/* * GStreamer * Copyright (C) <1999> Erik Walthinsen * Copyright (C) 2002,2007 David A. Schleef * Copyright (C) 2008 Julien Isorce * Copyright (C) 2015 Matthew Waters * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, * Boston, MA 02110-1301, USA. */ /** * SECTION:element-gltestsrc * * * * The gltestsrc element is used to produce test video texture. * The video test produced can be controlled with the "pattern" * property. * * Example launch line * * * gst-launch-1.0 -v gltestsrc pattern=smpte ! glimagesink * * Shows original SMPTE color bars in a window. * * */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "gstgltestsrc.h" #include "gltestsrc.h" #include #define USE_PEER_BUFFERALLOC #define SUPPORTED_GL_APIS (GST_GL_API_OPENGL | GST_GL_API_OPENGL3 | GST_GL_API_GLES2) GST_DEBUG_CATEGORY_STATIC (gl_test_src_debug); #define GST_CAT_DEFAULT gl_test_src_debug enum { PROP_0, PROP_PATTERN, PROP_TIMESTAMP_OFFSET, PROP_IS_LIVE /* FILL ME */ }; /* *INDENT-OFF* */ static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC, GST_PAD_ALWAYS, GST_STATIC_CAPS ("video/x-raw(" GST_CAPS_FEATURE_MEMORY_GL_MEMORY "), " "format = (string) RGBA, " "width = " GST_VIDEO_SIZE_RANGE ", " "height = " GST_VIDEO_SIZE_RANGE ", " "framerate = " GST_VIDEO_FPS_RANGE "," "texture-target = (string) 2D") ); /* *INDENT-ON* */ #define gst_gl_test_src_parent_class parent_class G_DEFINE_TYPE (GstGLTestSrc, gst_gl_test_src, GST_TYPE_PUSH_SRC); static void gst_gl_test_src_set_pattern (GstGLTestSrc * gltestsrc, int pattern_type); static void gst_gl_test_src_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec); static void gst_gl_test_src_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec); static gboolean gst_gl_test_src_setcaps (GstBaseSrc * bsrc, GstCaps * caps); static GstCaps *gst_gl_test_src_fixate (GstBaseSrc * bsrc, GstCaps * caps); static gboolean gst_gl_test_src_is_seekable (GstBaseSrc * psrc); static gboolean gst_gl_test_src_do_seek (GstBaseSrc * bsrc, GstSegment * segment); static gboolean gst_gl_test_src_query (GstBaseSrc * bsrc, GstQuery * query); static void gst_gl_test_src_set_context (GstElement * element, GstContext * context); static GstStateChangeReturn gst_gl_test_src_change_state (GstElement * element, GstStateChange transition); static void gst_gl_test_src_get_times (GstBaseSrc * basesrc, GstBuffer * buffer, GstClockTime * start, GstClockTime * end); static GstFlowReturn gst_gl_test_src_fill (GstPushSrc * psrc, GstBuffer * buffer); static gboolean gst_gl_test_src_start (GstBaseSrc * basesrc); static gboolean gst_gl_test_src_stop (GstBaseSrc * basesrc); static gboolean gst_gl_test_src_decide_allocation (GstBaseSrc * basesrc, GstQuery * query); static void gst_gl_test_src_callback (gpointer stuff); static gboolean gst_gl_test_src_init_shader (GstGLTestSrc * gltestsrc); #define GST_TYPE_GL_TEST_SRC_PATTERN (gst_gl_test_src_pattern_get_type ()) static GType gst_gl_test_src_pattern_get_type (void) { static GType gl_test_src_pattern_type = 0; static const GEnumValue pattern_types[] = { {GST_GL_TEST_SRC_SMPTE, "SMPTE 100% color bars", "smpte"}, {GST_GL_TEST_SRC_SNOW, "Random (television snow)", "snow"}, {GST_GL_TEST_SRC_BLACK, "100% Black", "black"}, {GST_GL_TEST_SRC_WHITE, "100% White", "white"}, {GST_GL_TEST_SRC_RED, "Red", "red"}, {GST_GL_TEST_SRC_GREEN, "Green", "green"}, {GST_GL_TEST_SRC_BLUE, "Blue", "blue"}, {GST_GL_TEST_SRC_CHECKERS1, "Checkers 1px", "checkers-1"}, {GST_GL_TEST_SRC_CHECKERS2, "Checkers 2px", "checkers-2"}, {GST_GL_TEST_SRC_CHECKERS4, "Checkers 4px", "checkers-4"}, {GST_GL_TEST_SRC_CHECKERS8, "Checkers 8px", "checkers-8"}, {GST_GL_TEST_SRC_CIRCULAR, "Circular", "circular"}, {GST_GL_TEST_SRC_BLINK, "Blink", "blink"}, {GST_GL_TEST_SRC_MANDELBROT, "Mandelbrot Fractal", "mandelbrot"}, {0, NULL, NULL} }; if (!gl_test_src_pattern_type) { gl_test_src_pattern_type = g_enum_register_static ("GstGLTestSrcPattern", pattern_types); } return gl_test_src_pattern_type; } static void gst_gl_test_src_class_init (GstGLTestSrcClass * klass) { GObjectClass *gobject_class; GstBaseSrcClass *gstbasesrc_class; GstPushSrcClass *gstpushsrc_class; GstElementClass *element_class; GST_DEBUG_CATEGORY_INIT (gl_test_src_debug, "gltestsrc", 0, "Video Test Source"); gobject_class = (GObjectClass *) klass; gstbasesrc_class = (GstBaseSrcClass *) klass; gstpushsrc_class = (GstPushSrcClass *) klass; element_class = GST_ELEMENT_CLASS (klass); gobject_class->set_property = gst_gl_test_src_set_property; gobject_class->get_property = gst_gl_test_src_get_property; g_object_class_install_property (gobject_class, PROP_PATTERN, g_param_spec_enum ("pattern", "Pattern", "Type of test pattern to generate", GST_TYPE_GL_TEST_SRC_PATTERN, GST_GL_TEST_SRC_SMPTE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); g_object_class_install_property (gobject_class, PROP_TIMESTAMP_OFFSET, g_param_spec_int64 ("timestamp-offset", "Timestamp offset", "An offset added to timestamps set on buffers (in ns)", G_MININT64, G_MAXINT64, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); g_object_class_install_property (gobject_class, PROP_IS_LIVE, g_param_spec_boolean ("is-live", "Is Live", "Whether to act as a live source", FALSE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); gst_element_class_set_metadata (element_class, "Video test source", "Source/Video", "Creates a test video stream", "David A. Schleef "); gst_element_class_add_static_pad_template (element_class, &src_factory); element_class->set_context = gst_gl_test_src_set_context; element_class->change_state = gst_gl_test_src_change_state; gstbasesrc_class->set_caps = gst_gl_test_src_setcaps; gstbasesrc_class->is_seekable = gst_gl_test_src_is_seekable; gstbasesrc_class->do_seek = gst_gl_test_src_do_seek; gstbasesrc_class->query = gst_gl_test_src_query; gstbasesrc_class->get_times = gst_gl_test_src_get_times; gstbasesrc_class->start = gst_gl_test_src_start; gstbasesrc_class->stop = gst_gl_test_src_stop; gstbasesrc_class->fixate = gst_gl_test_src_fixate; gstbasesrc_class->decide_allocation = gst_gl_test_src_decide_allocation; gstpushsrc_class->fill = gst_gl_test_src_fill; } static void gst_gl_test_src_init (GstGLTestSrc * src) { gst_gl_test_src_set_pattern (src, GST_GL_TEST_SRC_SMPTE); src->timestamp_offset = 0; /* we operate in time */ gst_base_src_set_format (GST_BASE_SRC (src), GST_FORMAT_TIME); gst_base_src_set_live (GST_BASE_SRC (src), FALSE); } static GstCaps * gst_gl_test_src_fixate (GstBaseSrc * bsrc, GstCaps * caps) { GstStructure *structure; GST_DEBUG ("fixate"); caps = gst_caps_make_writable (caps); structure = gst_caps_get_structure (caps, 0); gst_structure_fixate_field_nearest_int (structure, "width", 320); gst_structure_fixate_field_nearest_int (structure, "height", 240); gst_structure_fixate_field_nearest_fraction (structure, "framerate", 30, 1); caps = GST_BASE_SRC_CLASS (parent_class)->fixate (bsrc, caps); return caps; } static void gst_gl_test_src_set_pattern (GstGLTestSrc * gltestsrc, gint pattern_type) { gltestsrc->set_pattern = pattern_type; } static void gst_gl_test_src_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec) { GstGLTestSrc *src = GST_GL_TEST_SRC (object); switch (prop_id) { case PROP_PATTERN: gst_gl_test_src_set_pattern (src, g_value_get_enum (value)); break; case PROP_TIMESTAMP_OFFSET: src->timestamp_offset = g_value_get_int64 (value); break; case PROP_IS_LIVE: gst_base_src_set_live (GST_BASE_SRC (src), g_value_get_boolean (value)); break; default: break; } } static void gst_gl_test_src_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec) { GstGLTestSrc *src = GST_GL_TEST_SRC (object); switch (prop_id) { case PROP_PATTERN: g_value_set_enum (value, src->set_pattern); break; case PROP_TIMESTAMP_OFFSET: g_value_set_int64 (value, src->timestamp_offset); break; case PROP_IS_LIVE: g_value_set_boolean (value, gst_base_src_is_live (GST_BASE_SRC (src))); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); break; } } static gboolean gst_gl_test_src_setcaps (GstBaseSrc * bsrc, GstCaps * caps) { GstGLTestSrc *gltestsrc = GST_GL_TEST_SRC (bsrc); GST_DEBUG ("setcaps"); if (!gst_video_info_from_caps (&gltestsrc->out_info, caps)) goto wrong_caps; gltestsrc->negotiated = TRUE; gst_caps_replace (&gltestsrc->out_caps, caps); return TRUE; /* ERRORS */ wrong_caps: { GST_WARNING ("wrong caps"); return FALSE; } } static void gst_gl_test_src_set_context (GstElement * element, GstContext * context) { GstGLTestSrc *src = GST_GL_TEST_SRC (element); gst_gl_handle_set_context (element, context, &src->display, &src->other_context); if (src->display) gst_gl_display_filter_gl_api (src->display, SUPPORTED_GL_APIS); GST_ELEMENT_CLASS (parent_class)->set_context (element, context); } static gboolean gst_gl_test_src_query (GstBaseSrc * bsrc, GstQuery * query) { gboolean res = FALSE; GstGLTestSrc *src; src = GST_GL_TEST_SRC (bsrc); switch (GST_QUERY_TYPE (query)) { case GST_QUERY_CONTEXT: { const gchar *context_type; GstContext *context, *old_context; res = gst_gl_handle_context_query ((GstElement *) src, query, &src->display, &src->other_context); if (src->display) gst_gl_display_filter_gl_api (src->display, SUPPORTED_GL_APIS); gst_query_parse_context_type (query, &context_type); if (g_strcmp0 (context_type, "gst.gl.local_context") == 0) { GstStructure *s; gst_query_parse_context (query, &old_context); if (old_context) context = gst_context_copy (old_context); else context = gst_context_new ("gst.gl.local_context", FALSE); s = gst_context_writable_structure (context); gst_structure_set (s, "context", GST_GL_TYPE_CONTEXT, src->context, NULL); gst_query_set_context (query, context); gst_context_unref (context); res = src->context != NULL; } GST_LOG_OBJECT (src, "context query of type %s %i", context_type, res); if (res) return res; break; } case GST_QUERY_CONVERT: { GstFormat src_fmt, dest_fmt; gint64 src_val, dest_val; gst_query_parse_convert (query, &src_fmt, &src_val, &dest_fmt, &dest_val); res = gst_video_info_convert (&src->out_info, src_fmt, src_val, dest_fmt, &dest_val); gst_query_set_convert (query, src_fmt, src_val, dest_fmt, dest_val); return res; } default: break; } return GST_BASE_SRC_CLASS (parent_class)->query (bsrc, query); } static void gst_gl_test_src_get_times (GstBaseSrc * basesrc, GstBuffer * buffer, GstClockTime * start, GstClockTime * end) { /* for live sources, sync on the timestamp of the buffer */ if (gst_base_src_is_live (basesrc)) { GstClockTime timestamp = GST_BUFFER_TIMESTAMP (buffer); if (GST_CLOCK_TIME_IS_VALID (timestamp)) { /* get duration to calculate end time */ GstClockTime duration = GST_BUFFER_DURATION (buffer); if (GST_CLOCK_TIME_IS_VALID (duration)) *end = timestamp + duration; *start = timestamp; } } else { *start = -1; *end = -1; } } static gboolean gst_gl_test_src_do_seek (GstBaseSrc * bsrc, GstSegment * segment) { GstClockTime time; GstGLTestSrc *src; src = GST_GL_TEST_SRC (bsrc); segment->time = segment->start; time = segment->position; /* now move to the time indicated */ if (src->out_info.fps_n) { src->n_frames = gst_util_uint64_scale (time, src->out_info.fps_n, src->out_info.fps_d * GST_SECOND); } else src->n_frames = 0; if (src->out_info.fps_n) { src->running_time = gst_util_uint64_scale (src->n_frames, src->out_info.fps_d * GST_SECOND, src->out_info.fps_n); } else { /* FIXME : Not sure what to set here */ src->running_time = 0; } g_return_val_if_fail (src->running_time <= time, FALSE); return TRUE; } static gboolean gst_gl_test_src_is_seekable (GstBaseSrc * psrc) { /* we're seekable... */ return TRUE; } static gboolean gst_gl_test_src_init_shader (GstGLTestSrc * gltestsrc) { if (gst_gl_context_get_gl_api (gltestsrc->context)) { /* blocking call, wait until the opengl thread has compiled the shader */ // if (gltestsrc->vertex_src == NULL) // return FALSE; // return gst_gl_context_gen_shader (gltestsrc->context, gltestsrc->vertex_src, // gltestsrc->fragment_src, &gltestsrc->shader); } return TRUE; } static GstFlowReturn gst_gl_test_src_fill (GstPushSrc * psrc, GstBuffer * buffer) { GstGLTestSrc *src = GST_GL_TEST_SRC (psrc); GstClockTime next_time; gint width, height; GstVideoFrame out_frame; GstGLSyncMeta *sync_meta; guint out_tex; if (G_UNLIKELY (!src->negotiated || !src->context)) goto not_negotiated; width = GST_VIDEO_INFO_WIDTH (&src->out_info); height = GST_VIDEO_INFO_HEIGHT (&src->out_info); /* 0 framerate and we are at the second frame, eos */ if (G_UNLIKELY (GST_VIDEO_INFO_FPS_N (&src->out_info) == 0 && src->n_frames == 1)) goto eos; if (!gst_video_frame_map (&out_frame, &src->out_info, buffer, GST_MAP_WRITE | GST_MAP_GL)) { return GST_FLOW_NOT_NEGOTIATED; } out_tex = *(guint *) out_frame.data[0]; if (!gst_gl_context_use_fbo_v2 (src->context, width, height, src->fbo, src->depthbuffer, out_tex, gst_gl_test_src_callback, (gpointer) src)) { gst_video_frame_unmap (&out_frame); goto gl_error; } gst_video_frame_unmap (&out_frame); if (!src->gl_result) goto gl_error; sync_meta = gst_buffer_get_gl_sync_meta (buffer); if (sync_meta) gst_gl_sync_meta_set_sync_point (sync_meta, src->context); GST_BUFFER_TIMESTAMP (buffer) = src->timestamp_offset + src->running_time; GST_BUFFER_OFFSET (buffer) = src->n_frames; src->n_frames++; GST_BUFFER_OFFSET_END (buffer) = src->n_frames; if (src->out_info.fps_n) { next_time = gst_util_uint64_scale_int (src->n_frames * GST_SECOND, src->out_info.fps_d, src->out_info.fps_n); GST_BUFFER_DURATION (buffer) = next_time - src->running_time; } else { next_time = src->timestamp_offset; /* NONE means forever */ GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE; } src->running_time = next_time; return GST_FLOW_OK; gl_error: { GST_ELEMENT_ERROR (src, RESOURCE, NOT_FOUND, (_("failed to draw pattern")), (_("A GL error occured"))); return GST_FLOW_NOT_NEGOTIATED; } not_negotiated: { GST_ELEMENT_ERROR (src, CORE, NEGOTIATION, (NULL), (_("format wasn't negotiated before get function"))); return GST_FLOW_NOT_NEGOTIATED; } eos: { GST_DEBUG_OBJECT (src, "eos: 0 framerate, frame %d", (gint) src->n_frames); return GST_FLOW_EOS; } } static gboolean gst_gl_test_src_start (GstBaseSrc * basesrc) { GstGLTestSrc *src = GST_GL_TEST_SRC (basesrc); if (!gst_gl_ensure_element_data (src, &src->display, &src->other_context)) return FALSE; gst_gl_display_filter_gl_api (src->display, SUPPORTED_GL_APIS); src->running_time = 0; src->n_frames = 0; src->negotiated = FALSE; return TRUE; } static gboolean gst_gl_test_src_stop (GstBaseSrc * basesrc) { GstGLTestSrc *src = GST_GL_TEST_SRC (basesrc); gst_caps_replace (&src->out_caps, NULL); if (src->context) { if (src->shader) { gst_object_unref (src->shader); src->shader = NULL; } //blocking call, delete the FBO gst_gl_context_del_fbo (src->context, src->fbo, src->depthbuffer); gst_object_unref (src->context); src->context = NULL; } if (src->src_impl) { src->src_funcs->free (src->src_impl); src->src_impl = NULL; } return TRUE; } static gboolean _find_local_gl_context (GstGLTestSrc * src) { GstQuery *query; GstContext *context; const GstStructure *s; if (src->context) return TRUE; query = gst_query_new_context ("gst.gl.local_context"); if (!src->context && gst_gl_run_query (GST_ELEMENT (src), query, GST_PAD_SRC)) { gst_query_parse_context (query, &context); if (context) { s = gst_context_get_structure (context); gst_structure_get (s, "context", GST_GL_TYPE_CONTEXT, &src->context, NULL); } } if (!src->context && gst_gl_run_query (GST_ELEMENT (src), query, GST_PAD_SINK)) { gst_query_parse_context (query, &context); if (context) { s = gst_context_get_structure (context); gst_structure_get (s, "context", GST_GL_TYPE_CONTEXT, &src->context, NULL); } } GST_DEBUG_OBJECT (src, "found local context %p", src->context); gst_query_unref (query); if (src->context) return TRUE; return FALSE; } static gboolean gst_gl_test_src_decide_allocation (GstBaseSrc * basesrc, GstQuery * query) { GstGLTestSrc *src = GST_GL_TEST_SRC (basesrc); GstBufferPool *pool = NULL; GstStructure *config; GstCaps *caps; guint min, max, size; gboolean update_pool; GError *error = NULL; guint out_width, out_height; if (!gst_gl_ensure_element_data (src, &src->display, &src->other_context)) return FALSE; gst_gl_display_filter_gl_api (src->display, SUPPORTED_GL_APIS); _find_local_gl_context (src); if (!src->context) { GST_OBJECT_LOCK (src->display); do { if (src->context) { gst_object_unref (src->context); src->context = NULL; } /* just get a GL context. we don't care */ src->context = gst_gl_display_get_gl_context_for_thread (src->display, NULL); if (!src->context) { if (!gst_gl_display_create_context (src->display, src->other_context, &src->context, &error)) { GST_OBJECT_UNLOCK (src->display); goto context_error; } } } while (!gst_gl_display_add_context (src->display, src->context)); GST_OBJECT_UNLOCK (src->display); } if ((gst_gl_context_get_gl_api (src->context) & SUPPORTED_GL_APIS) == 0) goto unsupported_gl_api; out_width = GST_VIDEO_INFO_WIDTH (&src->out_info); out_height = GST_VIDEO_INFO_HEIGHT (&src->out_info); if (!gst_gl_context_gen_fbo (src->context, out_width, out_height, &src->fbo, &src->depthbuffer)) goto context_error; gst_query_parse_allocation (query, &caps, NULL); if (gst_query_get_n_allocation_pools (query) > 0) { gst_query_parse_nth_allocation_pool (query, 0, &pool, &size, &min, &max); update_pool = TRUE; } else { GstVideoInfo vinfo; gst_video_info_init (&vinfo); gst_video_info_from_caps (&vinfo, caps); size = vinfo.size; min = max = 0; update_pool = FALSE; } if (!pool || !GST_IS_GL_BUFFER_POOL (pool)) { /* can't use this pool */ if (pool) gst_object_unref (pool); pool = gst_gl_buffer_pool_new (src->context); } config = gst_buffer_pool_get_config (pool); gst_buffer_pool_config_set_params (config, caps, size, min, max); gst_buffer_pool_config_add_option (config, GST_BUFFER_POOL_OPTION_VIDEO_META); if (gst_query_find_allocation_meta (query, GST_GL_SYNC_META_API_TYPE, NULL)) gst_buffer_pool_config_add_option (config, GST_BUFFER_POOL_OPTION_GL_SYNC_META); gst_buffer_pool_config_add_option (config, GST_BUFFER_POOL_OPTION_VIDEO_GL_TEXTURE_UPLOAD_META); gst_buffer_pool_set_config (pool, config); if (update_pool) gst_query_set_nth_allocation_pool (query, 0, pool, size, min, max); else gst_query_add_allocation_pool (query, pool, size, min, max); gst_gl_test_src_init_shader (src); gst_object_unref (pool); return TRUE; unsupported_gl_api: { GstGLAPI gl_api = gst_gl_context_get_gl_api (src->context); gchar *gl_api_str = gst_gl_api_to_string (gl_api); gchar *supported_gl_api_str = gst_gl_api_to_string (SUPPORTED_GL_APIS); GST_ELEMENT_ERROR (src, RESOURCE, BUSY, ("GL API's not compatible context: %s supported: %s", gl_api_str, supported_gl_api_str), (NULL)); g_free (supported_gl_api_str); g_free (gl_api_str); return FALSE; } context_error: { GST_ELEMENT_ERROR (src, RESOURCE, NOT_FOUND, ("%s", error->message), (NULL)); g_clear_error (&error); if (src->context) gst_object_unref (src->context); src->context = NULL; return FALSE; } } //opengl scene static void gst_gl_test_src_callback (gpointer stuff) { GstGLTestSrc *src = GST_GL_TEST_SRC (stuff); const struct SrcFuncs *funcs; funcs = src->src_funcs; if (!funcs || src->set_pattern != src->active_pattern) { if (src->src_impl && funcs) funcs->free (src->src_impl); src->src_funcs = funcs = gst_gl_test_src_get_src_funcs_for_pattern (src->set_pattern); if (funcs == NULL) { GST_ERROR_OBJECT (src, "Could not find an implementation of the " "requested pattern"); src->gl_result = FALSE; return; } src->src_impl = funcs->new (src); if (!(src->gl_result = funcs->init (src->src_impl, src->context, &src->out_info))) { GST_ERROR_OBJECT (src, "Failed to initialize pattern"); return; } src->active_pattern = src->set_pattern; } src->gl_result = funcs->fill_bound_fbo (src->src_impl); if (!src->gl_result) GST_ERROR_OBJECT (src, "Failed to render the pattern"); } static GstStateChangeReturn gst_gl_test_src_change_state (GstElement * element, GstStateChange transition) { GstGLTestSrc *src = GST_GL_TEST_SRC (element); GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS; GST_DEBUG_OBJECT (src, "changing state: %s => %s", gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)), gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition))); switch (transition) { case GST_STATE_CHANGE_NULL_TO_READY: if (!gst_gl_ensure_element_data (element, &src->display, &src->other_context)) return GST_STATE_CHANGE_FAILURE; gst_gl_display_filter_gl_api (src->display, SUPPORTED_GL_APIS); break; default: break; } ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition); if (ret == GST_STATE_CHANGE_FAILURE) return ret; switch (transition) { case GST_STATE_CHANGE_READY_TO_NULL: if (src->other_context) { gst_object_unref (src->other_context); src->other_context = NULL; } if (src->display) { gst_object_unref (src->display); src->display = NULL; } break; default: break; } return ret; }