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Diffstat (limited to 'src/libac3/downmix.c')
| -rw-r--r-- | src/libac3/downmix.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/src/libac3/downmix.c b/src/libac3/downmix.c new file mode 100644 index 000000000..df71d5e3d --- /dev/null +++ b/src/libac3/downmix.c @@ -0,0 +1,158 @@ +/* + * imdct.c + * + * Copyright (C) Aaron Holtzman - May 1999 + * + * This file is part of ac3dec, a free Dolby AC-3 stream decoder. + * + * ac3dec 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, or (at your option) + * any later version. + * + * ac3dec 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 GNU Make; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + * + * + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <stdlib.h> +#include <stdio.h> +#include <math.h> + +#include "ac3.h" +#include "ac3_internal.h" + +#include "downmix.h" + +void downmix_3f_2r_to_2ch (float *samples, dm_par_t *dm_par) +{ + int i; + float *left, *right, *center, *left_sur, *right_sur; + float left_tmp, right_tmp; + + left = samples; + right = samples + 256 * 2; + center = samples + 256; + left_sur = samples + 256 * 3; + right_sur = samples + 256 * 4; + + for (i=0; i < 256; i++) { + left_tmp = dm_par->unit * *left + dm_par->clev * *center + dm_par->slev * *left_sur++; + right_tmp= dm_par->unit * *right++ + dm_par->clev * *center + dm_par->slev * *right_sur++; + *left++ = left_tmp; + *center++ = right_tmp; + } +} + + +void downmix_2f_2r_to_2ch (float *samples, dm_par_t *dm_par) +{ + int i; + float *left, *right, *left_sur, *right_sur; + float left_tmp, right_tmp; + + left = &samples[0]; + right = &samples[256]; + left_sur = &samples[512]; + right_sur = &samples[768]; + + for (i = 0; i < 256; i++) { + left_tmp = dm_par->unit * *left + dm_par->slev * *left_sur++; + right_tmp= dm_par->unit * *right + dm_par->slev * *right_sur++; + *left++ = left_tmp; + *right++ = right_tmp; + } +} + + +void downmix_3f_1r_to_2ch (float *samples, dm_par_t *dm_par) +{ + int i; + float *left, *right, *center, *right_sur; + float left_tmp, right_tmp; + + left = &samples[0]; + right = &samples[512]; + center = &samples[256]; + right_sur = &samples[768]; + + for (i = 0; i < 256; i++) { + left_tmp = dm_par->unit * *left + dm_par->clev * *center - dm_par->slev * *right_sur; + right_tmp= dm_par->unit * *right++ + dm_par->clev * *center + dm_par->slev * *right_sur++; + *left++ = left_tmp; + *center++ = right_tmp; + } +} + + +void downmix_2f_1r_to_2ch (float *samples, dm_par_t *dm_par) +{ + int i; + float *left, *right, *right_sur; + float left_tmp, right_tmp; + + left = &samples[0]; + right = &samples[256]; + right_sur = &samples[512]; + + for (i = 0; i < 256; i++) { + left_tmp = dm_par->unit * *left - dm_par->slev * *right_sur; + right_tmp= dm_par->unit * *right + dm_par->slev * *right_sur++; + *left++ = left_tmp; + *right++ = right_tmp; + } +} + + +void downmix_3f_0r_to_2ch (float *samples, dm_par_t *dm_par) +{ + int i; + float *left, *right, *center; + float left_tmp, right_tmp; + + left = &samples[0]; + center = &samples[256]; + right = &samples[512]; + + for (i = 0; i < 256; i++) { + left_tmp = dm_par->unit * *left + dm_par->clev * *center; + right_tmp= dm_par->unit * *right++ + dm_par->clev * *center; + *left++ = left_tmp; + *center++ = right_tmp; + } +} + +void stream_sample_2ch_to_s16 (int16_t *s16_samples, float *left, float *right) +{ + int i; + + for (i=0; i < 256; i++) { + *s16_samples++ = (int16_t) *left++; + *s16_samples++ = (int16_t) *right++; + } +} + + +void stream_sample_1ch_to_s16 (int16_t *s16_samples, float *center) +{ + int i; + float tmp; + + for (i=0; i < 256; i++) { + *s16_samples++ = tmp = (int16_t) (0.7071f * *center++); + *s16_samples++ = tmp; + } +} + + |