libs/gst/base/gstbasesink.c: Rearrange the latency query code. We always want to...

Original commit message from CVS:
* libs/gst/base/gstbasesink.c: (gst_base_sink_query_latency),
(gst_base_sink_send_event):
Rearrange the latency query code. We always want to do the upstream
query, even if we are not live so that the upstream elements can get the
latency results too. If we fail doing the query and we are live, we
return TRUE afterwards.

diff --git a/ChangeLog b/ChangeLog
index c8ffe4eaef55f1773c76762b8abfb130ec71483b..d110a367202b666356faafefde0e77caff26eee9 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2008-04-25  Wim Taymans  <wim.taymans@collabora.co.uk>
+
+       * libs/gst/base/gstbasesink.c: (gst_base_sink_query_latency),
+       (gst_base_sink_send_event):
+       Rearrange the latency query code. We always want to do the upstream
+       query, even if we are not live so that the upstream elements can get the
+       latency results too. If we fail doing the query and we are live, we
+       return TRUE afterwards.
+
 2008-04-24  Stefan Kost  <ensonic@users.sf.net>
 
        patch by: Jason Zhao <e3423c@motorola.com>

diff --git a/libs/gst/base/gstbasesink.c b/libs/gst/base/gstbasesink.c
index 054d1bfc87af8a2b81638e443d62ee4ca700cd9f..62f6872047e51a94e2e17062dab65cd661b27d98 100644 (file)
--- a/libs/gst/base/gstbasesink.c
+++ b/libs/gst/base/gstbasesink.c
@@ -912,19 +912,16 @@ gst_base_sink_query_latency (GstBaseSink * sink, gboolean * live,
   max = -1;
   us_live = FALSE;
 
-  /* we are live */
-  if (l) {
-    if (have_latency) {
-      /* we are live and ready for a latency query */
-      query = gst_query_new_latency ();
-
-      /* ask the peer for the latency */
-      if (!(res = gst_base_sink_peer_query (sink, query)))
-        goto query_failed;
-
+  if (have_latency) {
+    GST_DEBUG_OBJECT (sink, "we are ready for LATENCY query");
+    /* we are ready for a latency query this is when we preroll or when we are
+     * not async. */
+    query = gst_query_new_latency ();
+
+    /* ask the peer for the latency */
+    if ((res = gst_base_sink_peer_query (sink, query))) {
       /* get upstream min and max latency */
       gst_query_parse_latency (query, &us_live, &us_min, &us_max);
-      gst_query_unref (query);
 
       if (us_live) {
         /* upstream live, use its latency, subclasses should use these
@@ -932,37 +929,38 @@ gst_base_sink_query_latency (GstBaseSink * sink, gboolean * live,
         min = us_min;
         max = us_max;
       }
-    } else {
-      /* we are live but are not yet ready for a latency query */
-      res = FALSE;
     }
+    gst_query_unref (query);
   } else {
-    /* not live, result is always TRUE */
-    res = TRUE;
+    GST_DEBUG_OBJECT (sink, "we are not yet ready for LATENCY query");
+    res = FALSE;
   }
 
-  GST_DEBUG_OBJECT (sink, "latency query: live: %d, have_latency %d,"
-      " upstream: %d, min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT, l,
-      have_latency, us_live, GST_TIME_ARGS (min), GST_TIME_ARGS (max));
-
-  if (live)
-    *live = l;
-  if (upstream_live)
-    *upstream_live = us_live;
-  if (min_latency)
-    *min_latency = min;
-  if (max_latency)
-    *max_latency = max;
+  /* not live, we tried to do the query, if it failed we return TRUE anyway */
+  if (!res) {
+    if (!l) {
+      res = TRUE;
+      GST_DEBUG_OBJECT (sink, "latency query failed but we are not live");
+    } else {
+      GST_DEBUG_OBJECT (sink, "latency query failed and we are live");
+    }
+  }
 
-  return res;
+  if (res) {
+    GST_DEBUG_OBJECT (sink, "latency query: live: %d, have_latency %d,"
+        " upstream: %d, min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT, l,
+        have_latency, us_live, GST_TIME_ARGS (min), GST_TIME_ARGS (max));
 
-  /* ERRORS */
-query_failed:
-  {
-    GST_DEBUG_OBJECT (sink, "latency query failed");
-    gst_query_unref (query);
-    return FALSE;
+    if (live)
+      *live = l;
+    if (upstream_live)
+      *upstream_live = us_live;
+    if (min_latency)
+      *min_latency = min;
+    if (max_latency)
+      *max_latency = max;
   }
+  return res;
 }
 
 static void
@@ -2932,13 +2930,20 @@ gst_base_sink_send_event (GstElement * element, GstEvent * event)
 
       gst_event_parse_latency (event, &latency);
 
+      /* store the latency. We use this to adjust the running_time before syncing
+       * it to the clock. */
       GST_OBJECT_LOCK (element);
       basesink->priv->latency = latency;
       GST_OBJECT_UNLOCK (element);
       GST_DEBUG_OBJECT (basesink, "latency set to %" GST_TIME_FORMAT,
           GST_TIME_ARGS (latency));
 
-      /* don't forward, yet */
+      /* don't forward, yet. FIXME. The latency event should likely be forwarded
+       * to upstream element so that they can configure themselves. Each element
+       * would subtract the amount of LATENCY it can maximally compensate for. 
+       * It's currently not very useful; even if this sink cannot compensate for
+       * all the latency, upstream will block while this sink waits which will
+       * trigger implicit buffering and latency there. */
       forward = FALSE;
       break;
     }