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Diffstat (limited to 'src/share/grabbag/replaygain.c')
| -rw-r--r-- | src/share/grabbag/replaygain.c | 669 |
1 files changed, 669 insertions, 0 deletions
diff --git a/src/share/grabbag/replaygain.c b/src/share/grabbag/replaygain.c new file mode 100644 index 0000000..32c9603 --- /dev/null +++ b/src/share/grabbag/replaygain.c @@ -0,0 +1,669 @@ +/* grabbag - Convenience lib for various routines common to several tools + * Copyright (C) 2002-2009 Josh Coalson + * Copyright (C) 2011-2023 Xiph.Org Foundation + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <locale.h> +#include <math.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#if defined _MSC_VER || defined __MINGW32__ +#include <io.h> /* for chmod() */ +#endif +#include <sys/stat.h> /* for stat(), maybe chmod() */ + +#include "FLAC/assert.h" +#include "FLAC/metadata.h" +#include "FLAC/stream_decoder.h" +#include "share/grabbag.h" +#include "share/replaygain_analysis.h" +#include "share/safe_str.h" + +#ifdef local_min +#undef local_min +#endif +#define local_min(a,b) ((a)<(b)?(a):(b)) + +#ifdef local_max +#undef local_max +#endif +#define local_max(a,b) ((a)>(b)?(a):(b)) + +#ifdef abs32 +#undef abs32 +#endif +#define abs32(a) (((a)==INT32_MIN)?INT32_MAX:abs(a)) + +static const char *reference_format_ = "%s=%2.1f dB"; +static const char *gain_format_ = "%s=%+2.2f dB"; +static const char *peak_format_ = "%s=%1.8f"; + +static double album_peak_, title_peak_; + +const uint32_t GRABBAG__REPLAYGAIN_MAX_TAG_SPACE_REQUIRED = 190; +/* + FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 29 + 1 + 8 + + FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 21 + 1 + 10 + + FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 21 + 1 + 12 + + FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 21 + 1 + 10 + + FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 21 + 1 + 12 +*/ + +const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_REFERENCE_LOUDNESS = (const FLAC__byte * const)"REPLAYGAIN_REFERENCE_LOUDNESS"; +const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN = (const FLAC__byte * const)"REPLAYGAIN_TRACK_GAIN"; +const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK = (const FLAC__byte * const)"REPLAYGAIN_TRACK_PEAK"; +const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN = (const FLAC__byte * const)"REPLAYGAIN_ALBUM_GAIN"; +const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK = (const FLAC__byte * const)"REPLAYGAIN_ALBUM_PEAK"; + + +static FLAC__bool get_file_stats_(const char *filename, struct flac_stat_s *stats) +{ + FLAC__ASSERT(0 != filename); + FLAC__ASSERT(0 != stats); + return (0 == flac_stat(filename, stats)); +} + +static void set_file_stats_(const char *filename, struct flac_stat_s *stats) +{ + FLAC__ASSERT(0 != filename); + FLAC__ASSERT(0 != stats); + + (void)flac_chmod(filename, stats->st_mode); +} + +static FLAC__bool append_tag_(FLAC__StreamMetadata *block, const char *format, const FLAC__byte *name, float value) +{ + char buffer[256]; + char *saved_locale; + FLAC__StreamMetadata_VorbisComment_Entry entry; + + FLAC__ASSERT(0 != block); + FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT); + FLAC__ASSERT(0 != format); + FLAC__ASSERT(0 != name); + + buffer[sizeof(buffer)-1] = '\0'; + /* + * We need to save the old locale and switch to "C" because the locale + * influences the formatting of %f and we want it a certain way. + */ + saved_locale = strdup(setlocale(LC_ALL, 0)); + if (0 == saved_locale) + return false; + setlocale(LC_ALL, "C"); + flac_snprintf(buffer, sizeof(buffer), format, name, value); + setlocale(LC_ALL, saved_locale); + free(saved_locale); + + entry.entry = (FLAC__byte *)buffer; + entry.length = strlen(buffer); + + return FLAC__metadata_object_vorbiscomment_append_comment(block, entry, /*copy=*/true); +} + +FLAC__bool grabbag__replaygain_is_valid_sample_frequency(uint32_t sample_frequency) +{ + return ValidGainFrequency( sample_frequency ); +} + +FLAC__bool grabbag__replaygain_init(uint32_t sample_frequency) +{ + title_peak_ = album_peak_ = 0.0; + return InitGainAnalysis((long)sample_frequency) == INIT_GAIN_ANALYSIS_OK; +} + +FLAC__bool grabbag__replaygain_analyze(const FLAC__int32 * const input[], FLAC__bool is_stereo, uint32_t bps, uint32_t samples) +{ + /* using a small buffer improves data locality; we'd like it to fit easily in the dcache */ + static flac_float_t lbuffer[2048], rbuffer[2048]; + static const uint32_t nbuffer = sizeof(lbuffer) / sizeof(lbuffer[0]); + FLAC__int32 block_peak = 0, s; + uint32_t i, j; + + FLAC__ASSERT(bps >= FLAC__MIN_BITS_PER_SAMPLE && bps <= FLAC__MAX_BITS_PER_SAMPLE); + FLAC__ASSERT(FLAC__MIN_BITS_PER_SAMPLE == 4 && FLAC__MAX_BITS_PER_SAMPLE == 32); + + if(bps == 16) { + if(is_stereo) { + j = 0; + while(samples > 0) { + const uint32_t n = local_min(samples, nbuffer); + for(i = 0; i < n; i++, j++) { + s = input[0][j]; + lbuffer[i] = (flac_float_t)s; + s = abs(s); + block_peak = local_max(block_peak, s); + + s = input[1][j]; + rbuffer[i] = (flac_float_t)s; + s = abs(s); + block_peak = local_max(block_peak, s); + } + samples -= n; + if(AnalyzeSamples(lbuffer, rbuffer, n, 2) != GAIN_ANALYSIS_OK) + return false; + } + } + else { + j = 0; + while(samples > 0) { + const uint32_t n = local_min(samples, nbuffer); + for(i = 0; i < n; i++, j++) { + s = input[0][j]; + lbuffer[i] = (flac_float_t)s; + s = abs(s); + block_peak = local_max(block_peak, s); + } + samples -= n; + if(AnalyzeSamples(lbuffer, 0, n, 1) != GAIN_ANALYSIS_OK) + return false; + } + } + } + else { + const double scale = ( + (bps > 16)? + (double)1. / (double)(1u << (bps - 16)) : + (double)(1u << (16 - bps)) + ); + + if(is_stereo) { + j = 0; + while(samples > 0) { + const uint32_t n = local_min(samples, nbuffer); + for(i = 0; i < n; i++, j++) { + s = input[0][j]; + lbuffer[i] = (flac_float_t)(scale * (double)s); + s = abs32(s); + block_peak = local_max(block_peak, s); + + s = input[1][j]; + rbuffer[i] = (flac_float_t)(scale * (double)s); + s = abs32(s); + block_peak = local_max(block_peak, s); + } + samples -= n; + if(AnalyzeSamples(lbuffer, rbuffer, n, 2) != GAIN_ANALYSIS_OK) + return false; + } + } + else { + j = 0; + while(samples > 0) { + const uint32_t n = local_min(samples, nbuffer); + for(i = 0; i < n; i++, j++) { + s = input[0][j]; + lbuffer[i] = (flac_float_t)(scale * (double)s); + s = abs32(s); + block_peak = local_max(block_peak, s); + } + samples -= n; + if(AnalyzeSamples(lbuffer, 0, n, 1) != GAIN_ANALYSIS_OK) + return false; + } + } + } + + { + const double peak_scale = (double)(1u << (bps - 1)); + double peak = (double)block_peak / peak_scale; + if(peak > title_peak_) + title_peak_ = peak; + if(peak > album_peak_) + album_peak_ = peak; + } + + return true; +} + +void grabbag__replaygain_get_album(float *gain, float *peak) +{ + *gain = (float)GetAlbumGain(); + *peak = (float)album_peak_; + album_peak_ = 0.0; +} + +void grabbag__replaygain_get_title(float *gain, float *peak) +{ + *gain = (float)GetTitleGain(); + *peak = (float)title_peak_; + title_peak_ = 0.0; +} + + +typedef struct { + uint32_t channels; + uint32_t bits_per_sample; + uint32_t sample_rate; + FLAC__bool error; +} DecoderInstance; + +static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data) +{ + DecoderInstance *instance = (DecoderInstance*)client_data; + const uint32_t bits_per_sample = frame->header.bits_per_sample; + const uint32_t channels = frame->header.channels; + const uint32_t sample_rate = frame->header.sample_rate; + const uint32_t samples = frame->header.blocksize; + + (void)decoder; + + if( + !instance->error && + (channels == 2 || channels == 1) && + bits_per_sample == instance->bits_per_sample && + channels == instance->channels && + sample_rate == instance->sample_rate + ) { + instance->error = !grabbag__replaygain_analyze(buffer, channels==2, bits_per_sample, samples); + } + else { + instance->error = true; + } + + if(!instance->error) + return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE; + else + return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT; +} + +static void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data) +{ + DecoderInstance *instance = (DecoderInstance*)client_data; + + (void)decoder; + + if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO) { + instance->bits_per_sample = metadata->data.stream_info.bits_per_sample; + instance->channels = metadata->data.stream_info.channels; + instance->sample_rate = metadata->data.stream_info.sample_rate; + + if(instance->channels != 1 && instance->channels != 2) { + instance->error = true; + return; + } + + if(!grabbag__replaygain_is_valid_sample_frequency(instance->sample_rate)) { + instance->error = true; + return; + } + } +} + +static void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data) +{ + DecoderInstance *instance = (DecoderInstance*)client_data; + + (void)decoder, (void)status; + + instance->error = true; +} + +const char *grabbag__replaygain_analyze_file(const char *filename, float *title_gain, float *title_peak) +{ + DecoderInstance instance; + FLAC__StreamDecoder *decoder = FLAC__stream_decoder_new(); + + if(0 == decoder) + return "memory allocation error"; + + instance.error = false; + + /* It does these three by default but lets be explicit: */ + FLAC__stream_decoder_set_md5_checking(decoder, false); + FLAC__stream_decoder_set_metadata_ignore_all(decoder); + FLAC__stream_decoder_set_metadata_respond(decoder, FLAC__METADATA_TYPE_STREAMINFO); + + if(FLAC__stream_decoder_init_file(decoder, filename, write_callback_, metadata_callback_, error_callback_, &instance) != FLAC__STREAM_DECODER_INIT_STATUS_OK) { + FLAC__stream_decoder_delete(decoder); + return "initializing decoder"; + } + + if(!FLAC__stream_decoder_process_until_end_of_stream(decoder) || instance.error) { + FLAC__stream_decoder_delete(decoder); + return "decoding file"; + } + + FLAC__stream_decoder_delete(decoder); + + grabbag__replaygain_get_title(title_gain, title_peak); + + return 0; +} + +const char *grabbag__replaygain_store_to_vorbiscomment(FLAC__StreamMetadata *block, float album_gain, float album_peak, float title_gain, float title_peak) +{ + const char *error; + + if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_reference(block))) + return error; + + if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_title(block, title_gain, title_peak))) + return error; + + if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_album(block, album_gain, album_peak))) + return error; + + return 0; +} + +const char *grabbag__replaygain_store_to_vorbiscomment_reference(FLAC__StreamMetadata *block) +{ + FLAC__ASSERT(0 != block); + FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT); + + if(FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_REFERENCE_LOUDNESS) < 0) + return "memory allocation error"; + + if(!append_tag_(block, reference_format_, GRABBAG__REPLAYGAIN_TAG_REFERENCE_LOUDNESS, ReplayGainReferenceLoudness)) + return "memory allocation error"; + + return 0; +} + +const char *grabbag__replaygain_store_to_vorbiscomment_album(FLAC__StreamMetadata *block, float album_gain, float album_peak) +{ + FLAC__ASSERT(0 != block); + FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT); + + if( + FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN) < 0 || + FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK) < 0 + ) + return "memory allocation error"; + + if( + !append_tag_(block, gain_format_, GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN, album_gain) || + !append_tag_(block, peak_format_, GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK, album_peak) + ) + return "memory allocation error"; + + return 0; +} + +const char *grabbag__replaygain_store_to_vorbiscomment_title(FLAC__StreamMetadata *block, float title_gain, float title_peak) +{ + FLAC__ASSERT(0 != block); + FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT); + + if( + FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN) < 0 || + FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK) < 0 + ) + return "memory allocation error"; + + if( + !append_tag_(block, gain_format_, GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN, title_gain) || + !append_tag_(block, peak_format_, GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK, title_peak) + ) + return "memory allocation error"; + + return 0; +} + +static const char *store_to_file_pre_(const char *filename, FLAC__Metadata_Chain **chain, FLAC__StreamMetadata **block) +{ + FLAC__Metadata_Iterator *iterator; + const char *error; + FLAC__bool found_vc_block = false; + + if(0 == (*chain = FLAC__metadata_chain_new())) + return "memory allocation error"; + + if(!FLAC__metadata_chain_read(*chain, filename)) { + error = FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(*chain)]; + FLAC__metadata_chain_delete(*chain); + return error; + } + + if(0 == (iterator = FLAC__metadata_iterator_new())) { + FLAC__metadata_chain_delete(*chain); + return "memory allocation error"; + } + + FLAC__metadata_iterator_init(iterator, *chain); + + do { + *block = FLAC__metadata_iterator_get_block(iterator); + if((*block)->type == FLAC__METADATA_TYPE_VORBIS_COMMENT) + found_vc_block = true; + } while(!found_vc_block && FLAC__metadata_iterator_next(iterator)); + + if(!found_vc_block) { + /* create a new block */ + *block = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT); + if(0 == *block) { + FLAC__metadata_chain_delete(*chain); + FLAC__metadata_iterator_delete(iterator); + return "memory allocation error"; + } + while(FLAC__metadata_iterator_next(iterator)) + ; + if(!FLAC__metadata_iterator_insert_block_after(iterator, *block)) { + error = FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(*chain)]; + FLAC__metadata_chain_delete(*chain); + FLAC__metadata_iterator_delete(iterator); + return error; + } + /* iterator is left pointing to new block */ + FLAC__ASSERT(FLAC__metadata_iterator_get_block(iterator) == *block); + } + + FLAC__metadata_iterator_delete(iterator); + + FLAC__ASSERT(0 != *block); + FLAC__ASSERT((*block)->type == FLAC__METADATA_TYPE_VORBIS_COMMENT); + + return 0; +} + +static const char *store_to_file_post_(const char *filename, FLAC__Metadata_Chain *chain, FLAC__bool preserve_modtime) +{ + struct flac_stat_s stats; + const FLAC__bool have_stats = get_file_stats_(filename, &stats); + + (void)grabbag__file_change_stats(filename, /*read_only=*/false); + + FLAC__metadata_chain_sort_padding(chain); + if(!FLAC__metadata_chain_write(chain, /*use_padding=*/true, preserve_modtime)) { + const char *error; + error = FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)]; + FLAC__metadata_chain_delete(chain); + return error; + } + + FLAC__metadata_chain_delete(chain); + + if(have_stats) + set_file_stats_(filename, &stats); + + return 0; +} + +const char *grabbag__replaygain_store_to_file(const char *filename, float album_gain, float album_peak, float title_gain, float title_peak, FLAC__bool preserve_modtime) +{ + FLAC__Metadata_Chain *chain; + FLAC__StreamMetadata *block = NULL; + const char *error; + + if(0 != (error = store_to_file_pre_(filename, &chain, &block))) + return error; + + if(0 != (error = grabbag__replaygain_store_to_vorbiscomment(block, album_gain, album_peak, title_gain, title_peak))) { + FLAC__metadata_chain_delete(chain); + return error; + } + + if(0 != (error = store_to_file_post_(filename, chain, preserve_modtime))) + return error; + + return 0; +} + +const char *grabbag__replaygain_store_to_file_reference(const char *filename, FLAC__bool preserve_modtime) +{ + FLAC__Metadata_Chain *chain; + FLAC__StreamMetadata *block = NULL; + const char *error; + + if(0 != (error = store_to_file_pre_(filename, &chain, &block))) + return error; + + if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_reference(block))) { + FLAC__metadata_chain_delete(chain); + return error; + } + + if(0 != (error = store_to_file_post_(filename, chain, preserve_modtime))) + return error; + + return 0; +} + +const char *grabbag__replaygain_store_to_file_album(const char *filename, float album_gain, float album_peak, FLAC__bool preserve_modtime) +{ + FLAC__Metadata_Chain *chain; + FLAC__StreamMetadata *block = NULL; + const char *error; + + if(0 != (error = store_to_file_pre_(filename, &chain, &block))) + return error; + + if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_album(block, album_gain, album_peak))) { + FLAC__metadata_chain_delete(chain); + return error; + } + + if(0 != (error = store_to_file_post_(filename, chain, preserve_modtime))) + return error; + + return 0; +} + +const char *grabbag__replaygain_store_to_file_title(const char *filename, float title_gain, float title_peak, FLAC__bool preserve_modtime) +{ + FLAC__Metadata_Chain *chain; + FLAC__StreamMetadata *block = NULL; + const char *error; + + if(0 != (error = store_to_file_pre_(filename, &chain, &block))) + return error; + + if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_title(block, title_gain, title_peak))) { + FLAC__metadata_chain_delete(chain); + return error; + } + + if(0 != (error = store_to_file_post_(filename, chain, preserve_modtime))) + return error; + + return 0; +} + +static FLAC__bool parse_double_(const FLAC__StreamMetadata_VorbisComment_Entry *entry, double *val) +{ + char s[32], *end; + const char *p, *q; + double v; + + FLAC__ASSERT(0 != entry); + FLAC__ASSERT(0 != val); + + p = (const char *)entry->entry; + q = strchr(p, '='); + if(0 == q) + return false; + q++; + safe_strncpy(s, q, local_min(sizeof(s), (size_t) (entry->length - (q-p)))); + + v = strtod(s, &end); + if(end == s) + return false; + + *val = v; + return true; +} + +FLAC__bool grabbag__replaygain_load_from_vorbiscomment(const FLAC__StreamMetadata *block, FLAC__bool album_mode, FLAC__bool strict, double *reference, double *gain, double *peak) +{ + int reference_offset, gain_offset, peak_offset; + char *saved_locale; + FLAC__bool res = true; + + FLAC__ASSERT(0 != block); + FLAC__ASSERT(0 != reference); + FLAC__ASSERT(0 != gain); + FLAC__ASSERT(0 != peak); + FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT); + + /* Default to current level until overridden by a detected tag; this + * will always be true until we change replaygain_analysis.c + */ + *reference = ReplayGainReferenceLoudness; + + /* + * We need to save the old locale and switch to "C" because the locale + * influences the behaviour of strtod and we want it a certain way. + */ + saved_locale = strdup(setlocale(LC_ALL, 0)); + if (0 == saved_locale) + return false; + setlocale(LC_ALL, "C"); + + if(0 <= (reference_offset = FLAC__metadata_object_vorbiscomment_find_entry_from(block, /*offset=*/0, (const char *)GRABBAG__REPLAYGAIN_TAG_REFERENCE_LOUDNESS))) + (void)parse_double_(block->data.vorbis_comment.comments + reference_offset, reference); + + if(0 > (gain_offset = FLAC__metadata_object_vorbiscomment_find_entry_from(block, /*offset=*/0, (const char *)(album_mode? GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN : GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN)))) + res = false; + if(0 > (peak_offset = FLAC__metadata_object_vorbiscomment_find_entry_from(block, /*offset=*/0, (const char *)(album_mode? GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK : GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK)))) + res = false; + + if(res && !parse_double_(block->data.vorbis_comment.comments + gain_offset, gain)) + res = false; + if(res && !parse_double_(block->data.vorbis_comment.comments + peak_offset, peak)) + res = false; + if(res && *peak < 0.0) + res = false; + + setlocale(LC_ALL, saved_locale); + free(saved_locale); + + /* something failed; retry with strict */ + if (!res && !strict) + res = grabbag__replaygain_load_from_vorbiscomment(block, !album_mode, /*strict=*/true, reference, gain, peak); + + return res; +} + +double grabbag__replaygain_compute_scale_factor(double peak, double gain, double preamp, FLAC__bool prevent_clipping) +{ + double scale; + FLAC__ASSERT(peak >= 0.0); + gain += preamp; + scale = (float) pow(10.0, gain * 0.05); + if(prevent_clipping && peak > 0.0) { + const double max_scale = (float)(1.0 / peak); + if(scale > max_scale) + scale = max_scale; + } + return scale; +} |