register int k; + word brp, drpp, Nr; + + /* Check the limits of Nr. + */ + Nr = Ncr < 40 || Ncr > 120 ? S->nrp : Ncr; + S->nrp = Nr; + assert(Nr >= 40 && Nr <= 120); + + /* Decoding of the LTP gain bcr + */ + brp = gsm_QLB[ bcr ]; + + /* Computation of the reconstructed short term residual + * signal drp[0..39] + */ + assert(brp != MIN_WORD); + + for (k = 0; k <= 39; k++) { + drpp = GSM_MULT_R( brp, drp[ k - Nr ] ); + drp[k] = GSM_ADD( erp[k], drpp ); + } + + /* + * Update of the reconstructed short term residual signal + * drp[ -1..-120 ] + */ + + for (k = 0; k <= 119; k++) drp[ -120 + k ] = drp[ -80 + k ]; +}