Improve latency by waiting for the next keyframe

Instead of caching all the data from the previous keyframe till right now and
sending it to the client in a burst, since latency is important, we instead wait
for the next keyframe before sending buffers to the clients. This will lead to
a delay of upto 128 frames before the stream starts.

The keyframe distance and hence the delay can be tweaked by setting the
"keyframe-max-dist" property on vp8enc in src/encode.c:create_webm_profile()

1 files changed, 1 insertions, 28 deletions

diff --git a/src/encode.c b/src/encode.c
index 4054c89..5e33980 100644
--- a/src/encode.c
+++ b/src/encode.c
@@ -95,27 +95,6 @@ out:
   return;
 }
 
-static void
-update_keyframe_buffer_cb (GstElement         *fakesink,
-                           GstBuffer          *buffer,
-                           GstPad             *pad,
-                           TranscodeServerCtx *ctx)
-{
-  if (GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DECODE_ONLY) ||
-      GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_CORRUPTED) ||
-      GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_GAP) ||
-      GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DROPPABLE))
-    return;
-  
-  if (!GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DELTA_UNIT))
-    gst_buffer_list_foreach (ctx->keyframe,
-                             stp_unref_gst_buffer, NULL);
-
-  gst_buffer_ref (buffer);
-  gst_buffer_list_add (ctx->keyframe, buffer);
-  return;
-}
-
 static GstEncodingProfile *
 create_webm_profile (void)
 {
@@ -197,8 +176,7 @@ stp_encode_from_msg (TranscodeServerCtx *ctx)
 
   /* Ensure that the stream is always realtime */
   g_object_set (fakesink,
-                "sync", TRUE,
-                "signal-handoffs", TRUE, NULL);
+                "sync", TRUE, NULL);
 
   gst_bin_add_many (GST_BIN (ctx->pipeline), encodebin, tee, q1, fakesink, NULL);
   gst_element_link_many (encodebin, tee, q1, fakesink, NULL);
@@ -228,11 +206,6 @@ stp_encode_from_msg (TranscodeServerCtx *ctx)
   g_free (tmp);
 #endif
 
-  ctx->keyframe = gst_buffer_list_new ();
-
-  g_signal_connect (fakesink, "handoff",
-                    G_CALLBACK (update_keyframe_buffer_cb), ctx);
-
   /* The pads of decodebin and encodebin are dynamic,
    * so those will be linked when streams/pads are added */