1 /* GStreamer ReplayGain limiter
3 * Copyright (C) 2007 Rene Stadler <mail@renestadler.de>
5 * gstrglimiter.c: Element to apply signal compression to raw audio data
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public License
9 * as published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
24 * SECTION:element-rglimiter
25 * @see_also: #GstRgVolume
27 * This element applies signal compression/limiting to raw audio data. It
28 * performs strict hard limiting with soft-knee characteristics, using a
29 * threshold of -6 dB. This type of filter is mentioned in the proposed <ulink
30 * url="http://replaygain.org">ReplayGain standard</ulink>.
33 * <title>Example launch line</title>
35 * gst-launch filesrc location=filename.ext ! decodebin ! audioconvert \
36 * ! rgvolume pre-amp=6.0 headroom=10.0 ! rglimiter \
37 * ! audioconvert ! audioresample ! alsasink
38 * ]|Playback of a file
49 #include "gstrglimiter.h"
51 GST_DEBUG_CATEGORY_STATIC (gst_rg_limiter_debug);
52 #define GST_CAT_DEFAULT gst_rg_limiter_debug
60 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
61 GST_PAD_SINK, GST_PAD_ALWAYS, GST_STATIC_CAPS ("audio/x-raw-float, "
62 "width = (int) 32, channels = (int) [1, MAX], "
63 "rate = (int) [1, MAX], endianness = (int) BYTE_ORDER"));
65 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
66 GST_PAD_SRC, GST_PAD_ALWAYS, GST_STATIC_CAPS ("audio/x-raw-float, "
67 "width = (int) 32, channels = (int) [1, MAX], "
68 "rate = (int) [1, MAX], endianness = (int) BYTE_ORDER"));
70 GST_BOILERPLATE (GstRgLimiter, gst_rg_limiter, GstBaseTransform,
71 GST_TYPE_BASE_TRANSFORM);
73 static void gst_rg_limiter_set_property (GObject * object, guint prop_id,
74 const GValue * value, GParamSpec * pspec);
75 static void gst_rg_limiter_get_property (GObject * object, guint prop_id,
76 GValue * value, GParamSpec * pspec);
78 static GstFlowReturn gst_rg_limiter_transform_ip (GstBaseTransform * base,
82 gst_rg_limiter_base_init (gpointer g_class)
84 GstElementClass *element_class = g_class;
86 gst_element_class_add_static_pad_template (element_class, &src_factory);
87 gst_element_class_add_static_pad_template (element_class, &sink_factory);
88 gst_element_class_set_details_simple (element_class, "ReplayGain limiter",
89 "Filter/Effect/Audio",
90 "Apply signal compression to raw audio data",
91 "Ren\xc3\xa9 Stadler <mail@renestadler.de>");
93 GST_DEBUG_CATEGORY_INIT (gst_rg_limiter_debug, "rglimiter", 0,
94 "ReplayGain limiter element");
98 gst_rg_limiter_class_init (GstRgLimiterClass * klass)
100 GObjectClass *gobject_class;
101 GstBaseTransformClass *trans_class;
103 gobject_class = (GObjectClass *) klass;
105 gobject_class->set_property = gst_rg_limiter_set_property;
106 gobject_class->get_property = gst_rg_limiter_get_property;
108 g_object_class_install_property (gobject_class, PROP_ENABLED,
109 g_param_spec_boolean ("enabled", "Enabled", "Enable processing", TRUE,
110 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
112 trans_class = GST_BASE_TRANSFORM_CLASS (klass);
113 trans_class->transform_ip = GST_DEBUG_FUNCPTR (gst_rg_limiter_transform_ip);
114 trans_class->passthrough_on_same_caps = FALSE;
118 gst_rg_limiter_init (GstRgLimiter * filter, GstRgLimiterClass * gclass)
120 GstBaseTransform *base = GST_BASE_TRANSFORM (filter);
122 gst_base_transform_set_passthrough (base, FALSE);
123 gst_base_transform_set_gap_aware (base, TRUE);
125 filter->enabled = TRUE;
129 gst_rg_limiter_set_property (GObject * object, guint prop_id,
130 const GValue * value, GParamSpec * pspec)
132 GstRgLimiter *filter = GST_RG_LIMITER (object);
136 filter->enabled = g_value_get_boolean (value);
137 gst_base_transform_set_passthrough (GST_BASE_TRANSFORM (filter),
141 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
147 gst_rg_limiter_get_property (GObject * object, guint prop_id,
148 GValue * value, GParamSpec * pspec)
150 GstRgLimiter *filter = GST_RG_LIMITER (object);
154 g_value_set_boolean (value, filter->enabled);
157 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
163 #define THRES 0.5 /* ca. -6 dB */
164 #define COMPL 0.5 /* LIMIT - THRESH */
167 gst_rg_limiter_transform_ip (GstBaseTransform * base, GstBuffer * buf)
169 GstRgLimiter *filter = GST_RG_LIMITER (base);
174 if (!filter->enabled)
177 if (GST_BUFFER_FLAG_IS_SET (buf, GST_BUFFER_FLAG_GAP))
180 input = (gfloat *) GST_BUFFER_DATA (buf);
181 count = GST_BUFFER_SIZE (buf) / sizeof (gfloat);
183 for (i = count; i--;) {
185 *input = tanhf ((*input - THRES) / COMPL) * COMPL + THRES;
186 else if (*input < -THRES)
187 *input = tanhf ((*input + THRES) / COMPL) * COMPL - THRES;