[FFmpeg-devel] [PATCH] cmdutils: make the "-help filter=" output less confusing

[Michael Niedermayer]

Example:
Filter overlay
  Overlay a video source on top of the input.
    Inputs:
      1st: main (video)
      2nd: overlay (video)
    Outputs:
      1st: default (video)

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
---
 cmdutils.c |   18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/cmdutils.c b/cmdutils.c
index 2b5ba33..3464b7a 100644
--- a/cmdutils.c
+++ b/cmdutils.c
@@ -1635,6 +1635,20 @@ static void show_help_muxer(const char *name)
         show_help_children(fmt->priv_class, AV_OPT_FLAG_ENCODING_PARAM);
 }
 
+static const char* ordinal_suffix(int i)
+{
+    av_assert0(i >= 0);
+    if (i/10%10 != 1) {
+        switch(i%10) {
+        case 1: return "st";
+        case 2: return "nd";
+        case 3: return "rd";
+        }
+    }
+
+    return "th";
+}
+
 #if CONFIG_AVFILTER
 static void show_help_filter(const char *name)
 {
@@ -1656,7 +1670,7 @@ static void show_help_filter(const char *name)
     printf("    Inputs:\n");
     count = avfilter_pad_count(f->inputs);
     for (i = 0; i < count; i++) {
-        printf("        %d %s (%s)\n", i, avfilter_pad_get_name(f->inputs, i),
+        printf("      %d%s: %s (%s)\n", i+1, ordinal_suffix(i+1), avfilter_pad_get_name(f->inputs, i),
                media_type_string(avfilter_pad_get_type(f->inputs, i)));
     }
     if (f->flags & AVFILTER_FLAG_DYNAMIC_INPUTS)
@@ -1667,7 +1681,7 @@ static void show_help_filter(const char *name)
     printf("    Outputs:\n");
     count = avfilter_pad_count(f->outputs);
     for (i = 0; i < count; i++) {
-        printf("        %d %s (%s)\n", i, avfilter_pad_get_name(f->outputs, i),
+        printf("      %d%s: %s (%s)\n", i+1, ordinal_suffix(i+1), avfilter_pad_get_name(f->outputs, i),
                media_type_string(avfilter_pad_get_type(f->outputs, i)));
     }
     if (f->flags & AVFILTER_FLAG_DYNAMIC_OUTPUTS)
-- 
1.7.9.5