/* the Music Player Daemon (MPD) * Copyright (C) 2008 Max Kellermann <max@duempel.org> * This project's homepage is: 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "pcm_channels.h" #include "utils.h" #include "log.h" #include <assert.h> static void pcm_convert_channels_16_1_to_2(int16_t *dest, const int16_t *src, unsigned num_frames) { while (num_frames-- > 0) { int16_t value = *src++; *dest++ = value; *dest++ = value; } } static void pcm_convert_channels_16_2_to_1(int16_t *dest, const int16_t *src, unsigned num_frames) { while (num_frames-- > 0) { int32_t a = *src++, b = *src++; *dest++ = (a + b) / 2; } } static void pcm_convert_channels_16_n_to_2(int16_t *dest, unsigned src_channels, const int16_t *src, unsigned num_frames) { unsigned c; assert(src_channels > 0); while (num_frames-- > 0) { int32_t sum = 0; int16_t value; for (c = 0; c < src_channels; ++c) sum += *src++; value = sum / (int)src_channels; /* XXX this is actually only mono ... */ *dest++ = value; *dest++ = value; } } const int16_t * pcm_convert_channels_16(int8_t dest_channels, int8_t src_channels, const int16_t *src, size_t src_size, size_t *dest_size_r) { static int16_t *buf; static size_t len; unsigned num_frames = src_size / src_channels / sizeof(*src); unsigned dest_size = num_frames * dest_channels * sizeof(*src); if (dest_size > len) { len = dest_size; buf = xrealloc(buf, len); } *dest_size_r = dest_size; if (src_channels == 1 && dest_channels == 2) pcm_convert_channels_16_1_to_2(buf, src, num_frames); else if (src_channels == 2 && dest_channels == 1) pcm_convert_channels_16_2_to_1(buf, src, num_frames); else if (dest_channels == 2) pcm_convert_channels_16_n_to_2(buf, src_channels, src, num_frames); else { ERROR("conversion %u->%u channels is not supported\n", src_channels, dest_channels); return NULL; } return buf; } static void pcm_convert_channels_24_1_to_2(int32_t *dest, const int32_t *src, unsigned num_frames) { while (num_frames-- > 0) { int32_t value = *src++; *dest++ = value; *dest++ = value; } } static void pcm_convert_channels_24_2_to_1(int32_t *dest, const int32_t *src, unsigned num_frames) { while (num_frames-- > 0) { int32_t a = *src++, b = *src++; *dest++ = (a + b) / 2; } } static void pcm_convert_channels_24_n_to_2(int32_t *dest, unsigned src_channels, const int32_t *src, unsigned num_frames) { unsigned c; assert(src_channels > 0); while (num_frames-- > 0) { int32_t sum = 0; int32_t value; for (c = 0; c < src_channels; ++c) sum += *src++; value = sum / (int)src_channels; /* XXX this is actually only mono ... */ *dest++ = value; *dest++ = value; } } const int32_t * pcm_convert_channels_24(int8_t dest_channels, int8_t src_channels, const int32_t *src, size_t src_size, size_t *dest_size_r) { static int32_t *buf; static size_t len; unsigned num_frames = src_size / src_channels / sizeof(*src); unsigned dest_size = num_frames * dest_channels * sizeof(*src); if (dest_size > len) { len = dest_size; buf = xrealloc(buf, len); } *dest_size_r = dest_size; if (src_channels == 1 && dest_channels == 2) pcm_convert_channels_24_1_to_2(buf, src, num_frames); else if (src_channels == 2 && dest_channels == 1) pcm_convert_channels_24_2_to_1(buf, src, num_frames); else if (dest_channels == 2) pcm_convert_channels_24_n_to_2(buf, src_channels, src, num_frames); else { ERROR("conversion %u->%u channels is not supported\n", src_channels, dest_channels); return NULL; } return buf; }