lavfi: mark filters with dynamic number of inputs or outputs with special flags

This will be useful in avtools in the following commits.
Any other caller might also want to know this information.

1 files changed, 18 insertions, 0 deletions

diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index dffb2e56d9..dd29ec0564 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -373,6 +373,19 @@ const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
 
 /**
+ * The number of the filter inputs is not determined just by AVFilter.inputs.
+ * The filter might add additional inputs during initialization depending on the
+ * options supplied to it.
+ */
+#define AVFILTER_FLAG_DYNAMIC_INPUTS        (1 << 0)
+/**
+ * The number of the filter outputs is not determined just by AVFilter.outputs.
+ * The filter might add additional outputs during initialization depending on
+ * the options supplied to it.
+ */
+#define AVFILTER_FLAG_DYNAMIC_OUTPUTS       (1 << 1)
+
+/**
  * Filter definition. This defines the pads a filter contains, and all the
  * callback functions used to interact with the filter.
  */
@@ -394,6 +407,11 @@ typedef struct AVFilter {
      */
     const AVClass *priv_class;
 
+    /**
+     * A combination of AVFILTER_FLAG_*
+     */
+    int flags;
+
     /*****************************************************************
      * All fields below this line are not part of the public API. They
      * may not be used outside of libavfilter and can be changed and