Implement DEMUX_SET_NEXT_DEMUX_TIME in alsa & oss

This makes it possible to use the alsa and oss modules as slaves to
modules such as v4l2 and screen. (The other way around isn't supported
at the moment.)

modules/access/alsa.c

@@ -130,6 +130,8 @@ struct demux_sys_t
     snd_pcm_t *p_alsa_pcm;
     size_t i_alsa_frame_size;
     int i_alsa_chunk_size;
+
+    int64_t i_next_demux_date; /* Used to handle alsa:// as input-slave properly */
 };
 
 static int FindMainDevice( demux_t *p_demux )
@@ -179,6 +181,7 @@ static int DemuxOpen( vlc_object_t *p_this )
     p_sys->i_pts = var_CreateGetInteger( p_demux, CFG_PREFIX "caching" );
     p_sys->p_es = NULL;
     p_sys->p_block = NULL;
+    p_sys->i_next_demux_date = -1;
 
     if( p_demux->psz_path && *p_demux->psz_path )
         p_sys->psz_device = p_demux->psz_path;
@@ -242,6 +245,10 @@ static int DemuxControl( demux_t *p_demux, int i_query, va_list args )
             *pi64 = mdate();
             return VLC_SUCCESS;
 
+        case DEMUX_SET_NEXT_DEMUX_TIME:
+            p_sys->i_next_demux_date = (int64_t)va_arg( args, int64_t );
+            return VLC_SUCCESS;
+
         /* TODO implement others */
         default:
             return VLC_EGENERIC;
@@ -257,31 +264,47 @@ static int Demux( demux_t *p_demux )
 {
     demux_sys_t *p_sys = p_demux->p_sys;
 
-    int i_wait = snd_pcm_wait( p_sys->p_alsa_pcm, 500 );
-    switch( i_wait )
+    block_t *p_block = NULL;
+
+    do
     {
-        case 1:
+        if( p_block )
         {
-            block_t *p_block = GrabAudio( p_demux );
-            if( p_block )
-            {
-                es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
-                es_out_Send( p_demux->out, p_sys->p_es, p_block );
-            }
+            es_out_Send( p_demux->out, p_sys->p_es, p_block );
+            p_block = NULL;
         }
 
-        case -EPIPE:
-            /* xrun */
-            snd_pcm_prepare( p_sys->p_alsa_pcm );
-            break;
-        case -ESTRPIPE:
+        /* Wait for data */
+        int i_wait = snd_pcm_wait( p_sys->p_alsa_pcm, 500 );
+        switch( i_wait )
         {
-            /* suspend */
-            int i_resume = snd_pcm_resume( p_sys->p_alsa_pcm );
-            if( i_resume < 0 && i_resume != -EAGAIN ) snd_pcm_prepare( p_sys->p_alsa_pcm );
-            break;
+            case 1:
+            {
+                p_block = GrabAudio( p_demux );
+                if( p_block )
+                    es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
+            }
+
+            /* FIXME: this is a copy paste from below. Shouldn't be needed
+             * twice. */
+            case -EPIPE:
+                /* xrun */
+                snd_pcm_prepare( p_sys->p_alsa_pcm );
+                break;
+            case -ESTRPIPE:
+            {
+                /* suspend */
+                int i_resume = snd_pcm_resume( p_sys->p_alsa_pcm );
+                if( i_resume < 0 && i_resume != -EAGAIN ) snd_pcm_prepare( p_sys->p_alsa_pcm );
+                break;
+            }
+            /* </FIXME> */
         }
-    }
+    } while( p_block && p_sys->i_next_demux_date > 0 &&
+             p_block->i_pts < p_sys->i_next_demux_date );
+
+    if( p_block )
+        es_out_Send( p_demux->out, p_sys->p_es, p_block );
 
     return 1;
 }

modules/access/oss.c

@@ -124,6 +124,8 @@ struct demux_sys_t
     size_t i_max_frame_size;
     block_t *p_block;
     es_out_id_t *p_es;
+
+    int64_t i_next_demux_date; /* Used to handle oss:// as input-slave properly */
 };
 
 static int FindMainDevice( demux_t *p_demux )
@@ -171,6 +173,7 @@ static int DemuxOpen( vlc_object_t *p_this )
     p_sys->i_fd = -1;
     p_sys->p_es = NULL;
     p_sys->p_block = NULL;
+    p_sys->i_next_demux_date = -1;
 
     if( p_demux->psz_path && *p_demux->psz_path )
         p_sys->psz_device = p_demux->psz_path;
@@ -230,6 +233,10 @@ static int DemuxControl( demux_t *p_demux, int i_query, va_list args )
             *pi64 = mdate();
             return VLC_SUCCESS;
 
+        case DEMUX_SET_NEXT_DEMUX_TIME:
+            p_sys->i_next_demux_date = (int64_t)va_arg( args, int64_t );
+            return VLC_SUCCESS;
+
         /* TODO implement others */
         default:
             return VLC_EGENERIC;
@@ -250,19 +257,31 @@ static int Demux( demux_t *p_demux )
     fd.events = POLLIN|POLLPRI;
     fd.revents = 0;
 
-    /* Wait for data */
-    if( poll( &fd, 1, 500 ) ) /* Timeout after 0.5 seconds since I don't know if pf_demux can be blocking. */
+    block_t *p_block = NULL;
+
+    do
     {
-        if( fd.revents & (POLLIN|POLLPRI) )
+        if( p_block )
         {
-            block_t *p_block = GrabAudio( p_demux );
-            if( p_block )
+            es_out_Send( p_demux->out, p_sys->p_es, p_block );
+            p_block = NULL;
+        }
+
+        /* Wait for data */
+        if( poll( &fd, 1, 500 ) ) /* Timeout after 0.5 seconds since I don't know if pf_demux can be blocking. */
+        {
+            if( fd.revents & (POLLIN|POLLPRI) )
             {
-                es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
-                es_out_Send( p_demux->out, p_sys->p_es, p_block );
+                p_block = GrabAudio( p_demux );
+                if( p_block )
+                    es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
             }
         }
-    }
+    } while( p_block && p_sys->i_next_demux_date > 0 &&
+             p_block->i_pts < p_sys->i_next_demux_date );
+
+    if( p_block )
+        es_out_Send( p_demux->out, p_sys->p_es, p_block );
 
     return 1;
 }