[gst-devel] Problem creating second pad on ffmpeg 3GP muxer

[Geraldine Rougier]

Hi,

I am using 3GP muxer plugin from gstffmpeg and trying the following 
pipeline :

filesrc ! 3GP demux ! 3GP mux ! filesink

When the source file is audio or video only I have no problem, but with 
audio/video files I can not link the second pad created by the demuxer 
to the muxer.
The "gst_pad_link" function returns the following error : 
GST_PAD_LINK_NOFORMAT.

I tried two scenarii in order to link demuxer and muxer pads (the same 
is applied for audio pad):

1- pl_sinkpad_mux = gst_element_get_request_pad (pl_ctx->p_mux, "video_0");
    if (pl_sinkpad_mux==NULL)
    {
      g_print("Video sink pad is not available\n");
      return;
    }

  vl_status = gst_pad_link (srcpad, pl_sinkpad_mux);
  if(vl_status != GST_PAD_LINK_OK)
  {
    g_print ("Could not link src pad and muxer sink pad, vl_status = 
%d\n", vl_status);
    return;
  }
  gst_object_unref( pl_sinkpad_mux );


2- GstCaps *pl_caps = NULL;
    pl_caps = gst_caps_new_simple ("video/x-h263",
            NULL);
    if (!pl_caps)
    {
      g_print("could not gst_caps_new_simple\n");
      return;
    }
    //Request new video muxer sinkpad.
    pl_sinkpad_mux = gst_element_get_compatible_pad(pl_ctx->p_mux, 
srcpad, pl_caps);
    if (pl_sinkpad_mux==NULL)
    {
      g_print("Video sink pad is not available\n");
      return;
    }
    if ((gst_pad_set_caps(pl_sinkpad_mux, pl_caps)) == FALSE)
    {
      fprintf(stderr, "could not gst_pad_set_caps\n");
      return;
    }
    gst_caps_unref(pl_caps);

  vl_status = gst_pad_link (srcpad, pl_sinkpad_mux);
  if(vl_status != GST_PAD_LINK_OK)
  {
    g_print ("Could not link src pad and muxer sink pad, vl_status = 
%d\n", vl_status);
    return;
  }
  gst_object_unref( pl_sinkpad_mux );


The problem always appears when linking the second pad, no matter if it 
is the audio one or the video one.

I don't know what I'm missing :(
Any help is welcome :)

Thanks,

GG