From 1ccc93df078ecea5f0928df5ef4a8513009c9a3a Mon Sep 17 00:00:00 2001
From: Mathieu Duponchelle <mathieu@centricular.com>
Date: Tue, 1 Aug 2023 00:28:52 +0200
Subject: [PATCH] webrtcsink: don't forget to setup encoders for discoveries

The "encoder-setup" signal must also be emitted for the encoders
used in discovery pipelines in order for the default settings to
be applied.

This otherwise meant that for instance the x264 encoder would
use a 60 frames latency, greatly delaying startup.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1327>
---
 net/webrtc/src/webrtcsink/imp.rs | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/net/webrtc/src/webrtcsink/imp.rs b/net/webrtc/src/webrtcsink/imp.rs
index 0681d3d0..d3e77492 100644
--- a/net/webrtc/src/webrtcsink/imp.rs
+++ b/net/webrtc/src/webrtcsink/imp.rs
@@ -2144,6 +2144,7 @@ impl WebRTCSink {
 
     async fn run_discovery_pipeline(
         element: &super::WebRTCSink,
+        stream_name: &str,
         codec: &Codec,
         caps: &gst::Caps,
     ) -> Result<gst::Structure, Error> {
@@ -2173,7 +2174,12 @@ impl WebRTCSink {
         gst::Element::link_many(elements_slice)
             .with_context(|| format!("Running discovery pipeline for caps {}", caps))?;
 
-        let (_, _, pay) = setup_encoding(&pipe.0, &capsfilter, caps, codec, None, true)?;
+        let (enc, _, pay) = setup_encoding(&pipe.0, &capsfilter, caps, codec, None, true)?;
+
+        element.emit_by_name::<bool>(
+            "encoder-setup",
+            &[&"discovery".to_string(), &stream_name, &enc],
+        );
 
         let sink = make_element("fakesink", None)?;
 
@@ -2260,7 +2266,9 @@ impl WebRTCSink {
         let futs = codecs
             .iter()
             .filter(|(_, codec)| codec.is_video() == is_video)
-            .map(|(_, codec)| WebRTCSink::run_discovery_pipeline(element, codec, &sink_caps));
+            .map(|(_, codec)| {
+                WebRTCSink::run_discovery_pipeline(element, &name, codec, &sink_caps)
+            });
 
         for ret in futures::future::join_all(futs).await {
             match ret {
@@ -2719,7 +2727,8 @@ impl ObjectImpl for WebRTCSink {
                     .build(),
                 /**
                  * RsWebRTCSink::encoder-setup:
-                 * @consumer_id: Identifier of the consumer
+                 * @consumer_id: Identifier of the consumer, or "discovery"
+                 *   when the encoder is used in a discovery pipeline.
                  * @pad_name: The name of the corresponding input pad
                  * @encoder: The constructed encoder
                  *