lavfi/setfield: add "progressive" option

Add "prog" parameter value, and deprecate numeric values.
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>

doc/filters.texi

@@ -2534,19 +2534,21 @@ Force field for the output video frame.
 The @code{setfield} filter marks the interlace type field for the
 output frames. It does not change the input frame, but only sets the
 corresponding property, which affects how the frame is treated by
-followig filters (e.g. @code{fieldorder} or @code{yadif}).
+following filters (e.g. @code{fieldorder} or @code{yadif}).
 
-It accepts a parameter representing an integer or a string, which can
-assume the following values:
+It accepts a string parameter, which can assume the following values:
 @table @samp
-@item -1, auto
+@item auto
 Keep the same field property.
 
-@item 0, bff
+@item bff
 Mark the frame as bottom-field-first.
 
-@item 1, tff
+@item tff
 Mark the frame as top-field-first.
+
+@item prog
+Mark the frame as progressive.
 @end table
 
 @section setpts

libavfilter/version.h

@@ -30,7 +30,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR  2
 #define LIBAVFILTER_VERSION_MINOR 71
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MICRO 102
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_setfield.c

@@ -40,21 +40,24 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
         if (sscanf(args, "%d%c", &setfield->top_field_first, &c) != 1) {
             if      (!strcmp("tff",  args)) setfield->top_field_first = 1;
             else if (!strcmp("bff",  args)) setfield->top_field_first = 0;
+            else if (!strcmp("prog", args)) setfield->top_field_first = 2;
             else if (!strcmp("auto", args)) setfield->top_field_first = -1;
             else {
                 av_log(ctx, AV_LOG_ERROR, "Invalid argument '%s'\n", args);
                 return AVERROR(EINVAL);
             }
+        } else {
+            if (setfield->top_field_first < -1 || setfield->top_field_first > 1) {
+                av_log(ctx, AV_LOG_ERROR,
+                       "Provided integer value %d must be included between -1 and +1\n",
+                       setfield->top_field_first);
+                return AVERROR(EINVAL);
+            }
+            av_log(ctx, AV_LOG_WARNING,
+                   "Using -1/0/1 is deprecated, use auto/tff/bff/prog\n", args);
         }
     }
 
-    if (setfield->top_field_first < -1 || setfield->top_field_first > 1) {
-        av_log(ctx, AV_LOG_ERROR,
-               "Provided integer value %d must be included between -1 and +1\n",
-               setfield->top_field_first);
-        return AVERROR(EINVAL);
-    }
-
     return 0;
 }
 
@@ -63,7 +66,9 @@ static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
     SetFieldContext *setfield = inlink->dst->priv;
     AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
 
-    if (setfield->top_field_first != -1) {
+    if (setfield->top_field_first == 2) {
+        outpicref->video->interlaced = 0;
+    } else if (setfield->top_field_first != -1) {
         outpicref->video->interlaced = 1;
         outpicref->video->top_field_first = setfield->top_field_first;
     }