lavfi: replace passthrough_filter_frame with a flag.

With the introduction of AVFilterContext->is_disabled, we can simplify
the custom passthrough mode in filters.

This commit is technically a small compat break, but the timeline was
introduced very recently.

Doxy by Stefano Sabatini.

1 files changed, 18 insertions, 15 deletions

diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index a79c86c2be..822eca7af2 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -385,19 +385,6 @@ struct AVFilterPad {
     int needs_fifo;
 
     int needs_writable;
-
-    /**
-     * Passthrough filtering callback.
-     *
-     * If a filter supports timeline editing (in case
-     * AVFILTER_FLAG_SUPPORT_TIMELINE is enabled) then it can implement a
-     * custom passthrough callback to update its local context (for example to
-     * keep a frame reference, or simply send the filter to a custom outlink).
-     * The filter must not do any change to the frame in this callback.
-     *
-     * Input pads only.
-     */
-    int (*passthrough_filter_frame)(AVFilterLink *link, AVFrame *frame);
 };
 #endif
 
@@ -444,9 +431,25 @@ enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
 /**
  * Some filters support a generic "enable" expression option that can be used
  * to enable or disable a filter in the timeline. Filters supporting this
- * option have this flag set.
+ * option have this flag set. When the enable expression is false, the default
+ * no-op filter_frame() function is called in place of the filter_frame()
+ * callback defined on each input pad, thus the frame is passed unchanged to
+ * the next filters.
+ */
+#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC  (1 << 16)
+/**
+ * Same as AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, except that the filter will
+ * have its filter_frame() callback(s) called as usual even when the enable
+ * expression is false. The filter will disable filtering within the
+ * filter_frame() callback(s) itself, for example executing code depending on
+ * the AVFilterContext->is_disabled value.
+ */
+#define AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL (1 << 17)
+/**
+ * Handy mask to test whether the filter supports or no the timeline feature
+ * (internally or generically).
  */
-#define AVFILTER_FLAG_SUPPORT_TIMELINE      (1 << 16)
+#define AVFILTER_FLAG_SUPPORT_TIMELINE (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)
 
 /**
  * Filter definition. This defines the pads a filter contains, and all the