/*____________________________________________________________________________ FreeAmp - The Free MP3 Player MP3 Decoder originally Copyright (C) 1995-1997 Xing Technology Corp. http://www.xingtech.com Portions Copyright (C) 1998-1999 EMusic.com This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. $Id: hwin.c,v 1.5 1999/10/19 07:13:08 elrod Exp $ ____________________________________________________________________________*/ /**** hwin.c *************************************************** Layer III hybrid window/filter ******************************************************************/ #include #include #include #include #include "mp3struct.h" ////@@@@extern int band_limit_nsb; typedef float ARRAY36[36]; /*-- windows by block type --*/ static float win[4][36]; // effectively a constant /*====================================================================*/ void imdct18(float f[]); /* 18 point */ void imdct6_3(float f[]); /* 6 point */ /*====================================================================*/ ARRAY36 *hwin_init_addr() { return win; } /*====================================================================*/ int hybrid(float xin[], float xprev[], float y[18][32], int btype, int nlong, int ntot, int nprev) { int i, j; float *x, *x0; float xa, xb; int n; int nout; if (btype == 2) btype = 0; x = xin; x0 = xprev; /*-- do long blocks (if any) --*/ n = (nlong + 17) / 18; /* number of dct's to do */ for (i = 0; i < n; i++) { imdct18(x); for (j = 0; j < 9; j++) { y[j][i] = x0[j] + win[btype][j] * x[9 + j]; y[9 + j][i] = x0[9 + j] + win[btype][9 + j] * x[17 - j]; } /* window x for next time x0 */ for (j = 0; j < 4; j++) { xa = x[j]; xb = x[8 - j]; x[j] = win[btype][18 + j] * xb; x[8 - j] = win[btype][(18 + 8) - j] * xa; x[9 + j] = win[btype][(18 + 9) + j] * xa; x[17 - j] = win[btype][(18 + 17) - j] * xb; } xa = x[j]; x[j] = win[btype][18 + j] * xa; x[9 + j] = win[btype][(18 + 9) + j] * xa; x += 18; x0 += 18; } /*-- do short blocks (if any) --*/ n = (ntot + 17) / 18; /* number of 6 pt dct's triples to do */ for (; i < n; i++) { imdct6_3(x); for (j = 0; j < 3; j++) { y[j][i] = x0[j]; y[3 + j][i] = x0[3 + j]; y[6 + j][i] = x0[6 + j] + win[2][j] * x[3 + j]; y[9 + j][i] = x0[9 + j] + win[2][3 + j] * x[5 - j]; y[12 + j][i] = x0[12 + j] + win[2][6 + j] * x[2 - j] + win[2][j] * x[(6 + 3) + j]; y[15 + j][i] = x0[15 + j] + win[2][9 + j] * x[j] + win[2][3 + j] * x[(6 + 5) - j]; } /* window x for next time x0 */ for (j = 0; j < 3; j++) { x[j] = win[2][6 + j] * x[(6 + 2) - j] + win[2][j] * x[(12 + 3) + j]; x[3 + j] = win[2][9 + j] * x[6 + j] + win[2][3 + j] * x[(12 + 5) - j]; } for (j = 0; j < 3; j++) { x[6 + j] = win[2][6 + j] * x[(12 + 2) - j]; x[9 + j] = win[2][9 + j] * x[12 + j]; } for (j = 0; j < 3; j++) { x[12 + j] = 0.0f; x[15 + j] = 0.0f; } x += 18; x0 += 18; } /*--- overlap prev if prev longer that current --*/ n = (nprev + 17) / 18; for (; i < n; i++) { for (j = 0; j < 18; j++) y[j][i] = x0[j]; x0 += 18; } nout = 18 * i; /*--- clear remaining only to band limit --*/ for (; i < pMP3Stream->band_limit_nsb; i++) { for (j = 0; j < 18; j++) y[j][i] = 0.0f; } return nout; } /*--------------------------------------------------------------------*/ /*--------------------------------------------------------------------*/ /*-- convert to mono, add curr result to y, window and add next time to current left */ int hybrid_sum(float xin[], float xin_left[], float y[18][32], int btype, int nlong, int ntot) { int i, j; float *x, *x0; float xa, xb; int n; int nout; if (btype == 2) btype = 0; x = xin; x0 = xin_left; /*-- do long blocks (if any) --*/ n = (nlong + 17) / 18; /* number of dct's to do */ for (i = 0; i < n; i++) { imdct18(x); for (j = 0; j < 9; j++) { y[j][i] += win[btype][j] * x[9 + j]; y[9 + j][i] += win[btype][9 + j] * x[17 - j]; } /* window x for next time x0 */ for (j = 0; j < 4; j++) { xa = x[j]; xb = x[8 - j]; x0[j] += win[btype][18 + j] * xb; x0[8 - j] += win[btype][(18 + 8) - j] * xa; x0[9 + j] += win[btype][(18 + 9) + j] * xa; x0[17 - j] += win[btype][(18 + 17) - j] * xb; } xa = x[j]; x0[j] += win[btype][18 + j] * xa; x0[9 + j] += win[btype][(18 + 9) + j] * xa; x += 18; x0 += 18; } /*-- do short blocks (if any) --*/ n = (ntot + 17) / 18; /* number of 6 pt dct's triples to do */ for (; i < n; i++) { imdct6_3(x); for (j = 0; j < 3; j++) { y[6 + j][i] += win[2][j] * x[3 + j]; y[9 + j][i] += win[2][3 + j] * x[5 - j]; y[12 + j][i] += win[2][6 + j] * x[2 - j] + win[2][j] * x[(6 + 3) + j]; y[15 + j][i] += win[2][9 + j] * x[j] + win[2][3 + j] * x[(6 + 5) - j]; } /* window x for next time */ for (j = 0; j < 3; j++) { x0[j] += win[2][6 + j] * x[(6 + 2) - j] + win[2][j] * x[(12 + 3) + j]; x0[3 + j] += win[2][9 + j] * x[6 + j] + win[2][3 + j] * x[(12 + 5) - j]; } for (j = 0; j < 3; j++) { x0[6 + j] += win[2][6 + j] * x[(12 + 2) - j]; x0[9 + j] += win[2][9 + j] * x[12 + j]; } x += 18; x0 += 18; } nout = 18 * i; return nout; } /*--------------------------------------------------------------------*/ void sum_f_bands(float a[], float b[], int n) { int i; for (i = 0; i < n; i++) a[i] += b[i]; } /*--------------------------------------------------------------------*/ /*--------------------------------------------------------------------*/ void FreqInvert(float y[18][32], int n) { int i, j; n = (n + 17) / 18; for (j = 0; j < 18; j += 2) { for (i = 0; i < n; i += 2) { y[1 + j][1 + i] = -y[1 + j][1 + i]; } } } /*--------------------------------------------------------------------*/