1 /* GStreamer
2 * Copyright (C) <2011> Wim Taymans <wim.taymans@gmail.com>
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 */
19
20 /**
21 * SECTION:gstaudiometa
22 * @title: GstAudio meta
23 * @short_description: Buffer metadata for audio downmix matrix handling
24 *
25 * #GstAudioDownmixMeta defines an audio downmix matrix to be send along with
26 * audio buffers. These functions in this module help to create and attach the
27 * meta as well as extracting it.
28 */
29 #ifdef HAVE_CONFIG_H
30 #include "config.h"
31 #endif
32
33 #include <string.h>
34
35 #include "gstaudiometa.h"
36
37 static gboolean
gst_audio_downmix_meta_init(GstMeta * meta,gpointer params,GstBuffer * buffer)38 gst_audio_downmix_meta_init (GstMeta * meta, gpointer params,
39 GstBuffer * buffer)
40 {
41 GstAudioDownmixMeta *dmeta = (GstAudioDownmixMeta *) meta;
42
43 dmeta->from_position = dmeta->to_position = NULL;
44 dmeta->from_channels = dmeta->to_channels = 0;
45 dmeta->matrix = NULL;
46
47 return TRUE;
48 }
49
50 static void
gst_audio_downmix_meta_free(GstMeta * meta,GstBuffer * buffer)51 gst_audio_downmix_meta_free (GstMeta * meta, GstBuffer * buffer)
52 {
53 GstAudioDownmixMeta *dmeta = (GstAudioDownmixMeta *) meta;
54
55 g_free (dmeta->from_position);
56 if (dmeta->matrix) {
57 g_free (*dmeta->matrix);
58 g_free (dmeta->matrix);
59 }
60 }
61
62 static gboolean
gst_audio_downmix_meta_transform(GstBuffer * dest,GstMeta * meta,GstBuffer * buffer,GQuark type,gpointer data)63 gst_audio_downmix_meta_transform (GstBuffer * dest, GstMeta * meta,
64 GstBuffer * buffer, GQuark type, gpointer data)
65 {
66 GstAudioDownmixMeta *smeta, *dmeta;
67
68 smeta = (GstAudioDownmixMeta *) meta;
69
70 if (GST_META_TRANSFORM_IS_COPY (type)) {
71 dmeta = gst_buffer_add_audio_downmix_meta (dest, smeta->from_position,
72 smeta->from_channels, smeta->to_position, smeta->to_channels,
73 (const gfloat **) smeta->matrix);
74 if (!dmeta)
75 return FALSE;
76 } else {
77 /* return FALSE, if transform type is not supported */
78 return FALSE;
79 }
80
81 return TRUE;
82 }
83
84 /**
85 * gst_buffer_get_audio_downmix_meta_for_channels:
86 * @buffer: a #GstBuffer
87 * @to_position: (array length=to_channels): the channel positions of
88 * the destination
89 * @to_channels: The number of channels of the destination
90 *
91 * Find the #GstAudioDownmixMeta on @buffer for the given destination
92 * channel positions.
93 *
94 * Returns: (transfer none): the #GstAudioDownmixMeta on @buffer.
95 */
96 GstAudioDownmixMeta *
gst_buffer_get_audio_downmix_meta_for_channels(GstBuffer * buffer,const GstAudioChannelPosition * to_position,gint to_channels)97 gst_buffer_get_audio_downmix_meta_for_channels (GstBuffer * buffer,
98 const GstAudioChannelPosition * to_position, gint to_channels)
99 {
100 gpointer state = NULL;
101 GstMeta *meta;
102 const GstMetaInfo *info = GST_AUDIO_DOWNMIX_META_INFO;
103
104 while ((meta = gst_buffer_iterate_meta (buffer, &state))) {
105 if (meta->info->api == info->api) {
106 GstAudioDownmixMeta *ameta = (GstAudioDownmixMeta *) meta;
107 if (ameta->to_channels == to_channels &&
108 memcmp (ameta->to_position, to_position,
109 sizeof (GstAudioChannelPosition) * to_channels) == 0)
110 return ameta;
111 }
112 }
113 return NULL;
114 }
115
116 /**
117 * gst_buffer_add_audio_downmix_meta:
118 * @buffer: a #GstBuffer
119 * @from_position: (array length=from_channels): the channel positions
120 * of the source
121 * @from_channels: The number of channels of the source
122 * @to_position: (array length=to_channels): the channel positions of
123 * the destination
124 * @to_channels: The number of channels of the destination
125 * @matrix: The matrix coefficients.
126 *
127 * Attaches #GstAudioDownmixMeta metadata to @buffer with the given parameters.
128 *
129 * @matrix is an two-dimensional array of @to_channels times @from_channels
130 * coefficients, i.e. the i-th output channels is constructed by multiplicating
131 * the input channels with the coefficients in @matrix[i] and taking the sum
132 * of the results.
133 *
134 * Returns: (transfer none): the #GstAudioDownmixMeta on @buffer.
135 */
136 GstAudioDownmixMeta *
gst_buffer_add_audio_downmix_meta(GstBuffer * buffer,const GstAudioChannelPosition * from_position,gint from_channels,const GstAudioChannelPosition * to_position,gint to_channels,const gfloat ** matrix)137 gst_buffer_add_audio_downmix_meta (GstBuffer * buffer,
138 const GstAudioChannelPosition * from_position, gint from_channels,
139 const GstAudioChannelPosition * to_position, gint to_channels,
140 const gfloat ** matrix)
141 {
142 GstAudioDownmixMeta *meta;
143 gint i;
144
145 g_return_val_if_fail (from_position != NULL, NULL);
146 g_return_val_if_fail (from_channels > 0, NULL);
147 g_return_val_if_fail (to_position != NULL, NULL);
148 g_return_val_if_fail (to_channels > 0, NULL);
149 g_return_val_if_fail (matrix != NULL, NULL);
150
151 meta =
152 (GstAudioDownmixMeta *) gst_buffer_add_meta (buffer,
153 GST_AUDIO_DOWNMIX_META_INFO, NULL);
154
155 meta->from_channels = from_channels;
156 meta->to_channels = to_channels;
157
158 meta->from_position =
159 g_new (GstAudioChannelPosition, meta->from_channels + meta->to_channels);
160 meta->to_position = meta->from_position + meta->from_channels;
161 memcpy (meta->from_position, from_position,
162 sizeof (GstAudioChannelPosition) * meta->from_channels);
163 memcpy (meta->to_position, to_position,
164 sizeof (GstAudioChannelPosition) * meta->to_channels);
165
166 meta->matrix = g_new (gfloat *, meta->to_channels);
167 meta->matrix[0] = g_new (gfloat, meta->from_channels * meta->to_channels);
168 memcpy (meta->matrix[0], matrix[0], sizeof (gfloat) * meta->from_channels);
169 for (i = 1; i < meta->to_channels; i++) {
170 meta->matrix[i] = meta->matrix[0] + i * meta->from_channels;
171 memcpy (meta->matrix[i], matrix[i], sizeof (gfloat) * meta->from_channels);
172 }
173
174 return meta;
175 }
176
177 GType
gst_audio_downmix_meta_api_get_type(void)178 gst_audio_downmix_meta_api_get_type (void)
179 {
180 static GType type;
181 static const gchar *tags[] =
182 { GST_META_TAG_AUDIO_STR, GST_META_TAG_AUDIO_CHANNELS_STR, NULL };
183
184 if (g_once_init_enter (&type)) {
185 GType _type = gst_meta_api_type_register ("GstAudioDownmixMetaAPI", tags);
186 g_once_init_leave (&type, _type);
187 }
188 return type;
189 }
190
191 const GstMetaInfo *
gst_audio_downmix_meta_get_info(void)192 gst_audio_downmix_meta_get_info (void)
193 {
194 static const GstMetaInfo *audio_downmix_meta_info = NULL;
195
196 if (g_once_init_enter ((GstMetaInfo **) & audio_downmix_meta_info)) {
197 const GstMetaInfo *meta =
198 gst_meta_register (GST_AUDIO_DOWNMIX_META_API_TYPE,
199 "GstAudioDownmixMeta", sizeof (GstAudioDownmixMeta),
200 gst_audio_downmix_meta_init, gst_audio_downmix_meta_free,
201 gst_audio_downmix_meta_transform);
202 g_once_init_leave ((GstMetaInfo **) & audio_downmix_meta_info,
203 (GstMetaInfo *) meta);
204 }
205 return audio_downmix_meta_info;
206 }
207
208 static gboolean
gst_audio_clipping_meta_init(GstMeta * meta,gpointer params,GstBuffer * buffer)209 gst_audio_clipping_meta_init (GstMeta * meta, gpointer params,
210 GstBuffer * buffer)
211 {
212 GstAudioClippingMeta *cmeta = (GstAudioClippingMeta *) meta;
213
214 cmeta->format = GST_FORMAT_UNDEFINED;
215 cmeta->start = cmeta->end = 0;
216
217 return TRUE;
218 }
219
220 static gboolean
gst_audio_clipping_meta_transform(GstBuffer * dest,GstMeta * meta,GstBuffer * buffer,GQuark type,gpointer data)221 gst_audio_clipping_meta_transform (GstBuffer * dest, GstMeta * meta,
222 GstBuffer * buffer, GQuark type, gpointer data)
223 {
224 GstAudioClippingMeta *smeta, *dmeta;
225
226 smeta = (GstAudioClippingMeta *) meta;
227
228 if (GST_META_TRANSFORM_IS_COPY (type)) {
229 GstMetaTransformCopy *copy = data;
230
231 if (copy->region)
232 return FALSE;
233
234 dmeta =
235 gst_buffer_add_audio_clipping_meta (dest, smeta->format, smeta->start,
236 smeta->end);
237 if (!dmeta)
238 return FALSE;
239 } else {
240 /* TODO: Could implement an automatic transform for resampling */
241 /* return FALSE, if transform type is not supported */
242 return FALSE;
243 }
244
245 return TRUE;
246 }
247
248 /**
249 * gst_buffer_add_audio_clipping_meta:
250 * @buffer: a #GstBuffer
251 * @format: GstFormat of @start and @stop, GST_FORMAT_DEFAULT is samples
252 * @start: Amount of audio to clip from start of buffer
253 * @end: Amount of to clip from end of buffer
254 *
255 * Attaches #GstAudioClippingMeta metadata to @buffer with the given parameters.
256 *
257 * Returns: (transfer none): the #GstAudioClippingMeta on @buffer.
258 *
259 * Since: 1.8
260 */
261 GstAudioClippingMeta *
gst_buffer_add_audio_clipping_meta(GstBuffer * buffer,GstFormat format,guint64 start,guint64 end)262 gst_buffer_add_audio_clipping_meta (GstBuffer * buffer,
263 GstFormat format, guint64 start, guint64 end)
264 {
265 GstAudioClippingMeta *meta;
266
267 g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, NULL);
268
269 meta =
270 (GstAudioClippingMeta *) gst_buffer_add_meta (buffer,
271 GST_AUDIO_CLIPPING_META_INFO, NULL);
272
273 meta->format = format;
274 meta->start = start;
275 meta->end = end;
276
277 return meta;
278 }
279
280 GType
gst_audio_clipping_meta_api_get_type(void)281 gst_audio_clipping_meta_api_get_type (void)
282 {
283 static GType type;
284 static const gchar *tags[] =
285 { GST_META_TAG_AUDIO_STR, GST_META_TAG_AUDIO_RATE_STR, NULL };
286
287 if (g_once_init_enter (&type)) {
288 GType _type = gst_meta_api_type_register ("GstAudioClippingMetaAPI", tags);
289 g_once_init_leave (&type, _type);
290 }
291 return type;
292 }
293
294 const GstMetaInfo *
gst_audio_clipping_meta_get_info(void)295 gst_audio_clipping_meta_get_info (void)
296 {
297 static const GstMetaInfo *audio_clipping_meta_info = NULL;
298
299 if (g_once_init_enter ((GstMetaInfo **) & audio_clipping_meta_info)) {
300 const GstMetaInfo *meta =
301 gst_meta_register (GST_AUDIO_CLIPPING_META_API_TYPE,
302 "GstAudioClippingMeta", sizeof (GstAudioClippingMeta),
303 gst_audio_clipping_meta_init, NULL,
304 gst_audio_clipping_meta_transform);
305 g_once_init_leave ((GstMetaInfo **) & audio_clipping_meta_info,
306 (GstMetaInfo *) meta);
307 }
308 return audio_clipping_meta_info;
309 }
310
311
312 static gboolean
gst_audio_meta_init(GstMeta * meta,gpointer params,GstBuffer * buffer)313 gst_audio_meta_init (GstMeta * meta, gpointer params, GstBuffer * buffer)
314 {
315 GstAudioMeta *ameta = (GstAudioMeta *) meta;
316
317 gst_audio_info_init (&ameta->info);
318 ameta->samples = 0;
319 ameta->offsets = NULL;
320
321 return TRUE;
322 }
323
324 static void
gst_audio_meta_free(GstMeta * meta,GstBuffer * buffer)325 gst_audio_meta_free (GstMeta * meta, GstBuffer * buffer)
326 {
327 GstAudioMeta *ameta = (GstAudioMeta *) meta;
328
329 if (ameta->offsets && ameta->offsets != ameta->priv_offsets_arr)
330 g_slice_free1 (ameta->info.channels * sizeof (gsize), ameta->offsets);
331 }
332
333 static gboolean
gst_audio_meta_transform(GstBuffer * dest,GstMeta * meta,GstBuffer * buffer,GQuark type,gpointer data)334 gst_audio_meta_transform (GstBuffer * dest, GstMeta * meta,
335 GstBuffer * buffer, GQuark type, gpointer data)
336 {
337 GstAudioMeta *smeta, *dmeta;
338
339 smeta = (GstAudioMeta *) meta;
340
341 if (GST_META_TRANSFORM_IS_COPY (type)) {
342 dmeta = gst_buffer_add_audio_meta (dest, &smeta->info, smeta->samples,
343 smeta->offsets);
344 if (!dmeta)
345 return FALSE;
346 } else {
347 /* return FALSE, if transform type is not supported */
348 return FALSE;
349 }
350
351 return TRUE;
352 }
353
354 /**
355 * gst_buffer_add_audio_meta:
356 * @buffer: a #GstBuffer
357 * @info: the audio properties of the buffer
358 * @samples: the number of valid samples in the buffer
359 * @offsets: (nullable): the offsets (in bytes) where each channel plane starts
360 * in the buffer or %NULL to calculate it (see below); must be %NULL also
361 * when @info->layout is %GST_AUDIO_LAYOUT_INTERLEAVED
362 *
363 * Allocates and attaches a #GstAudioMeta on @buffer, which must be writable
364 * for that purpose. The fields of the #GstAudioMeta are directly populated
365 * from the arguments of this function.
366 *
367 * When @info->layout is %GST_AUDIO_LAYOUT_NON_INTERLEAVED and @offsets is
368 * %NULL, the offsets are calculated with a formula that assumes the planes are
369 * tightly packed and in sequence:
370 * offsets[channel] = channel * @samples * sample_stride
371 *
372 * It is not allowed for channels to overlap in memory,
373 * i.e. for each i in [0, channels), the range
374 * [@offsets[i], @offsets[i] + @samples * sample_stride) must not overlap
375 * with any other such range. This function will assert if the parameters
376 * specified cause this restriction to be violated.
377 *
378 * It is, obviously, also not allowed to specify parameters that would cause
379 * out-of-bounds memory access on @buffer. This is also checked, which means
380 * that you must add enough memory on the @buffer before adding this meta.
381 *
382 * Returns: (transfer none): the #GstAudioMeta that was attached on the @buffer
383 *
384 * Since: 1.16
385 */
386 GstAudioMeta *
gst_buffer_add_audio_meta(GstBuffer * buffer,const GstAudioInfo * info,gsize samples,gsize offsets[])387 gst_buffer_add_audio_meta (GstBuffer * buffer, const GstAudioInfo * info,
388 gsize samples, gsize offsets[])
389 {
390 GstAudioMeta *meta;
391 gint i;
392 gsize plane_size;
393
394 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
395 g_return_val_if_fail (info != NULL, NULL);
396 g_return_val_if_fail (GST_AUDIO_INFO_IS_VALID (info), NULL);
397 g_return_val_if_fail (GST_AUDIO_INFO_FORMAT (info) !=
398 GST_AUDIO_FORMAT_UNKNOWN, NULL);
399 g_return_val_if_fail (info->layout == GST_AUDIO_LAYOUT_NON_INTERLEAVED
400 || !offsets, NULL);
401
402 meta =
403 (GstAudioMeta *) gst_buffer_add_meta (buffer, GST_AUDIO_META_INFO, NULL);
404
405 meta->info = *info;
406 meta->samples = samples;
407 plane_size = samples * info->finfo->width / 8;
408
409 if (info->layout == GST_AUDIO_LAYOUT_NON_INTERLEAVED) {
410 #ifndef G_DISABLE_CHECKS
411 gsize max_offset = 0;
412 gint j;
413 #endif
414
415 if (G_UNLIKELY (info->channels > 8))
416 meta->offsets = g_slice_alloc (info->channels * sizeof (gsize));
417 else
418 meta->offsets = meta->priv_offsets_arr;
419
420 if (offsets) {
421 for (i = 0; i < info->channels; i++) {
422 meta->offsets[i] = offsets[i];
423 #ifndef G_DISABLE_CHECKS
424 max_offset = MAX (max_offset, offsets[i]);
425 for (j = 0; j < info->channels; j++) {
426 if (i != j && !(offsets[j] + plane_size <= offsets[i]
427 || offsets[i] + plane_size <= offsets[j])) {
428 g_critical ("GstAudioMeta properties would cause channel memory "
429 "areas to overlap! offsets: %" G_GSIZE_FORMAT " (%d), %"
430 G_GSIZE_FORMAT " (%d) with plane size %" G_GSIZE_FORMAT,
431 offsets[i], i, offsets[j], j, plane_size);
432 gst_buffer_remove_meta (buffer, (GstMeta *) meta);
433 return NULL;
434 }
435 }
436 #endif
437 }
438 } else {
439 /* default offsets assume channels are laid out sequentially in memory */
440 for (i = 0; i < info->channels; i++)
441 meta->offsets[i] = i * plane_size;
442 #ifndef G_DISABLE_CHECKS
443 max_offset = meta->offsets[info->channels - 1];
444 #endif
445 }
446
447 #ifndef G_DISABLE_CHECKS
448 if (max_offset + plane_size > gst_buffer_get_size (buffer)) {
449 g_critical ("GstAudioMeta properties would cause "
450 "out-of-bounds memory access on the buffer: max_offset %"
451 G_GSIZE_FORMAT ", samples %" G_GSIZE_FORMAT ", bps %u, buffer size %"
452 G_GSIZE_FORMAT, max_offset, samples, info->finfo->width / 8,
453 gst_buffer_get_size (buffer));
454 gst_buffer_remove_meta (buffer, (GstMeta *) meta);
455 return NULL;
456 }
457 #endif
458 }
459
460 return meta;
461 }
462
463 GType
gst_audio_meta_api_get_type(void)464 gst_audio_meta_api_get_type (void)
465 {
466 static GType type;
467 static const gchar *tags[] = {
468 GST_META_TAG_AUDIO_STR, GST_META_TAG_AUDIO_CHANNELS_STR,
469 GST_META_TAG_AUDIO_RATE_STR, NULL
470 };
471
472 if (g_once_init_enter (&type)) {
473 GType _type = gst_meta_api_type_register ("GstAudioMetaAPI", tags);
474 g_once_init_leave (&type, _type);
475 }
476 return type;
477 }
478
479 const GstMetaInfo *
gst_audio_meta_get_info(void)480 gst_audio_meta_get_info (void)
481 {
482 static const GstMetaInfo *audio_meta_info = NULL;
483
484 if (g_once_init_enter ((GstMetaInfo **) & audio_meta_info)) {
485 const GstMetaInfo *meta = gst_meta_register (GST_AUDIO_META_API_TYPE,
486 "GstAudioMeta", sizeof (GstAudioMeta),
487 gst_audio_meta_init,
488 gst_audio_meta_free,
489 gst_audio_meta_transform);
490 g_once_init_leave ((GstMetaInfo **) & audio_meta_info,
491 (GstMetaInfo *) meta);
492 }
493 return audio_meta_info;
494 }
495
496 /**
497 * gst_audio_level_meta_api_get_type:
498 *
499 * Return the #GType associated with #GstAudioLevelMeta.
500 *
501 * Returns: a #GType
502 *
503 * Since: 1.20
504 */
505 GType
gst_audio_level_meta_api_get_type(void)506 gst_audio_level_meta_api_get_type (void)
507 {
508 static GType type = 0;
509 static const gchar *tags[] = { NULL };
510
511 if (g_once_init_enter (&type)) {
512 GType _type = gst_meta_api_type_register ("GstAudioLevelMetaAPI", tags);
513 g_once_init_leave (&type, _type);
514 }
515 return type;
516 }
517
518 static gboolean
gst_audio_level_meta_init(GstMeta * meta,gpointer params,GstBuffer * buffer)519 gst_audio_level_meta_init (GstMeta * meta, gpointer params, GstBuffer * buffer)
520 {
521 GstAudioLevelMeta *dmeta = (GstAudioLevelMeta *) meta;
522
523 dmeta->level = 127;
524 dmeta->voice_activity = FALSE;
525
526 return TRUE;
527 }
528
529 static gboolean
gst_audio_level_meta_transform(GstBuffer * dst,GstMeta * meta,GstBuffer * src,GQuark type,gpointer data)530 gst_audio_level_meta_transform (GstBuffer * dst, GstMeta * meta,
531 GstBuffer * src, GQuark type, gpointer data)
532 {
533 if (GST_META_TRANSFORM_IS_COPY (type)) {
534 GstAudioLevelMeta *smeta = (GstAudioLevelMeta *) meta;
535 GstAudioLevelMeta *dmeta;
536
537 dmeta = gst_buffer_add_audio_level_meta (dst, smeta->level,
538 smeta->voice_activity);
539 if (dmeta == NULL)
540 return FALSE;
541 } else {
542 /* return FALSE, if transform type is not supported */
543 return FALSE;
544 }
545
546 return TRUE;
547 }
548
549 /**
550 * gst_audio_level_meta_get_info:
551 *
552 * Return the #GstMetaInfo associated with #GstAudioLevelMeta.
553 *
554 * Returns: (transfer none): a #GstMetaInfo
555 *
556 * Since: 1.20
557 */
558 const GstMetaInfo *
gst_audio_level_meta_get_info(void)559 gst_audio_level_meta_get_info (void)
560 {
561 static const GstMetaInfo *audio_level_meta_info = NULL;
562
563 if (g_once_init_enter (&audio_level_meta_info)) {
564 const GstMetaInfo *meta = gst_meta_register (GST_AUDIO_LEVEL_META_API_TYPE,
565 "GstAudioLevelMeta",
566 sizeof (GstAudioLevelMeta),
567 gst_audio_level_meta_init,
568 (GstMetaFreeFunction) NULL,
569 gst_audio_level_meta_transform);
570 g_once_init_leave (&audio_level_meta_info, meta);
571 }
572 return audio_level_meta_info;
573 }
574
575 /**
576 * gst_buffer_add_audio_level_meta:
577 * @buffer: a #GstBuffer
578 * @level: the -dBov from 0-127 (127 is silence).
579 * @voice_activity: whether the buffer contains voice activity.
580 *
581 * Attaches audio level information to @buffer. (RFC 6464)
582 *
583 * Returns: (transfer none) (nullable): the #GstAudioLevelMeta on @buffer.
584 *
585 * Since: 1.20
586 */
587 GstAudioLevelMeta *
gst_buffer_add_audio_level_meta(GstBuffer * buffer,guint8 level,gboolean voice_activity)588 gst_buffer_add_audio_level_meta (GstBuffer * buffer, guint8 level,
589 gboolean voice_activity)
590 {
591 GstAudioLevelMeta *meta;
592
593 g_return_val_if_fail (buffer != NULL, NULL);
594
595 meta = (GstAudioLevelMeta *) gst_buffer_add_meta (buffer,
596 GST_AUDIO_LEVEL_META_INFO, NULL);
597 if (!meta)
598 return NULL;
599
600 meta->level = level;
601 meta->voice_activity = voice_activity;
602
603 return meta;
604 }
605
606 /**
607 * gst_buffer_get_audio_level_meta:
608 * @buffer: a #GstBuffer
609 *
610 * Find the #GstAudioLevelMeta on @buffer.
611 *
612 * Returns: (transfer none) (nullable): the #GstAudioLevelMeta or %NULL when
613 * there is no such metadata on @buffer.
614 *
615 * Since: 1.20
616 */
617 GstAudioLevelMeta *
gst_buffer_get_audio_level_meta(GstBuffer * buffer)618 gst_buffer_get_audio_level_meta (GstBuffer * buffer)
619 {
620 return (GstAudioLevelMeta *) gst_buffer_get_meta (buffer,
621 gst_audio_level_meta_api_get_type ());
622 }
623