Modify metadata_register API for support individual metric propagation.

libvmaf/include/libvmaf/libvmaf.h

@@ -257,6 +257,7 @@ int vmaf_feature_score_at_index(VmafContext *vmaf, const char *feature_name,
  * Metadata structure.
  *
  * @param feature_name   Name of the feature to fetch.
+ *                       vmaf going to take ownership of this string.
  *
  * @param picture_index  Picture index.
  *
@@ -285,6 +286,31 @@ typedef struct VmafMetadataConfiguration {
     void *data;
 } VmafMetadataConfiguration;
 
+
+/**
+ * Metadata flags.
+ *
+ * Features can provide additional metrics about the score. To propagate those,
+ * the `VmafMetadataFlags` enum should be used for specifying which information should be
+ * propagated to the metadata.
+ *
+ * @param VMAF_METADATA_FLAG_NONE         No flags.
+ *
+ * @param VMAF_METADATA_FLAG_FEATURE      Include all indivual metrics.
+ *
+ * @param VMAF_METADATA_FLAG_MODEL        Propagate only model score.
+ *
+ * @param VMAF_METADATA_FLAG_FEATURE_NAME Propagate only given feature name..
+ *
+ */
+
+enum VmafMetadataFlags {
+    VMAF_METADATA_FLAG_NONE = 0,
+    VMAF_METADATA_FLAG_FEATURE = 1 << 0,
+    VMAF_METADATA_FLAG_MODEL = 1 << 1,
+    VMAF_METADATA_FLAG_FEATURE_NAME = 1 << 2,
+};
+
 /**
  * Register a callback to receive VMAF metadata.
  *
@@ -296,7 +322,20 @@ typedef struct VmafMetadataConfiguration {
  * @return 0 on success, or < 0 (a negative errno code) on error.
  */
 
-int vmaf_register_metadata_handler(VmafContext *vmaf, VmafMetadataConfiguration cfg);
+int vmaf_register_metadata_handler(VmafContext *vmaf, VmafMetadataConfiguration cfg, uint64_t flags);
+
+/**
+ * Get the number of registered metadata handlers.
+ *
+ * @param vmaf  The VMAF context allocated with `vmaf_init()`.
+ *
+ * @param count Number of registered metadata handlers.
+ *
+ *
+ * @return 0 on success, or < 0 (a negative errno code) on error.
+ */
+
+int vmaf_get_metadata_handler_count(VmafContext *vmaf, unsigned *count);
 
 /**
  * Pooled VMAF score for a specific interval.

libvmaf/src/feature/feature_collector.c

@@ -27,6 +27,7 @@
 #include "metadata_handler.h"
 #include "feature_collector.h"
 #include "feature_name.h"
+#include "feature_extractor.h"
 #include "libvmaf/libvmaf.h"
 #include "log.h"
 #include "predict.h"
@@ -290,6 +291,25 @@ int vmaf_feature_collector_register_metadata(VmafFeatureCollector *feature_colle
     return 0;
 }
 
+int vmaf_feature_collector_get_metadata_count(VmafFeatureCollector *feature_collector,
+                                              unsigned *count)
+{
+    if (!feature_collector) return -EINVAL;
+    if (!count) return -EINVAL;
+
+    VmafCallbackList *metadata = feature_collector->metadata;
+    unsigned cnt = 0;
+    VmafCallbackItem *iter = metadata ? metadata->head : NULL;
+    while (iter) {
+        cnt++;
+        iter = iter->next;
+    }
+
+    *count = cnt;
+
+    return 0;
+}
+
 static FeatureVector *find_feature_vector(VmafFeatureCollector *fc,
                                           const char *feature_name)
 {

libvmaf/src/feature/feature_collector.h

@@ -70,6 +70,9 @@ int vmaf_feature_collector_append(VmafFeatureCollector *feature_collector,
 int vmaf_feature_collector_register_metadata(VmafFeatureCollector *feature_collector,
                                              VmafMetadataConfiguration metadata_cfg);
 
+int vmaf_feature_collector_get_metadata_count(VmafFeatureCollector *feature_collector,
+                                              unsigned *count);
+
 int vmaf_feature_collector_append_with_dict(VmafFeatureCollector *fc,
         VmafDictionary *dict, const char *feature_name, double score,
         unsigned index);

libvmaf/src/libvmaf.c

@@ -744,13 +744,36 @@ int vmaf_read_pictures(VmafContext *vmaf, VmafPicture *ref, VmafPicture *dist,
     return err;
 }
 
-int vmaf_register_metadata_handler(VmafContext *vmaf, VmafMetadataConfiguration cfg)
+int vmaf_register_metadata_handler(VmafContext *vmaf, VmafMetadataConfiguration cfg, uint64_t flags)
 {
     if (!vmaf) return -EINVAL;
 
+    if (flags & VMAF_METADATA_FLAG_FEATURE) {
+        VmafFeatureExtractor *fex = vmaf_get_feature_extractor_by_name(cfg.feature_name);
+        if (!fex) return -EINVAL;
+        int err = 0;
+        for (unsigned i = 0; fex->provided_features[i] != NULL; i++) {
+            VmafMetadataConfiguration new_cfg = { 0 };
+            new_cfg.data = cfg.data;
+            new_cfg.callback = cfg.callback;
+            new_cfg.feature_name = strdup(fex->provided_features[i]);
+            err = vmaf_feature_collector_register_metadata(vmaf->feature_collector, new_cfg);
+            if (err) return err;
+        }
+        return 0;
+    }
+
     return vmaf_feature_collector_register_metadata(vmaf->feature_collector, cfg);
 }
 
+int vmaf_get_metadata_handler_count(VmafContext *vmaf, unsigned *count)
+{
+    if (!vmaf) return -EINVAL;
+    if (!count) return -EINVAL;
+
+    return vmaf_feature_collector_get_metadata_count(vmaf->feature_collector, count);
+}
+
 int vmaf_feature_score_at_index(VmafContext *vmaf, const char *feature_name,
                                 double *score, unsigned index)
 {

libvmaf/src/metadata_handler.c

@@ -69,6 +69,8 @@ int vmaf_metadata_destroy(VmafCallbackList *metadata)
     VmafCallbackItem *iter = metadata->head;
     while (iter) {
         VmafCallbackItem *next = iter->next;
+        if (iter->metadata_cfg.feature_name)
+            free(iter->metadata_cfg.feature_name);
         free(iter);
         iter = next;
     }

libvmaf/test/test_predict.c

@@ -88,7 +88,7 @@ static char* test_propagate_metadata()
     };
 
     VmafMetadataConfiguration m = {
-        .feature_name = "vmaf",
+        .feature_name = strdup("vmaf"),
         .callback = set_meta,
         .data     = &meta_data,
     };
@@ -127,6 +127,7 @@ static char* test_propagate_metadata()
     vmaf_feature_collector_destroy(feature_collector);
 
     m.data = NULL;
+    m.feature_name = strdup("vmaf");
     err = vmaf_feature_collector_init(&feature_collector);
     mu_assert("problem during vmaf_feature_collector_init", !err);
 
@@ -142,6 +143,7 @@ static char* test_propagate_metadata()
     vmaf_feature_collector_destroy(feature_collector);
 
     m.callback = NULL;
+    m.feature_name = strdup("vmaf");
     err = vmaf_feature_collector_init(&feature_collector);
     mu_assert("problem during vmaf_feature_collector_init", !err);
 

libvmaf/test/test_propagate_metadata.c

@@ -55,7 +55,7 @@ static char *test_propagate_metadata_append()
     int err = vmaf_metadata_init(&propagate_metadata);
     mu_assert("problem during vmaf_propagate_metadata_init", !err);
 
-    VmafMetadataConfiguration metadata_config;
+    VmafMetadataConfiguration metadata_config = {0};
     metadata_config.callback = set_meta;
     metadata_config.data = NULL;