Gstreamer with visual C++ express 2010 - tutorial 1

Question

I'm new to Gstreamer, and I have problems when I compile the tutorial 1 of Gstreamer. I'm using Windows 7 64 bit with visual c++ express 2010, and Gstreamer SDK 2012.11 32 bits (downloaded from here). Here is the code :

#include "stdafx.h"
#include <gst/gst.h>

int main(int argc, char *argv[]) {
  GstElement *pipeline;
  GstBus *bus;
  GstMessage *msg;

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

  /* Build the pipeline */
  pipeline = gst_parse_launch ("playbin2 uri=file://E:/test_1.MOV", NULL);

  /* Start playing */
  gst_element_set_state (pipeline, GST_STATE_PLAYING);

  /* Wait until error or EOS */
  bus = gst_element_get_bus (pipeline);
  msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS);

  /* Free resources */
  if (msg != NULL)
    gst_message_unref (msg);
  gst_object_unref (bus);
  gst_element_set_state (pipeline, GST_STATE_NULL);
  gst_object_unref (pipeline);
  return 0;
}

First error :

error C2664: 'gst_bus_timed_pop_filtered' : cannot convert parameter 3 from 'int' to 'GstMessageType'

So I just removed GST_MESSAGE_ERROR from the code. So the line is now :

msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_EOS);

I had the same problem with Ubuntu. But after that, in Ubuntu, I could play a video.

Second error : But with Windows, the compilation is good, but when I try to run it, I have thoses errors :

GStreamer-CRITICAL **: gst_element_set_state: assertion 'GST_IS_ELEMENT <element>' failed
GStreamer-CRITICAL **: gst_element_get_bus: assertion 'GST_IS_ELEMENT <element>' failed
GStreamer-CRITICAL **: gst_bus_timed_pop_filtered: assertion 'GST_IS_BUS <bus>' failed
GStreamer-CRITICAL **: gst_object_unref: assertion 'object=!NULL' failed
GStreamer-CRITICAL **: gst_element_set_state: assertion 'GST_IS_ELEMENT <element>' failed
GStreamer-CRITICAL **: gst_object_unref: assertion 'object=!NULL' failed

I don't really understand why it works with ubuntu and not with Windows. And I really don't know how to solve this problem. Could you help me please ?

Regards,

Answer 1

lFirst error

Probably the code is compiled as C++, which is a bit more strict at enum casts. Try replacing: GST_MESSAGE_ERROR | GST_MESSAGE_EOS with (GstMessageType)(GST_MESSAGE_ERROR | GST_MESSAGE_EOS)

Second error

There is high probability, that the line:

pipeline = gst_parse_launch ("playbin2 uri=file://E:/test_1.MOV", NULL);

returns NULL, and the rest of errors are result of this. Why it could return NULL? There are many reasons. Maybe you have not installed plugin with "playbin2"? Try this:

• Pass a pointer to GError structure as second parameter to gst_parse_launch (it has a message field which can give you some hint)
• Pass --gst-debug-level=4 or even higher as a commandline parameter when running your program. You will see many informations at console output, the reason of failure will be somewhere there.