| /* grabbag - Convenience lib for various routines common to several tools |
| * Copyright (C) 2002,2003,2004,2005 Josh Coalson |
| * |
| * 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 "share/grabbag.h" |
| #include "share/replaygain_analysis.h" |
| #include "FLAC/assert.h" |
| #include "FLAC/file_decoder.h" |
| #include "FLAC/metadata.h" |
| #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() */ |
| |
| #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)) |
| |
| static const char *peak_format_ = "%s=%1.8f"; |
| static const char *gain_format_ = "%s=%+2.2f dB"; |
| |
| static double album_peak_, title_peak_; |
| |
| const unsigned GRABBAG__REPLAYGAIN_MAX_TAG_SPACE_REQUIRED = 148; |
| /* |
| 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_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 stat *stats) |
| { |
| FLAC__ASSERT(0 != filename); |
| FLAC__ASSERT(0 != stats); |
| return (0 == stat(filename, stats)); |
| } |
| |
| static void set_file_stats_(const char *filename, struct stat *stats) |
| { |
| FLAC__ASSERT(0 != filename); |
| FLAC__ASSERT(0 != stats); |
| |
| (void)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 != name); |
| FLAC__ASSERT(0 != value); |
| |
| 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 = setlocale(LC_ALL, 0); |
| setlocale(LC_ALL, "C"); |
| #if defined _MSC_VER || defined __MINGW32__ |
| _snprintf(buffer, sizeof(buffer)-1, format, name, value); |
| #else |
| snprintf(buffer, sizeof(buffer)-1, format, name, value); |
| #endif |
| setlocale(LC_ALL, 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(unsigned sample_frequency) |
| { |
| static const unsigned valid_sample_rates[] = { |
| 8000, |
| 11025, |
| 12000, |
| 16000, |
| 22050, |
| 24000, |
| 32000, |
| 44100, |
| 48000 |
| }; |
| static const unsigned n_valid_sample_rates = sizeof(valid_sample_rates) / sizeof(valid_sample_rates[0]); |
| |
| unsigned i; |
| |
| for(i = 0; i < n_valid_sample_rates; i++) |
| if(sample_frequency == valid_sample_rates[i]) |
| return true; |
| return false; |
| } |
| |
| FLAC__bool grabbag__replaygain_init(unsigned 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, unsigned bps, unsigned samples) |
| { |
| /* using a small buffer improves data locality; we'd like it to fit easily in the dcache */ |
| static Float_t lbuffer[2048], rbuffer[2048]; |
| static const unsigned nbuffer = sizeof(lbuffer) / sizeof(lbuffer[0]); |
| FLAC__int32 block_peak = 0, s; |
| unsigned i, j; |
| |
| FLAC__ASSERT(bps >= 4 && bps <= FLAC__REFERENCE_CODEC_MAX_BITS_PER_SAMPLE); |
| FLAC__ASSERT(FLAC__MIN_BITS_PER_SAMPLE == 4); |
| /* |
| * We use abs() on a FLAC__int32 which is undefined for the most negative value. |
| * If the reference codec ever handles 32bps we will have to write a special |
| * case here. |
| */ |
| FLAC__ASSERT(FLAC__REFERENCE_CODEC_MAX_BITS_PER_SAMPLE < 32); |
| |
| if(bps == 16) { |
| if(is_stereo) { |
| j = 0; |
| while(samples > 0) { |
| const unsigned n = local_min(samples, nbuffer); |
| for(i = 0; i < n; i++, j++) { |
| s = input[0][j]; |
| lbuffer[i] = (Float_t)s; |
| s = abs(s); |
| block_peak = local_max(block_peak, s); |
| |
| s = input[1][j]; |
| rbuffer[i] = (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 unsigned n = local_min(samples, nbuffer); |
| for(i = 0; i < n; i++, j++) { |
| s = input[0][j]; |
| lbuffer[i] = (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 { /* bps must be < 32 according to above assertion */ |
| const double scale = ( |
| (bps > 16)? |
| (double)1. / (double)(1u << (bps - 16)) : |
| (double)(1u << (16 - bps)) |
| ); |
| |
| if(is_stereo) { |
| j = 0; |
| while(samples > 0) { |
| const unsigned n = local_min(samples, nbuffer); |
| for(i = 0; i < n; i++, j++) { |
| s = input[0][j]; |
| lbuffer[i] = (Float_t)(scale * (double)s); |
| s = abs(s); |
| block_peak = local_max(block_peak, s); |
| |
| s = input[1][j]; |
| rbuffer[i] = (Float_t)(scale * (double)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 unsigned n = local_min(samples, nbuffer); |
| for(i = 0; i < n; i++, j++) { |
| s = input[0][j]; |
| lbuffer[i] = (Float_t)(scale * (double)s); |
| s = abs(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 { |
| unsigned channels; |
| unsigned bits_per_sample; |
| unsigned sample_rate; |
| FLAC__bool error; |
| } DecoderInstance; |
| |
| static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__FileDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data) |
| { |
| DecoderInstance *instance = (DecoderInstance*)client_data; |
| const unsigned bits_per_sample = frame->header.bits_per_sample; |
| const unsigned channels = frame->header.channels; |
| const unsigned sample_rate = frame->header.sample_rate; |
| const unsigned 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__FileDecoder *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__FileDecoder *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__FileDecoder *decoder = FLAC__file_decoder_new(); |
| |
| if(0 == decoder) |
| return "memory allocation error"; |
| |
| instance.error = false; |
| |
| /* It does these three by default but lets be explicit: */ |
| FLAC__file_decoder_set_md5_checking(decoder, false); |
| FLAC__file_decoder_set_metadata_ignore_all(decoder); |
| FLAC__file_decoder_set_metadata_respond(decoder, FLAC__METADATA_TYPE_STREAMINFO); |
| |
| FLAC__file_decoder_set_filename(decoder, filename); |
| FLAC__file_decoder_set_write_callback(decoder, write_callback_); |
| FLAC__file_decoder_set_metadata_callback(decoder, metadata_callback_); |
| FLAC__file_decoder_set_error_callback(decoder, error_callback_); |
| FLAC__file_decoder_set_client_data(decoder, &instance); |
| |
| if(FLAC__file_decoder_init(decoder) != FLAC__FILE_DECODER_OK) { |
| FLAC__file_decoder_delete(decoder); |
| return "initializing decoder"; |
| } |
| |
| if(!FLAC__file_decoder_process_until_end_of_file(decoder) || instance.error) { |
| FLAC__file_decoder_delete(decoder); |
| return "decoding file"; |
| } |
| |
| FLAC__file_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_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_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, peak_format_, GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK, album_peak) || |
| !append_tag_(block, gain_format_, GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN, album_gain) |
| ) |
| 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, peak_format_, GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK, title_peak) || |
| !append_tag_(block, gain_format_, GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN, title_gain) |
| ) |
| 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 stat 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)) { |
| FLAC__metadata_chain_delete(chain); |
| return FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)]; |
| } |
| |
| 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; |
| 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_album(const char *filename, float album_gain, float album_peak, FLAC__bool preserve_modtime) |
| { |
| FLAC__Metadata_Chain *chain; |
| FLAC__StreamMetadata *block; |
| 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; |
| 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++; |
| memset(s, 0, sizeof(s)-1); |
| strncpy(s, q, local_min(sizeof(s)-1, 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, double *gain, double *peak) |
| { |
| int gain_offset, peak_offset; |
| |
| FLAC__ASSERT(0 != block); |
| FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT); |
| |
| 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)))) |
| return 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)))) |
| return false; |
| |
| if(!parse_double_(block->data.vorbis_comment.comments + gain_offset, gain)) |
| return false; |
| if(!parse_double_(block->data.vorbis_comment.comments + peak_offset, peak)) |
| return false; |
| |
| return true; |
| } |
| |
| 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; |
| } |