replaygain.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

/* 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 FLAC__byte *tag_title_gain_ = "REPLAYGAIN_TRACK_GAIN";
static const FLAC__byte *tag_title_peak_ = "REPLAYGAIN_TRACK_PEAK";
static const FLAC__byte *tag_album_gain_ = "REPLAYGAIN_ALBUM_GAIN";
static const FLAC__byte *tag_album_peak_ = "REPLAYGAIN_ALBUM_PEAK";
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
*/


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;