1 /* GStreamer audio filter base class
2 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
3 * Copyright (C) <2003> David Schleef <ds@schleef.org>
4 * Copyright (C) <2007> Tim-Philipp Müller <tim centricular net>
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 */
21
22 /**
23 * SECTION:gstaudiofilter
24 * @title: GstAudioFilter
25 * @short_description: Base class for simple audio filters
26 *
27 * #GstAudioFilter is a #GstBaseTransform<!-- -->-derived base class for simple audio
28 * filters, ie. those that output the same format that they get as input.
29 *
30 * #GstAudioFilter will parse the input format for you (with error checking)
31 * before calling your setup function. Also, elements deriving from
32 * #GstAudioFilter may use gst_audio_filter_class_add_pad_templates() from
33 * their class_init function to easily configure the set of caps/formats that
34 * the element is able to handle.
35 *
36 * Derived classes should override the #GstAudioFilterClass.setup() and
37 * #GstBaseTransformClass.transform_ip() and/or
38 * #GstBaseTransformClass.transform()
39 * virtual functions in their class_init function.
40 */
41
42 #ifdef HAVE_CONFIG_H
43 #include "config.h"
44 #endif
45
46 #include "gstaudiofilter.h"
47
48 #include <string.h>
49
50 GST_DEBUG_CATEGORY_STATIC (audiofilter_dbg);
51 #define GST_CAT_DEFAULT audiofilter_dbg
52
53 static GstStateChangeReturn gst_audio_filter_change_state (GstElement * element,
54 GstStateChange transition);
55 static gboolean gst_audio_filter_set_caps (GstBaseTransform * btrans,
56 GstCaps * incaps, GstCaps * outcaps);
57 static gboolean gst_audio_filter_get_unit_size (GstBaseTransform * btrans,
58 GstCaps * caps, gsize * size);
59 static GstFlowReturn gst_audio_filter_submit_input_buffer (GstBaseTransform *
60 btrans, gboolean is_discont, GstBuffer * input);
61
62 #define do_init G_STMT_START { \
63 GST_DEBUG_CATEGORY_INIT (audiofilter_dbg, "audiofilter", 0, "audiofilter"); \
64 } G_STMT_END
65
66 G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GstAudioFilter, gst_audio_filter,
67 GST_TYPE_BASE_TRANSFORM, do_init);
68
69 static gboolean
gst_audio_filter_transform_meta(GstBaseTransform * trans,GstBuffer * inbuf,GstMeta * meta,GstBuffer * outbuf)70 gst_audio_filter_transform_meta (GstBaseTransform * trans, GstBuffer * inbuf,
71 GstMeta * meta, GstBuffer * outbuf)
72 {
73 const GstMetaInfo *info = meta->info;
74 const gchar *const *tags;
75
76 tags = gst_meta_api_type_get_tags (info->api);
77
78 if (!tags || (g_strv_length ((gchar **) tags) == 1
79 && gst_meta_api_type_has_tag (info->api,
80 g_quark_from_string (GST_META_TAG_AUDIO_STR))))
81 return TRUE;
82
83 return
84 GST_BASE_TRANSFORM_CLASS (gst_audio_filter_parent_class)->transform_meta
85 (trans, inbuf, meta, outbuf);
86 }
87
88 static void
gst_audio_filter_class_init(GstAudioFilterClass * klass)89 gst_audio_filter_class_init (GstAudioFilterClass * klass)
90 {
91 GstBaseTransformClass *basetrans_class = (GstBaseTransformClass *) klass;
92 GstElementClass *gstelement_class = (GstElementClass *) klass;
93
94 gstelement_class->change_state =
95 GST_DEBUG_FUNCPTR (gst_audio_filter_change_state);
96 basetrans_class->set_caps = GST_DEBUG_FUNCPTR (gst_audio_filter_set_caps);
97 basetrans_class->get_unit_size =
98 GST_DEBUG_FUNCPTR (gst_audio_filter_get_unit_size);
99 basetrans_class->transform_meta = gst_audio_filter_transform_meta;
100 basetrans_class->submit_input_buffer = gst_audio_filter_submit_input_buffer;
101 }
102
103 static void
gst_audio_filter_init(GstAudioFilter * self)104 gst_audio_filter_init (GstAudioFilter * self)
105 {
106 gst_audio_info_init (&self->info);
107 }
108
109 /* we override the state change vfunc here instead of GstBaseTransform's stop
110 * vfunc, so GstAudioFilter-derived elements can override ::stop() for their
111 * own purposes without having to worry about chaining up */
112 static GstStateChangeReturn
gst_audio_filter_change_state(GstElement * element,GstStateChange transition)113 gst_audio_filter_change_state (GstElement * element, GstStateChange transition)
114 {
115 GstStateChangeReturn ret;
116 GstAudioFilter *filter = GST_AUDIO_FILTER (element);
117
118 ret =
119 GST_ELEMENT_CLASS (gst_audio_filter_parent_class)->change_state (element,
120 transition);
121 if (ret == GST_STATE_CHANGE_FAILURE)
122 return ret;
123
124 switch (transition) {
125 case GST_STATE_CHANGE_PAUSED_TO_READY:
126 case GST_STATE_CHANGE_READY_TO_NULL:
127 gst_audio_info_init (&filter->info);
128 break;
129 default:
130 break;
131 }
132
133 return ret;
134 }
135
136 static gboolean
gst_audio_filter_set_caps(GstBaseTransform * btrans,GstCaps * incaps,GstCaps * outcaps)137 gst_audio_filter_set_caps (GstBaseTransform * btrans, GstCaps * incaps,
138 GstCaps * outcaps)
139 {
140 GstAudioFilterClass *klass;
141 GstAudioFilter *filter = GST_AUDIO_FILTER (btrans);
142 GstAudioInfo info;
143 gboolean ret = TRUE;
144
145 GST_LOG_OBJECT (filter, "caps: %" GST_PTR_FORMAT, incaps);
146 GST_LOG_OBJECT (filter, "info: %d", GST_AUDIO_FILTER_RATE (filter));
147
148 if (!gst_audio_info_from_caps (&info, incaps))
149 goto invalid_format;
150
151 klass = GST_AUDIO_FILTER_GET_CLASS (filter);
152
153 if (klass->setup)
154 ret = klass->setup (filter, &info);
155
156 if (ret) {
157 filter->info = info;
158 GST_LOG_OBJECT (filter, "configured caps: %" GST_PTR_FORMAT, incaps);
159 }
160
161 return ret;
162
163 /* ERROR */
164 invalid_format:
165 {
166 GST_WARNING_OBJECT (filter, "couldn't parse %" GST_PTR_FORMAT, incaps);
167 return FALSE;
168 }
169 }
170
171 static GstFlowReturn
gst_audio_filter_submit_input_buffer(GstBaseTransform * btrans,gboolean is_discont,GstBuffer * input)172 gst_audio_filter_submit_input_buffer (GstBaseTransform * btrans,
173 gboolean is_discont, GstBuffer * input)
174 {
175 GstAudioFilter *filter = GST_AUDIO_FILTER (btrans);
176
177 if (btrans->segment.format == GST_FORMAT_TIME) {
178 input =
179 gst_audio_buffer_clip (input, &btrans->segment, filter->info.rate,
180 filter->info.bpf);
181
182 if (!input)
183 return GST_FLOW_OK;
184 }
185
186 return
187 GST_BASE_TRANSFORM_CLASS
188 (gst_audio_filter_parent_class)->submit_input_buffer (btrans, is_discont,
189 input);
190 }
191
192 static gboolean
gst_audio_filter_get_unit_size(GstBaseTransform * btrans,GstCaps * caps,gsize * size)193 gst_audio_filter_get_unit_size (GstBaseTransform * btrans, GstCaps * caps,
194 gsize * size)
195 {
196 GstAudioInfo info;
197
198 if (!gst_audio_info_from_caps (&info, caps))
199 return FALSE;
200
201 *size = GST_AUDIO_INFO_BPF (&info);
202
203 return TRUE;
204 }
205
206 /**
207 * gst_audio_filter_class_add_pad_templates:
208 * @klass: an #GstAudioFilterClass
209 * @allowed_caps: what formats the filter can handle, as #GstCaps
210 *
211 * Convenience function to add pad templates to this element class, with
212 * @allowed_caps as the caps that can be handled.
213 *
214 * This function is usually used from within a GObject class_init function.
215 */
216 void
gst_audio_filter_class_add_pad_templates(GstAudioFilterClass * klass,GstCaps * allowed_caps)217 gst_audio_filter_class_add_pad_templates (GstAudioFilterClass * klass,
218 GstCaps * allowed_caps)
219 {
220 GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
221 GstPadTemplate *pad_template;
222
223 g_return_if_fail (GST_IS_AUDIO_FILTER_CLASS (klass));
224 g_return_if_fail (GST_IS_CAPS (allowed_caps));
225
226 pad_template = gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
227 allowed_caps);
228 gst_element_class_add_pad_template (element_class, pad_template);
229
230 pad_template = gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
231 allowed_caps);
232 gst_element_class_add_pad_template (element_class, pad_template);
233 }
234