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, 16 deletions

diff --git a/libavfilter/vf_format.c b/libavfilter/vf_format.c
index 24b1c9ca61..04c265f59f 100644
--- a/libavfilter/vf_format.c
+++ b/libavfilter/vf_format.c
@@ -154,13 +154,6 @@ static const AVFilterPad avfilter_vf_format_inputs[] = {
     },
 };
 
-static const AVFilterPad avfilter_vf_format_outputs[] = {
-    {
-        .name = "default",
-        .type = AVMEDIA_TYPE_VIDEO
-    },
-};
-
 const AVFilter ff_vf_format = {
     .name          = "format",
     .description   = NULL_IF_CONFIG_SMALL("Convert the input video to one of the specified pixel formats."),
@@ -174,7 +167,7 @@ const AVFilter ff_vf_format = {
     .flags         = AVFILTER_FLAG_METADATA_ONLY,
 
     FILTER_INPUTS(avfilter_vf_format_inputs),
-    FILTER_OUTPUTS(avfilter_vf_format_outputs),
+    FILTER_OUTPUTS(ff_video_default_filterpad),
 
     FILTER_QUERY_FUNC(query_formats),
 };
@@ -190,13 +183,6 @@ static const AVFilterPad avfilter_vf_noformat_inputs[] = {
     },
 };
 
-static const AVFilterPad avfilter_vf_noformat_outputs[] = {
-    {
-        .name = "default",
-        .type = AVMEDIA_TYPE_VIDEO
-    },
-};
-
 const AVFilter ff_vf_noformat = {
     .name          = "noformat",
     .description   = NULL_IF_CONFIG_SMALL("Force libavfilter not to use any of the specified pixel formats for the input to the next filter."),
@@ -210,7 +196,7 @@ const AVFilter ff_vf_noformat = {
     .flags         = AVFILTER_FLAG_METADATA_ONLY,
 
     FILTER_INPUTS(avfilter_vf_noformat_inputs),
-    FILTER_OUTPUTS(avfilter_vf_noformat_outputs),
+    FILTER_OUTPUTS(ff_video_default_filterpad),
 
     FILTER_QUERY_FUNC(query_formats),
 };