/* * Copyright (C) 2003-2011 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 "pcm_volume.h" #include "pcm_utils.h" #include "audio_format.h" #include <glib.h> #include <stdint.h> #include <string.h> #undef G_LOG_DOMAIN #define G_LOG_DOMAIN "pcm_volume" static void pcm_volume_change_8(int8_t *buffer, const int8_t *end, int volume) { while (buffer < end) { int32_t sample = *buffer; sample = (sample * volume + pcm_volume_dither() + PCM_VOLUME_1 / 2) / PCM_VOLUME_1; *buffer++ = pcm_range(sample, 8); } } static void pcm_volume_change_16(int16_t *buffer, const int16_t *end, int volume) { while (buffer < end) { int32_t sample = *buffer; sample = (sample * volume + pcm_volume_dither() + PCM_VOLUME_1 / 2) / PCM_VOLUME_1; *buffer++ = pcm_range(sample, 16); } } #ifdef __i386__ /** * Optimized volume function for i386. Use the EDX:EAX 2*32 bit * multiplication result instead of emulating 64 bit multiplication. */ static inline int32_t pcm_volume_sample_24(int32_t sample, int32_t volume, G_GNUC_UNUSED int32_t dither) { int32_t result; asm(/* edx:eax = sample * volume */ "imul %2\n" /* "add %3, %1\n" dithering disabled for now, because we have no overflow check - is dithering really important here? */ /* eax = edx:eax / PCM_VOLUME_1 */ "sal $22, %%edx\n" "shr $10, %1\n" "or %%edx, %1\n" : "=a"(result) : "0"(sample), "r"(volume) /* , "r"(dither) */ : "edx" ); return result; } #endif static void pcm_volume_change_24(int32_t *buffer, const int32_t *end, int volume) { while (buffer < end) { #ifdef __i386__ /* assembly version for i386 */ int32_t sample = *buffer; sample = pcm_volume_sample_24(sample, volume, pcm_volume_dither()); #else /* portable version */ int64_t sample = *buffer; sample = (sample * volume + pcm_volume_dither() + PCM_VOLUME_1 / 2) / PCM_VOLUME_1; #endif *buffer++ = pcm_range(sample, 24); } } static void pcm_volume_change_32(int32_t *buffer, const int32_t *end, int volume) { while (buffer < end) { #ifdef __i386__ /* assembly version for i386 */ int32_t sample = *buffer; *buffer++ = pcm_volume_sample_24(sample, volume, 0); #else /* portable version */ int64_t sample = *buffer; sample = (sample * volume + pcm_volume_dither() + PCM_VOLUME_1 / 2) / PCM_VOLUME_1; *buffer++ = pcm_range_64(sample, 32); #endif } } static void pcm_volume_change_float(float *buffer, const float *end, float volume) { while (buffer < end) { float sample = *buffer; sample *= volume; *buffer++ = sample; } } bool pcm_volume(void *buffer, size_t length, enum sample_format format, int volume) { if (volume == PCM_VOLUME_1) return true; if (volume <= 0) { memset(buffer, 0, length); return true; } const void *end = pcm_end_pointer(buffer, length); switch (format) { case SAMPLE_FORMAT_UNDEFINED: case SAMPLE_FORMAT_S24: /* not implemented */ return false; case SAMPLE_FORMAT_S8: pcm_volume_change_8(buffer, end, volume); return true; case SAMPLE_FORMAT_S16: pcm_volume_change_16(buffer, end, volume); return true; case SAMPLE_FORMAT_S24_P32: pcm_volume_change_24(buffer, end, volume); return true; case SAMPLE_FORMAT_S32: pcm_volume_change_32(buffer, end, volume); return true; case SAMPLE_FORMAT_FLOAT: pcm_volume_change_float(buffer, end, pcm_volume_to_float(volume)); return true; } /* unreachable */ assert(false); return false; }