[gst-devel] newbie question -- mpegdemux signals

[Thomas Comiotto]

Hi there, 

I'm having some troubles with the mpeg-player example from the gstreamer 
docs-- the code listed there doesn't seem to work neither with the stable 
release (0.6-0) nor the latest one (0.7-3). The code runs without dropping 
any errors or warnings for the duration of the video and finally terminates 
with an eos from filesrc. It never enters the callback function for 
mpegdemux's new-pad signal. What callback function fits mpegdemux's  
'new-pad' (underscore or not?) signal? gst-inspect-06 lists no signals for 
this element. Does the demuxer send out this signal at all? How can I 
implement the dynamic pads needed for mpeg parsing/decoding? Below the code 
taken from the docs...

I am running Debian testing on a I386 box. 

Thanx, 
-t

====

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

void
eof (GstElement *src)
{
	g_print ("have eos, quitting\n");
	exit (0);
}


gboolean
idle_func (gpointer data)
{
	gst_bin_iterate (GST_BIN (data));
	return TRUE;
}

void
new_pad_created (GstElement *parse, GstPad *pad, GstElement *pipeline)
{
	GstElement *decode_video = NULL;
	GstElement *decode_audio, *play, *color, *show;
	GstElement *audio_queue, *video_queue;
	GstElement *audio_thread, *video_thread;

	g_print ("****** a new pad %s was created\n", gst_pad_get_name (pad));

	gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_PAUSED);

	if (strncmp (gst_pad_get_name (pad), "audio_", 6) == 0) {

		decode_audio = gst_element_factory_make ("mad", "decode_audio");
		g_return_if_fail (decode_audio != NULL);
		play = gst_element_factory_make ("osssink", "play_audio");
		g_return_if_fail (play != NULL);

		audio_thread = gst_thread_new ("audio_thread");
		g_return_if_fail (audio_thread != NULL);

		audio_queue = gst_element_factory_make ("queue", "audio_queue");
		g_return_if_fail (audio_queue != NULL);

		gst_bin_add_many (GST_BIN (audio_thread), audio_queue, decode_audio, play, 
NULL);

		gst_element_add_ghost_pad (audio_thread, gst_element_get_pad (audio_queue, 
"sink"), "sink");
		gst_element_link (audio_queue, decode_audio);
		gst_element_link (decode_audio, play);

		gst_bin_add (GST_BIN (pipeline), audio_thread);

		gst_pad_link (pad, gst_element_get_pad (audio_thread, "sink"));

		g_print ("setting to READY state\n");
		gst_element_set_state (GST_ELEMENT (audio_thread), GST_STATE_READY);
	}
	else if (strncmp (gst_pad_get_name (pad), "video_", 6) == 0) {

		decode_video = gst_element_factory_make ("mpeg2dec", "decode_video");
		g_return_if_fail (decode_video != NULL);

		color = gst_element_factory_make ("colorspace", "color");
		g_return_if_fail (color != NULL);

		show = gst_element_factory_make ("xvideosink", "show");
		g_return_if_fail (show != NULL);

		video_queue = gst_element_factory_make ("queue", "video_queue");
		g_return_if_fail (video_queue != NULL);

		video_thread = gst_thread_new ("video_thread");
		g_return_if_fail (video_thread != NULL);

		gst_bin_add_many (GST_BIN (video_thread), video_queue, decode_video, color, 
show, NULL);

		gst_element_add_ghost_pad (video_thread, gst_element_get_pad (video_queue, 
"sink"), "sink");
		gst_element_link (video_queue, decode_video);
		gst_element_link_many (decode_video, color, show, NULL);
		gst_bin_add (GST_BIN (pipeline), video_thread);

		gst_pad_link (pad, gst_element_get_pad (video_thread, "sink"));

		g_print ("setting to READY state\n");
		gst_element_set_state (GST_ELEMENT (video_thread), GST_STATE_READY);
	}
	
	gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_PLAYING);
}

int
main (int argc, char *argv[])
{
	GstElement *pipeline, *src, *demux;

	gst_init (&argc, &argv);

	pipeline = gst_pipeline_new ("pipeline");
	g_return_val_if_fail (pipeline != NULL, -1);

	src = gst_element_factory_make ("filesrc", "src");
	g_return_val_if_fail (src != NULL, -1);

	if (argc < 2)
		g_error ("Please specify a video file to play !");
	g_object_set (G_OBJECT (src), "location", argv[1], NULL);

	demux = gst_element_factory_make ("mpegdemux", "demux");
	g_return_val_if_fail (demux != NULL, -1);

	gst_bin_add_many (GST_BIN (pipeline), src, demux, NULL);

	g_signal_connect (G_OBJECT (demux), "new-pad", G_CALLBACK (new_pad_created), 
pipeline);

	g_signal_connect (G_OBJECT (src), "eos", G_CALLBACK (eof), NULL);

	gst_element_link (src, demux);

	gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_PLAYING);

	g_idle_add (idle_func, pipeline);

	gst_main ();

	return 0;
}