GstAnalyticsKeypointMtd

This metadata type represents individual keypoints with 2D or 3D positions. Keypoints can be grouped using GstAnalyticsGroupMtd with semantic tags (e.g., "hand-21-kp", "pose-17-kp", "face-68-kp").

Skeleton links between keypoints are represented as relations using GST_ANALYTICS_REL_TYPE_RELATE_TO, allowing standard relation queries to traverse the skeleton structure.

Creating Keypoint Groups

The most common usage is to create a group of keypoints with skeleton structure:

 GstAnalyticsGroupMtd hand_group;
 gint positions[] = {100, 200, 150, 250, ...}; // 21 x,y pairs for hand
 gfloat confidences[] = {0.9f, 0.85f, 0.95f, ...};
 gint skeleton_pairs[] = {0, 1, 1, 2, 2, 3, ...}; // 20 links (40 values)

 gst_analytics_relation_meta_add_keypoints_group(rmeta,
     "hand-21-kp", GST_ANALYTICS_KEYPOINT_DIMENSIONS_2D,
     42, positions, 21, confidences, NULL, 40, skeleton_pairs, &hand_group);

Iterating Through Keypoints

Iterate keypoints in a group with type filtering:

 GstAnalyticsMtd member;
 gpointer state = NULL;
 while (gst_analytics_group_mtd_iterate(&hand_group, &state,
         gst_analytics_keypoint_mtd_get_mtd_type(), &member)) {
     gint x, y, z;
     gfloat conf;
     GstAnalyticsKeypointDimensions dim;
     gst_analytics_keypoint_mtd_get_position((GstAnalyticsKeypointMtd*)&member,
         &x, &y, &z, &dim);
     gst_analytics_keypoint_mtd_get_confidence((GstAnalyticsKeypointMtd*)&member,
         &conf);
     g_print("Keypoint at (%d, %d) confidence: %.2f\n", x, y, conf);
 }

Querying Skeleton Links

Verify skeleton connections between keypoints:

 // Get first two keypoints
 GstAnalyticsMtd wrist_kp, thumb_kp;
 gst_analytics_group_mtd_get_member(&hand_group, 0, &wrist_kp);
 gst_analytics_group_mtd_get_member(&hand_group, 1, &thumb_kp);

 // Verify skeleton link exists
 gboolean has_link = gst_analytics_relation_meta_exist(rmeta,
     wrist_kp.id, thumb_kp.id, 1,
     GST_ANALYTICS_REL_TYPE_RELATE_TO, NULL);
 if (has_link) {
     g_print("Skeleton link exists between wrist and thumb\n");
 }

Relating Keypoints to Other Metadata

Since keypoints are GstAnalyticsMtd, they can participate in relations:

 // Get first keypoint
 GstAnalyticsMtd keypoint;
 gst_analytics_group_mtd_get_member(&hand_group, 0, &keypoint);

 // Relate to object detection
 gst_analytics_relation_meta_set_relation(rmeta,
     GST_ANALYTICS_REL_TYPE_CONTAINED_BY, keypoint.id, od_mtd.id);

gboolean
gst_analytics_keypoint_mtd_get_confidence (const GstAnalyticsKeypointMtd * handle,
                                           gfloat * confidence)

function GstAnalytics.KeypointMtd.prototype.get_confidence(): {
    // javascript wrapper for 'gst_analytics_keypoint_mtd_get_confidence'
}

def GstAnalytics.KeypointMtd.get_confidence (self):
    #python wrapper for 'gst_analytics_keypoint_mtd_get_confidence'

gboolean
gst_analytics_keypoint_mtd_get_position (const GstAnalyticsKeypointMtd * handle,
                                         gint * x,
                                         gint * y,
                                         gint * z,
                                         GstAnalyticsKeypointDimensions * dimension)

function GstAnalytics.KeypointMtd.prototype.get_position(): {
    // javascript wrapper for 'gst_analytics_keypoint_mtd_get_position'
}

def GstAnalytics.KeypointMtd.get_position (self):
    #python wrapper for 'gst_analytics_keypoint_mtd_get_position'

gboolean
gst_analytics_keypoint_mtd_get_visibility_flags (const GstAnalyticsKeypointMtd * handle,
                                                 guint8 * visibility_flags)

function GstAnalytics.KeypointMtd.prototype.get_visibility_flags(): {
    // javascript wrapper for 'gst_analytics_keypoint_mtd_get_visibility_flags'
}

def GstAnalytics.KeypointMtd.get_visibility_flags (self):
    #python wrapper for 'gst_analytics_keypoint_mtd_get_visibility_flags'

GstAnalyticsMtdType
gst_analytics_keypoint_mtd_get_mtd_type ()

function GstAnalytics.KeypointMtd.prototype.get_mtd_type(): {
    // javascript wrapper for 'gst_analytics_keypoint_mtd_get_mtd_type'
}

def GstAnalytics.KeypointMtd.get_mtd_type ():
    #python wrapper for 'gst_analytics_keypoint_mtd_get_mtd_type'