From bfabee12e202edc6c85c949b7075c6e922ca33b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miroslav=20=C5=A0ediv=C3=BD?= <sedivy.miro@gmail.com>
Date: Tue, 7 Feb 2023 21:43:14 +0100
Subject: [PATCH] gst emit video keyframe on demand. (#27)

---
 pkg/gst/gst.c  | 12 ++++++++++++
 pkg/gst/gst.go |  9 ++++++++-
 pkg/gst/gst.h  |  2 ++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/pkg/gst/gst.c b/pkg/gst/gst.c
index e538f5d1..86e97dce 100644
--- a/pkg/gst/gst.c
+++ b/pkg/gst/gst.c
@@ -200,3 +200,15 @@ gboolean gstreamer_pipeline_set_caps_resolution(GstPipelineCtx *ctx, const gchar
   gst_object_unref(el);
   return TRUE;
 }
+
+gboolean gstreamer_pipeline_emit_video_keyframe(GstPipelineCtx *ctx) {
+	GstClock *clock = gst_pipeline_get_clock(GST_PIPELINE(ctx->pipeline));
+	gst_object_ref(clock);
+
+	GstClockTime time = gst_clock_get_time(clock);
+	GstClockTime now = time - gst_element_get_base_time(ctx->pipeline);
+	gst_object_unref(clock);
+
+	GstEvent *keyFrameEvent = gst_video_event_new_downstream_force_key_unit(now, time, now, TRUE, 0);
+	return gst_element_send_event(GST_ELEMENT(ctx->pipeline), keyFrameEvent);
+}
diff --git a/pkg/gst/gst.go b/pkg/gst/gst.go
index 3a9e686a..14bdc6dd 100644
--- a/pkg/gst/gst.go
+++ b/pkg/gst/gst.go
@@ -1,7 +1,7 @@
 package gst
 
 /*
-#cgo pkg-config: gstreamer-1.0 gstreamer-app-1.0
+#cgo pkg-config: gstreamer-1.0 gstreamer-app-1.0 gstreamer-video-1.0
 
 #include "gst.h"
 */
@@ -46,6 +46,8 @@ type Pipeline interface {
 	SetPropInt(binName string, prop string, value int) bool
 	SetCapsFramerate(binName string, numerator, denominator int) bool
 	SetCapsResolution(binName string, width, height int) bool
+	// emit video keyframe
+	EmitVideoKeyframe() bool
 }
 
 type pipeline struct {
@@ -177,6 +179,11 @@ func (p *pipeline) SetCapsResolution(binName string, width, height int) bool {
 	return ok == C.TRUE
 }
 
+func (p *pipeline) EmitVideoKeyframe() bool {
+	ok := C.gstreamer_pipeline_emit_video_keyframe(p.ctx)
+	return ok == C.TRUE
+}
+
 // gst-inspect-1.0
 func CheckPlugins(plugins []string) error {
 	var plugin *C.GstPlugin
diff --git a/pkg/gst/gst.h b/pkg/gst/gst.h
index a562ec34..619170e7 100644
--- a/pkg/gst/gst.h
+++ b/pkg/gst/gst.h
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <gst/gst.h>
 #include <gst/app/gstappsrc.h>
+#include <gst/video/video.h>
 
 typedef struct GstPipelineCtx {
   int pipelineId;
@@ -25,3 +26,4 @@ void gstreamer_pipeline_push(GstPipelineCtx *ctx, void *buffer, int bufferLen);
 gboolean gstreamer_pipeline_set_prop_int(GstPipelineCtx *ctx, char *binName, char *prop, gint value);
 gboolean gstreamer_pipeline_set_caps_framerate(GstPipelineCtx *ctx, const gchar* binName, gint numerator, gint denominator);
 gboolean gstreamer_pipeline_set_caps_resolution(GstPipelineCtx *ctx, const gchar* binName, gint width, gint height);
+gboolean gstreamer_pipeline_emit_video_keyframe(GstPipelineCtx *ctx);