Add placeholder feature to bridge module ("No Signal" anyone?)

This commit allows using the bridge-out and bridge-in module to
configure a placeholder stream. This placeholder stream replaces the
input stream if it dies for more than place-holder ms.

Example configuration:
 # The input
 new test broadcast enabled
 setup test input /home/antoine/media/wall-e/Sample.avi
 setup test output #duplicate{dst=bridge-out,select=video,dst=bridge-out,select=audio}

 # The placeholder
 new master broadcast enabled
 setup master input /home/antoine/media/wall-e/wall-e.avi
 setup master output #bridge-in{placeholder,placeholder-delay=5000}:display

 # control test play
 control master play

Placeholder and input should have the same format (aspect ratio, dimension,
codec, ...). Connect to VLC's telnet interface and issue some
"control test play" and "control test stop" commands to simulate input loss.
The placeholder stream should kick in after 5000 ms (5 s) of input loss.

modules/stream_out/bridge.c

 /*****************************************************************************
  * bridge.c: bridge stream output module
  *****************************************************************************
- * Copyright (C) 2005 the VideoLAN team
+ * Copyright (C) 2005-2008 the VideoLAN team
  * $Id$
  *
  * Authors: Christophe Massiot <massiot@via.ecp.fr>
+ *          Antoine Cellerier <dionoea at videolan dot org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -61,6 +62,17 @@
     "Name of this bridge-in instance. If you do not need more " \
     "than one bridge-in at a time, you can discard this option." )
 
+#define PLACEHOLDER_TEXT N_( "Fallback to placeholder stream when out of data" )
+#define PLACEHOLDER_LONGTEXT N_( \
+    "If set to true, the bridge will discard all input elementary streams " \
+    "except if it doesn't receive data from another bridge-in. This can " \
+    "be used to configure a place holder stream when the real source " \
+    "breaks. Source and placeholder streams should have the same format. " )
+
+#define PLACEHOLDER_DELAY_TEXT N_( "Place holder delay" )
+#define PLACEHOLDER_DELAY_LONGTEXT N_( \
+    "Delay (in ms) before the place holder kicks in." )
+
 static int  OpenOut ( vlc_object_t * );
 static void CloseOut( vlc_object_t * );
 static int  OpenIn  ( vlc_object_t * );
@@ -97,6 +109,10 @@ vlc_module_begin();
                  ID_OFFSET_LONGTEXT, false );
     add_string( SOUT_CFG_PREFIX_IN "name", "default", NULL,
                 NAME_TEXT, NAME_LONGTEXT, false );
+    add_bool( SOUT_CFG_PREFIX_IN "placeholder", false, NULL,
+              PLACEHOLDER_TEXT, PLACEHOLDER_LONGTEXT, false );
+    add_integer( SOUT_CFG_PREFIX_IN "placeholder-delay", 200, NULL,
+                 PLACEHOLDER_DELAY_TEXT, PLACEHOLDER_DELAY_LONGTEXT, false );
     set_callbacks( OpenIn, CloseIn );
 
 vlc_module_end();
@@ -110,7 +126,7 @@ static const char *const ppsz_sout_options_out[] = {
 };
 
 static const char *const ppsz_sout_options_in[] = {
-    "delay", "id-offset", "name", NULL
+    "delay", "id-offset", "name", "placeholder", "placeholder-delay", NULL
 };
 
 static sout_stream_id_t *AddOut ( sout_stream_t *, es_format_t * );
@@ -362,6 +378,13 @@ typedef struct in_sout_stream_sys_t
     mtime_t i_delay;
 
     char *psz_name;
+
+    bool b_placeholder;
+    mtime_t i_placeholder_delay;
+    sout_stream_id_t *id_video;
+    mtime_t i_last_video;
+    sout_stream_id_t *id_audio;
+    mtime_t i_last_audio;
 } in_sout_stream_sys_t;
 
 /*****************************************************************************
@@ -405,6 +428,17 @@ static int OpenIn( vlc_object_t *p_this )
     }
     free( val.psz_string );
 
+    var_Get( p_stream, SOUT_CFG_PREFIX_IN "placeholder", &val );
+    p_sys->b_placeholder = val.b_bool;
+
+    var_Get( p_stream, SOUT_CFG_PREFIX_IN "placeholder-delay", &val );
+    p_sys->i_placeholder_delay = (mtime_t)val.i_int * 1000;
+
+    p_sys->i_last_video = 0;
+    p_sys->i_last_audio = 0;
+    p_sys->id_video = NULL;
+    p_sys->id_audio = NULL;
+
     p_stream->pf_add    = AddIn;
     p_stream->pf_del    = DelIn;
     p_stream->pf_send   = SendIn;
@@ -432,18 +466,58 @@ static void CloseIn( vlc_object_t * p_this )
     free( p_sys );
 }
 
+struct sout_stream_id_t
+{
+    sout_stream_id_t *id;
+    int i_cat; /* es category. Used for placeholder option */
+};
+
 static sout_stream_id_t * AddIn( sout_stream_t *p_stream, es_format_t *p_fmt )
 {
     in_sout_stream_sys_t *p_sys = (in_sout_stream_sys_t *)p_stream->p_sys;
 
-    return p_sys->p_out->pf_add( p_sys->p_out, p_fmt );
+    sout_stream_id_t *id = malloc( sizeof( sout_stream_id_t ) );
+    if( !id ) return NULL;
+
+    id->id = p_sys->p_out->pf_add( p_sys->p_out, p_fmt );
+    if( !id->id )
+    {
+        free( id );
+        return NULL;
+    }
+
+    if( p_sys->b_placeholder )
+    {
+        id->i_cat = p_fmt->i_cat;
+        switch( p_fmt->i_cat )
+        {
+            case VIDEO_ES:
+                if( p_sys->id_video != NULL )
+                    msg_Err( p_stream, "We already had a video es!" );
+                p_sys->id_video = id->id;
+                break;
+            case AUDIO_ES:
+                if( p_sys->id_audio != NULL )
+                    msg_Err( p_stream, "We already had an audio es!" );
+                p_sys->id_audio = id->id;
+                break;
+        }
+    }
+
+    return id;
 }
 
 static int DelIn( sout_stream_t *p_stream, sout_stream_id_t *id )
 {
     in_sout_stream_sys_t *p_sys = (in_sout_stream_sys_t *)p_stream->p_sys;
 
-    return p_sys->p_out->pf_del( p_sys->p_out, id );
+    if( id == p_sys->id_video ) p_sys->id_video = NULL;
+    if( id == p_sys->id_audio ) p_sys->id_audio = NULL;
+
+    int ret = p_sys->p_out->pf_del( p_sys->p_out, id->id );
+
+    free( id );
+    return ret;
 }
 
 static int SendIn( sout_stream_t *p_stream, sout_stream_id_t *id,
@@ -453,20 +527,19 @@ static int SendIn( sout_stream_t *p_stream, sout_stream_id_t *id,
     bridge_t *p_bridge;
     bool b_no_es = true;
     int i;
+    int i_date = mdate();
 
     /* First forward the packet for our own ES */
-    p_sys->p_out->pf_send( p_sys->p_out, id, p_buffer );
+    if( !p_sys->b_placeholder )
+        p_sys->p_out->pf_send( p_sys->p_out, id->id, p_buffer );
 
     /* Then check all bridged streams */
     vlc_mutex_lock( p_sys->p_lock );
 
     p_bridge = GetBridge( p_stream, p_sys->psz_name );
-    if ( p_bridge == NULL )
-    {
-        vlc_mutex_unlock( p_sys->p_lock );
-        return VLC_SUCCESS;
-    }
 
+    if( p_bridge )
+    {
     for ( i = 0; i < p_bridge->i_es_num; i++ )
     {
         if ( !p_bridge->pp_es[i]->b_empty )
@@ -474,13 +547,13 @@ static int SendIn( sout_stream_t *p_stream, sout_stream_id_t *id,
 
         while ( p_bridge->pp_es[i]->p_block != NULL
                  && (p_bridge->pp_es[i]->p_block->i_dts + p_sys->i_delay
-                       < mdate()
+                       < i_date
                       || p_bridge->pp_es[i]->p_block->i_dts + p_sys->i_delay
                           < p_bridge->pp_es[i]->i_last) )
         {
             block_t *p_block = p_bridge->pp_es[i]->p_block;
             msg_Dbg( p_stream, "dropping a packet (%"PRId64 ")",
-                     mdate() - p_block->i_dts - p_sys->i_delay );
+                     i_date - p_block->i_dts - p_sys->i_delay );
             p_bridge->pp_es[i]->p_block
                 = p_bridge->pp_es[i]->p_block->p_next;
             block_Release( p_block );
@@ -527,7 +600,7 @@ static int SendIn( sout_stream_t *p_stream, sout_stream_id_t *id,
         if ( p_bridge->pp_es[i]->p_block == NULL )
         {
             if ( p_bridge->pp_es[i]->id != NULL
-                  && p_bridge->pp_es[i]->i_last < mdate() )
+                  && p_bridge->pp_es[i]->i_last < i_date )
             {
                 p_sys->p_out->pf_del( p_sys->p_out, p_bridge->pp_es[i]->id );
                 p_bridge->pp_es[i]->fmt.i_id -= p_sys->i_id_offset;
@@ -547,7 +620,23 @@ static int SendIn( sout_stream_t *p_stream, sout_stream_id_t *id,
                 p_block->i_dts += p_sys->i_delay;
                 p_block = p_block->p_next;
             }
-            p_sys->p_out->pf_send( p_sys->p_out, p_bridge->pp_es[i]->id,
+            sout_stream_id_t *newid = NULL;
+            if( p_sys->b_placeholder )
+            {
+                switch( p_bridge->pp_es[i]->fmt.i_cat )
+                {
+                    case VIDEO_ES:
+                        p_sys->i_last_video = i_date;
+                        newid = p_sys->id_video;
+                        break;
+                    case AUDIO_ES:
+                        newid = p_sys->id_audio;
+                        p_sys->i_last_audio = i_date;
+                        break;
+                }
+            }
+            p_sys->p_out->pf_send( p_sys->p_out,
+                                   newid ? newid : p_bridge->pp_es[i]->id,
                                    p_bridge->pp_es[i]->p_block );
         }
         else
@@ -568,6 +657,31 @@ static int SendIn( sout_stream_t *p_stream, sout_stream_id_t *id,
         free( p_bridge );
         var_Destroy( p_libvlc, p_sys->psz_name );
     }
+    }
+
+    if( p_sys->b_placeholder )
+    {
+        switch( id->i_cat )
+        {
+            case VIDEO_ES:
+                if( p_sys->i_last_video + p_sys->i_placeholder_delay < i_date )
+                    p_sys->p_out->pf_send( p_sys->p_out, id->id, p_buffer );
+                else
+                    block_Release( p_buffer );
+                break;
+
+            case AUDIO_ES:
+                if( p_sys->i_last_audio + p_sys->i_placeholder_delay < i_date )
+                    p_sys->p_out->pf_send( p_sys->p_out, id->id, p_buffer );
+                else
+                    block_Release( p_buffer );
+                break;
+
+            default:
+                block_Release( p_buffer ); /* FIXME: placeholder subs anyone? */
+                break;
+        }
+    }
 
     vlc_mutex_unlock( p_sys->p_lock );