3 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
4 * Copyright (C) 2002,2007 David A. Schleef <ds@schleef.org>
5 * Copyright (C) 2008 Julien Isorce <julien.isorce@gmail.com>
6 * Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
7 * Copyright (C) 2019 Philippe Normand <philn@igalia.com>
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Library General Public
11 * License as published by the Free Software Foundation; either
12 * version 2 of the License, or (at your option) any later version.
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Library General Public License for more details.
19 * You should have received a copy of the GNU Library General Public
20 * License along with this library; if not, write to the
21 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
22 * Boston, MA 02110-1301, USA.
29 #include <gst/gl/gl.h>
30 #include <gst/gst-i18n-plugin.h>
33 * SECTION:gstglbasesrc
34 * @short_description: #GstPushSrc subclass for injecting OpenGL resources in a pipeline
35 * @title: GstGLBaseSrc
36 * @see_also: #GstPushSrc
38 * #GstGLBaseSrc handles the nitty gritty details of retrieving an OpenGL
39 * context. It also provided some wrappers around #GstBaseSrc's `start()` and
40 * `stop()` virtual methods that ensure an OpenGL context is available and
41 * current in the calling thread.
46 #define GST_CAT_DEFAULT gst_gl_base_src_debug
47 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
49 struct _GstGLBaseSrcPrivate
51 GstGLContext *other_context;
54 gint64 timestamp_offset; /* base offset */
55 gint64 n_frames; /* total frames sent */
60 GRecMutex context_lock;
70 #define gst_gl_base_src_parent_class parent_class
71 G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GstGLBaseSrc, gst_gl_base_src,
72 GST_TYPE_PUSH_SRC, G_ADD_PRIVATE (GstGLBaseSrc)
73 GST_DEBUG_CATEGORY_INIT (gst_gl_base_src_debug,
74 "glbasesrc", 0, "glbasesrc element");
77 static void gst_gl_base_src_finalize (GObject * object);
78 static void gst_gl_base_src_set_property (GObject * object, guint prop_id,
79 const GValue * value, GParamSpec * pspec);
80 static void gst_gl_base_src_get_property (GObject * object, guint prop_id,
81 GValue * value, GParamSpec * pspec);
83 static gboolean gst_gl_base_src_setcaps (GstBaseSrc * bsrc, GstCaps * caps);
84 static gboolean gst_gl_base_src_query (GstBaseSrc * bsrc, GstQuery * query);
85 static void gst_gl_base_src_set_context (GstElement * element,
86 GstContext * context);
87 static GstStateChangeReturn gst_gl_base_src_change_state (GstElement * element,
88 GstStateChange transition);
90 static void gst_gl_base_src_get_times (GstBaseSrc * basesrc,
91 GstBuffer * buffer, GstClockTime * start, GstClockTime * end);
92 static GstFlowReturn gst_gl_base_src_fill (GstPushSrc * psrc,
94 static gboolean gst_gl_base_src_start (GstBaseSrc * basesrc);
95 static gboolean gst_gl_base_src_stop (GstBaseSrc * basesrc);
96 static gboolean gst_gl_base_src_decide_allocation (GstBaseSrc * basesrc,
98 static gboolean gst_gl_base_src_do_seek (GstBaseSrc * basesrc,
99 GstSegment * segment);
101 static gboolean gst_gl_base_src_default_gl_start (GstGLBaseSrc * src);
102 static void gst_gl_base_src_default_gl_stop (GstGLBaseSrc * src);
103 static gboolean gst_gl_base_src_default_fill_gl_memory (GstGLBaseSrc * src,
106 static gboolean gst_gl_base_src_find_gl_context_unlocked (GstGLBaseSrc * src);
109 gst_gl_base_src_class_init (GstGLBaseSrcClass * klass)
111 GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
112 GstBaseSrcClass *gstbasesrc_class = GST_BASE_SRC_CLASS (klass);
113 GstPushSrcClass *gstpushsrc_class = GST_PUSH_SRC_CLASS (klass);
114 GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
116 gobject_class->finalize = gst_gl_base_src_finalize;
117 gobject_class->set_property = gst_gl_base_src_set_property;
118 gobject_class->get_property = gst_gl_base_src_get_property;
120 g_object_class_install_property (gobject_class,
121 PROP_TIMESTAMP_OFFSET, g_param_spec_int64 ("timestamp-offset",
123 "An offset added to timestamps set on buffers (in ns)", G_MININT64,
124 G_MAXINT64, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
126 element_class->set_context = GST_DEBUG_FUNCPTR (gst_gl_base_src_set_context);
127 element_class->change_state =
128 GST_DEBUG_FUNCPTR (gst_gl_base_src_change_state);
130 gstbasesrc_class->set_caps = GST_DEBUG_FUNCPTR (gst_gl_base_src_setcaps);
131 gstbasesrc_class->query = GST_DEBUG_FUNCPTR (gst_gl_base_src_query);
132 gstbasesrc_class->get_times = GST_DEBUG_FUNCPTR (gst_gl_base_src_get_times);
133 gstbasesrc_class->start = GST_DEBUG_FUNCPTR (gst_gl_base_src_start);
134 gstbasesrc_class->stop = GST_DEBUG_FUNCPTR (gst_gl_base_src_stop);
135 gstbasesrc_class->decide_allocation =
136 GST_DEBUG_FUNCPTR (gst_gl_base_src_decide_allocation);
137 gstbasesrc_class->do_seek = GST_DEBUG_FUNCPTR (gst_gl_base_src_do_seek);
139 gstpushsrc_class->fill = GST_DEBUG_FUNCPTR (gst_gl_base_src_fill);
141 klass->supported_gl_api = GST_GL_API_ANY;
142 klass->gl_start = GST_DEBUG_FUNCPTR (gst_gl_base_src_default_gl_start);
143 klass->gl_stop = GST_DEBUG_FUNCPTR (gst_gl_base_src_default_gl_stop);
144 klass->fill_gl_memory =
145 GST_DEBUG_FUNCPTR (gst_gl_base_src_default_fill_gl_memory);
149 gst_gl_base_src_init (GstGLBaseSrc * src)
151 src->priv = gst_gl_base_src_get_instance_private (src);
152 src->priv->timestamp_offset = 0;
153 g_rec_mutex_init (&src->priv->context_lock);
155 /* we operate in time */
156 gst_base_src_set_format (GST_BASE_SRC (src), GST_FORMAT_TIME);
157 gst_base_src_set_live (GST_BASE_SRC (src), FALSE);
161 gst_gl_base_src_finalize (GObject * object)
163 GstGLBaseSrc *src = GST_GL_BASE_SRC (object);
165 g_rec_mutex_clear (&src->priv->context_lock);
167 G_OBJECT_CLASS (parent_class)->finalize (object);
171 gst_gl_base_src_set_property (GObject * object, guint prop_id,
172 const GValue * value, GParamSpec * pspec)
174 GstGLBaseSrc *src = GST_GL_BASE_SRC (object);
177 case PROP_TIMESTAMP_OFFSET:
178 src->priv->timestamp_offset = g_value_get_int64 (value);
186 gst_gl_base_src_get_property (GObject * object, guint prop_id,
187 GValue * value, GParamSpec * pspec)
189 GstGLBaseSrc *src = GST_GL_BASE_SRC (object);
192 case PROP_TIMESTAMP_OFFSET:
193 g_value_set_int64 (value, src->priv->timestamp_offset);
196 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
202 gst_gl_base_src_setcaps (GstBaseSrc * bsrc, GstCaps * caps)
204 GstGLBaseSrc *glbasesrc = GST_GL_BASE_SRC (bsrc);
206 GST_DEBUG_OBJECT (bsrc, "set caps %" GST_PTR_FORMAT, caps);
208 if (!gst_video_info_from_caps (&glbasesrc->out_info, caps))
211 glbasesrc->priv->negotiated = TRUE;
213 gst_caps_replace (&glbasesrc->out_caps, caps);
220 GST_WARNING_OBJECT (bsrc, "wrong caps");
226 gst_gl_base_src_set_context (GstElement * element, GstContext * context)
228 GstGLBaseSrc *src = GST_GL_BASE_SRC (element);
229 GstGLBaseSrcClass *klass = GST_GL_BASE_SRC_GET_CLASS (src);
230 GstGLDisplay *old_display, *new_display;
232 g_rec_mutex_lock (&src->priv->context_lock);
233 old_display = src->display ? gst_object_ref (src->display) : NULL;
234 gst_gl_handle_set_context (element, context, &src->display,
235 &src->priv->other_context);
237 gst_gl_display_filter_gl_api (src->display, klass->supported_gl_api);
238 new_display = src->display ? gst_object_ref (src->display) : NULL;
240 if (old_display && new_display) {
241 if (old_display != new_display) {
242 gst_clear_object (&src->context);
243 if (gst_gl_base_src_find_gl_context_unlocked (src)) {
244 gst_pad_mark_reconfigure (GST_BASE_SRC_PAD (src));
248 gst_clear_object (&old_display);
249 gst_clear_object (&new_display);
250 g_rec_mutex_unlock (&src->priv->context_lock);
252 GST_ELEMENT_CLASS (parent_class)->set_context (element, context);
256 gst_gl_base_src_query (GstBaseSrc * bsrc, GstQuery * query)
258 gboolean res = FALSE;
261 src = GST_GL_BASE_SRC (bsrc);
263 switch (GST_QUERY_TYPE (query)) {
264 case GST_QUERY_CONTEXT:
266 GstGLDisplay *display = NULL;
267 GstGLContext *other = NULL, *local = NULL;
270 g_rec_mutex_lock (&src->priv->context_lock);
272 display = gst_object_ref (src->display);
274 local = gst_object_ref (src->context);
275 if (src->priv->other_context)
276 other = gst_object_ref (src->priv->other_context);
277 g_rec_mutex_unlock (&src->priv->context_lock);
279 ret = gst_gl_handle_context_query ((GstElement *) src, query,
280 display, local, other);
282 gst_clear_object (&display);
283 gst_clear_object (&other);
284 gst_clear_object (&local);
290 case GST_QUERY_CONVERT:
292 GstFormat src_fmt, dest_fmt;
293 gint64 src_val, dest_val;
295 gst_query_parse_convert (query, &src_fmt, &src_val, &dest_fmt, &dest_val);
297 gst_video_info_convert (&src->out_info, src_fmt, src_val, dest_fmt,
299 gst_query_set_convert (query, src_fmt, src_val, dest_fmt, dest_val);
307 return GST_BASE_SRC_CLASS (parent_class)->query (bsrc, query);
311 gst_gl_base_src_get_times (GstBaseSrc * basesrc, GstBuffer * buffer,
312 GstClockTime * start, GstClockTime * end)
314 /* for live sources, sync on the timestamp of the buffer */
315 if (gst_base_src_is_live (basesrc)) {
316 GstClockTime timestamp = GST_BUFFER_TIMESTAMP (buffer);
318 if (GST_CLOCK_TIME_IS_VALID (timestamp)) {
319 /* get duration to calculate end time */
320 GstClockTime duration = GST_BUFFER_DURATION (buffer);
322 if (GST_CLOCK_TIME_IS_VALID (duration))
323 *end = timestamp + duration;
333 gst_gl_base_src_default_gl_start (GstGLBaseSrc * src)
339 gst_gl_base_src_gl_start (GstGLContext * context, gpointer data)
341 GstGLBaseSrc *src = GST_GL_BASE_SRC (data);
342 GstGLBaseSrcClass *src_class = GST_GL_BASE_SRC_GET_CLASS (src);
344 GST_INFO_OBJECT (src, "starting");
345 gst_gl_insert_debug_marker (src->context,
346 "starting element %s", GST_OBJECT_NAME (src));
348 src->priv->gl_started = src_class->gl_start (src);
352 gst_gl_base_src_default_gl_stop (GstGLBaseSrc * src)
357 gst_gl_base_src_gl_stop (GstGLContext * context, gpointer data)
359 GstGLBaseSrc *src = GST_GL_BASE_SRC (data);
360 GstGLBaseSrcClass *src_class = GST_GL_BASE_SRC_GET_CLASS (src);
362 GST_INFO_OBJECT (src, "stopping");
363 gst_gl_insert_debug_marker (src->context,
364 "stopping element %s", GST_OBJECT_NAME (src));
366 src->priv->out_tex = NULL;
368 if (src->priv->gl_started)
369 src_class->gl_stop (src);
371 src->priv->gl_started = FALSE;
375 gst_gl_base_src_default_fill_gl_memory (GstGLBaseSrc * src, GstGLMemory * mem)
381 _fill_gl (GstGLContext * context, GstGLBaseSrc * src)
383 GstGLBaseSrcClass *klass = GST_GL_BASE_SRC_GET_CLASS (src);
385 GST_TRACE_OBJECT (src, "filling gl memory %p", src->priv->out_tex);
386 src->priv->gl_result = klass->fill_gl_memory (src, src->priv->out_tex);
390 gst_gl_base_src_fill (GstPushSrc * psrc, GstBuffer * buffer)
392 GstGLBaseSrc *src = GST_GL_BASE_SRC (psrc);
393 GstClockTime next_time;
394 GstVideoFrame out_frame;
395 GstGLSyncMeta *sync_meta;
397 g_rec_mutex_lock (&src->priv->context_lock);
398 if (G_UNLIKELY (!src->priv->negotiated || !src->context))
401 /* 0 framerate and we are at the second frame, eos */
402 if (G_UNLIKELY (GST_VIDEO_INFO_FPS_N (&src->out_info) == 0
403 && src->priv->n_frames == 1))
406 if (!gst_video_frame_map (&out_frame, &src->out_info, buffer,
407 GST_MAP_WRITE | GST_MAP_GL)) {
408 return GST_FLOW_NOT_NEGOTIATED;
411 src->priv->out_tex = (GstGLMemory *) out_frame.map[0].memory;
413 gst_gl_context_thread_add (src->context, (GstGLContextThreadFunc) _fill_gl,
415 gst_video_frame_unmap (&out_frame);
416 if (!src->priv->gl_result)
419 sync_meta = gst_buffer_get_gl_sync_meta (buffer);
421 gst_gl_sync_meta_set_sync_point (sync_meta, src->context);
422 g_rec_mutex_unlock (&src->priv->context_lock);
424 GST_BUFFER_TIMESTAMP (buffer) =
425 src->priv->timestamp_offset + src->running_time;
426 GST_BUFFER_OFFSET (buffer) = src->priv->n_frames;
427 src->priv->n_frames++;
428 GST_BUFFER_OFFSET_END (buffer) = src->priv->n_frames;
429 if (src->out_info.fps_n) {
430 next_time = gst_util_uint64_scale_int (src->priv->n_frames * GST_SECOND,
431 src->out_info.fps_d, src->out_info.fps_n);
432 GST_BUFFER_DURATION (buffer) = next_time - src->running_time;
434 next_time = src->priv->timestamp_offset;
435 /* NONE means forever */
436 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
439 src->running_time = next_time;
445 g_rec_mutex_unlock (&src->priv->context_lock);
446 GST_ELEMENT_ERROR (src, RESOURCE, NOT_FOUND, (_("failed to draw pattern")),
447 (_("A GL error occurred")));
448 return GST_FLOW_NOT_NEGOTIATED;
452 g_rec_mutex_unlock (&src->priv->context_lock);
453 GST_ELEMENT_ERROR (src, CORE, NEGOTIATION, (NULL),
454 (_("format wasn't negotiated before get function")));
455 return GST_FLOW_NOT_NEGOTIATED;
459 g_rec_mutex_unlock (&src->priv->context_lock);
460 GST_DEBUG_OBJECT (src, "eos: 0 framerate, frame %d",
461 (gint) src->priv->n_frames);
467 gst_gl_base_src_start (GstBaseSrc * basesrc)
469 GstGLBaseSrc *src = GST_GL_BASE_SRC (basesrc);
471 src->running_time = 0;
472 src->priv->n_frames = 0;
473 src->priv->negotiated = FALSE;
479 gst_gl_base_src_stop (GstBaseSrc * basesrc)
481 GstGLBaseSrc *src = GST_GL_BASE_SRC (basesrc);
483 g_rec_mutex_lock (&src->priv->context_lock);
484 gst_caps_replace (&src->out_caps, NULL);
487 if (src->priv->gl_started)
488 gst_gl_context_thread_add (src->context, gst_gl_base_src_gl_stop, src);
490 gst_object_unref (src->context);
493 g_rec_mutex_unlock (&src->priv->context_lock);
499 _find_local_gl_context_unlocked (GstGLBaseSrc * src)
501 GstGLContext *context, *prev_context;
504 if (src->context && src->context->display == src->display)
507 context = prev_context = src->context;
508 g_rec_mutex_unlock (&src->priv->context_lock);
509 /* we need to drop the lock to query as another element may also be
510 * performing a context query on us which would also attempt to take the
511 * context_lock. Our query could block on the same lock in the other element.
514 gst_gl_query_local_gl_context (GST_ELEMENT (src), GST_PAD_SRC, &context);
515 g_rec_mutex_lock (&src->priv->context_lock);
517 if (src->context != prev_context) {
518 /* we need to recheck everything since we dropped the lock and the
519 * context has changed */
520 if (src->context && src->context->display == src->display) {
521 if (context != src->context)
522 gst_clear_object (&context);
527 if (context->display == src->display) {
528 src->context = context;
531 if (context != src->context)
532 gst_clear_object (&context);
538 gst_gl_base_src_find_gl_context_unlocked (GstGLBaseSrc * src)
540 GstGLBaseSrcClass *klass = GST_GL_BASE_SRC_GET_CLASS (src);
541 GError *error = NULL;
542 gboolean new_context = FALSE;
544 GST_DEBUG_OBJECT (src, "attempting to find an OpenGL context, existing %"
545 GST_PTR_FORMAT, src->context);
550 if (!gst_gl_ensure_element_data (src, &src->display,
551 &src->priv->other_context))
554 gst_gl_display_filter_gl_api (src->display, klass->supported_gl_api);
556 _find_local_gl_context_unlocked (src);
559 GST_OBJECT_LOCK (src->display);
562 gst_object_unref (src->context);
565 /* just get a GL context. we don't care */
567 gst_gl_display_get_gl_context_for_thread (src->display, NULL);
569 if (!gst_gl_display_create_context (src->display,
570 src->priv->other_context, &src->context, &error)) {
571 GST_OBJECT_UNLOCK (src->display);
575 } while (!gst_gl_display_add_context (src->display, src->context));
576 GST_OBJECT_UNLOCK (src->display);
578 GST_INFO_OBJECT (src, "found OpenGL context %" GST_PTR_FORMAT, src->context);
580 if (new_context || !src->priv->gl_started) {
581 if (src->priv->gl_started)
582 gst_gl_context_thread_add (src->context, gst_gl_base_src_gl_stop, src);
585 if ((gst_gl_context_get_gl_api (src->
586 context) & klass->supported_gl_api) == 0)
587 goto unsupported_gl_api;
590 gst_gl_context_thread_add (src->context, gst_gl_base_src_gl_start, src);
592 if (!src->priv->gl_started)
600 GstGLAPI gl_api = gst_gl_context_get_gl_api (src->context);
601 gchar *gl_api_str = gst_gl_api_to_string (gl_api);
602 gchar *supported_gl_api_str =
603 gst_gl_api_to_string (klass->supported_gl_api);
604 GST_ELEMENT_ERROR (src, RESOURCE, BUSY,
605 ("GL API's not compatible context: %s supported: %s", gl_api_str,
606 supported_gl_api_str), (NULL));
608 g_free (supported_gl_api_str);
615 GST_ELEMENT_ERROR (src, RESOURCE, NOT_FOUND, ("%s", error->message),
617 g_clear_error (&error);
619 GST_ELEMENT_ERROR (src, RESOURCE, NOT_FOUND, (NULL), (NULL));
622 gst_object_unref (src->context);
628 GST_ELEMENT_ERROR (src, LIBRARY, INIT,
629 ("Subclass failed to initialize."), (NULL));
635 gst_gl_base_src_decide_allocation (GstBaseSrc * basesrc, GstQuery * query)
637 GstGLBaseSrc *src = GST_GL_BASE_SRC (basesrc);
638 GstGLContext *context;
639 GstBufferPool *pool = NULL;
640 GstStructure *config;
642 guint min, max, size;
643 gboolean update_pool;
645 g_rec_mutex_lock (&src->priv->context_lock);
646 if (!gst_gl_base_src_find_gl_context_unlocked (src)) {
647 g_rec_mutex_unlock (&src->priv->context_lock);
650 context = gst_object_ref (src->context);
651 g_rec_mutex_unlock (&src->priv->context_lock);
653 gst_query_parse_allocation (query, &caps, NULL);
655 if (gst_query_get_n_allocation_pools (query) > 0) {
656 gst_query_parse_nth_allocation_pool (query, 0, &pool, &size, &min, &max);
662 gst_video_info_init (&vinfo);
663 gst_video_info_from_caps (&vinfo, caps);
669 if (!pool || !GST_IS_GL_BUFFER_POOL (pool)) {
670 /* can't use this pool */
672 gst_object_unref (pool);
673 pool = gst_gl_buffer_pool_new (context);
675 config = gst_buffer_pool_get_config (pool);
677 gst_buffer_pool_config_set_params (config, caps, size, min, max);
678 gst_buffer_pool_config_add_option (config, GST_BUFFER_POOL_OPTION_VIDEO_META);
679 if (gst_query_find_allocation_meta (query, GST_GL_SYNC_META_API_TYPE, NULL))
680 gst_buffer_pool_config_add_option (config,
681 GST_BUFFER_POOL_OPTION_GL_SYNC_META);
682 gst_buffer_pool_config_add_option (config,
683 GST_BUFFER_POOL_OPTION_VIDEO_GL_TEXTURE_UPLOAD_META);
685 gst_buffer_pool_set_config (pool, config);
688 gst_query_set_nth_allocation_pool (query, 0, pool, size, min, max);
690 gst_query_add_allocation_pool (query, pool, size, min, max);
692 gst_object_unref (pool);
693 gst_object_unref (context);
698 static GstStateChangeReturn
699 gst_gl_base_src_change_state (GstElement * element, GstStateChange transition)
701 GstGLBaseSrc *src = GST_GL_BASE_SRC (element);
702 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
704 GST_DEBUG_OBJECT (src, "changing state: %s => %s",
705 gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
706 gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));
708 ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
709 if (ret == GST_STATE_CHANGE_FAILURE)
712 switch (transition) {
713 case GST_STATE_CHANGE_READY_TO_NULL:
714 g_rec_mutex_lock (&src->priv->context_lock);
715 gst_clear_object (&src->priv->other_context);
716 gst_clear_object (&src->display);
717 g_rec_mutex_unlock (&src->priv->context_lock);
727 gst_gl_base_src_do_seek (GstBaseSrc * basesrc, GstSegment * segment)
729 GstGLBaseSrc *src = GST_GL_BASE_SRC (basesrc);
731 segment->time = segment->start;
732 time = segment->position;
734 /* now move to the time indicated */
735 if (src->out_info.fps_n) {
736 src->priv->n_frames = gst_util_uint64_scale (time,
737 src->out_info.fps_n, src->out_info.fps_d * GST_SECOND);
739 src->priv->n_frames = 0;
741 if (src->out_info.fps_n) {
742 src->running_time = gst_util_uint64_scale (src->priv->n_frames,
743 src->out_info.fps_d * GST_SECOND, src->out_info.fps_n);
745 /* FIXME : Not sure what to set here */
746 src->running_time = 0;
749 g_return_val_if_fail (src->running_time <= time, FALSE);
751 return GST_BASE_SRC_CLASS (parent_class)->do_seek (basesrc, segment);