1 /*****************************************************************************
2 * fixed32.c : fixed-point software volume
3 *****************************************************************************
4 * Copyright (C) 2011 RĂ©mi Denis-Courmont
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU Lesser General Public License as published by
8 * the Free Software Foundation; either version 2.1 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
19 *****************************************************************************/
25 #include <vlc_common.h>
26 #include <vlc_plugin.h>
28 #include <vlc_aout_mixer.h>
30 static int Activate (vlc_object_t *);
33 set_category (CAT_AUDIO)
34 set_subcategory (SUBCAT_AUDIO_MISC)
35 set_description (N_("Fixed-point audio mixer"))
36 set_capability ("audio mixer", 9)
37 set_callbacks (Activate, NULL)
40 static void FilterFI32 (audio_mixer_t *, block_t *, float);
41 static void FilterS16N (audio_mixer_t *, block_t *, float);
43 static int Activate (vlc_object_t *obj)
45 audio_mixer_t *mixer = (audio_mixer_t *)obj;
47 switch (mixer->format)
50 mixer->mix = FilterFI32;
53 mixer->mix = FilterS16N;
61 static void FilterFI32 (audio_mixer_t *mixer, block_t *block, float volume)
63 const int64_t mult = volume * FIXED32_ONE;
65 if (mult == FIXED32_ONE)
68 int32_t *p = (int32_t *)block->p_buffer;
70 for (size_t n = block->i_buffer / sizeof (*p); n > 0; n--)
72 *p = (*p * mult) >> FIXED32_FRACBITS;
79 static void FilterS16N (audio_mixer_t *mixer, block_t *block, float volume)
81 const int32_t mult = volume * 0x10000;
86 int16_t *p = (int16_t *)block->p_buffer;
88 for (size_t n = block->i_buffer / sizeof (*p); n > 0; n--)
90 *p = (*p * mult) >> 16;