baseparse: fix reverse playback with upstream demuxers that support it

Don't just return FALSE for seek events with negative rates when
operating in push mode. An upstream demuxer may support this just
fine, so if we're not operating in pull mode always check upstream
first if it can handle the seek event. This fixes reverse playback
where the upstream demuxer supports it (e.g. with qtdemux). The
same code would work fine in 0.10, because baseparse will just
call the default pad event handler if FALSE was returned from the
baseparse event handler, and the pad event handler will just
forward it upstream. In 0.11 the baseclass or subclass is
responsible for chaining up to the parent class or forwarding the
event upstream in any case.

Disable reverse playback in pull mode for now, there seems to
be something going wrong with the segment configuration in that
case.

diff --git a/libs/gst/base/gstbaseparse.c b/libs/gst/base/gstbaseparse.c
index 102ca72..5f4118f 100644 (file)
--- a/libs/gst/base/gstbaseparse.c
+++ b/libs/gst/base/gstbaseparse.c
@@ -3747,6 +3747,13 @@ gst_base_parse_handle_seek (GstBaseParse * parse, GstEvent * event)
   GstSegment seeksegment = { 0, };
   GstClockTime start_ts;
 
+  /* try upstream first, unless we're driving the streaming thread ourselves */
+  if (parse->priv->pad_mode != GST_PAD_MODE_PULL) {
+    res = gst_pad_push_event (parse->sinkpad, gst_event_ref (event));
+    if (res)
+      goto done;
+  }
+
   gst_event_parse_seek (event, &rate, &format, &flags,
       &start_type, &start, &stop_type, &stop);
 
@@ -3755,16 +3762,17 @@ gst_base_parse_handle_seek (GstBaseParse * parse, GstEvent * event)
       GST_TIME_FORMAT, gst_format_get_name (format), rate,
       start_type, GST_TIME_ARGS (start), stop_type, GST_TIME_ARGS (stop));
 
-  /* no negative rates in push mode */
+  /* we can only handle TIME */
+  if (format != GST_FORMAT_TIME)
+    goto done;
+
+  /* no negative rates in push mode (unless upstream takes care of that, but
+   * we've already tried upstream and it didn't handle the seek request) */
   if (rate < 0.0 && parse->priv->pad_mode == GST_PAD_MODE_PUSH)
     goto negative_rate;
 
-  /* For any format other than TIME, see if upstream handles
-   * it directly or fail. For TIME, try upstream, but do it ourselves if
-   * it fails upstream */
-  res = gst_pad_push_event (parse->sinkpad, event);
-  if (format != GST_FORMAT_TIME || res)
-    goto done;
+  if (rate < 0.0 && parse->priv->pad_mode == GST_PAD_MODE_PULL)
+    goto negative_rate_pull_mode;
 
   if (start_type != GST_SEEK_TYPE_SET ||
       (stop_type != GST_SEEK_TYPE_SET && stop_type != GST_SEEK_TYPE_NONE))
@@ -3955,9 +3963,16 @@ gst_base_parse_handle_seek (GstBaseParse * parse, GstEvent * event)
   }
 
 done:
+  gst_event_unref (event);
   return res;
 
   /* ERRORS */
+negative_rate_pull_mode:
+  {
+    GST_FIXME_OBJECT (parse, "negative playback in pull mode needs fixing");
+    res = FALSE;
+    goto done;
+  }
 negative_rate:
   {
     GST_DEBUG_OBJECT (parse, "negative playback rates delegated upstream.");