af_lavfi: implement af-metadata property

Works like vf-metadata. Unfortunately requires some code duplication
(even though it's not much).

Fixes #2311.

3 files changed, 37 insertions, 0 deletions

diff --git a/audio/filter/af.c b/audio/filter/af.c
index ba08c1ed9b..3f73ad9c58 100644
--- a/audio/filter/af.c
+++ b/audio/filter/af.c
@@ -695,6 +695,18 @@ void af_control_all(struct af_stream *s, int cmd, void *arg)
         af->control(af, cmd, arg);
 }
 
+int af_control_by_label(struct af_stream *s, int cmd, void *arg, bstr label)
+{
+    char *label_str = bstrdup0(NULL, label);
+    struct af_instance *cur = af_find_by_label(s, label_str);
+    talloc_free(label_str);
+    if (cur) {
+        return cur->control ? cur->control(cur, cmd, arg) : CONTROL_NA;
+    } else {
+        return CONTROL_UNKNOWN;
+    }
+}
+
 // Used by filters to add a filtered frame to the output queue.
 // Ownership of frame is transferred from caller to the filter chain.
 void af_add_output_frame(struct af_instance *af, struct mp_audio *frame)
diff --git a/audio/filter/af.h b/audio/filter/af.h
index 944ac54427..199486509c 100644
--- a/audio/filter/af.h
+++ b/audio/filter/af.h
@@ -127,6 +127,7 @@ enum af_control {
     AF_CONTROL_GET_PAN_BALANCE,
     AF_CONTROL_SET_PLAYBACK_SPEED,
     AF_CONTROL_SET_PLAYBACK_SPEED_RESAMPLE,
+    AF_CONTROL_GET_METADATA,
 };
 
 // Argument for AF_CONTROL_SET_PAN_LEVEL
@@ -145,6 +146,7 @@ int af_remove_by_label(struct af_stream *s, char *label);
 struct af_instance *af_find_by_label(struct af_stream *s, char *label);
 struct af_instance *af_control_any_rev(struct af_stream *s, int cmd, void *arg);
 void af_control_all(struct af_stream *s, int cmd, void *arg);
+int af_control_by_label(struct af_stream *s, int cmd, void *arg, bstr label);
 void af_seek_reset(struct af_stream *s);
 
 void af_add_output_frame(struct af_instance *af, struct mp_audio *frame);
diff --git a/audio/filter/af_lavfi.c b/audio/filter/af_lavfi.c
index 249a560fb6..a40904aa78 100644
--- a/audio/filter/af_lavfi.c
+++ b/audio/filter/af_lavfi.c
@@ -34,11 +34,14 @@
 #include <libavfilter/buffersink.h>
 #include <libavfilter/buffersrc.h>
 
+#include "config.h"
+
 #include "audio/format.h"
 #include "audio/fmt-conversion.h"
 #include "af.h"
 
 #include "common/av_common.h"
+#include "common/tags.h"
 
 #include "options/m_option.h"
 
@@ -63,6 +66,8 @@ struct priv {
 
     bool eof;
 
+    struct mp_tags *metadata;
+
     // options
     char *cfg_graph;
     char **cfg_avopts;
@@ -213,6 +218,12 @@ static int control(struct af_instance *af, int cmd, void *arg)
 
         return mp_audio_config_equals(in, &orig_in) ? AF_OK : AF_FALSE;
     }
+    case AF_CONTROL_GET_METADATA:
+        if (p->metadata) {
+            *(struct mp_tags *)arg = *p->metadata;
+            return CONTROL_OK;
+        }
+        return CONTROL_NA;
     case AF_CONTROL_RESET:
         reset(af);
         return AF_OK;
@@ -220,6 +231,17 @@ static int control(struct af_instance *af, int cmd, void *arg)
     return AF_UNKNOWN;
 }
 
+static void get_metadata_from_av_frame(struct af_instance *af, AVFrame *frame)
+{
+#if HAVE_AVFRAME_METADATA
+    struct priv *p = af->priv;
+    if (!p->metadata)
+        p->metadata = talloc_zero(p, struct mp_tags);
+
+    mp_tags_copy_from_av_dictionary(p->metadata, av_frame_get_metadata(frame));
+#endif
+}
+
 static int filter_frame(struct af_instance *af, struct mp_audio *data)
 {
     struct priv *p = af->priv;
@@ -307,6 +329,7 @@ static int filter_out(struct af_instance *af)
         af->delay = in_time - out_time;
     }
 
+    get_metadata_from_av_frame(af, frame);
     af_add_output_frame(af, out);
     av_frame_free(&frame);
     return 0;