shm-stream-transmitter: Add property to control the buffer-time

Allow the transmitter to buffer how much can be maximally queued in the
shmsink before blocking. Default to 20 miliseconds.

For audio network packets tend to be around 20ms is size, so 20ms is a
suitable size for audio.

For video, 20 miliseconds is less then one frame at 30 fps, so with 20ms
as default at most one video frame will be queued up in the shm sink.

3 files changed, 32 insertions, 2 deletions

diff --git a/transmitters/shm/fs-shm-stream-transmitter.c b/transmitters/shm/fs-shm-stream-transmitter.c
index 23c45f26..45682584 100644
--- a/transmitters/shm/fs-shm-stream-transmitter.c
+++ b/transmitters/shm/fs-shm-stream-transmitter.c
@@ -98,6 +98,7 @@ enum
   PROP_SENDING,
   PROP_PREFERRED_LOCAL_CANDIDATES,
   PROP_CREATE_LOCAL_CANDIDATES,
+  PROP_BUFFER_TIME,
 };
 
 struct _FsShmStreamTransmitterPrivate
@@ -127,6 +128,8 @@ struct _FsShmStreamTransmitterPrivate
 
   ShmSrc **shm_src;
   ShmSink **shm_sink;
+
+  guint64 buffer_time;
 };
 
 #define FS_SHM_STREAM_TRANSMITTER_GET_PRIVATE(o)  \
@@ -227,6 +230,12 @@ fs_shm_stream_transmitter_class_init (FsShmStreamTransmitterClass *klass)
     PROP_CREATE_LOCAL_CANDIDATES,
     pspec);
 
+  pspec = g_param_spec_uint64 ("buffer-time",
+    "BufferTime",
+    "Maximum Size of the outgoing buffer in nanoseconds",
+    0, G_MAXUINT64, 20 * GST_MSECOND,
+    G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS);
+  g_object_class_install_property (gobject_class, PROP_BUFFER_TIME, pspec);
 
   gobject_class->dispose = fs_shm_stream_transmitter_dispose;
   gobject_class->finalize = fs_shm_stream_transmitter_finalize;
@@ -309,6 +318,9 @@ fs_shm_stream_transmitter_get_property (GObject *object,
     case PROP_CREATE_LOCAL_CANDIDATES:
       g_value_set_boolean (value, self->priv->create_local_candidates);
       break;
+    case PROP_BUFFER_TIME:
+      g_value_set_uint64 (value, self->priv->buffer_time);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -344,6 +356,9 @@ fs_shm_stream_transmitter_set_property (GObject *object,
     case PROP_CREATE_LOCAL_CANDIDATES:
       self->priv->create_local_candidates = g_value_get_boolean (value);
       break;
+    case PROP_BUFFER_TIME:
+      self->priv->buffer_time = g_value_get_uint64 (value);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -414,7 +429,8 @@ fs_shm_stream_transmitter_add_sink (FsShmStreamTransmitter *self,
 
   self->priv->shm_sink[candidate->component_id] =
     fs_shm_transmitter_get_shm_sink (self->priv->transmitter,
-        candidate->component_id, candidate->ip, ready_cb, connected_cb,
+        candidate->component_id, candidate->ip, self->priv->buffer_time,
+        ready_cb, connected_cb,
         self, error);
 
   if (self->priv->shm_sink[candidate->component_id] == NULL)
@@ -571,7 +587,8 @@ fs_shm_stream_transmitter_gather_local_candidates (
 
       self->priv->shm_sink[c] =
         fs_shm_transmitter_get_shm_sink (self->priv->transmitter,
-          c, path, ready_cb, connected_cb, self, error);
+          c, path, self->priv->buffer_time,
+          ready_cb, connected_cb, self, error);
       g_free (path);
 
       if (self->priv->shm_sink[c] == NULL)
diff --git a/transmitters/shm/fs-shm-transmitter.c b/transmitters/shm/fs-shm-transmitter.c
index 5bd049f6..e0b11062 100644
--- a/transmitters/shm/fs-shm-transmitter.c
+++ b/transmitters/shm/fs-shm-transmitter.c
@@ -732,6 +732,7 @@ ShmSink *
 fs_shm_transmitter_get_shm_sink (FsShmTransmitter *self,
     guint component,
     const gchar *path,
+    guint64 buffer_time,
     ready ready_func,
     connection connected_func,
     gpointer cb_data,
@@ -767,6 +768,17 @@ fs_shm_transmitter_get_shm_sink (FsShmTransmitter *self,
       "sync" , FALSE,
       NULL);
 
+  if (g_object_class_find_property (G_OBJECT_GET_CLASS (elem), "buffer-time"))
+  {
+    GST_DEBUG ("Configured shmsink with a %"G_GUINT64_FORMAT" buffer-time",
+      buffer_time);
+    g_object_set (elem, "buffer-time", buffer_time, NULL);
+  }
+  else
+  {
+    GST_DEBUG ("No buffer-time property in shmsink, not setting");
+  }
+
   if (ready_func)
     g_signal_connect (self->priv->gst_sink, "ready", G_CALLBACK (ready_cb),
         shm);
diff --git a/transmitters/shm/fs-shm-transmitter.h b/transmitters/shm/fs-shm-transmitter.h
index 978c3049..9fccb391 100644
--- a/transmitters/shm/fs-shm-transmitter.h
+++ b/transmitters/shm/fs-shm-transmitter.h
@@ -106,6 +106,7 @@ gboolean fs_shm_transmitter_check_shm_src (FsShmTransmitter *self,
 ShmSink *fs_shm_transmitter_get_shm_sink (FsShmTransmitter *self,
     guint component,
     const gchar *path,
+    guint64 buffer_time,
     ready ready_func,
     connection connected_fubnc,
     gpointer cb_data,