ext/dv/gstdvdemux.c: Add srcpads only when needed and remove them again when going back to READY. This prevents stall...

Original commit message from CVS:
* ext/dv/gstdvdemux.c: (gst_dvdemux_add_video_pad),
(gst_dvdemux_add_audio_pad), (gst_dvdemux_remove_pads),
(gst_dvdemux_demux_audio), (gst_dvdemux_demux_video),
(gst_dvdemux_chain), (gst_dvdemux_loop),
(gst_dvdemux_change_state):
Add srcpads only when needed and remove them again when going
back to READY. This prevents stalled pipelines if there's no
audio inside the DV stream, which happens for many MXF files.

ChangeLog

@@ -1,3 +1,14 @@
+2008-12-09  Sebastian Dröge  <sebastian.droege@collabora.co.uk>
+
+	* ext/dv/gstdvdemux.c: (gst_dvdemux_add_video_pad),
+	(gst_dvdemux_add_audio_pad), (gst_dvdemux_remove_pads),
+	(gst_dvdemux_demux_audio), (gst_dvdemux_demux_video),
+	(gst_dvdemux_chain), (gst_dvdemux_loop),
+	(gst_dvdemux_change_state):
+	Add srcpads only when needed and remove them again when going
+	back to READY. This prevents stalled pipelines if there's no
+	audio inside the DV stream, which happens for many MXF files.
+
 2008-12-09  Sebastian Dröge  <sebastian.droege@collabora.co.uk>
 
 	* tests/check/elements/souphttpsrc.c: (GST_START_TEST),

ext/dv/gstdvdemux.c

@@ -292,8 +292,11 @@ gst_dvdemux_reset (GstDVDemux * dvdemux)
 }
 
 static void
-gst_dvdemux_add_pads (GstDVDemux * dvdemux)
+gst_dvdemux_add_video_pad (GstDVDemux * dvdemux)
 {
+  if (dvdemux->videosrcpad)
+    return;
+
   dvdemux->videosrcpad =
       gst_pad_new_from_static_template (&video_src_temp, "video");
   gst_pad_set_query_function (dvdemux->videosrcpad,
@@ -306,6 +309,21 @@ gst_dvdemux_add_pads (GstDVDemux * dvdemux)
   gst_pad_set_active (dvdemux->videosrcpad, TRUE);
   gst_element_add_pad (GST_ELEMENT (dvdemux), dvdemux->videosrcpad);
 
+  if (dvdemux->videosrcpad && dvdemux->audiosrcpad)
+    gst_element_no_more_pads (GST_ELEMENT (dvdemux));
+
+  gst_pad_push_event (dvdemux->videosrcpad, gst_event_new_new_segment (FALSE,
+          dvdemux->byte_segment.rate, GST_FORMAT_TIME,
+          dvdemux->time_segment.start, dvdemux->time_segment.stop,
+          dvdemux->time_segment.start));
+}
+
+static void
+gst_dvdemux_add_audio_pad (GstDVDemux * dvdemux)
+{
+  if (dvdemux->audiosrcpad)
+    return;
+
   dvdemux->audiosrcpad =
       gst_pad_new_from_static_template (&audio_src_temp, "audio");
   gst_pad_set_query_function (dvdemux->audiosrcpad,
@@ -318,7 +336,26 @@ gst_dvdemux_add_pads (GstDVDemux * dvdemux)
   gst_pad_set_active (dvdemux->audiosrcpad, TRUE);
   gst_element_add_pad (GST_ELEMENT (dvdemux), dvdemux->audiosrcpad);
 
+  if (dvdemux->videosrcpad && dvdemux->audiosrcpad)
     gst_element_no_more_pads (GST_ELEMENT (dvdemux));
+
+  gst_pad_push_event (dvdemux->audiosrcpad, gst_event_new_new_segment (FALSE,
+          dvdemux->byte_segment.rate, GST_FORMAT_TIME,
+          dvdemux->time_segment.start, dvdemux->time_segment.stop,
+          dvdemux->time_segment.start));
+}
+
+static void
+gst_dvdemux_remove_pads (GstDVDemux * dvdemux)
+{
+  if (dvdemux->videosrcpad) {
+    gst_element_remove_pad (GST_ELEMENT (dvdemux), dvdemux->videosrcpad);
+    dvdemux->videosrcpad = NULL;
+  }
+  if (dvdemux->audiosrcpad) {
+    gst_element_remove_pad (GST_ELEMENT (dvdemux), dvdemux->audiosrcpad);
+    dvdemux->audiosrcpad = NULL;
+  }
 }
 
 static gboolean
@@ -1186,40 +1223,18 @@ gst_dvdemux_demux_audio (GstDVDemux * dvdemux, GstBuffer * buffer,
     guint64 duration)
 {
   gint num_samples;
-  gint frequency, channels;
   GstFlowReturn ret;
   const guint8 *data;
 
-  frequency = dv_get_frequency (dvdemux->decoder);
-  channels = dv_get_num_channels (dvdemux->decoder);
-
   data = GST_BUFFER_DATA (buffer);
 
-  /* check if format changed */
-  if ((frequency != dvdemux->frequency) || (channels != dvdemux->channels)) {
-    GstCaps *caps;
-
-    dvdemux->frequency = frequency;
-    dvdemux->channels = channels;
-
-    /* and set new caps */
-    caps = gst_caps_new_simple ("audio/x-raw-int",
-        "rate", G_TYPE_INT, frequency,
-        "depth", G_TYPE_INT, 16,
-        "width", G_TYPE_INT, 16,
-        "signed", G_TYPE_BOOLEAN, TRUE,
-        "channels", G_TYPE_INT, channels,
-        "endianness", G_TYPE_INT, G_BYTE_ORDER, NULL);
-    gst_pad_set_caps (dvdemux->audiosrcpad, caps);
-    gst_caps_unref (caps);
-  }
-
   dv_decode_full_audio (dvdemux->decoder, data, dvdemux->audio_buffers);
 
   if ((num_samples = dv_get_num_samples (dvdemux->decoder)) > 0) {
     gint16 *a_ptr;
     gint i, j;
     GstBuffer *outbuf;
+    gint frequency, channels;
 
     outbuf = gst_buffer_new_and_alloc (num_samples *
         sizeof (gint16) * dvdemux->channels);
@@ -1241,6 +1256,31 @@ gst_dvdemux_demux_audio (GstDVDemux * dvdemux, GstBuffer * buffer,
     dvdemux->audio_offset += num_samples;
     GST_BUFFER_OFFSET_END (outbuf) = dvdemux->audio_offset;
 
+    if (!dvdemux->audiosrcpad)
+      gst_dvdemux_add_audio_pad (dvdemux);
+
+    /* check if format changed */
+    frequency = dv_get_frequency (dvdemux->decoder);
+    channels = dv_get_num_channels (dvdemux->decoder);
+
+    if ((frequency != dvdemux->frequency) || (channels != dvdemux->channels)) {
+      GstCaps *caps;
+
+      dvdemux->frequency = frequency;
+      dvdemux->channels = channels;
+
+      /* and set new caps */
+      caps = gst_caps_new_simple ("audio/x-raw-int",
+          "rate", G_TYPE_INT, frequency,
+          "depth", G_TYPE_INT, 16,
+          "width", G_TYPE_INT, 16,
+          "signed", G_TYPE_BOOLEAN, TRUE,
+          "channels", G_TYPE_INT, channels,
+          "endianness", G_TYPE_INT, G_BYTE_ORDER, NULL);
+      gst_pad_set_caps (dvdemux->audiosrcpad, caps);
+      gst_caps_unref (caps);
+    }
+
     gst_buffer_set_caps (outbuf, GST_PAD_CAPS (dvdemux->audiosrcpad));
 
     ret = gst_pad_push (dvdemux->audiosrcpad, outbuf);
@@ -1262,6 +1302,9 @@ gst_dvdemux_demux_video (GstDVDemux * dvdemux, GstBuffer * buffer,
   gboolean wide;
   GstFlowReturn ret = GST_FLOW_OK;
 
+  if (!dvdemux->videosrcpad)
+    gst_dvdemux_add_video_pad (dvdemux);
+
   /* get params */
   /* framerate is already up-to-date */
   height = (dvdemux->PAL ? PAL_HEIGHT : NTSC_HEIGHT);
@@ -1511,10 +1554,6 @@ gst_dvdemux_chain (GstPad * pad, GstBuffer * buffer)
     /* FIXME, adjust frame_offset and other counters */
   }
 
-  /* temporary hack? Can't do this from the state change */
-  if (G_UNLIKELY (!dvdemux->videosrcpad))
-    gst_dvdemux_add_pads (dvdemux);
-
   gst_adapter_push (dvdemux->adapter, buffer);
 
   /* Apparently dv_parse_header can read from the body of the frame
@@ -1551,10 +1590,6 @@ gst_dvdemux_loop (GstPad * pad)
   dvdemux = GST_DVDEMUX (gst_pad_get_parent (pad));
 
   if (G_UNLIKELY (g_atomic_int_get (&dvdemux->found_header) == 0)) {
-    /* add pads.. why is this again? */
-    if (!dvdemux->videosrcpad)
-      gst_dvdemux_add_pads (dvdemux);
-
     GST_DEBUG_OBJECT (dvdemux, "pulling first buffer");
     /* pull in NTSC sized buffer to figure out the frame
      * length */
@@ -1785,6 +1820,8 @@ gst_dvdemux_change_state (GstElement * element, GstStateChange transition)
       gst_adapter_clear (dvdemux->adapter);
       dv_decoder_free (dvdemux->decoder);
       dvdemux->decoder = NULL;
+
+      gst_dvdemux_remove_pads (dvdemux);
       break;
     case GST_STATE_CHANGE_READY_TO_NULL:
     {