--sout-udp-rtcp option to force RTCP usage.

(Currently RTCP only Sender Reports are implemented.)

RTCP is auto-enabled for RTP/TS but this could be used by the RTP stream
output plugin to enable RTCP too (in that case, RTP encapsulation is done
in the stream output plugin, so the access output cannot know if it should
do RTCP or not).

modules/access_output/udp.c

@@ -102,6 +102,9 @@ static void Close( vlc_object_t * );
                        "directly, without trying to fill the MTU (ie, " \
                        "without trying to make the biggest possible packets " \
                        "in order to improve streaming)." )
+#define RTCP_TEXT N_("Force RTCP Sender Reports")
+#define RTCP_LONGTEXT N_("Sends RTCP Sender Report packets even if " \
+                         "RTP encapsulation is not done")
 #define AUTO_MCAST_TEXT N_("Automatic multicast streaming")
 #define AUTO_MCAST_LONGTEXT N_("Allocates an outbound multicast address " \
                                "automatically.")
@@ -119,11 +122,13 @@ vlc_module_begin();
     add_integer( SOUT_CFG_PREFIX "group", 1, NULL, GROUP_TEXT, GROUP_LONGTEXT,
                                  VLC_TRUE );
     add_suppressed_integer( SOUT_CFG_PREFIX "late" );
-    add_bool( SOUT_CFG_PREFIX "raw",  0, NULL, RAW_TEXT, RAW_LONGTEXT,
+    add_bool( SOUT_CFG_PREFIX "raw",  VLC_FALSE, NULL, RAW_TEXT, RAW_LONGTEXT,
                                  VLC_TRUE );
-    add_bool( SOUT_CFG_PREFIX "auto-mcast", 0, NULL, AUTO_MCAST_TEXT,
+    add_bool( SOUT_CFG_PREFIX "rtcp",  VLC_FALSE, NULL, RTCP_TEXT, RTCP_LONGTEXT,
+              VLC_TRUE );
+    add_bool( SOUT_CFG_PREFIX "auto-mcast", VLC_FALSE, NULL, AUTO_MCAST_TEXT,
               AUTO_MCAST_LONGTEXT, VLC_TRUE );
-    add_bool( SOUT_CFG_PREFIX "udplite", 0, NULL, UDPLITE_TEXT, UDPLITE_LONGTEXT, VLC_TRUE );
+    add_bool( SOUT_CFG_PREFIX "udplite", VLC_FALSE, NULL, UDPLITE_TEXT, UDPLITE_LONGTEXT, VLC_TRUE );
     add_integer( SOUT_CFG_PREFIX "cscov", 12, NULL, CSCOV_TEXT, CSCOV_LONGTEXT, VLC_TRUE );
 
     set_capability( "sout access", 100 );
@@ -141,6 +146,7 @@ static const char *ppsz_sout_options[] = {
     "caching",
     "group",
     "raw",
+    "rtcp",
     "lite",
     "cscov",
     NULL
@@ -190,7 +196,7 @@ struct sout_access_out_sys_t
 {
     int                 i_mtu;
 
-    vlc_bool_t          b_rtpts;  // 1 if add rtp/ts header
+    vlc_bool_t          b_rtpts; // true for RTP/MP2 encapsulation
     vlc_bool_t          b_mtu_warning;
     uint16_t            i_sequence_number;
     uint32_t            i_ssrc;
@@ -223,6 +229,7 @@ static int Open( vlc_object_t *p_this )
     int                 i_handle;
 
     vlc_value_t         val;
+    vlc_bool_t          b_rtcp = VLC_FALSE;
 
     config_ChainParse( p_access, SOUT_CFG_PREFIX,
                        ppsz_sout_options, p_access->p_cfg );
@@ -247,7 +254,11 @@ static int Open( vlc_object_t *p_this )
     if( p_access->psz_access != NULL )
     {
         if (strcmp (p_access->psz_access, "rtp") == 0)
-            p_sys->b_rtpts = VLC_TRUE;
+            p_sys->b_rtpts = b_rtcp = VLC_TRUE;
+        else
+            /* This option is really only meant for the RTP streaming output
+             * plugin. Doing RTCP for raw UDP will yield weird results. */
+            b_rtcp = var_GetBool (p_access, SOUT_CFG_PREFIX"rtcp");
     }
 
     if (var_GetBool (p_access, SOUT_CFG_PREFIX"lite"))
@@ -366,7 +377,7 @@ static int Open( vlc_object_t *p_this )
     p_sys->i_sequence_number = rand()&0xffff;
     p_sys->i_ssrc            = rand()&0xffffffff;
 
-    if (p_sys->b_rtpts && OpenRTCP (p_access, proto))
+    if (b_rtcp && OpenRTCP (p_access, proto))
     {
         msg_Err (p_access, "cannot initialize RTCP sender");
         net_Close (i_handle);
@@ -819,6 +830,9 @@ static int OpenRTCP (sout_access_out_t *obj, int proto)
 
 static void CloseRTCP (sout_access_thread_t *obj)
 {
+    if (obj->rtcp_handle == -1)
+        return;
+
     uint8_t *ptr = obj->rtcp_data;
     /* Bye */
     ptr[0] = (2 << 6) | 1; /* V = 2, P = 0, SC = 1 */
@@ -829,9 +843,7 @@ static void CloseRTCP (sout_access_thread_t *obj)
     /* We are THE sender, so we are more important than anybody else, so
      * we can afford not to check bandwidth constraints here. */
     send (obj->rtcp_handle, obj->rtcp_data, 8, 0);
-
-    if (obj->rtcp_handle != -1)
-        net_Close (obj->rtcp_handle);
+    net_Close (obj->rtcp_handle);
 }
 
 static void SendRTCP (sout_access_thread_t *obj, uint32_t timestamp)