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author | Max Kellermann <max@duempel.org> | 2013-04-09 01:24:52 +0200 |
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committer | Max Kellermann <max@duempel.org> | 2013-04-09 01:24:52 +0200 |
commit | c654c7630aad220a4935c34b076e107b6b0561a5 (patch) | |
tree | 7ca6e4e30bee7153ed54f302467140180d77490d /src/PcmDither.cxx | |
parent | 3f3b26fb0ee090bfc1321572904aa94deca42a84 (diff) | |
download | mpd-c654c7630aad220a4935c34b076e107b6b0561a5.tar.gz mpd-c654c7630aad220a4935c34b076e107b6b0561a5.tar.xz mpd-c654c7630aad220a4935c34b076e107b6b0561a5.zip |
pcm_*: move to src/pcm/
Diffstat (limited to 'src/PcmDither.cxx')
-rw-r--r-- | src/PcmDither.cxx | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/src/PcmDither.cxx b/src/PcmDither.cxx deleted file mode 100644 index 98d0d443e..000000000 --- a/src/PcmDither.cxx +++ /dev/null @@ -1,89 +0,0 @@ -/* - * Copyright (C) 2003-2013 The Music Player Daemon Project - * http://www.musicpd.org - * - * 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., - * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. - */ - -#include "config.h" -#include "PcmDither.hxx" -#include "PcmPrng.hxx" - -inline int16_t -PcmDither::Dither24To16(int_fast32_t sample) -{ - constexpr unsigned from_bits = 24; - constexpr unsigned to_bits = 16; - constexpr unsigned scale_bits = from_bits - to_bits; - constexpr int_fast32_t round = 1 << (scale_bits - 1); - constexpr int_fast32_t mask = (1 << scale_bits) - 1; - constexpr int_fast32_t ONE = 1 << (from_bits - 1); - constexpr int_fast32_t MIN = -ONE; - constexpr int_fast32_t MAX = ONE - 1; - - sample += error[0] - error[1] + error[2]; - - error[2] = error[1]; - error[1] = error[0] / 2; - - /* round */ - int_fast32_t output = sample + round; - - int_fast32_t rnd = pcm_prng(random); - output += (rnd & mask) - (random & mask); - - random = rnd; - - /* clip */ - if (output > MAX) { - output = MAX; - - if (sample > MAX) - sample = MAX; - } else if (output < MIN) { - output = MIN; - - if (sample < MIN) - sample = MIN; - } - - output &= ~mask; - - error[0] = sample - output; - - return (int16_t)(output >> scale_bits); -} - -void -PcmDither::Dither24To16(int16_t *dest, const int32_t *src, - const int32_t *src_end) -{ - while (src < src_end) - *dest++ = Dither24To16(*src++); -} - -inline int16_t -PcmDither::Dither32To16(int_fast32_t sample) -{ - return Dither24To16(sample >> 8); -} - -void -PcmDither::Dither32To16(int16_t *dest, const int32_t *src, - const int32_t *src_end) -{ - while (src < src_end) - *dest++ = Dither32To16(*src++); -} |