After pausing and make changes nothing was applied when get back to playing state!

[ibrahim suliman]

The code below is to stream mpeg4 video (using v4l2src element of the following capabilities: width=640, height=480, frame rate=30/1) over a network using a updsink element and the capabilities values should change to (width=352, height=288, frame rate=15/1) after pressing "1" on the keyboard. I tried to do this by pausing the pipeline after  the "1" is pressed and then re-setting the caps to the new values and then get the pipeline into playing state again but this did not work for me.
I get the caps values printed before pausing the pipeline and after the changes made and I can see that the changes were done but not applied when the pipeline is brought to playing state again. 

please help.......

you can playback this stream by typing into a new terminal the following command just before running the code below:
gst-launch udpsrc multicast-group=127.0.0.1 port=8999 ! mpeg4videoparse ! ffdec_mpeg4 ! ffmpegcolorspace ! autovideosink

======================
#include <gst/gst.h>
#include <glib.h>
#include <stdio.h>
#include <glib-object.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;
   }

int main (int argc, char *argv[])
{
   GMainLoop *loop;
   GstElement *pipeline, *source, *filter, *vrate, *encoder, *conv, *sink;
   GstBus *bus;
   GstCaps *filtercaps; 
   gint width, height, num, denom;
   const GstStructure *str;

   /* 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 ("video-player");
   source = gst_element_factory_make ("v4l2src", "file-source");
   vrate = gst_element_factory_make ("videorate", "video-rate");
   filter = gst_element_factory_make ("capsfilter", "filter");
   conv = gst_element_factory_make ("ffmpegcolorspace","converter");
   encoder = gst_element_factory_make ("ffenc_mpeg4","mpeg-decoder");
   sink = gst_element_factory_make ("udpsink","audio-output");


   if (!pipeline || !source || !filter || !vrate || !conv || !encoder || !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 */
   filtercaps = gst_caps_new_simple ("video/x-raw-yuv",
"width", G_TYPE_INT, 640,
"height", G_TYPE_INT, 480,
"framerate", GST_TYPE_FRACTION, 30, 1,
NULL);

   g_object_set (G_OBJECT (filter), "caps", filtercaps, NULL);
   gst_caps_unref (filtercaps);
   g_object_set (G_OBJECT (encoder), "bitrate" , 384 ,  NULL);
   g_object_set (G_OBJECT (sink), "host" , argv[1] ,  NULL);
   g_object_set (G_OBJECT (sink), "port" , 8999 ,  NULL);
   g_object_set (G_OBJECT (sink), "async" , FALSE ,  NULL);

   
   /* we add a message handler */
   bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
   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, vrate, filter, conv, encoder, sink, NULL);

   /* we link the elements together */
   /* file-source -> ogg-demuxer ~> vorbis-decoder -> converter -> alsa-output */
   gst_element_link_many (source, vrate, filter, conv, encoder,  sink, NULL);


        
   /* Set the pipeline to "playing" state*/
   g_print ("Now playing: \n");
   gst_element_set_state (pipeline, GST_STATE_PLAYING);
   
      
   /* Print out the frame size and rate */
   str = gst_caps_get_structure (filtercaps, 0);
   if (!gst_structure_get_int (str, "width", &width) || !gst_structure_get_int (str, "height", &height) || 
       !gst_structure_get_fraction (str, "framerate", &num, &denom)) 
   g_print ("No width/height available\n");
   g_print ("The video size of this set of capabilities is %dx%d and the frame rate is %d/%d\n", width, height, num, denom);
   


   /* Pausing the streame */ 
   int in;
   if (scanf ("%d", &in) == 1){
g_print ("Now pausing: \n");
   gst_element_set_state (pipeline, GST_STATE_PAUSED );
g_assert (GST_STATE (pipeline) == GST_STATE_PAUSED);
g_assert (GST_STATE (source) == GST_STATE_PAUSED);
g_assert (GST_STATE (filter) == GST_STATE_PAUSED);
g_assert (GST_STATE (vrate) == GST_STATE_PAUSED);
g_assert (GST_STATE (encoder) == GST_STATE_PAUSED);
g_assert (GST_STATE (conv) == GST_STATE_PAUSED);
g_assert (GST_STATE (sink) == GST_STATE_PAUSED);

/* apply the alterations to the caps now */
gst_caps_set_simple (filtercaps, "width", G_TYPE_INT, 352, "height", G_TYPE_INT, 288, "framerate", GST_TYPE_FRACTION, 15, 1, NULL);    
        
        /* Print out the frame size and rate after alteration*/
str = gst_caps_get_structure (filtercaps, 0);
        if (!gst_structure_get_int (str, "width", &width) || !gst_structure_get_int (str, "height", &height) || 
    !gst_structure_get_fraction (str, "framerate", &num, &denom)) 
   g_print ("No width/height available\n");
g_print ("The video size of this set of capabilities is %dx%d and the frame rate is %d/%d\n", width, height, num, denom);
/* set back to playing */
gst_element_set_state (pipeline, GST_STATE_PLAYING);

g_assert (GST_STATE (pipeline) == GST_STATE_PLAYING);
g_assert (GST_STATE (source) == GST_STATE_PLAYING);
g_assert (GST_STATE (filter) == GST_STATE_PLAYING);
g_assert (GST_STATE (vrate) == GST_STATE_PLAYING);
g_assert (GST_STATE (encoder) == GST_STATE_PLAYING);
g_assert (GST_STATE (conv) == GST_STATE_PLAYING);
g_assert (GST_STATE (sink) == GST_STATE_PLAYING);
    }
     

   /* Iterate */
   g_print ("Running...\n");
   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);
   g_print ("Deleting pipeline\n");
   gst_object_unref (GST_OBJECT (pipeline));

   return 0;
}


Cheers.

Ibra
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