avfilter: Deduplicate default video inputs/outputs

Lots of video filters use a very simple input or output:
An array with a single AVFilterPad whose name is "default"
and whose type is AVMEDIA_TYPE_VIDEO; everything else is unset.

Given that we never use pointer equality for inputs or outputs*,
we can simply use a single AVFilterPad instead of dozens; this
even saves .data.rel.ro (8312B here) as well as relocations.

*: In fact, several filters (like the filters in vf_lut.c)
already use the same outputs; furthermore, ff_filter_alloc()
duplicates the input and output pads so that we do not even
work with the pads directly.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 2 insertions, 8 deletions

diff --git a/libavfilter/f_sidedata.c b/libavfilter/f_sidedata.c
index 23e95d0b8a..208b457804 100644
--- a/libavfilter/f_sidedata.c
+++ b/libavfilter/f_sidedata.c
@@ -31,6 +31,7 @@
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
+#include "video.h"
 
 enum SideDataMode {
     SIDEDATA_SELECT,
@@ -161,13 +162,6 @@ static const AVFilterPad inputs[] = {
     },
 };
 
-static const AVFilterPad outputs[] = {
-    {
-        .name = "default",
-        .type = AVMEDIA_TYPE_VIDEO,
-    },
-};
-
 const AVFilter ff_vf_sidedata = {
     .name        = "sidedata",
     .description = NULL_IF_CONFIG_SMALL("Manipulate video frame side data."),
@@ -175,7 +169,7 @@ const AVFilter ff_vf_sidedata = {
     .priv_class  = &sidedata_class,
     .init        = init,
     FILTER_INPUTS(inputs),
-    FILTER_OUTPUTS(outputs),
+    FILTER_OUTPUTS(ff_video_default_filterpad),
     .flags       = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
                    AVFILTER_FLAG_METADATA_ONLY,
 };