<div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Hello,</div><div> </div><div>Tutorial 3 is great and explains how to dynamically add pads: </div><div><a href="https://gstreamer.freedesktop.org/documentation/tutorials/basic/dynamic-pipelines.html">https://gstreamer.freedesktop.org/documentation/tutorials/basic/dynamic-pipelines.html</a></div><div> </div><div>When I try to do the exercise to add a video converter and video sink, I get a ton of messages and the audio and video do not work. Any pointers on what am I doing incorrect? </div><div> </div><div>Here is my code:</div><div>#include <gst/gst.h> /* Structure to contain all our information, so we can pass it to callbacks */ typedef struct _CustomData { GstElement *pipeline; GstElement *source; GstElement *audio_convert; GstElement *video_convert; GstElement *audio_sink; GstElement *video_sink; } CustomData; /* Handler for the pad-added signal */ static void pad_added_handler (GstElement *src, GstPad *pad, CustomData *data); int main(int argc, char *argv[]) { CustomData data; GstBus *bus; GstMessage *msg; GstStateChangeReturn ret; gboolean terminate = FALSE; /* Initialize GStreamer */ gst_init (&argc, &argv); /* Create the elements */ data.source = gst_element_factory_make ("uridecodebin", "source"); data.audio_convert = gst_element_factory_make ("audioconvert", "audio_convert"); data.video_convert = gst_element_factory_make ("videoconvert", "video_convert"); data.audio_sink = gst_element_factory_make ("autoaudiosink", "audio_sink"); data.video_sink = gst_element_factory_make ("autovideosink", "video_sink"); /* Create the empty pipeline */ data.pipeline = gst_pipeline_new ("test-pipeline"); if (!data.pipeline || !data.source || !data.audio_convert || !data.audio_sink || !data.video_convert || !data.video_sink) { g_printerr ("Not all elements could be created.\n"); return -1; } /* Build the pipeline. Note that we are NOT linking the source at this * point. We will do it later. */ gst_bin_add_many (GST_BIN (data.pipeline), data.source, data.audio_convert , data.video_convert, data.audio_sink, data.video_sink, NULL); if (!gst_element_link (data.audio_convert, data.audio_sink)) { g_printerr ("audio_convert -> audio_sink elements could not be linked.\n"); gst_object_unref (data.pipeline); return -1; } if (!gst_element_link (data.video_convert, data.video_sink)) { g_printerr ("video_convert -> video_sink elements could not be linked.\n"); gst_object_unref (data.pipeline); return -1; } /* Set the URI to play */ g_object_set (data.source, "uri", "<a href="https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.webm">https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.webm</a>", NULL); /* Connect to the pad-added signal */ g_signal_connect (data.source, "pad-added", G_CALLBACK (pad_added_handler), &data); /* Start playing */ ret = gst_element_set_state (data.pipeline, GST_STATE_PLAYING); if (ret == GST_STATE_CHANGE_FAILURE) { g_printerr ("Unable to set the pipeline to the playing state.\n"); gst_object_unref (data.pipeline); return -1; } /* Listen to the bus */ bus = gst_element_get_bus (data.pipeline); do { msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_STATE_CHANGED | GST_MESSAGE_ERROR | GST_MESSAGE_EOS); /* Parse message */ if (msg != NULL) { GError *err; gchar *debug_info; switch (GST_MESSAGE_TYPE (msg)) { case GST_MESSAGE_ERROR: gst_message_parse_error (msg, &err, &debug_info); g_printerr ("Error received from element %s: %s\n", GST_OBJECT_NAME (msg->src), err->message); g_printerr ("Debugging information: %s\n", debug_info ? debug_info : "none"); g_clear_error (&err); g_free (debug_info); terminate = TRUE; break; case GST_MESSAGE_EOS: g_print ("End-Of-Stream reached.\n"); terminate = TRUE; break; case GST_MESSAGE_STATE_CHANGED: /* We are only interested in state-changed messages from the pipeline */ if (GST_MESSAGE_SRC (msg) == GST_OBJECT (data.pipeline)) { GstState old_state, new_state, pending_state; gst_message_parse_state_changed (msg, &old_state, &new_state, &pending_state); g_print ("Pipeline state changed from %s to %s:\n", gst_element_state_get_name (old_state), gst_element_state_get_name (new_state)); } break; default: /* We should not reach here */ g_printerr ("Unexpected message received.\n"); break; } gst_message_unref (msg); } } while (!terminate); /* Free resources */ gst_object_unref (bus); gst_element_set_state (data.pipeline, GST_STATE_NULL); gst_object_unref (data.pipeline); return 0; } /* This function will be called by the pad-added signal */ static void pad_added_handler (GstElement *src, GstPad *new_pad, CustomData *data) { GstPad *audio_sink_pad = gst_element_get_static_pad (data->audio_convert, "audio_sink"); GstPad *video_sink_pad = gst_element_get_static_pad (data->video_convert, "video_sink"); GstPadLinkReturn ret; GstCaps *new_pad_caps = NULL; GstStructure *new_pad_struct = NULL; const gchar *new_pad_type = NULL; g_print ("Received new pad '%s' from '%s':\n", GST_PAD_NAME (new_pad), GST_ELEMENT_NAME (src)); /* If our converter is already linked, we have nothing to do here if (gst_pad_is_linked (sink_pad)) { g_print ("We are already linked. Ignoring.\n"); goto exit; } */ /* Check the new pad's type */ new_pad_caps = gst_pad_get_current_caps (new_pad); new_pad_struct = gst_caps_get_structure (new_pad_caps, 0); new_pad_type = gst_structure_get_name (new_pad_struct); // Check for audio if (g_str_has_prefix (new_pad_type, "audio/x-raw")) { /* Attempt the link */ ret = gst_pad_link (new_pad, audio_sink_pad); if (GST_PAD_LINK_FAILED (ret)) { g_print ("Type is '%s' but link failed.\n", new_pad_type); } else { g_print ("Link succeeded (type '%s').\n", new_pad_type); } goto exit; } else if (g_str_has_prefix (new_pad_type, "video/x-raw")) { /* Attempt the link */ ret = gst_pad_link (new_pad, video_sink_pad); if (GST_PAD_LINK_FAILED (ret)) { g_print ("Type is '%s' but link failed.\n", new_pad_type); } else { g_print ("Link succeeded (type '%s').\n", new_pad_type); } goto exit; } else { g_print ("It has type '%s' which is not raw audio or video. Ignoring.\n", new_pad_type); goto exit; } exit: /* Unreference the new pad's caps, if we got them */ if (new_pad_caps != NULL) gst_caps_unref (new_pad_caps); /* Unreference the sink pad */ gst_object_unref (audio_sink_pad); gst_object_unref (video_sink_pad); } </div><div> </div><div>Here is the output:</div><div>Pipeline state changed from NULL to READY: Received new pad 'src_0' from 'source': (basic-tutorial-3c:30218): GStreamer-CRITICAL **: gst_pad_link_full: assertion 'GST_IS_PAD (sinkpad)' failed Type is 'video/x-raw' but link failed. (basic-tutorial-3c:30218): GStreamer-CRITICAL **: gst_object_unref: assertion 'object != NULL' failed (basic-tutorial-3c:30218): GStreamer-CRITICAL **: gst_object_unref: assertion 'object != NULL' failed Received new pad 'src_1' from 'source': (basic-tutorial-3c:30218): GStreamer-CRITICAL **: gst_pad_link_full: assertion 'GST_IS_PAD (sinkpad)' failed Type is 'audio/x-raw' but link failed. (basic-tutorial-3c:30218): GStreamer-CRITICAL **: gst_object_unref: assertion 'object != NULL' failed (basic-tutorial-3c:30218): GStreamer-CRITICAL **: gst_object_unref: assertion 'object != NULL' failed Error received from element matroskademux0: GStreamer encountered a general stream error. Debugging information: matroska-demux.c(4761): gst_matroska_demux_loop (): /GstPipeline:test-pipeline/GstURIDecodeBin:source/GstDecodeBin:decodebin0/GstMatroskaDemux:matroskademux0: stream stopped, reason not-linked </div><div>Can someone please comment what am I doing incorrect?</div><div> </div><div> </div></div></div></div></div>