filter_chain: add a specific function to clear (empty) a filter chain

filter_chain_Reset is reserved for restating new input/output formats and does
not allow empty format anymore.

filter_chain_Clear doesn't change the input/output formats, only remove all the
filters.

include/vlc_filter.h

@@ -350,11 +350,18 @@ VLC_API void filter_chain_Delete( filter_chain_t * );
  * reset p_fmt_in and p_fmt_out to the new values.
  *
  * \param p_chain pointer to filter chain
- * \param p_fmt_in new fmt_in params, may be NULL to leave input fmt unchanged
- * \param p_fmt_out new fmt_out params, may be NULL to leave output fmt unchanged
+ * \param p_fmt_in new fmt_in params
+ * \param p_fmt_out new fmt_out params
  */
 VLC_API void filter_chain_Reset( filter_chain_t *, const es_format_t *, const es_format_t * );
 
+/**
+ * Remove all existing filters
+ *
+ * \param p_chain pointer to filter chain
+ */
+VLC_API void filter_chain_Clear(filter_chain_t *);
+
 /**
  * Append a filter to the chain.
  *

modules/video_chroma/chain.c

@@ -457,7 +457,7 @@ static int CreateChain( filter_t *p_parent, const es_format_t *p_fmt_mid )
     return VLC_SUCCESS;
 error:
     //Clean up.
-    filter_chain_Reset( p_sys->p_chain, NULL, NULL );
+    filter_chain_Clear( p_sys->p_chain );
     return VLC_EGENERIC;
 }
 
@@ -491,7 +491,7 @@ static int CreateResizeChromaChain( filter_t *p_parent, const es_format_t *p_fmt
                                               NULL, &p_parent->fmt_out );
 
     if( i_ret != VLC_SUCCESS )
-        filter_chain_Reset( p_sys->p_chain, NULL, NULL );
+        filter_chain_Clear( p_sys->p_chain );
     return i_ret;
 }
 

src/libvlccore.sym

@@ -112,6 +112,7 @@ filter_chain_IsEmpty
 filter_chain_MouseFilter
 filter_chain_NewVideo
 filter_chain_Reset
+filter_chain_Clear
 filter_chain_SubFilter
 filter_chain_VideoFilter
 filter_chain_VideoFlush

src/misc/filter_chain.c

@@ -149,13 +149,18 @@ filter_chain_t *filter_chain_NewVideo( vlc_object_t *obj, bool allow_change,
     return chain;
 }
 
+void filter_chain_Clear( filter_chain_t *p_chain )
+{
+    while( p_chain->first != NULL )
+        filter_chain_DeleteFilter( p_chain, &p_chain->first->filter );
+}
+
 /**
  * Filter chain destruction
  */
 void filter_chain_Delete( filter_chain_t *p_chain )
 {
-    while( p_chain->first != NULL )
-        filter_chain_DeleteFilter( p_chain, &p_chain->first->filter );
+    filter_chain_Clear( p_chain );
 
     es_format_Clean( &p_chain->fmt_in );
     es_format_Clean( &p_chain->fmt_out );
@@ -168,19 +173,15 @@ void filter_chain_Delete( filter_chain_t *p_chain )
 void filter_chain_Reset( filter_chain_t *p_chain, const es_format_t *p_fmt_in,
                          const es_format_t *p_fmt_out )
 {
-    while( p_chain->first != NULL )
-        filter_chain_DeleteFilter( p_chain, &p_chain->first->filter );
+    filter_chain_Clear( p_chain );
 
-    if( p_fmt_in )
-    {
-        es_format_Clean( &p_chain->fmt_in );
-        es_format_Copy( &p_chain->fmt_in, p_fmt_in );
-    }
-    if( p_fmt_out )
-    {
-        es_format_Clean( &p_chain->fmt_out );
-        es_format_Copy( &p_chain->fmt_out, p_fmt_out );
-    }
+    assert(p_fmt_in != NULL);
+    es_format_Clean( &p_chain->fmt_in );
+    es_format_Copy( &p_chain->fmt_in, p_fmt_in );
+
+    assert(p_fmt_out != NULL);
+    es_format_Clean( &p_chain->fmt_out );
+    es_format_Copy( &p_chain->fmt_out, p_fmt_out );
 }
 
 static filter_t *filter_chain_AppendInner( filter_chain_t *chain,

src/video_output/vout_subpictures.c

@@ -1806,7 +1806,7 @@ void spu_PutSubpicture(spu_t *spu, subpicture_t *subpic)
                 filter_chain_ForEach(sys->filter_chain,
                                      SubFilterDelProxyCallbacks,
                                      sys->vout);
-            filter_chain_Reset(sys->filter_chain, NULL, NULL);
+            filter_chain_Clear(sys->filter_chain);
 
             filter_chain_AppendFromString(spu->p->filter_chain, chain_update);
             if (sys->vout)
@@ -1815,7 +1815,7 @@ void spu_PutSubpicture(spu_t *spu, subpicture_t *subpic)
                                      sys->vout);
         }
         else
-            filter_chain_Reset(sys->filter_chain, NULL, NULL);
+            filter_chain_Clear(sys->filter_chain);
 
         /* "sub-source"  was formerly "sub-filter", so now the "sub-filter"
         configuration may contain sub-filters or sub-sources configurations.
@@ -1913,7 +1913,7 @@ subpicture_t *spu_Render(spu_t *spu,
                 filter_chain_ForEach(sys->source_chain,
                                      SubSourceDelProxyCallbacks,
                                      sys->vout);
-        filter_chain_Reset(sys->source_chain, NULL, NULL);
+        filter_chain_Clear(sys->source_chain);
 
         filter_chain_AppendFromString(spu->p->source_chain, chain_update);
         if (sys->vout)