render.c

#include <gst/gst.h>
#include <stdlib.h>
#include <string.h>

#define SEEK_DEFAULT_POS -1

/* Structure to contain all our information, so we can pass it around */
typedef struct _CustomData {
  GstElement *playbin;  /* Our one and only element */
  gboolean playing;      /* Are we in the PLAYING state? */
  gboolean terminate;    /* Should we terminate execution? */
  gboolean seek_enabled; /* Is seeking enabled for this media? */
  gboolean seek_done;    /* Have we performed the seek already? */
  gint64 duration;       /* How long does this media last, in nanoseconds */
} CustomData;

/* Forward definition of the message processing function */
static void handle_message (CustomData *data, GstMessage *msg);

/**
 * Usage: ./render <uri> <start_frame> <end_frame>
 * start_frame and end_frame should be a number >= 0 for seek
 * if end_frame == -1 then it indicates the end of seek position
 * should not be set.
 */
int main(int argc, char *argv[]) {
  CustomData data;
  GstBus *bus;
  GstMessage *msg;
  GstStateChangeReturn ret;
  const char *uri;
  gint64 start_frame;
  gint64 end_frame;

  if (argc == 4) {
	  uri = argv[1]; 
	  start_frame = (gint64) strtol (argv[2], NULL, 10) * 1000 / 30;
	  if (strcmp(argv[3], "-1") != 0)
		  end_frame = (gint64) strtol (argv[3], NULL, 10) * 1000 / 30;
	  else
		  end_frame = -1;
  } else {
	  g_print ("Usage: ./render <uri> <start_frame> <end_frame>\n");
	  exit(1);
  }

  data.playing = FALSE;
  data.terminate = FALSE;
  data.seek_enabled = FALSE;
  data.seek_done = FALSE;
  data.duration = GST_CLOCK_TIME_NONE;

  /* Initialize GStreamer */
  gst_init (&argc, &argv);

  /* Create the elements */
  data.playbin = gst_element_factory_make ("playbin", "playbin");

  if (!data.playbin) {
    g_printerr ("Not all elements could be created.\n");
    return -1;
  }

  /* Set the URI to play */
  g_object_set (data.playbin, "uri", uri, NULL);

  /* for Jetson tx2 to play 4k video */
  GstElement *sink;
  sink = gst_element_factory_make ("nveglglessink", NULL);
  g_object_set (data.playbin, "video-sink", sink, NULL);

  /* Start playing */
  ret = gst_element_set_state (data.playbin, 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.playbin);
    return -1;
  }

  /* Listen to the bus */
  bus = gst_element_get_bus (data.playbin);
  do {
    msg = gst_bus_timed_pop_filtered (bus, 100 * GST_MSECOND,
        GST_MESSAGE_STATE_CHANGED | GST_MESSAGE_ERROR | GST_MESSAGE_EOS | GST_MESSAGE_DURATION);

    /* Parse message */
    if (msg != NULL) {
      handle_message (&data, msg);
    } else {
      /* We got no message, this means the timeout expired */
      if (data.playing) {
        gint64 current = -1;

        /* Query the current position of the stream */
        if (!gst_element_query_position (data.playbin, GST_FORMAT_TIME, &current)) {
          g_printerr ("Could not query current position.\n");
        }

        /* If we didn't know it yet, query the stream duration */
        if (!GST_CLOCK_TIME_IS_VALID (data.duration)) {
          if (!gst_element_query_duration (data.playbin, GST_FORMAT_TIME, &data.duration)) {
            g_printerr ("Could not query current duration.\n");
          }
        }

        /* Print current position and total duration */
        g_print ("Position %" GST_TIME_FORMAT " / %" GST_TIME_FORMAT "\r",
            GST_TIME_ARGS (current), GST_TIME_ARGS (data.duration));

        /* If seeking is enabled, we have not done it yet, and the time is right, seek */
        if (data.seek_enabled && !data.seek_done) {
          g_print ("\nReached 10s, performing seek...\n");
		  if (end_frame == SEEK_DEFAULT_POS) {
			  gst_element_seek (data.playbin,
					  1.0,
					  GST_FORMAT_TIME,
					  GST_SEEK_FLAG_FLUSH,
					  GST_SEEK_TYPE_SET,
					  start_frame * GST_MSECOND,
					  GST_SEEK_TYPE_NONE,
					  SEEK_DEFAULT_POS);
		  } else {
			  gst_element_seek (data.playbin,
					  1.0,
					  GST_FORMAT_TIME,
					  GST_SEEK_FLAG_FLUSH,
					  GST_SEEK_TYPE_SET,
					  start_frame * GST_MSECOND,
					  GST_SEEK_TYPE_SET,
					  end_frame * GST_MSECOND);
		  }
          data.seek_done = TRUE;
        }
      }
    }
  } while (!data.terminate);

  /* Free resources */
  gst_object_unref (bus);
  gst_element_set_state (data.playbin, GST_STATE_NULL);
  gst_object_unref (data.playbin);
  return 0;
}

static void handle_message (CustomData *data, GstMessage *msg) {
  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);
      data->terminate = TRUE;
      break;
    case GST_MESSAGE_EOS:
      g_print ("End-Of-Stream reached.\n");
      data->terminate = TRUE;
      break;
    case GST_MESSAGE_DURATION:
      /* The duration has changed, mark the current one as invalid */
      data->duration = GST_CLOCK_TIME_NONE;
      break;
    case GST_MESSAGE_STATE_CHANGED: {
      GstState old_state, new_state, pending_state;
      gst_message_parse_state_changed (msg, &old_state, &new_state, &pending_state);
      if (GST_MESSAGE_SRC (msg) == GST_OBJECT (data->playbin)) {
        g_print ("Pipeline state changed from %s to %s:\n",
            gst_element_state_get_name (old_state), gst_element_state_get_name (new_state));

        /* Remember whether we are in the PLAYING state or not */
        data->playing = (new_state == GST_STATE_PLAYING);

        if (data->playing) {
          /* We just moved to PLAYING. Check if seeking is possible */
          GstQuery *query;
          gint64 start, end;
          query = gst_query_new_seeking (GST_FORMAT_TIME);
          if (gst_element_query (data->playbin, query)) {
            gst_query_parse_seeking (query, NULL, &data->seek_enabled, &start, &end);
            if (data->seek_enabled) {
              g_print ("Seeking is ENABLED from %" GST_TIME_FORMAT " to %" GST_TIME_FORMAT "\n",
                  GST_TIME_ARGS (start), GST_TIME_ARGS (end));
            } else {
              g_print ("Seeking is DISABLED for this stream.\n");
            }
          }
          else {
            g_printerr ("Seeking query failed.");
          }
          gst_query_unref (query);
        }
      }
    } break;
    default:
      /* We should not reach here */
      g_printerr ("Unexpected message received.\n");
      break;
  }
  gst_message_unref (msg);
}

compile: gcc -g render.c -o render pkg-config --cflags --libs gstreamer-1.0
run: ./render file:///home/nvidia/workspace/gstreamer-try/rhino-4k.mp4 10 20
The first argument is the uri, 10 is the start frame, 20 is the end frame.