From ba9064de9af710f1215cf8ad0c7094d190dbfade Mon Sep 17 00:00:00 2001
From: Nirbheek Chauhan <nirbheek@centricular.com>
Date: Thu, 17 Jul 2014 17:31:21 +0530
Subject: appsink: Force encodebin to create a keyframe when a client connects

This avoids long waits when, for instance, the fps is 3, since the
keyframe-max-dist is 128
---
 Makefile   |  2 +-
 src/main.c | 18 +++++++++++++++---
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index c73b121..daf90c8 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ DEBUG_CFLAGS	:= -O0 -ggdb -Wall -fsanitize=address -fno-omit-frame-pointer -DENC
 CFLAGS		:= -O0 -ggdb -Wall -fno-omit-frame-pointer -DENCODE_DEBUG
 #CFLAGS		:= -O3 -march=native -Wall
 PKGCONFIG 	:= pkg-config
-LIBS		:= $(shell $(PKGCONFIG) --libs --cflags glib-2.0 gio-unix-2.0 libsoup-2.4 gstreamer-pbutils-1.0) -lrt
+LIBS		:= $(shell $(PKGCONFIG) --libs --cflags glib-2.0 gio-unix-2.0 libsoup-2.4 gstreamer-pbutils-1.0 gstreamer-video-1.0) -lrt
 
 SERVER_NAME	:= stp-server
 SRC_OBJS	:= $(addprefix src/,debug/local-play.o lib.o encode.o)
diff --git a/src/main.c b/src/main.c
index c489f55..2d3e537 100644
--- a/src/main.c
+++ b/src/main.c
@@ -21,6 +21,7 @@
  */
 
 #include <glib-unix.h>
+#include <gst/video/video.h>
 
 #include "lib.h"
 #include "encode.h"
@@ -240,10 +241,11 @@ GET:
     /* A GET request was received. We connect from the pipeline to the
      * client requesting the stream and start writing the response. */
     GstCaps *caps = NULL;
+    GstEvent *event;
     GstBuffer *buffer;
     GstFlowReturn ret;
     GstStateChangeReturn state_change;
-    GstElement *bin, *tee, *q2, *appsink;
+    GstElement *encodebin, *bin, *tee, *q2, *appsink;
     GstPadTemplate *template;
     GstPad *srcpad, *sinkpadq2;
     TranscodeClientCtx *client_ctx;
@@ -322,7 +324,7 @@ GET:
     buffer = stp_get_streamheader_from_caps (caps);
     if (!buffer) {
       g_critical ("Unable to get streamheader from caps");
-      goto nostreamheader;
+      goto force_key_unit;
     }
 
     ret = gst_pad_push (srcpad, buffer);
@@ -332,7 +334,17 @@ GET:
       goto err;
     }
 
-nostreamheader:
+force_key_unit:
+    encodebin = gst_bin_get_by_name (GST_BIN (server_ctx->pipeline),
+                                     "encodebin");
+    event = gst_video_event_new_downstream_force_key_unit (GST_CLOCK_TIME_NONE,
+                                                           GST_CLOCK_TIME_NONE,
+                                                           GST_CLOCK_TIME_NONE,
+                                                           FALSE, 1);
+    if (!gst_element_send_event (encodebin, event))
+      g_critical ("Couldn't send upstream key unit event!");
+    gst_object_unref (encodebin);
+
     client_ctx->appsink = appsink;
 
     g_signal_connect (appsink, "new-sample",
-- 
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