diff options
Diffstat (limited to 'libs/libsndfile/src/GSM610/decode.c')
-rw-r--r-- | libs/libsndfile/src/GSM610/decode.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/libs/libsndfile/src/GSM610/decode.c b/libs/libsndfile/src/GSM610/decode.c new file mode 100644 index 0000000000..46db31825b --- /dev/null +++ b/libs/libsndfile/src/GSM610/decode.c @@ -0,0 +1,67 @@ +/* + * 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 "gsm610_priv.h" +#include "gsm.h" + +/* + * 4.3 FIXED POINT IMPLEMENTATION OF THE RPE-LTP DECODER + */ + +static void Postprocessing ( + struct gsm_state * S, + register word * s) +{ + register int k; + register word msr = S->msr; + register word tmp; + + for (k = 160; k--; s++) { + tmp = GSM_MULT_R( msr, 28180 ); + msr = GSM_ADD(*s, tmp); /* Deemphasis */ + *s = GSM_ADD(msr, msr) & 0xFFF8; /* Truncation & Upscaling */ + } + S->msr = msr; +} + +void Gsm_Decoder ( + struct gsm_state * S, + + word * LARcr, /* [0..7] IN */ + + word * Ncr, /* [0..3] IN */ + word * bcr, /* [0..3] IN */ + word * Mcr, /* [0..3] IN */ + word * xmaxcr, /* [0..3] IN */ + word * xMcr, /* [0..13*4] IN */ + + word * s) /* [0..159] OUT */ +{ + int j, k; + word erp[40], wt[160]; + word * drp = S->dp0 + 120; + + for (j=0; j <= 3; j++, xmaxcr++, bcr++, Ncr++, Mcr++, xMcr += 13) { + + Gsm_RPE_Decoding( /*-S,-*/ *xmaxcr, *Mcr, xMcr, erp ); + Gsm_Long_Term_Synthesis_Filtering( S, *Ncr, *bcr, erp, drp ); + + for (k = 0; k <= 39; k++) wt[ j * 40 + k ] = drp[ k ]; + } + + Gsm_Short_Term_Synthesis_Filter( S, LARcr, wt, s ); + Postprocessing(S, s); +} +/* +** Do not edit or modify anything in this comment block. +** The arch-tag line is a file identity tag for the GNU Arch +** revision control system. +** +** arch-tag: 11ae5b90-2e8b-400b-ac64-a69a1fc6cc41 +*/ + |