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, 1 insertions, 8 deletions

diff --git a/libavfilter/vf_blackframe.c b/libavfilter/vf_blackframe.c
index 4bcec86688..27198b318c 100644
--- a/libavfilter/vf_blackframe.c
+++ b/libavfilter/vf_blackframe.c
@@ -115,13 +115,6 @@ static const AVFilterPad avfilter_vf_blackframe_inputs[] = {
     },
 };
 
-static const AVFilterPad avfilter_vf_blackframe_outputs[] = {
-    {
-        .name = "default",
-        .type = AVMEDIA_TYPE_VIDEO
-    },
-};
-
 const AVFilter ff_vf_blackframe = {
     .name          = "blackframe",
     .description   = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
@@ -129,6 +122,6 @@ const AVFilter ff_vf_blackframe = {
     .priv_class    = &blackframe_class,
     .flags         = AVFILTER_FLAG_METADATA_ONLY,
     FILTER_INPUTS(avfilter_vf_blackframe_inputs),
-    FILTER_OUTPUTS(avfilter_vf_blackframe_outputs),
+    FILTER_OUTPUTS(ff_video_default_filterpad),
     FILTER_PIXFMTS_ARRAY(pix_fmts),
 };