180 lines
3.6 KiB
C
180 lines
3.6 KiB
C
/*
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* Copyright 2008-2013 Various Authors
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* Copyright 2004 Timo Hirvonen
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "pcm.h"
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#include "utils.h"
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#include <stdint.h>
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#include <stdlib.h>
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/*
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* Functions to convert PCM to 16-bit signed little-endian stereo
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*
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* Conversion for 8-bit PCM):
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* 1. phase
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* unsigned -> signed
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* mono -> stereo
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* 8 -> 16
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*
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* Conversion for 16-bit PCM:
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* 1. phase
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* be -> le
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* unsigned -> signed
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*
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* 2. phase
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* mono -> stereo
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*
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* There's no reason to split 8-bit conversion to 2 phases because we need to
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* use separate buffer for 8->16 conversion anyway.
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*
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* Conversions for 16-bit stereo can be done in place. 16-bit mono needs to be
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* converted to stereo so it's worthwhile to split the conversion to 2 phases.
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*/
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static void convert_u8_1ch_to_s16_2ch(void *dst, const void *src, int count)
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{
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int16_t *d = dst;
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const uint8_t *s = src;
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int i, j = 0;
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for (i = 0; i < count; i++) {
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int16_t sample = s[i] << 8;
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sample -= 32768;
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d[j++] = sample;
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d[j++] = sample;
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}
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}
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static void convert_s8_1ch_to_s16_2ch(void *dst, const void *src, int count)
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{
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int16_t *d = dst;
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const int8_t *s = src;
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int i, j = 0;
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for (i = 0; i < count; i++) {
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int16_t sample = s[i] << 8;
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d[j++] = sample;
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d[j++] = sample;
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}
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}
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static void convert_u8_2ch_to_s16_2ch(void *dst, const void *src, int count)
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{
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int16_t *d = dst;
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const int8_t *s = src;
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int i;
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for (i = 0; i < count; i++) {
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int16_t sample = s[i] << 8;
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sample -= 32768;
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d[i] = sample;
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}
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}
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static void convert_s8_2ch_to_s16_2ch(void *dst, const void *src, int count)
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{
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int16_t *d = dst;
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const int8_t *s = src;
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int i;
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for (i = 0; i < count; i++) {
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int16_t sample = s[i] << 8;
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d[i] = sample;
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}
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}
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static void convert_u16_le_to_s16_le(void *buf, int count)
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{
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int16_t *b = buf;
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int i;
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for (i = 0; i < count; i++) {
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int sample = (uint16_t)b[i];
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sample -= 32768;
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b[i] = sample;
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}
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}
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static void convert_u16_be_to_s16_le(void *buf, int count)
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{
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int16_t *b = buf;
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int i;
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for (i = 0; i < count; i++) {
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uint16_t u = b[i];
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int sample;
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u = swap_uint16(u);
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sample = (int)u - 32768;
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b[i] = sample;
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}
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}
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static void swap_s16_byte_order(void *buf, int count)
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{
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int16_t *b = buf;
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int i;
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for (i = 0; i < count; i++)
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b[i] = swap_uint16(b[i]);
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}
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static void convert_16_1ch_to_16_2ch(void *dst, const void *src, int count)
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{
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int16_t *d = dst;
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const int16_t *s = src;
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int i, j = 0;
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for (i = 0; i < count; i++) {
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d[j++] = s[i];
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d[j++] = s[i];
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}
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}
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/* index is ((bits >> 2) & 4) | (is_signed << 1) | (channels - 1) */
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pcm_conv_func pcm_conv[8] = {
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convert_u8_1ch_to_s16_2ch,
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convert_u8_2ch_to_s16_2ch,
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convert_s8_1ch_to_s16_2ch,
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convert_s8_2ch_to_s16_2ch,
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convert_16_1ch_to_16_2ch,
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NULL,
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convert_16_1ch_to_16_2ch,
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NULL
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};
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/* index is ((bits >> 2) & 4) | (is_signed << 1) | bigendian */
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pcm_conv_in_place_func pcm_conv_in_place[8] = {
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NULL,
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NULL,
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NULL,
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NULL,
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convert_u16_le_to_s16_le,
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convert_u16_be_to_s16_le,
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#ifdef WORDS_BIGENDIAN
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swap_s16_byte_order,
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NULL,
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#else
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NULL,
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swap_s16_byte_order,
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#endif
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};
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