fallbackswitch: only drop MISSING_DATA gap events pre queue

Regular gap events can be output by sources such as cefsrc in
normal operation, and should not trigger an active pad change.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/538>

2 files changed, 9 insertions, 3 deletions

diff --git a/utils/fallbackswitch/Cargo.toml b/utils/fallbackswitch/Cargo.toml
index e196afd00..b936090e1 100644
--- a/utils/fallbackswitch/Cargo.toml
+++ b/utils/fallbackswitch/Cargo.toml
@@ -39,6 +39,7 @@ pkg-config = "0.3"
 [features]
 default = ["libc"]
 v1_18 = ["gst-base/v1_18"]
+v1_20 = ["v1_18", "gst/v1_20"]
 # We already use 1.14 which is new enough for static build
 static = []
 
diff --git a/utils/fallbackswitch/src/fallbackswitch/imp.rs b/utils/fallbackswitch/src/fallbackswitch/imp.rs
index 8b059890d..618c2a506 100644
--- a/utils/fallbackswitch/src/fallbackswitch/imp.rs
+++ b/utils/fallbackswitch/src/fallbackswitch/imp.rs
@@ -963,6 +963,7 @@ impl AggregatorImpl for FallbackSwitch {
         Ok(())
     }
 
+    #[cfg(feature = "v1_20")]
     fn sink_event_pre_queue(
         &self,
         agg: &Self::Type,
@@ -972,9 +973,13 @@ impl AggregatorImpl for FallbackSwitch {
         use gst::EventView;
 
         match event.view() {
-            EventView::Gap(_) => {
-                gst_debug!(CAT, obj: agg_pad, "Dropping gap event");
-                Ok(gst::FlowSuccess::Ok)
+            EventView::Gap(gap) => {
+                if gap.gap_flags().contains(gst::GapFlags::DATA) {
+                    gst_debug!(CAT, obj: agg_pad, "Dropping gap event");
+                    Ok(gst::FlowSuccess::Ok)
+                } else {
+                    self.parent_sink_event_pre_queue(agg, agg_pad, event)
+                }
             }
             _ => self.parent_sink_event_pre_queue(agg, agg_pad, event),
         }