| 1 | //downmix.c: |
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| 2 | |
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| 3 | /* |
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| 4 | * Copyright (C) Philipp 'ph3-der-loewe' Schafft - December 2008 |
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| 5 | * |
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| 6 | * This file is part of libroardsp a part of RoarAudio, |
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| 7 | * a cross-platform sound system for both, home and professional use. |
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| 8 | * See README for details. |
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| 9 | * |
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| 10 | * This file is free software; you can redistribute it and/or modify |
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| 11 | * it under the terms of the GNU General Public License version 3 |
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| 12 | * as published by the Free Software Foundation. |
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| 13 | * |
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| 14 | * libroardsp is distributed in the hope that it will be useful, |
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| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 17 | * GNU General Public License for more details. |
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| 18 | * |
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| 19 | * You should have received a copy of the GNU General Public License |
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| 20 | * along with this software; see the file COPYING. If not, write to |
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| 21 | * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
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| 22 | * |
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| 23 | */ |
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| 24 | |
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| 25 | #include "libroardsp.h" |
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| 26 | |
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| 27 | int roardsp_downmix_init (struct roardsp_filter * filter, struct roar_stream * stream, int id) { |
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| 28 | int mode = ROARDSP_DOWNMIX_ARITHMETIC; |
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| 29 | |
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| 30 | roardsp_downmix_ctl(filter, ROARDSP_FCTL_MODE, &mode); |
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| 31 | |
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| 32 | ROAR_DBG("roardsp_downmix_init(*) = 0"); |
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| 33 | return 0; |
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| 34 | } |
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| 35 | |
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| 36 | int roardsp_downmix_calc162 (struct roardsp_filter * filter, void * data, size_t samples) { |
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| 37 | int16_t * samp = (int16_t *) data; |
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| 38 | register int32_t mode = (ROAR_INSTINT)filter->inst; |
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| 39 | register union { |
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| 40 | int32_t i32; |
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| 41 | int64_t i64; |
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| 42 | } s; |
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| 43 | size_t i; |
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| 44 | |
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| 45 | ROAR_DBG("roardsp_downmix_calc162(*): mode=%i", mode); |
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| 46 | |
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| 47 | switch (mode) { |
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| 48 | case ROARDSP_DOWNMIX_ARITHMETIC: |
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| 49 | for (i = 0; i < samples; i += 2) { |
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| 50 | s.i32 = (samp[i] + samp[i+1])/2; |
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| 51 | samp[i ] = s.i32; |
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| 52 | samp[i+1] = s.i32; |
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| 53 | } |
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| 54 | break; |
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| 55 | case ROARDSP_DOWNMIX_RMS: |
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| 56 | for (i = 0; i < samples; i += 2) { |
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| 57 | s.i64 = (int64_t)samp[i]*samp[i] + (int64_t)samp[i+1]*samp[i+1]; |
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| 58 | s.i64 = sqrt(s.i64); |
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| 59 | s.i64 /= 2; |
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| 60 | |
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| 61 | if ( (samp[i] + samp[i+1]) < 0 ) |
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| 62 | s.i64 *= -1; |
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| 63 | |
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| 64 | samp[i ] = s.i64; |
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| 65 | samp[i+1] = s.i64; |
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| 66 | } |
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| 67 | break; |
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| 68 | default: |
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| 69 | ROAR_DBG("roardsp_downmix_calc162(*) = -1 // unknown mode"); |
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| 70 | return -1; |
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| 71 | break; |
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| 72 | } |
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| 73 | |
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| 74 | ROAR_DBG("roardsp_downmix_calc162(*) = 0"); |
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| 75 | return 0; |
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| 76 | } |
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| 77 | |
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| 78 | int roardsp_downmix_ctl (struct roardsp_filter * filter, int cmd, void * data) { |
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| 79 | int32_t old; |
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| 80 | |
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| 81 | if ( cmd == ROARDSP_FCTL_MODE ) { |
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| 82 | old = (ROAR_INSTINT)filter->inst; |
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| 83 | filter->inst = (void*)(ROAR_INSTINT)*(int32_t*)data; |
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| 84 | *(int32_t*)data = old; |
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| 85 | } else { |
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| 86 | return -1; |
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| 87 | } |
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| 88 | |
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| 89 | |
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| 90 | return 0; |
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| 91 | } |
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| 92 | |
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| 93 | //ll |
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