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/* GStreamer ReplayGain limiter
*
* Copyright (C) 2007 Rene Stadler <mail@renestadler.de>
*
* gstrglimiter.c: Element to apply signal compression to raw audio data
*
* 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
*/
/**
* SECTION:element-rglimiter
* @see_also: #GstRgVolume
*
* This element applies signal compression/limiting to raw audio data. It
* performs strict hard limiting with soft-knee characteristics, using a
* threshold of -6 dB. This type of filter is mentioned in the proposed <ulink
* url="http://replaygain.org">ReplayGain standard</ulink>.
*
* <refsect2>
* <title>Example launch line</title>
* |[
* gst-launch filesrc location=filename.ext ! decodebin ! audioconvert \
* ! rgvolume pre-amp=6.0 headroom=10.0 ! rglimiter \
* ! audioconvert ! audioresample ! alsasink
* ]|Playback of a file
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <gst/gst.h>
#include <math.h>
#include "gstrglimiter.h"
GST_DEBUG_CATEGORY_STATIC (gst_rg_limiter_debug);
#define GST_CAT_DEFAULT gst_rg_limiter_debug
enum
{
PROP_0,
PROP_ENABLED,
};
static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK, GST_PAD_ALWAYS, GST_STATIC_CAPS ("audio/x-raw-float, "
"width = (int) 32, channels = (int) [1, MAX], "
"rate = (int) [1, MAX], endianness = (int) BYTE_ORDER"));
static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC, GST_PAD_ALWAYS, GST_STATIC_CAPS ("audio/x-raw-float, "
"width = (int) 32, channels = (int) [1, MAX], "
"rate = (int) [1, MAX], endianness = (int) BYTE_ORDER"));
GST_BOILERPLATE (GstRgLimiter, gst_rg_limiter, GstBaseTransform,
GST_TYPE_BASE_TRANSFORM);
static void gst_rg_limiter_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_rg_limiter_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static GstFlowReturn gst_rg_limiter_transform_ip (GstBaseTransform * base,
GstBuffer * buf);
static void
gst_rg_limiter_base_init (gpointer g_class)
{
GstElementClass *element_class = g_class;
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&src_factory));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&sink_factory));
gst_element_class_set_details_simple (element_class, "ReplayGain limiter",
"Filter/Effect/Audio",
"Apply signal compression to raw audio data",
"Ren\xc3\xa9 Stadler <mail@renestadler.de>");
GST_DEBUG_CATEGORY_INIT (gst_rg_limiter_debug, "rglimiter", 0,
"ReplayGain limiter element");
}
static void
gst_rg_limiter_class_init (GstRgLimiterClass * klass)
{
GObjectClass *gobject_class;
GstBaseTransformClass *trans_class;
gobject_class = (GObjectClass *) klass;
gobject_class->set_property = gst_rg_limiter_set_property;
gobject_class->get_property = gst_rg_limiter_get_property;
g_object_class_install_property (gobject_class, PROP_ENABLED,
g_param_spec_boolean ("enabled", "Enabled", "Enable processing", TRUE,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
trans_class = GST_BASE_TRANSFORM_CLASS (klass);
trans_class->transform_ip = GST_DEBUG_FUNCPTR (gst_rg_limiter_transform_ip);
trans_class->passthrough_on_same_caps = FALSE;
}
static void
gst_rg_limiter_init (GstRgLimiter * filter, GstRgLimiterClass * gclass)
{
GstBaseTransform *base = GST_BASE_TRANSFORM (filter);
gst_base_transform_set_passthrough (base, FALSE);
gst_base_transform_set_gap_aware (base, TRUE);
filter->enabled = TRUE;
}
static void
gst_rg_limiter_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstRgLimiter *filter = GST_RG_LIMITER (object);
switch (prop_id) {
case PROP_ENABLED:
filter->enabled = g_value_get_boolean (value);
gst_base_transform_set_passthrough (GST_BASE_TRANSFORM (filter),
!filter->enabled);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_rg_limiter_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstRgLimiter *filter = GST_RG_LIMITER (object);
switch (prop_id) {
case PROP_ENABLED:
g_value_set_boolean (value, filter->enabled);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
#define LIMIT 1.0
#define THRES 0.5 /* ca. -6 dB */
#define COMPL 0.5 /* LIMIT - THRESH */
static GstFlowReturn
gst_rg_limiter_transform_ip (GstBaseTransform * base, GstBuffer * buf)
{
GstRgLimiter *filter = GST_RG_LIMITER (base);
gfloat *input;
guint count;
guint i;
if (!filter->enabled)
return GST_FLOW_OK;
if (GST_BUFFER_FLAG_IS_SET (buf, GST_BUFFER_FLAG_GAP))
return GST_FLOW_OK;
input = (gfloat *) GST_BUFFER_DATA (buf);
count = GST_BUFFER_SIZE (buf) / sizeof (gfloat);
for (i = count; i--;) {
if (*input > THRES)
*input = tanhf ((*input - THRES) / COMPL) * COMPL + THRES;
else if (*input < -THRES)
*input = tanhf ((*input + THRES) / COMPL) * COMPL - THRES;
input++;
}
return GST_FLOW_OK;
}
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