From 1db66e5a3b7c54f015f61f4a8385a378d8d0dd36 Mon Sep 17 00:00:00 2001
From: Seungha Yang <seungha@centricular.com>
Date: Wed, 19 Oct 2022 23:03:15 +0900
Subject: [PATCH] fallbacksrc: Drop QoS event while pad is blocked

An element which creates QoS event might reference different
GstSegment timeline (e.g., fallback testsrc's one).
Then it can cause lots of buffers are being dropped in decoder,
because of the QoS events.

Drops the QoS event before we calculate appropriate pad offsets
from blocking pad probe.
---
 utils/fallbackswitch/src/fallbacksrc/imp.rs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/utils/fallbackswitch/src/fallbacksrc/imp.rs b/utils/fallbackswitch/src/fallbacksrc/imp.rs
index 3ec4f757..829d18f2 100644
--- a/utils/fallbackswitch/src/fallbacksrc/imp.rs
+++ b/utils/fallbackswitch/src/fallbacksrc/imp.rs
@@ -124,6 +124,7 @@ enum Source {
 struct Block {
     pad: gst::Pad,
     probe_id: gst::PadProbeId,
+    qos_probe_id: gst::PadProbeId,
     running_time: Option<gst::ClockTime>,
 }
 
@@ -2003,9 +2004,22 @@ impl FallbackSrc {
             )
             .unwrap();
 
+        let qos_probe_id = block_pad
+            .add_probe(gst::PadProbeType::EVENT_UPSTREAM, |_pad, info| {
+                if let Some(gst::PadProbeData::Event(ref ev)) = info.data {
+                    if let gst::EventView::Qos(_) = ev.view() {
+                        return gst::PadProbeReturn::Drop;
+                    }
+                }
+
+                gst::PadProbeReturn::Ok
+            })
+            .unwrap();
+
         Block {
             pad: block_pad.clone(),
             probe_id,
+            qos_probe_id,
             running_time: gst::ClockTime::NONE,
         }
     }
@@ -2120,6 +2134,7 @@ impl FallbackSrc {
                     fallback_source,
                 );
                 block.pad.remove_probe(block.probe_id);
+                block.pad.remove_probe(block.qos_probe_id);
             }
 
             gst::debug!(CAT, imp: self, "Live source, unblocking directly");
@@ -2337,6 +2352,7 @@ impl FallbackSrc {
                     block.pad.set_offset(offset);
                 }
                 block.pad.remove_probe(block.probe_id);
+                block.pad.remove_probe(block.qos_probe_id);
             }
 
             if let Some(block) = video_branch
@@ -2347,6 +2363,7 @@ impl FallbackSrc {
                     block.pad.set_offset(offset);
                 }
                 block.pad.remove_probe(block.probe_id);
+                block.pad.remove_probe(block.qos_probe_id);
             }
         } else if have_audio && want_audio {
             let audio_running_time = match audio_running_time {
@@ -2381,6 +2398,7 @@ impl FallbackSrc {
                     block.pad.set_offset(offset);
                 }
                 block.pad.remove_probe(block.probe_id);
+                block.pad.remove_probe(block.qos_probe_id);
             }
         } else if have_video && want_video {
             let video_running_time = match video_running_time {
@@ -2415,6 +2433,7 @@ impl FallbackSrc {
                     block.pad.set_offset(offset);
                 }
                 block.pad.remove_probe(block.probe_id);
+                block.pad.remove_probe(block.qos_probe_id);
             }
         }
     }
@@ -2905,6 +2924,7 @@ impl FallbackSrc {
                     source_srcpad.name()
                 );
                 block.pad.remove_probe(block.probe_id);
+                block.pad.remove_probe(block.qos_probe_id);
             }
             let switch_sinkpads = [state.audio_stream.as_ref(), state.video_stream.as_ref()]
                 .into_iter()