Implemented ForceKeyFrame for openh264 encoder (#319)

pkg/codec/openh264/bridge.cpp

@@ -80,6 +80,11 @@ Slice enc_encode(Encoder *e, Frame f, int *eresult) {
   SFrameBSInfo info = {0};
   Slice payload = {0};
 
+  if(e->force_key_frame == 1) {
+    info.eFrameType = videoFrameTypeI;
+    e->force_key_frame = 0;
+  }
+
   pic.iPicWidth = f.width;
   pic.iPicHeight = f.height;
   pic.iColorFormat = videoFormatI420;

pkg/codec/openh264/bridge.hpp

@@ -27,6 +27,7 @@ typedef struct Encoder {
   ISVCEncoder *engine;
   unsigned char *buff;
   int buff_size;
+  int force_key_frame;
 } Encoder;
 
 Encoder *enc_new(const EncoderOptions params, int *eresult);

pkg/codec/openh264/openh264.go

@@ -84,7 +84,8 @@ func (e *encoder) SetBitRate(b int) error {
 }
 
 func (e *encoder) ForceKeyFrame() error {
-	panic("ForceKeyFrame is not implemented")
+	e.engine.force_key_frame = C.int(1)
+	return nil
 }
 
 func (e *encoder) Close() error {