[vlc-devel] [PATCH 5/5] chroma_chain: try transform on smallest surface

[Francois Cartegnie]

---
 modules/video_chroma/chain.c | 50 +++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/modules/video_chroma/chain.c b/modules/video_chroma/chain.c
index 8b183d2686..4eff623e96 100644
--- a/modules/video_chroma/chain.c
+++ b/modules/video_chroma/chain.c
@@ -281,30 +281,38 @@ static picture_t *Chain( filter_t *p_filter, picture_t *p_pic )
 
 static int BuildTransformChain( filter_t *p_filter )
 {
+    const bool b_upscaling = (uint64_t) p_filter->fmt_in.video.i_width *
+                                        p_filter->fmt_in.video.i_height <=
+                             (uint64_t) p_filter->fmt_out.video.i_width *
+                                        p_filter->fmt_out.video.i_height;
+    const int i_first_step = b_upscaling ? 0 : 1;
 
-    es_format_t fmt_mid;
-    int i_ret;
-
-    /* Lets try transform first, then (potentially) resize+chroma */
-    msg_Dbg( p_filter, "Trying to build transform, then chroma+resize" );
-    es_format_Copy( &fmt_mid, &p_filter->fmt_in );
-    video_format_TransformTo(&fmt_mid.video, p_filter->fmt_out.video.orientation);
-    i_ret = CreateChain( p_filter, &fmt_mid );
-    es_format_Clean( &fmt_mid );
-    if( i_ret == VLC_SUCCESS )
-        return VLC_SUCCESS;
+    for( int i=0; i<2; i++ )
+    {
+        es_format_t fmt_mid;
 
-    /* Lets try resize+chroma first, then transform */
-    msg_Dbg( p_filter, "Trying to build chroma+resize, then transform" );
-    es_format_Copy( &fmt_mid, &p_filter->fmt_out );
-    /* Set mid format to same rotation as source,
-     * so we get proper scaling before transform */
-    video_format_TransformTo( &fmt_mid.video, p_filter->fmt_in.video.orientation );
-    i_ret = CreateChain( p_filter, &fmt_mid );
-    es_format_Clean( &fmt_mid );
-    if( i_ret == VLC_SUCCESS )
-        return VLC_SUCCESS;
+        if( (i_first_step + i) % 2 == 0 )
+        {
+            /* Lets try transform first, then (potentially) resize+chroma */
+            msg_Dbg( p_filter, "Trying to build transform, then chroma+resize" );
+            es_format_Copy( &fmt_mid, &p_filter->fmt_in );
+            video_format_TransformTo( &fmt_mid.video, p_filter->fmt_out.video.orientation );
+        }
+        else
+        {
+            /* Lets try resize+chroma first, then transform */
+            msg_Dbg( p_filter, "Trying to build chroma+resize, then transform" );
+            es_format_Copy( &fmt_mid, &p_filter->fmt_out );
+            /* Set mid format to same rotation as source,
+             * so we get proper scaling before transform */
+            video_format_TransformTo( &fmt_mid.video, p_filter->fmt_in.video.orientation );
+        }
 
+        int i_ret = CreateChain( p_filter, &fmt_mid );
+        es_format_Clean( &fmt_mid );
+        if( i_ret == VLC_SUCCESS )
+            return VLC_SUCCESS;
+    }
     return VLC_EGENERIC;
 }
 
-- 
2.21.0