1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>level</title>
<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
<link rel="home" href="index.html" title="GStreamer Good Plugins 1.0 Plugins Reference Manual">
<link rel="up" href="ch01.html" title="gst-plugins-good Elements">
<link rel="prev" href="gst-plugins-good-plugins-jpegenc.html" title="jpegenc">
<link rel="next" href="gst-plugins-good-plugins-matroskamux.html" title="matroskamux">
<meta name="generator" content="GTK-Doc V1.18 (XML mode)">
<link rel="stylesheet" href="style.css" type="text/css">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2">
<tr valign="middle">
<td><a accesskey="p" href="gst-plugins-good-plugins-jpegenc.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td>
<td><a accesskey="u" href="ch01.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td>
<td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td>
<th width="100%" align="center">GStreamer Good Plugins 1.0 Plugins Reference Manual</th>
<td><a accesskey="n" href="gst-plugins-good-plugins-matroskamux.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
</tr>
<tr><td colspan="5" class="shortcuts">
<a href="#gst-plugins-good-plugins-level.synopsis" class="shortcut">Top</a>
|
<a href="#gst-plugins-good-plugins-level.description" class="shortcut">Description</a>
|
<a href="#gst-plugins-good-plugins-level.object-hierarchy" class="shortcut">Object Hierarchy</a>
|
<a href="#gst-plugins-good-plugins-level.properties" class="shortcut">Properties</a>
</td></tr>
</table>
<div class="refentry">
<a name="gst-plugins-good-plugins-level"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="gst-plugins-good-plugins-level.top_of_page"></a>level</span></h2>
<p>level — RMS/Peak/Decaying Peak Level messager for audio/raw</p>
</td>
<td valign="top" align="right"></td>
</tr></table></div>
<div class="refsynopsisdiv">
<a name="gst-plugins-good-plugins-level.synopsis"></a><h2>Synopsis</h2>
<a name="GstLevel"></a><pre class="synopsis">struct <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel-struct" title="struct GstLevel">GstLevel</a>;
</pre>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-level.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="synopsis">
<a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a>
+----<a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a>
+----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstObject.html">GstObject</a>
+----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html">GstElement</a>
+----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstBaseTransform.html">GstBaseTransform</a>
+----GstLevel
</pre>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-level.properties"></a><h2>Properties</h2>
<pre class="synopsis">
"<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--interval" title='The "interval" property'>interval</a>" <span class="type">guint64</span> : Read / Write
"<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--message" title='The "message" property'>message</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write
"<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-falloff" title='The "peak-falloff" property'>peak-falloff</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read / Write
"<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-ttl" title='The "peak-ttl" property'>peak-ttl</a>" <span class="type">guint64</span> : Read / Write
"<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--post-messages" title='The "post-messages" property'>post-messages</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write
</pre>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-level.description"></a><h2>Description</h2>
<p>
Level analyses incoming audio buffers and, if the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--message" title='The "message" property'><span class="type">"message"</span></a> property
is <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><span class="type">TRUE</span></a>, generates an element message named
<code class="classname">"level"</code>:
after each interval of time given by the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--interval" title='The "interval" property'><span class="type">"interval"</span></a> property.
The message's structure contains these fields:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"timestamp"</code>:
the timestamp of the buffer that triggered the message.
</p></li>
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"stream-time"</code>:
the stream time of the buffer.
</p></li>
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"running-time"</code>:
the running_time of the buffer.
</p></li>
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"duration"</code>:
the duration of the buffer.
</p></li>
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"endtime"</code>:
the end time of the buffer that triggered the message as stream time (this
is deprecated, as it can be calculated from stream-time + duration)
</p></li>
<li class="listitem"><p>
<a href="http://library.gnome.org/devel/gobject/unstable/gobject-Value-arrays.html#GValueArray"><span class="type">GValueArray</span></a> of <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>
<code class="classname">"peak"</code>:
the peak power level in dB for each channel
</p></li>
<li class="listitem"><p>
<a href="http://library.gnome.org/devel/gobject/unstable/gobject-Value-arrays.html#GValueArray"><span class="type">GValueArray</span></a> of <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>
<code class="classname">"decay"</code>:
the decaying peak power level in dB for each channel
the decaying peak level follows the peak level, but starts dropping
if no new peak is reached after the time given by
the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-ttl" title='The "peak-ttl" property'>the time to live</a>.
When the decaying peak level drops, it does so at the decay rate
as specified by the
<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-falloff" title='The "peak-falloff" property'>the peak falloff rate</a>.
</p></li>
<li class="listitem"><p>
<a href="http://library.gnome.org/devel/gobject/unstable/gobject-Value-arrays.html#GValueArray"><span class="type">GValueArray</span></a> of <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>
<code class="classname">"rms"</code>:
the Root Mean Square (or average power) level in dB for each channel
</p></li>
</ul></div>
<p>
</p>
<p>
</p>
<div class="refsect2">
<a name="idp68313168"></a><h3>Example application</h3>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="comment">/* GStreamer</span>
<span class="comment"> * Copyright (C) 2000,2001,2002,2003,2005</span>
<span class="comment"> * Thomas Vander Stichele <thomas at apestaart dot org></span>
<span class="comment"> *</span>
<span class="comment"> * This library is free software; you can redistribute it and/or</span>
<span class="comment"> * modify it under the terms of the GNU Library General Public</span>
<span class="comment"> * License as published by the Free Software Foundation; either</span>
<span class="comment"> * version 2 of the License, or (at your option) any later version.</span>
<span class="comment"> *</span>
<span class="comment"> * This library is distributed in the hope that it will be useful,</span>
<span class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<span class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</span>
<span class="comment"> * Library General Public License for more details.</span>
<span class="comment"> *</span>
<span class="comment"> * You should have received a copy of the GNU Library General Public</span>
<span class="comment"> * License along with this library; if not, write to the</span>
<span class="comment"> * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,</span>
<span class="comment"> * Boston, MA 02110-1301, USA.</span>
<span class="comment"> */</span>
<span class="gtkdoc ppc">#include <string.h></span>
<span class="gtkdoc ppc">#include <math.h></span>
<span class="gtkdoc ppc">#define GLIB_DISABLE_DEPRECATION_WARNINGS</span>
<span class="gtkdoc ppc">#include <gst/gst.h></span>
<span class="gtkdoc kwb">static</span> gboolean
<span class="function">message_handler</span> <span class="gtkdoc opt">(</span>GstBus <span class="gtkdoc opt">*</span> bus<span class="gtkdoc opt">,</span> GstMessage <span class="gtkdoc opt">*</span> message<span class="gtkdoc opt">,</span> gpointer data<span class="gtkdoc opt">)</span>
<span class="gtkdoc opt">{</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(</span>message<span class="gtkdoc opt">-></span>type <span class="gtkdoc opt">==</span> GST_MESSAGE_ELEMENT<span class="gtkdoc opt">) {</span>
<span class="gtkdoc kwb">const</span> GstStructure <span class="gtkdoc opt">*</span>s <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstMessage.html#gst-message-get-structure">gst_message_get_structure</a></span> <span class="gtkdoc opt">(</span>message<span class="gtkdoc opt">);</span>
<span class="gtkdoc kwb">const</span> gchar <span class="gtkdoc opt">*</span>name <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstStructure.html#gst-structure-get-name">gst_structure_get_name</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">);</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(</span><span class="function">strcmp</span> <span class="gtkdoc opt">(</span>name<span class="gtkdoc opt">,</span> <span class="string">"level"</span><span class="gtkdoc opt">) ==</span> <span class="number">0</span><span class="gtkdoc opt">) {</span>
gint channels<span class="gtkdoc opt">;</span>
GstClockTime endtime<span class="gtkdoc opt">;</span>
gdouble rms_dB<span class="gtkdoc opt">,</span> peak_dB<span class="gtkdoc opt">,</span> decay_dB<span class="gtkdoc opt">;</span>
gdouble rms<span class="gtkdoc opt">;</span>
<span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>array_val<span class="gtkdoc opt">;</span>
<span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>value<span class="gtkdoc opt">;</span>
GValueArray <span class="gtkdoc opt">*</span>rms_arr<span class="gtkdoc opt">, *</span>peak_arr<span class="gtkdoc opt">, *</span>decay_arr<span class="gtkdoc opt">;</span>
gint i<span class="gtkdoc opt">;</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstStructure.html#gst-structure-get-clock-time">gst_structure_get_clock_time</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">,</span> <span class="string">"endtime"</span><span class="gtkdoc opt">, &</span>endtime<span class="gtkdoc opt">))</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Message-Logging.html#g-warning">g_warning</a></span> <span class="gtkdoc opt">(</span><span class="string">"Could not parse endtime"</span><span class="gtkdoc opt">);</span>
<span class="comment">/* the values are packed into GValueArrays with the value per channel */</span>
array_val <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstStructure.html#gst-structure-get-value">gst_structure_get_value</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">,</span> <span class="string">"rms"</span><span class="gtkdoc opt">);</span>
rms_arr <span class="gtkdoc opt">= (</span>GValueArray <span class="gtkdoc opt">*)</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-boxed">g_value_get_boxed</a></span> <span class="gtkdoc opt">(</span>array_val<span class="gtkdoc opt">);</span>
array_val <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstStructure.html#gst-structure-get-value">gst_structure_get_value</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">,</span> <span class="string">"peak"</span><span class="gtkdoc opt">);</span>
peak_arr <span class="gtkdoc opt">= (</span>GValueArray <span class="gtkdoc opt">*)</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-boxed">g_value_get_boxed</a></span> <span class="gtkdoc opt">(</span>array_val<span class="gtkdoc opt">);</span>
array_val <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstStructure.html#gst-structure-get-value">gst_structure_get_value</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">,</span> <span class="string">"decay"</span><span class="gtkdoc opt">);</span>
decay_arr <span class="gtkdoc opt">= (</span>GValueArray <span class="gtkdoc opt">*)</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-boxed">g_value_get_boxed</a></span> <span class="gtkdoc opt">(</span>array_val<span class="gtkdoc opt">);</span>
<span class="comment">/* we can get the number of channels as the length of any of the value</span>
<span class="comment"> * arrays */</span>
channels <span class="gtkdoc opt">=</span> rms_arr<span class="gtkdoc opt">-></span>n_values<span class="gtkdoc opt">;</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">"endtime: %"</span> GST_TIME_FORMAT <span class="string">", channels: %d</span><span class="gtkdoc esc">\n</span><span class="string">"</span><span class="gtkdoc opt">,</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstInfo.html#GST-TIME-ARGS:CAPS">GST_TIME_ARGS</a></span> <span class="gtkdoc opt">(</span>endtime<span class="gtkdoc opt">),</span> channels<span class="gtkdoc opt">);</span>
<span class="keyword">for</span> <span class="gtkdoc opt">(</span>i <span class="gtkdoc opt">=</span> <span class="number">0</span><span class="gtkdoc opt">;</span> i <span class="gtkdoc opt"><</span> channels<span class="gtkdoc opt">; ++</span>i<span class="gtkdoc opt">) {</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">"channel %d</span><span class="gtkdoc esc">\n</span><span class="string">"</span><span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
value <span class="gtkdoc opt">=</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Value-arrays.html#g-value-array-get-nth">g_value_array_get_nth</a></span> <span class="gtkdoc opt">(</span>rms_arr<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
rms_dB <span class="gtkdoc opt">=</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-double">g_value_get_double</a></span> <span class="gtkdoc opt">(</span>value<span class="gtkdoc opt">);</span>
value <span class="gtkdoc opt">=</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Value-arrays.html#g-value-array-get-nth">g_value_array_get_nth</a></span> <span class="gtkdoc opt">(</span>peak_arr<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
peak_dB <span class="gtkdoc opt">=</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-double">g_value_get_double</a></span> <span class="gtkdoc opt">(</span>value<span class="gtkdoc opt">);</span>
value <span class="gtkdoc opt">=</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Value-arrays.html#g-value-array-get-nth">g_value_array_get_nth</a></span> <span class="gtkdoc opt">(</span>decay_arr<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
decay_dB <span class="gtkdoc opt">=</span> <span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-double">g_value_get_double</a></span> <span class="gtkdoc opt">(</span>value<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">" RMS: %f dB, peak: %f dB, decay: %f dB</span><span class="gtkdoc esc">\n</span><span class="string">"</span><span class="gtkdoc opt">,</span>
rms_dB<span class="gtkdoc opt">,</span> peak_dB<span class="gtkdoc opt">,</span> decay_dB<span class="gtkdoc opt">);</span>
<span class="comment">/* converting from dB to normal gives us a value between 0.0 and 1.0 */</span>
rms <span class="gtkdoc opt">=</span> <span class="function">pow</span> <span class="gtkdoc opt">(</span><span class="number">10</span><span class="gtkdoc opt">,</span> rms_dB <span class="gtkdoc opt">/</span> <span class="number">20</span><span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">" normalized rms value: %f</span><span class="gtkdoc esc">\n</span><span class="string">"</span><span class="gtkdoc opt">,</span> rms<span class="gtkdoc opt">);</span>
<span class="gtkdoc opt">}</span>
<span class="gtkdoc opt">}</span>
<span class="gtkdoc opt">}</span>
<span class="comment">/* we handled the message we want, and ignored the ones we didn't want.</span>
<span class="comment"> * so the core can unref the message for us */</span>
<span class="keyword">return</span> TRUE<span class="gtkdoc opt">;</span>
<span class="gtkdoc opt">}</span>
<span class="gtkdoc kwb">int</span>
<span class="function">main</span> <span class="gtkdoc opt">(</span><span class="gtkdoc kwb">int</span> argc<span class="gtkdoc opt">,</span> <span class="gtkdoc kwb">char</span> <span class="gtkdoc opt">*</span>argv<span class="gtkdoc opt">[])</span>
<span class="gtkdoc opt">{</span>
GstElement <span class="gtkdoc opt">*</span>audiotestsrc<span class="gtkdoc opt">, *</span>audioconvert<span class="gtkdoc opt">, *</span>level<span class="gtkdoc opt">, *</span>fakesink<span class="gtkdoc opt">;</span>
GstElement <span class="gtkdoc opt">*</span>pipeline<span class="gtkdoc opt">;</span>
GstCaps <span class="gtkdoc opt">*</span>caps<span class="gtkdoc opt">;</span>
GstBus <span class="gtkdoc opt">*</span>bus<span class="gtkdoc opt">;</span>
guint watch_id<span class="gtkdoc opt">;</span>
GMainLoop <span class="gtkdoc opt">*</span>loop<span class="gtkdoc opt">;</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-Gst.html#gst-init">gst_init</a></span> <span class="gtkdoc opt">(&</span>argc<span class="gtkdoc opt">, &</span>argv<span class="gtkdoc opt">);</span>
caps <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstCaps.html#gst-caps-from-string">gst_caps_from_string</a></span> <span class="gtkdoc opt">(</span><span class="string">"audio/x-raw,channels=2"</span><span class="gtkdoc opt">);</span>
pipeline <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPipeline.html#gst-pipeline-new">gst_pipeline_new</a></span> <span class="gtkdoc opt">(</span>NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">);</span>
audiotestsrc <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">"audiotestsrc"</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>audiotestsrc<span class="gtkdoc opt">);</span>
audioconvert <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">"audioconvert"</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>audioconvert<span class="gtkdoc opt">);</span>
level <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">"level"</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>level<span class="gtkdoc opt">);</span>
fakesink <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">"fakesink"</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>fakesink<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstBin.html#gst-bin-add-many">gst_bin_add_many</a></span> <span class="gtkdoc opt">(</span><span class="function">GST_BIN</span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">),</span> audiotestsrc<span class="gtkdoc opt">,</span> audioconvert<span class="gtkdoc opt">,</span> level<span class="gtkdoc opt">,</span>
fakesink<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-link">gst_element_link</a></span> <span class="gtkdoc opt">(</span>audiotestsrc<span class="gtkdoc opt">,</span> audioconvert<span class="gtkdoc opt">))</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">"Failed to link audiotestsrc and audioconvert"</span><span class="gtkdoc opt">);</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-link-filtered">gst_element_link_filtered</a></span> <span class="gtkdoc opt">(</span>audioconvert<span class="gtkdoc opt">,</span> level<span class="gtkdoc opt">,</span> caps<span class="gtkdoc opt">))</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">"Failed to link audioconvert and level"</span><span class="gtkdoc opt">);</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-link">gst_element_link</a></span> <span class="gtkdoc opt">(</span>level<span class="gtkdoc opt">,</span> fakesink<span class="gtkdoc opt">))</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">"Failed to link level and fakesink"</span><span class="gtkdoc opt">);</span>
<span class="comment">/* make sure we'll get messages */</span>
<span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>level<span class="gtkdoc opt">),</span> <span class="string">"post-messages"</span><span class="gtkdoc opt">,</span> TRUE<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="comment">/* run synced and not as fast as we can */</span>
<span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>fakesink<span class="gtkdoc opt">),</span> <span class="string">"sync"</span><span class="gtkdoc opt">,</span> TRUE<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
bus <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-get-bus">gst_element_get_bus</a></span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">);</span>
watch_id <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstBus.html#gst-bus-add-watch">gst_bus_add_watch</a></span> <span class="gtkdoc opt">(</span>bus<span class="gtkdoc opt">,</span> message_handler<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-set-state">gst_element_set_state</a></span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">,</span> GST_STATE_PLAYING<span class="gtkdoc opt">);</span>
<span class="comment">/* we need to run a GLib main loop to get the messages */</span>
loop <span class="gtkdoc opt">=</span> <span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#g-main-loop-new">g_main_loop_new</a></span> <span class="gtkdoc opt">(</span>NULL<span class="gtkdoc opt">,</span> FALSE<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#g-main-loop-run">g_main_loop_run</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#g-source-remove">g_source_remove</a></span> <span class="gtkdoc opt">(</span>watch_id<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#g-main-loop-unref">g_main_loop_unref</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>
<span class="keyword">return</span> <span class="number">0</span><span class="gtkdoc opt">;</span>
<span class="gtkdoc opt">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
</div>
<p>
</p>
<div class="refsynopsisdiv">
<h2>Synopsis</h2>
<div class="refsect2">
<a name="idp67817328"></a><h3>Element Information</h3>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">plugin</span></p></td>
<td>
<a class="link" href="gst-plugins-good-plugins-plugin-level.html#plugin-level">level</a>
</td>
</tr>
<tr>
<td><p><span class="term">author</span></p></td>
<td>Thomas Vander Stichele <thomas at apestaart dot org></td>
</tr>
<tr>
<td><p><span class="term">class</span></p></td>
<td>Filter/Analyzer/Audio</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="idp65634896"></a><h3>Element Pads</h3>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>audio/x-raw, format=(string){ S8, S16LE, S32LE, F32LE, F64LE }, layout=(string)interleaved, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
</tr>
</tbody>
</table></div>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>src</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>source</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>audio/x-raw, format=(string){ S8, S16LE, S32LE, F32LE, F64LE }, layout=(string)interleaved, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<p>
</p>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-level.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="GstLevel-struct"></a><h3>struct GstLevel</h3>
<pre class="programlisting">struct GstLevel;</pre>
<p>
Opaque data structure.
</p>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-level.property-details"></a><h2>Property Details</h2>
<div class="refsect2">
<a name="GstLevel--interval"></a><h3>The <code class="literal">"interval"</code> property</h3>
<pre class="programlisting"> "interval" <span class="type">guint64</span> : Read / Write</pre>
<p>Interval of time between message posts (in nanoseconds).</p>
<p>Allowed values: >= 1</p>
<p>Default value: 100000000</p>
</div>
<hr>
<div class="refsect2">
<a name="GstLevel--message"></a><h3>The <code class="literal">"message"</code> property</h3>
<pre class="programlisting"> "message" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write</pre>
<p>Post a 'level' message for each passed interval (deprecated).</p>
<p>Default value: TRUE</p>
</div>
<hr>
<div class="refsect2">
<a name="GstLevel--peak-falloff"></a><h3>The <code class="literal">"peak-falloff"</code> property</h3>
<pre class="programlisting"> "peak-falloff" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read / Write</pre>
<p>Decay rate of decay peak after TTL (in dB/sec).</p>
<p>Allowed values: >= 0</p>
<p>Default value: 10</p>
</div>
<hr>
<div class="refsect2">
<a name="GstLevel--peak-ttl"></a><h3>The <code class="literal">"peak-ttl"</code> property</h3>
<pre class="programlisting"> "peak-ttl" <span class="type">guint64</span> : Read / Write</pre>
<p>Time To Live of decay peak before it falls back (in nanoseconds).</p>
<p>Default value: 300000000</p>
</div>
<hr>
<div class="refsect2">
<a name="GstLevel--post-messages"></a><h3>The <code class="literal">"post-messages"</code> property</h3>
<pre class="programlisting"> "post-messages" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write</pre>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Warning</h3>
<p><code class="literal">GstLevel:post-messages</code> is deprecated and should not be used in newly-written code. use the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--post-messages" title='The "post-messages" property'><span class="type">"post-messages"</span></a> property</p>
</div>
<p>
Post messages on the bus with level information.
</p>
<p>Default value: TRUE</p>
<p class="since">Since 1.1.0</p>
</div>
</div>
</div>
<div class="footer">
<hr>
Generated by GTK-Doc V1.18</div>
</body>
</html>
|
