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Hello,
I am new to gstreamer and tried to create a simple pipeline example that contains an appsrc and an appsink element. I am trying to continuously send a custom format buffer (simple 1Byte uint8 buffer) from appsrc to appsink. To achieve this I continuously push buffers into appsrc and wait for the "new_sample" callback to inform me about the arrival of new buffers at the sink side. The example code I posted below works as expected for the first buffer. The problem is that "new_sample" is only called once, even if I continuously push data into appsrc, which then results into a growing buffer on the source side. How can I fix appsink such that new_sample is called for every buffer pushed into appsrc? My code: #include <gst/gst.h> #include <string.h> #include <gst_dependencies_aux.h> #include <gst/app/gstappsrc.h> #include <gst/app/gstappsink.h> #define CHUNK_SIZE 1 /* Amount of bytes we are sending in each buffer */ /* Structure to contain all our information, so we can pass it to callbacks */ typedef struct _CustomData { GstElement *pipeline, *app_source, *app_sink; guint sourceid; /* To control the GSource */ GMainLoop *main_loop; /* GLib's Main Loop */ } CustomData; /* This method is called by the idle GSource in the mainloop, to feed CHUNK_SIZE bytes into appsrc. * The ide handler is added to the mainloop when appsrc requests us to start sending data (need-data signal) * and is removed when appsrc has enough data (enough-data signal). */ static gboolean push_data(CustomData *data) { GstBuffer *buffer; GstFlowReturn ret; int i; GstMapInfo map; gint8 *raw; /* Create a new empty buffer */ buffer = gst_buffer_new_and_alloc(CHUNK_SIZE); /* Generate simple uint8 buffer */ gst_buffer_map(buffer, &map, GST_MAP_WRITE); raw = (gint8 *)map.data; for (i = 0; i < CHUNK_SIZE; i++) { raw[i] = (gint8)(65); //Push simple uint8 } gst_buffer_unmap(buffer, &map); /* Push the buffer into the appsrc */ g_signal_emit_by_name(data->app_source, "push-buffer", buffer, &ret); /* Free the buffer now that we are done with it */ gst_buffer_unref(buffer); if (ret != GST_FLOW_OK) { /* We got some error, stop sending data */ return FALSE; } return TRUE; } /* This signal callback triggers when appsrc needs data. Here, we add an idle handler * to the mainloop to start pushing data into the appsrc */ static void start_feed(GstElement *source, guint size, CustomData *data) { if (data->sourceid == 0) { g_print("Start feeding\n"); data->sourceid = g_idle_add((GSourceFunc)push_data, data); } } /* This callback triggers when appsrc has enough data and we can stop sending. * We remove the idle handler from the mainloop */ static void stop_feed(GstElement *source, CustomData *data) { if (data->sourceid != 0) { g_print("Stop feeding\n"); g_source_remove(data->sourceid); data->sourceid = 0; } } /* The appsink has received a buffer */ static void new_sample(GstElement *sink, CustomData *data) { GstSample *sample; /* Retrieve the buffer */ g_signal_emit_by_name(sink, "pull-sample", &sample); if (sample) { GstBuffer* buffer = gst_sample_get_buffer(sample); GstMapInfo info; gboolean mapping_succ = gst_buffer_map(buffer, &info, GST_MAP_READ); // Confirm that correct buffer was received... g_print("Appsink: Buffer Received: Content = %u!\n", *info.data); g_print("received something...\n"); gst_buffer_unmap(buffer, &info); gst_buffer_unref((GstBuffer*)sample); } } /* This function is called when an error message is posted on the bus */ static void error_cb(GstBus *bus, GstMessage *msg, CustomData *data) { GError *err; gchar *debug_info; /* Print error details on the screen */ 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); g_main_loop_quit(data->main_loop); } /* This function is called when an error message is posted on the bus */ static void eos_cb(GstBus *bus, GstMessage *msg, CustomData *data) { g_print("End-Of-Stream reached.\n"); } int main(int argc, char *argv[]) { std::ostringstream gstPluginsPath("C:/svn/Microscope_Plattform_Sandbox/gst_video_playback/x64/Debug/gstreamer-1.0"); _putenv_s("GST_DEBUG_DUMP_DOT_DIR", "C:\\Temp\\"); _putenv_s("GST_PLUGIN_PATH_1_0", gstPluginsPath.str().c_str()); CustomData data; GstBus *bus; /* Initialize cumstom data structure */ memset(&data, 0, sizeof(data)); /* Initialize GStreamer */ gst_init(&argc, &argv); /* Create the elements */ data.app_source = gst_element_factory_make("appsrc", "app_source"); data.app_sink = gst_element_factory_make("appsink", "app_sink"); /* Create the empty pipeline */ data.pipeline = gst_pipeline_new("custom-pipeline"); if (!data.pipeline || !data.app_source || !data.app_sink) { g_printerr("Not all elements could be created.\n"); return -1; } /* Create custom properties*/ g_object_set(G_OBJECT(data.app_source), "caps", gst_caps_new_simple("custom", "format", G_TYPE_STRING, "U8", "width", G_TYPE_INT, 1, "height", G_TYPE_INT, 1, "framerate", GST_TYPE_FRACTION, 0, 1, NULL), NULL); g_object_set(G_OBJECT(data.app_sink), "caps", gst_caps_new_simple("custom", "format", G_TYPE_STRING, "U8", "width", G_TYPE_INT, 1, "height", G_TYPE_INT, 1, "framerate", GST_TYPE_FRACTION, 0, 1, NULL), NULL); /* Configure appsrc */ //g_object_set(data.app_source, "format", GST_FORMAT_TIME, NULL); g_signal_connect(data.app_source, "need-data", G_CALLBACK(start_feed), &data); //g_signal_connect(data.app_source, "enough-data", G_CALLBACK(stop_feed), &data); /* Configure appsink */ g_object_set(data.app_sink, "emit-signals", TRUE, NULL); //g_object_set(data.app_sink, "sync", TRUE, NULL); g_signal_connect(data.app_sink, "new-sample", G_CALLBACK(new_sample), &data); /* Link all elements that can be automatically linked because they have "Always" pads */ gst_bin_add_many(GST_BIN(data.pipeline), data.app_source, data.app_sink, NULL); if (gst_element_link_many(data.app_source, data.app_sink, NULL) != TRUE) { g_printerr("Elements could not be linked.\n"); gst_object_unref(data.pipeline); return -1; } /* Instruct the bus to emit signals for each received message, and connect to the interesting signals */ /* gst_element_get_bus is the same as gst_pipeline_get_but -> In this example pipeline is element, therfore the former...*/ bus = gst_element_get_bus(data.pipeline); gst_bus_add_signal_watch(bus); g_signal_connect(G_OBJECT(bus), "message::error", (GCallback)error_cb, &data); g_signal_connect(G_OBJECT(bus), "message::eos", (GCallback)eos_cb, &data); gst_object_unref(bus); /* Start playing the pipeline */ gst_element_set_state(data.pipeline, GST_STATE_PLAYING); if (!(data.app_source->current_state == GST_STATE_PLAYING)); { g_print("Wait for transition to playing state!\n"); } GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS((GstBin*)data.pipeline, GST_DEBUG_GRAPH_SHOW_ALL, "show_pipeline"); /* Create a GLib Main Loop and set it to run */ data.main_loop = g_main_loop_new(NULL, FALSE); g_main_loop_run(data.main_loop); /* Free resources */ gst_element_set_state(data.pipeline, GST_STATE_NULL); gst_object_unref(data.pipeline); return 0; }Thanks! -- Sent from: http://gstreamer-devel.966125.n4.nabble.com/ _______________________________________________ gstreamer-devel mailing list gstreamer-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
The code not accepted in my original post. You find the complete example
under: http://gstreamer-devel.966125.n4.nabble.com/appsrc-appsink-gt-only-one-buffer-received-td4685731.html -- Sent from: http://gstreamer-devel.966125.n4.nabble.com/ _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
On Fri, 2017-12-22 at 06:55 -0700, gst_starter wrote:
> The code not accepted in my original post. You find the complete > example under: > > http://gstreamer-devel.966125.n4.nabble.com/appsrc-appsink-gt-only-on > e-buffer-received-td4685731.html You're supposed to return a GstFlowReturn from the new-sample callback function, see gst-inspect-1.0 appsink. Try returning GST_FLOW_OK. Cheers -Tim -- Tim Müller, Centricular Ltd - http://www.centricular.com _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
In reply to this post by bulloid
Hi, 2017-12-22 16:55 GMT+03:00 gst_starter <[hidden email]>: The code not accepted in my original post. You find the complete example _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
In reply to this post by Tim Müller
Thank you Tim! The return value fixed the problem...
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