ffenc: Make keyframe forcing thread-safe

Make the keyframe forcing thread-safe, also emit a downstream event
to allow muxers or payloaders to react appropriately.

https://bugzilla.gnome.org/show_bug.cgi?id=602556

2 files changed, 29 insertions, 2 deletions

diff --git a/ext/ffmpeg/gstffmpegenc.c b/ext/ffmpeg/gstffmpegenc.c
index d9ceb49..fd0f205 100644
--- a/ext/ffmpeg/gstffmpegenc.c
+++ b/ext/ffmpeg/gstffmpegenc.c
@@ -686,11 +686,20 @@ gst_ffmpegenc_chain_video (GstPad * pad, GstBuffer * inbuf)
   GstFFMpegEnc *ffmpegenc = (GstFFMpegEnc *) (GST_PAD_PARENT (pad));
   GstBuffer *outbuf;
   gint ret_size = 0, frame_size;
+  gboolean force_keyframe;
 
   GST_DEBUG_OBJECT (ffmpegenc,
       "Received buffer of time %" GST_TIME_FORMAT,
       GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (inbuf)));
 
+  GST_OBJECT_LOCK (ffmpegenc);
+  force_keyframe = ffmpegenc->force_keyframe;
+  ffmpegenc->force_keyframe = FALSE;
+  GST_OBJECT_UNLOCK (ffmpegenc);
+
+  if (force_keyframe)
+    ffmpegenc->picture->pict_type = FF_I_TYPE;
+
   frame_size = gst_ffmpeg_avpicture_fill ((AVPicture *) ffmpegenc->picture,
       GST_BUFFER_DATA (inbuf),
       ffmpegenc->context->pix_fmt,
@@ -751,6 +760,14 @@ gst_ffmpegenc_chain_video (GstPad * pad, GstBuffer * inbuf)
   if (ffmpegenc->picture->pict_type)
     ffmpegenc->picture->pict_type = 0;
 
+  if (force_keyframe) {
+    gst_pad_push_event (ffmpegenc->srcpad,
+        gst_event_new_custom (GST_EVENT_CUSTOM_DOWNSTREAM,
+            gst_structure_new ("GstForceKeyUnit",
+                "timestamp", G_TYPE_UINT64, GST_BUFFER_TIMESTAMP (outbuf),
+                NULL)));
+  }
+
   return gst_pad_push (ffmpegenc->srcpad, outbuf);
 }
 
@@ -1028,13 +1045,18 @@ static gboolean
 gst_ffmpegenc_event_src (GstPad * pad, GstEvent * event)
 {
   GstFFMpegEnc *ffmpegenc = (GstFFMpegEnc *) (GST_PAD_PARENT (pad));
+  gboolean forward = TRUE;
 
   switch (GST_EVENT_TYPE (event)) {
     case GST_EVENT_CUSTOM_UPSTREAM:{
       const GstStructure *s;
       s = gst_event_get_structure (event);
       if (gst_structure_has_name (s, "GstForceKeyUnit")) {
-        ffmpegenc->picture->pict_type = FF_I_TYPE;
+        GST_OBJECT_LOCK (ffmpegenc);
+        ffmpegenc->force_keyframe = TRUE;
+        GST_OBJECT_UNLOCK (ffmpegenc);
+        forward = FALSE;
+        gst_event_unref (event);
       }
       break;
     }
@@ -1043,7 +1065,10 @@ gst_ffmpegenc_event_src (GstPad * pad, GstEvent * event)
       break;
   }
 
-  return gst_pad_push_event (ffmpegenc->sinkpad, event);
+  if (forward)
+    return gst_pad_push_event (ffmpegenc->sinkpad, event);
+  else
+    return TRUE;
 }
 
 static void
diff --git a/ext/ffmpeg/gstffmpegenc.h b/ext/ffmpeg/gstffmpegenc.h
index 3e4a6b1..c13a0d3 100644
--- a/ext/ffmpeg/gstffmpegenc.h
+++ b/ext/ffmpeg/gstffmpegenc.h
@@ -74,6 +74,8 @@ struct _GstFFMpegEnc
   /* other settings are copied over straight,
    * include a context here, rather than copy-and-past it from avcodec.h */
   AVCodecContext config;
+
+  gboolean force_keyframe;
 };
 
 typedef struct _GstFFMpegEncClass GstFFMpegEncClass;