How to extract video frames from pipeline through gstreamer-1.0???
yannick inizan
inizan.yannick at gmail.com
Sun Jun 28 10:15:51 PDT 2015
I use playbin element and emit "convert-sample" signal. raw data is
converted with GdkPixbuf
here an example (in Vala) : http://pastebin.com/Ex83wP6m
2015-06-28 16:49 GMT+02:00 Faran <m.faran.majeed at gmail.com>:
> I've written the following code to extract video frames but now am stuck.
> Could anyone please help???
>
> #include <gst/gst.h>
> #include <gst/app/gstappsrc.h>
> #include <gst/app/gstappsink.h>
> #include <glib.h>
>
> static gboolean
> bus_call (GstBus *bus,
> GstMessage *msg,
> gpointer data)
> {
> GMainLoop *loop = (GMainLoop *) data;
>
> switch (GST_MESSAGE_TYPE (msg)) {
>
> case GST_MESSAGE_EOS:
> g_print ("End of stream\n");
> g_main_loop_quit (loop);
> break;
>
> case GST_MESSAGE_ERROR: {
> gchar *debug;
> GError *error;
>
> gst_message_parse_error (msg, &error, &debug);
> g_free (debug);
>
> g_printerr ("Error: %s\n", error->message);
> g_error_free (error);
>
> g_main_loop_quit (loop);
> break;
> }
> default:
> break;
> }
>
> return TRUE;
> }
> static void sink_pad_add(GstElement *src, GstPad *pad, gpointer data)
> {
> g_print("\n This method is called when sink is padded \n");
> }
>
> static void
> on_pad_added (GstElement *src, GstPad *new_pad, gpointer data)
> {
> GstPad *sink_pad_audio, *sink_pad_video;
> GstElement *decoder = (GstElement *) data;
>
> /* We can now link this pad with the vorbis-decoder sink pad */
> g_print ("Dynamic pad created, linking demuxer/decoder\n");
>
> sink_pad_audio = gst_element_get_static_pad (decoder, "sink");
> //sink_pad_video = gst_element_get_static_pad (decoder, "sink");
>
> gst_pad_link (new_pad, sink_pad_audio);
> gst_object_unref (sink_pad_audio);
> }
> static void image_processing()
> {
> g_print("image processing method is called");
> }
>
>
> int
> main (int argc,
> char *argv[])
> {
> GMainLoop *loop;
>
> GstElement *pipeline, *source, *demuxer, *decoder, *conv, *sink;
> GstElement *video_decoder, *video_conv, *video_sink;
> GstBus *bus;
> guint bus_watch_id;
> GstElementFactory *factory;
> /* Initialisation */
> gst_init (&argc, &argv);
>
> loop = g_main_loop_new (NULL, FALSE);
>
>
> /* Check input arguments */
> if (argc != 2) {
> g_printerr ("Usage: %s <Ogg/Vorbis filename>\n", argv[0]);
> return -1;
> }
>
>
> /* Create gstreamer elements */
> pipeline = gst_pipeline_new ("audio-player");
> source = gst_element_factory_make ("filesrc", "source");
>
> demuxer = gst_element_factory_make ("oggdemux", "ogg-demuxer");
> video_decoder = gst_element_factory_make ("theoradec","video_decoder");
> video_conv = gst_element_factory_make
> ("videoconvert","video_convert");
> video_sink = gst_element_factory_make ("autovideosink","sink");
> if(!demuxer){g_print("qtdemuxer is not created");}
>
> if(!video_conv){g_print("video converter is not created");}
>
>
> if (!pipeline || !source || !demuxer || !decoder || !conv || !sink ||
> !video_decoder || !video_conv || !video_sink) {
> g_printerr ("One element could not be created. Exiting.\n");
> return -1;
> }
>
> /* Set up the pipeline */
>
> /* we set the input filename to the source element */
> g_object_set (G_OBJECT (source), "location", argv[1], NULL);
>
> /* we add a message handler */
> bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
> bus_watch_id = gst_bus_add_watch (bus, bus_call, loop);
> gst_object_unref (bus);
>
> /* we add all elements into the pipeline */
> /* file-source | ogg-demuxer | vorbis-decoder | converter | alsa-output
> */
> //gst_bin_add_many (GST_BIN (pipeline), source, demuxer, decoder, conv,
> sink /*,video_decoder, video_conv, video_sink*/, NULL);
>
> gst_bin_add_many (GST_BIN (pipeline), source, demuxer, video_decoder,
> video_conv, video_sink, NULL);
>
>
> /* we link the elements together */
> /* file-source -> ogg-demuxer ~> vorbis-decoder -> converter ->
> alsa-output */
> gst_element_link (source, demuxer);
>
> //gst_element_link_many (decoder, conv, sink, NULL); for .ogg audio
> gst_element_link_many (video_decoder, video_conv, video_sink, NULL); //
> for .ogg video
> /*if(!gst_element_link_many (video_conv, video_sink, NULL))
> {
> g_print("One of the element is not linking");
> }*/
> g_signal_connect (demuxer, "pad-added", G_CALLBACK (on_pad_added),
> video_decoder);
> g_signal_connect (video_conv, "pad-added", G_CALLBACK(sink_pad_add),
> video_sink);
> g_object_connect (video_conv, "pad-added", G_CALLBACK(sink_pad_add),
> video_sink);
> /* note that the demuxer will be linked to the decoder dynamically.
> The reason is that Ogg may contain various streams (for example
> audio and video). The source pad(s) will be created at run time,
> by the demuxer when it detects the amount and nature of streams.
> Therefore we connect a callback function which will be executed
> when the "pad-added" is emitted.*/
>
>
> /* Set the pipeline to "playing" state*/
> g_print ("Now playing: %s\n", argv[1]);
> gst_element_set_state (pipeline, GST_STATE_PLAYING);
>
> /* Iterate */
> g_print ("Running...\n");
> gchar *name;
> g_object_get(G_OBJECT (video_sink), "name", &name, NULL);
> factory = gst_element_factory_find ("autovideosink");
> g_print("The name of video_sink is %s \n", name);
> g_print ("The '%s' element is a member of the category %s.\n"
> "Description: %s\n",
> gst_plugin_feature_get_name (GST_PLUGIN_FEATURE (factory)),
> gst_element_factory_get_metadata (factory,
> GST_ELEMENT_METADATA_KLASS),
> gst_element_factory_get_metadata (factory,
> GST_ELEMENT_METADATA_DESCRIPTION));
>
> GstPad *pad = gst_element_get_static_pad(video_sink, name);
> //name = gst_pad_get_name (pad);
> g_print ("A new pad %s was created\n", name);
> g_free (name);
> GstCaps *c = gst_pad_get_pad_template_caps(pad);
> g_print("Th structure is %c", c);
> GstSample *sample;
> g_signal_emit_by_name (video_sink, "pull-sample", sample);
> GstCaps *caps = gst_sample_get_caps(sample);
> GstBuffer *buffer = gst_sample_get_buffer (sample);
> //buffer = gst_app_sink_pull_buffer(pro->sink)
> GstMapInfo map;
> gst_buffer_map (buffer, &map, GST_MAP_READ);
> gint width, height;
> const GstStructure *str;
> str = gst_caps_get_structure (caps, 0);
> gst_structure_get_int (str, "width", &width);
> gst_structure_get_int (str, "height", &height);
> g_print("The width is = %d", width);
> g_print("The height is = %d", height);
> cv::Mat frame(cv::Size(width, height), CV_8UC3, (char*)map.data, -3);
> cv::imwrite("Test2.jpg", frame);
>
>
> GstElement *rsink = gst_bin_get_by_name( GST_BIN( pipeline ), "sink" );
> GstSample *pstGstSample1;
> // pstGstSample1 = gst_app_sink_pull_sample( (GstAppSink *)rsink);
> //image_processing(pstGstSample1);
> g_main_loop_run (loop);
>
>
> /* Out of the main loop, clean up nicely */
> g_print ("Returned, stopping playback\n");
> gst_element_set_state (pipeline, GST_STATE_NULL);
> GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(pipeline), GST_DEBUG_GRAPH_SHOW_ALL
> ,"/home/siraj/Desktop/myplayer");
> g_print ("Deleting pipeline\n");
> gst_object_unref (GST_OBJECT (pipeline));
> g_source_remove (bus_watch_id);
> g_main_loop_unref (loop);
>
> return 0;
> }
>
>
>
> --
> View this message in context:
> http://gstreamer-devel.966125.n4.nabble.com/How-to-extract-video-frames-from-pipeline-through-gstreamer-1-0-tp4672495.html
> Sent from the GStreamer-devel mailing list archive at Nabble.com.
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>
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