Play avi-file

Andreas Büttner Andreas.Buettner87 at
Mon May 2 07:26:28 PDT 2011


I know the topic was already discussed, but I always receive a mistake by
using the following code(its nearly the code from a member here in the

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

static GstElement *source, *demuxer, *vdqueue, *vdsink, *decvd,

void on_pad_added (GstElement *element, GstPad *pad)

    gchar *name;
    name = gst_pad_get_name (pad);
    g_debug ("A new pad %s was created\n", name);

    GstCaps *caps;
    GstStructure *str;

    caps = gst_pad_get_caps (pad);
    g_assert (caps != NULL);
    str = gst_caps_get_structure (caps, 0);
    g_assert (str != NULL);

    if (g_strrstr (gst_structure_get_name (str), "video")) {
        g_debug ("Linking video pad to dec_vd");
        // Link it actually
        GstPad *targetsink = gst_element_get_pad (decvd, "sink");
        g_assert (targetsink != NULL);
        gst_pad_link (pad, targetsink);
        gst_object_unref (targetsink);

    gst_caps_unref (caps);

static gboolean
bus_call (GstBus *bus,
        GstMessage *msg,
        gpointer data)
    GMainLoop *loop = (GMainLoop *) data;

    switch (GST_MESSAGE_TYPE (msg)) {

        g_print ("End of stream\n");
        g_main_loop_quit (loop);

        gchar *debug;
        GError *error;

        gst_message_parse_error (msg, &error, &debug);

        g_printerr ("Error: %s (%s) \n", error->message, debug);
        g_free (debug);
        g_error_free (error);

        g_main_loop_quit (loop);

    return TRUE;

main (int argc,
        char *argv[])
    GMainLoop *loop;

    GstElement *pipeline;
    GstBus *bus;

    /* Initialisation */
    gst_init (&argc, &argv);

    loop = g_main_loop_new (NULL, FALSE);

    /* Check input arguments */
    if (argc != 2) {
        g_printerr ("Usage: %s <AVI filename>\n", argv[0]);
        return -1;

    /* Create gstreamer elements */
    pipeline = gst_pipeline_new ("media-player");
    source = gst_element_factory_make ("filesrc", "file-source");
    demuxer = gst_element_factory_make ("avidemux", "avi-demuxer");
    decvd = gst_element_factory_make ("decodebin", "video-decoder");
    vcolorspace = gst_element_factory_make ("ffmpegcolorspace",

    vdsink = gst_element_factory_make ("autovideosink", "video-sink");
    vdqueue = gst_element_factory_make ("queue", "video-queue");

    if (!pipeline || !source || !demuxer || !decvd || !vdsink
            || !vdqueue) {
        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 */
    g_object_set (G_OBJECT (source), "location", argv[1], 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);

    gst_bin_add_many (GST_BIN (pipeline), source, demuxer, decvd, vdqueue,
vdsink, NULL);

    gst_element_link (source, demuxer);
    gst_element_link (demuxer,vdqueue);
    gst_element_link (vdqueue, decvd);
    gst_element_link (decvd, vcolorspace);
    gst_element_link (vcolorspace, vdsink);

    g_signal_connect (demuxer, "pad-added", G_CALLBACK (on_pad_added),
    //g_signal_connect (decvd, "pad-added", G_CALLBACK (on_pad_added),

    /* Set the pipeline to "playing" state*/
    g_print ("Now playing: %s\n", argv[1]);
    gst_element_set_state (pipeline, 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;


I get the following mistake:

(play-avi2:4453): GStreamer-WARNING **: Trying to connect elements that
don't share a common ancestor: color-space and video-sink

(play-avi2:4453): GStreamer-WARNING **: Trying to connect elements that
don't share a common ancestor: color-space and video-sink
Now playing: avi-test2.avi
** (play-avi2:4453): DEBUG: A new pad video_00 was created

** (play-avi2:4453): DEBUG: Linking video pad to dec_vd
Error: Interner Datenstromfehler. (gstavidemux.c(5134): gst_avi_demux_loop
(): /GstPipeline:media-player/GstAviDemux:avi-demuxer:
streaming stopped, reason not-linked)
Returned, stopping playback
Deleting pipeline

I also tried the command-line tool:  gst-launch filesrc
location=avi-test2.avi ! avidemux name=demux demux.video_00 ! queue !
decodebin ! ffmpegcolorspace ! videoscale ! autovideosink

On this way it is working, but with the code it is not possible to play the
avi-file. I think the mistake is at the dynamic src-pad from the avidemuxer,
but I have no idea how to fix it.

Best regards, Andreas

Schon gehört? WEB.DE hat einen genialen Phishing-Filter in die
Toolbar eingebaut!

More information about the gstreamer-devel mailing list