static gboolean
gst_avi_mux_vidsink_set_caps (GstPad * pad, GstCaps * vscaps)
{

...

    else if (!strcmp (mimetype, "video/mpeg")) {
      gint mpegversion;

      gst_structure_get_int (structure, "mpegversion", &mpegversion);

      switch (mpegversion) {
        case 2:
          avimux->vids.compression = GST_MAKE_FOURCC ('M', 'P', 'G', '2');
          break;
        case 4:
          avimux->vids.compression = GST_MAKE_FOURCC ('D', 'I', 'V', 'X');
          break;
        default:
          GST_INFO("unhandled mpegversion : %d, fall back to fourcc=MPEG",mpegversion);
          avimux->vids.compression = GST_MAKE_FOURCC ('M', 'P', 'E', 'G');
          break;
      }
...