How to extract video frames from pipeline through gstreamer-1.0???
Zheng Xing
superxingzheng at gmail.com
Sun Jun 28 10:33:39 PDT 2015
If you have OpenCV, it will be easy.
Zheng Xing
Ph.D Student
Hanlon Financial Systems Lab
Stevens Institute of Technology
On Jun 28, 2015 1:22 PM, "yannick inizan" <inizan.yannick at gmail.com> wrote:
> 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.
>> _______________________________________________
>> gstreamer-devel mailing list
>> gstreamer-devel at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>
>
>
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