/*
- * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.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, USA.
+ * Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file compress.c paraslash's dynamic audio range compressor */
+/** \file compress.c Paraslash's dynamic audio range compressor. */
/*
- * Used ideas of AudioCompress, (C) 2002-2004 M. Hari Nezumi <magenta@trikuare.cx>
+ * Uses ideas of AudioCompress, (C) 2002-2004 M. Hari Nezumi <magenta@trikuare.cx>
*/
#include "para.h"
#include "compress_filter.cmdline.h"
#include "list.h"
+#include "sched.h"
#include "filter.h"
#include "string.h"
-/** the size of the output data buffer */
+/** The size of the output data buffer. */
#define COMPRESS_CHUNK_SIZE 40960
-/** data specific to the compress filter */
+/** Data specific to the compress filter. */
struct private_compress_data {
- /** the current multiplier */
+ /** The current multiplier. */
unsigned current_gain;
- /** points to the configuration data for this instance of the compress filter */
+ /** Points to the configuration data for this instance of the compress filter. */
struct compress_filter_args_info *conf;
- /** minimal admissible gain */
- unsigned min_gain;
- /** maximal admissible gain */
+ /** Maximal admissible gain. */
unsigned max_gain;
- /** number of samples already seen */
+ /** Number of samples already seen. */
unsigned num_samples;
- /** absolute value of the maximal sample in the current block */
+ /** Absolute value of the maximal sample in the current block. */
unsigned peak;
};
/* be careful in that heat, my dear */
int sample = *ip++, adjusted_sample;
- if (sample > 0) {
- adjusted_sample = (sample * pcd->current_gain)
- >> gain_shift;
- if (unlikely(adjusted_sample > 32767)) {
- adjusted_sample = 32767;
- pcd->current_gain = (pcd->current_gain +
- (1 << pcd->conf->inertia_arg)) / 2;
- pcd->peak = 0;
- } else
- if (adjusted_sample > pcd->peak)
- pcd->peak = sample;
- } else {
- adjusted_sample = -((-sample * pcd->current_gain)
- >> gain_shift);
- if (unlikely(adjusted_sample < -32768)) {
- adjusted_sample = -32768;
- pcd->current_gain = (pcd->current_gain +
- (1 << pcd->conf->inertia_arg)) / 2;
- pcd->peak = 0;
- } else
- if (-adjusted_sample > pcd->peak)
- pcd->peak = -adjusted_sample;
- }
- *op++ = adjusted_sample;
+ adjusted_sample = (PARA_ABS(sample) * pcd->current_gain)
+ >> gain_shift;
+ if (unlikely(adjusted_sample > 32767)) { /* clip */
+ PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
+ sample, adjusted_sample);
+ adjusted_sample = 32767;
+ pcd->current_gain = (3 * pcd->current_gain +
+ (1 << pcd->conf->inertia_arg)) / 4;
+ pcd->peak = 0;
+ } else
+ pcd->peak = PARA_MAX(pcd->peak, adjusted_sample);
+ *op++ = sample >= 0? adjusted_sample : -adjusted_sample;
if (likely(++pcd->num_samples & mask))
continue;
+// PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
+// pcd->peak);
if (pcd->peak < pcd->conf->target_level_arg) {
if (pcd->current_gain < pcd->max_gain)
pcd->current_gain++;
- } else {
- if (pcd->current_gain > pcd->min_gain + 1)
- pcd->current_gain -= 2;
- }
-// PARA_DEBUG_LOG("gain: %lu, peak: %d\n", pcd->current_gain,
-// pcd->peak);
+ } else
+ pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
+ 1 << pcd->conf->inertia_arg);
pcd->peak = 0;
-// PARA_INFO_LOG("sample: %lu\n", ABS(sample));
}
fn->loaded += length;
return length;
fn->bufsize = COMPRESS_CHUNK_SIZE;
fn->buf = para_malloc(fn->bufsize);
pcd->current_gain = 1 << pcd->conf->inertia_arg;
- pcd->min_gain = 1 << (pcd->conf->inertia_arg - pcd->conf->aggressiveness_arg);
pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
}
-/** the init function of the compress filter */
+/**
+ * The init function of the compress filter.
+ *
+ * \param f Pointer to the struct to initialize.
+ */
void compress_init(struct filter *f)
{
f->open = open_compress;
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