Playing .AVI file with GStreamer SDK in Windows

Question

I want to play an .AVI file using GStreamer in Windows 7. GStreamer SDK was installed as given in this link. Then a GStreamer SDK project was created and the following code was added to a C file as given is this link with the suggested corrections. Project properties -> Configurations properties -> Debugging -> Working directory was changed to "$(GSTREAMER_SDK_ROOT_X86)\bin" and the same was added to windows PATH variable as suggested in the installation link given above. When run the code, it just exits without playing the video, last few lines of the output is given below. Please note that I have installed 32 bit Gstreamer SDK on a 64 bit Windows 7.

Code:

#include<stdio.h>
#include<gst/gst.h>
#include<glib.h>

//Function to process message on bus of pipeline
gboolean process_message(GstBus *bus, GstMessage *msg,gpointer data);

//Function to add pad dynamically for ogg demux
void dynamic_addpad(GstElement *element, GstPad *pad, gpointer data);        
void dynamic_decodepad (GstElement* object, GstPad* arg0, gboolean arg1,gpointer user_data);

GstElement *source, *demuxer, *audio_decoder, *video_decoder, *audio_convertor,*video_convertor, *audio_sink,*video_sink,*audioqueue,*videoqueue;//*audio_demuxer, *video_demuxer,

int main(int argc,char* argv[]){
    GstPipeline *pipeline;
    GstBin *Bin;
    GstBus *bus;
    GMainLoop *Mainloop;

    gst_init (&argc,&argv);

    Mainloop = g_main_loop_new(NULL,FALSE);//NULL to use the current context and False to tell its not in running state

    GstElement *pipeline = gst_pipeline_new("PIPELINE");
    Bin = GST_BIN(pipeline);
    bus = gst_pipeline_get_bus(GST_PIPELINE(pipeline));

    source = gst_element_factory_make("filesrc","file-source");
    g_object_set(G_OBJECT(source), "location", "file:///C:/Video.avi", NULL);

    demuxer = gst_element_factory_make("avidemux","avi-demuxer");
    audioqueue = gst_element_factory_make("queue","Queue for audio");
    videoqueue = gst_element_factory_make("queue","Queue for video");
    audio_decoder = gst_element_factory_make("decodebin","a_decodebin");
    video_decoder = gst_element_factory_make("decodebin","decoderbin");//"Vorbis audio decoder","vorbis");
    audio_convertor = gst_element_factory_make("audioconvert","audio convertor");//"Audio converter","audioconvert");
    video_convertor = gst_element_factory_make("videoscale","video convertor");//"Audio converter","audioconvert");
    audio_sink = gst_element_factory_make("autoaudiosink","Auto audio sink");
    video_sink = gst_element_factory_make("xvimagesink","XV video sink ");

    if(!source || !demuxer || !audioqueue || !videoqueue || !video_decoder ||!audio_convertor || ! video_convertor || !audio_sink || !video_sink  ){   
        g_print("Could not not create element\n");
        return 0;
    }
    gst_bin_add(Bin,source);
    gst_bin_add_many(
        Bin,
        demuxer,
        audioqueue,videoqueue,
        audio_decoder,audio_convertor,
        video_decoder,video_convertor,
        audio_sink,video_sink,
        NULL);

    gst_element_link(source,demuxer);
    gst_element_link_many(audioqueue,audio_decoder,NULL);
    gst_element_link_many(audio_convertor,audio_sink,NULL);
    gst_element_link_many(videoqueue,video_decoder,NULL);
    gst_element_link_many(video_convertor,video_sink,NULL);

    g_signal_connect(demuxer,"pad-added",G_CALLBACK(dynamic_addpad),NULL);//demuxer and decoder are passed as instance and data as pads of both the elements are linked in dynamic_addpad

    g_signal_connect(audio_decoder,"new-decoded-pad",G_CALLBACK(dynamic_decodepad),NULL);
    g_signal_connect(video_decoder,"new-decoded-pad",G_CALLBACK(dynamic_decodepad),NULL);//demuxer and decoder are passed as instance and data as pads of both the elements are linked in dynamic_addpad
    gst_bus_add_watch(bus,process_message,Mainloop); //Mainloop is passed as user data as in the process_message actions are taken on the loop
    g_object_unref(bus);
    g_print("In playing state\n");
    gst_element_set_state(pipeline, GST_STATE_PLAYING);//Pipeline is also a bin and bin is also an element at abstract level and hence gst_element_set_state call is used to set state of pipeline.

    g_main_loop_run(Mainloop);
    g_print("In playing state2\n");
    gst_element_set_state(pipeline, GST_STATE_NULL);
    g_object_unref(G_OBJECT(pipeline));
}


//Function to process message on bus of pipeline
gboolean process_message(GstBus *bus, GstMessage *msg,gpointer data){
    GError *error;
    gchar *debug;
    GMainLoop *loop = (GMainLoop *)data;

    g_print(" In process message msg->type : %d\n",GST_MESSAGE_TYPE(msg));
    switch(GST_MESSAGE_TYPE(msg)){
        case   GST_MESSAGE_UNKNOWN :
            g_print("GST_MESSAGE_UNKNOWN \n");
            break;
        case   GST_MESSAGE_EOS     :
            g_print("GST_MESSAGE_EOS \n");
            g_main_loop_quit(loop);
            break;
        case   GST_MESSAGE_ERROR   :
            g_print("GST_MESSAGE_ERROR \n");
            gst_message_parse_error (msg, &error, &debug);
            g_free(debug);
            //if(!error)
            {
                g_print("GST_MESSAGE_ERROR message : %s \n",error->message);
            }
            g_main_loop_quit(loop);
            break;
        case   GST_MESSAGE_WARNING :
            g_print("GST_MESSAGE_WARNING  \n");
            break;
        case   GST_MESSAGE_INFO    :
            g_print("GST_MESSAGE_INFO \n");
            break;
        case   GST_MESSAGE_TAG     :
            g_print("GST_MESSAGE_TAG \n");
            break;
        case   GST_MESSAGE_BUFFERING:
            g_print("GST_MESSAGE_BUFFERING \n");
            break;
        case   GST_MESSAGE_STATE_CHANGED:
            g_print("GST_MESSAGE_STATE_CHANGED \n");
            break;
        default : 
            g_print("default \n");
            break;
    }
    return TRUE; //returns true always as it has to be always registered returning false will deregister the function
}

void dynamic_addpad(GstElement *element, GstPad *pad, gpointer data) {
    char* pad_name = gst_pad_get_name(pad);
    g_print(" In dynamic ADDING PAD %s\n", pad_name);

    if (g_str_has_prefix(pad_name,"audio")) {
        GstPad *audiodemuxsink = gst_element_get_static_pad(audioqueue,"sink");
        gst_pad_link(pad,audiodemuxsink );
    }
    else if (g_str_has_prefix(pad_name,"video")) {
        GstPad *videodemuxsink = gst_element_get_static_pad(videoqueue,"sink");
        gst_pad_link(pad,videodemuxsink );
    }
    g_free (pad_name);
}

void dynamic_decodepad (GstElement* object, GstPad* pad, gboolean arg1,gpointer user_data) {
    GstPad* videoconvertsink = gst_element_get_static_pad(video_convertor,"sink");
    if (gst_pad_can_link(pad,videoconvertsink)) {
        gst_pad_link(pad,videoconvertsink);
    }

    GstPad* audioconvertsink  = gst_element_get_static_pad(audio_convertor,"sink");
    if (gst_pad_can_link(pad,audioconvertsink)) {
        gst_pad_link(pad,audioconvertsink);
    }
}

Output:

The thread 'Win32 Thread' (0x19c4) has exited with code 0 (0x0).
The thread 'Win32 Thread' (0x2370) has exited with code 0 (0x0).
The thread 'Win32 Thread' (0x2040) has exited with code 0 (0x0).
The program '[5368] GstProject2.exe: Native' has exited with code 0 (0x0).

Answer 1

Finally I was able to play the AVI file using the following code which is based on this example in Gstreamer SDK website.

In command prompt: Option 1:

gst-launch-0.10 filesrc location=C:\\Video.avi ! decodebin2 name=dec ! queue ! ffmpegcolorspace ! autovideosink dec. ! queue ! audioconvert ! audioresample ! autoaudiosink

Option 2:

gst-launch-0.10 filesrc location=C:\\Video.avi ! decodebin2 name=dec ! ffmpegcolorspace ! autovideosink dec. ! audioconvert ! audioresample ! autoaudiosink

Option 3:

gst-launch-0.10 uridecodebin uri=file:///C:/Video.avi name=dec ! ffmpegcolorspace ! autovideosink dec. ! audioconvert ! autoaudiosink

In Visual Studio:

#include <gst/gst.h>

/* Structure to contain all our information, so we can pass it to callbacks */
typedef struct _CustomData {
  GstElement *pipeline;
  GstElement *source;
  GstElement *convert;
  GstElement *audio_sink;
  GstElement *colorspace;
  GstElement *video_sink;
} CustomData;

/* Handler for the pad-added signal */
static void pad_added_handler (GstElement *src, GstPad *pad, CustomData *data);

int main(int argc, char *argv[]) {
  CustomData data;
  GstBus *bus;
  GstMessage *msg;
  GstStateChangeReturn ret;
  gboolean terminate = FALSE;

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

  /* Create the elements */
  data.source = gst_element_factory_make ("uridecodebin", "source");
  data.convert = gst_element_factory_make ("audioconvert", "convert");
  data.audio_sink = gst_element_factory_make ("autoaudiosink", "audio_sink");
  data.colorspace = gst_element_factory_make ("ffmpegcolorspace", "colorspace");
  data.video_sink = gst_element_factory_make ("autovideosink", "video_sink");

  /* Create the empty pipeline */
  data.pipeline = gst_pipeline_new ("test-pipeline");

  if (!data.pipeline || !data.source || !data.convert || !data.audio_sink || !data.colorspace || !data.video_sink) {
    g_printerr ("Not all elements could be created.\n");
    return -1;
  }

  /* Build the pipeline. Note that we are NOT linking the source at this
   * point. We will do it later. */
  gst_bin_add_many (GST_BIN (data.pipeline), data.source, data.convert , data.audio_sink, data.colorspace, data.video_sink, NULL);
  if (!(gst_element_link (data.convert, data.audio_sink) && gst_element_link (data.colorspace, data.video_sink))) {
    g_printerr ("Elements could not be linked.\n");
    gst_object_unref (data.pipeline);
    return -1;
  }

  /* Set the URI to play */
  g_object_set (data.source, "uri", "file:///C:/Video.avi", NULL);

  /* Connect to the pad-added signal */
  g_signal_connect (data.source, "pad-added", G_CALLBACK (pad_added_handler), &data);

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

  /* Listen to the bus */
  bus = gst_element_get_bus (data.pipeline);
  do {
    msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_STATE_CHANGED | GST_MESSAGE_ERROR | GST_MESSAGE_EOS);

    /* Parse message */
    if (msg != NULL) {
      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);
          terminate = TRUE;
          break;
        case GST_MESSAGE_EOS:
          g_print ("End-Of-Stream reached.\n");
          terminate = TRUE;
          break;
        case GST_MESSAGE_STATE_CHANGED:
          /* We are only interested in state-changed messages from the pipeline */
          if (GST_MESSAGE_SRC (msg) == GST_OBJECT (data.pipeline)) {
            GstState old_state, new_state, pending_state;
            gst_message_parse_state_changed (msg, &old_state, &new_state, &pending_state);
            g_print ("Pipeline state changed from %s to %s:\n",
                gst_element_state_get_name (old_state), gst_element_state_get_name (new_state));
          }
          break;
        default:
          /* We should not reach here */
          g_printerr ("Unexpected message received.\n");
          break;
      }
      gst_message_unref (msg);
    }
  } while (!terminate);

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

/* This function will be called by the pad-added signal */
static void pad_added_handler (GstElement *src, GstPad *new_pad, CustomData *data) {
  GstPad *sink_pad_audio = gst_element_get_static_pad (data->convert, "sink");
  GstPad *sink_pad_video = gst_element_get_static_pad (data->colorspace, "sink");
  GstPadLinkReturn ret;
  GstCaps *new_pad_caps = NULL;
  GstStructure *new_pad_struct = NULL;
  const gchar *new_pad_type = NULL;

  g_print ("Received new pad '%s' from '%s':\n", GST_PAD_NAME (new_pad), GST_ELEMENT_NAME (src));

  ///* If our converter is already linked, we have nothing to do here */
  //if (gst_pad_is_linked (sink_pad)) {
  //  g_print ("  We are already linked. Ignoring.\n");
  //  goto exit;
  //}

  /* Check the new pad's type */
  new_pad_caps = gst_pad_get_caps (new_pad);
  new_pad_struct = gst_caps_get_structure (new_pad_caps, 0);
  new_pad_type = gst_structure_get_name (new_pad_struct);
  if (!g_str_has_prefix (new_pad_type, "audio/x-raw")) {
    g_print ("  It has type '%s' which is raw video. Connecting.\n", new_pad_type);
    /* Attempt the link */
    ret = gst_pad_link (new_pad, sink_pad_video);
    if (GST_PAD_LINK_FAILED (ret)) {
    g_print ("  Type is '%s' but link failed.\n", new_pad_type);
    } else {
    g_print ("  Link succeeded (type '%s').\n", new_pad_type);
    }
    goto exit;
  }

  /* Attempt the link */
  ret = gst_pad_link (new_pad, sink_pad_audio);
  if (GST_PAD_LINK_FAILED (ret)) {
    g_print ("  Type is '%s' but link failed.\n", new_pad_type);
  } else {
    g_print ("  Link succeeded (type '%s').\n", new_pad_type);
  }

exit:
  /* Unreference the new pad's caps, if we got them */
  if (new_pad_caps != NULL)
    gst_caps_unref (new_pad_caps);

  /* Unreference the sink pad */
  gst_object_unref (sink_pad_audio);
  gst_object_unref (sink_pad_video);
}