remove redundant distribution policy expiresAt

Assisted-by: Claude Code

js/docs/src/content/docs/video-metadata/c2pa-integration.md

···
 
 ```json
 {
-  "active_manifest": "urn:c2pa:bb3d7649-9cab-49b9-aaa5-635193c10015",
+  "active_manifest": "urn:c2pa:66130743-a4cd-4f73-a4c7-201079ef127a",
   "manifests": {
-    "urn:c2pa:bb3d7649-9cab-49b9-aaa5-635193c10015": {
+    "urn:c2pa:66130743-a4cd-4f73-a4c7-201079ef127a": {
       "claim_generator_info": [
         {
           "name": "c2pa-rs",
···
           "org.contentauth.c2pa_rs": "0.58.0"
         }
       ],
-      "title": "Livestream Segment at 2025-11-05T16:08:56.428Z",
-      "instance_id": "xmp:iid:013f5406-2e1e-4459-be38-ee9bb13d97b7",
+      "title": "Livestream Segment at 2025-11-13T20:41:30.499Z",
+      "instance_id": "xmp:iid:a031a30d-e1eb-4548-a20f-6453e15c2ace",
       "ingredients": [],
       "assertions": [
         {
···
             "actions": [
               {
                 "action": "c2pa.created",
-                "when": "2025-11-05T16:08:56.428Z"
+                "when": "2025-11-13T20:41:30.499Z"
               },
               {
                 "action": "c2pa.published",
-                "when": "2025-11-05T16:08:56.428Z"
+                "when": "2025-11-13T20:41:30.499Z"
               }
             ],
             "allActionsIncluded": false
···
               }
             ],
             "alg": "sha256",
-            "hash": "Uj/4bjqYZpu9ks+tSJ5F0inOE/E9gnnflyrT2m3a7n8=",
+            "hash": "ZHobn5CtL1NsTLAMMPT8D7koSrMr2Ijm5eJt73ED4HA=",
             "name": "jumbf manifest"
           }
         },
···
           "label": "cawg.metadata",
           "data": {
             "@context": {
-              "Iptc4xmpExt": "http://iptc.org/std/Iptc4xmpExt/2008-02-29/",
               "photoshop": "http://ns.adobe.com/photoshop/1.0/",
-              "dc": "http://purl.org/dc/elements/1.1/",
               "xmpRights": "http://ns.adobe.com/xap/1.0/rights/",
-              "streamplace": "https://ns.stream.place/metadata/0.1"
+              "Iptc4xmpExt": "http://iptc.org/std/Iptc4xmpExt/2008-02-29/",
+              "dc": "http://purl.org/dc/elements/1.1/"
             },
             "xmpRights:UsageTerms": "All rights reserved",
-            "dc:title": "Test",
-            "streamplace:distributionPolicy": {
-              "deleteAfter": "2025-11-05T16:13:56.000Z"
-            },
-            "dc:date": "2025-11-05T16:08:56.428Z",
             "dc:creator": "did:plc:2j2ounbiyi3ftihronlw5qhj",
+            "dc:date": "2025-11-13T20:41:30.499Z",
             "Iptc4xmpExt:ContentWarning": [
               "cwarn:flashingLights"
-            ]
+            ],
+            "dc:title": "Test"
           },
           "kind": "Json"
         },
···
       "signature_info": {
         "issuer": "Streamplace",
         "common_name": "did:key:zQ3shiYS17LRhT7x6mfd6HfsHHzz1aD9DpGJUP3aT5f2ghdAy",
-        "cert_serial_number": "154067456662585157774248475905339097818"
+        "cert_serial_number": "34409281865771434870888029768053492928"
       },
-      "label": "urn:c2pa:bb3d7649-9cab-49b9-aaa5-635193c10015"
+      "label": "urn:c2pa:66130743-a4cd-4f73-a4c7-201079ef127a"
     }
-  },
+  }
 }
 ```
 

pkg/media/manifest_builder.go

···
 						"Iptc4xmpExt": "http://iptc.org/std/Iptc4xmpExt/2008-02-29/",
 						"photoshop":   "http://ns.adobe.com/photoshop/1.0/",
 						"xmpRights":   "http://ns.adobe.com/xap/1.0/rights/",
-						"streamplace": "https://ns.stream.place/metadata/0.1",
 					},
 					"dc:creator": streamerName,
 					"dc:title":   "livestream",
···
 			// Unknown warnings remain unchanged
 		}
 		mani["assertions"].([]obj)[1]["data"].(obj)["Iptc4xmpExt:ContentWarning"] = metadata.ContentWarnings.Warnings
-	}
-
-	if metadata.DistributionPolicy != nil {
-		// Convert the distribution policy duration to an absolute expiry timestamp
-		// deleteAfter is in seconds, startTimeMillis is in milliseconds
-		if metadata.DistributionPolicy.DeleteAfter != nil {
-			// Calculate expiry: start time (seconds) + duration (seconds) = expiry timestamp (seconds)
-			startTimeSeconds := startTimeMillis / 1000
-			expiresAtSeconds := startTimeSeconds + *metadata.DistributionPolicy.DeleteAfter
-
-			// Convert to ISO 8601 datetime string for C2PA manifest
-			// Note: In the manifest, we store this in "deleteAfter" field but with timestamp value instead of duration
-			deleteAfterTimestamp := aqtime.FromMillis(expiresAtSeconds * 1000).String()
-
-			mani["assertions"].([]obj)[1]["data"].(obj)["streamplace:distributionPolicy"] = obj{
-				"deleteAfter": deleteAfterTimestamp,
-			}
-		}
 	}
 
 	return mani

pkg/media/media.go

···
 	"fmt"
 	"io"
 	"sync"
-	"time"
 
 	"github.com/google/uuid"
 	"github.com/pion/interceptor"
···
 const CertFile = "cert.pem"
 const SegmentsDir = "segments"
 
-var StreamplaceMetadata = "cawg.metadata"
+const StreamplaceMetadata = "cawg.metadata"
 
 type MediaManager struct {
 	cli                 *config.CLI
···
 
 // extractDistributionPolicy extracts distribution policy from the C2PA manifest
 func extractDistributionPolicy(mani *c2patypes.Manifest, segmentStart aqtime.AQTime) *model.DistributionPolicy {
-	ass := findAssertion(mani, StreamplaceMetadata)
-	if ass == nil {
-		return nil
-	}
-
-	data, ok := ass.Data.(map[string]interface{})
-	if !ok {
-		return nil
-	}
-
-	policy, ok := data["streamplace:distributionPolicy"]
-	if !ok {
-		return nil
-	}
-
-	policyMap, ok := policy.(map[string]interface{})
-	if !ok {
+	metadataConfig := extractMetadataConfiguration(mani)
+	if metadataConfig == nil {
 		return nil
 	}
 
-	expiry, ok := policyMap["deleteAfter"]
-	if !ok {
+	if metadataConfig.DistributionPolicy == nil {
 		return nil
 	}
 
-	// deleteAfter now contains a timestamp string (RFC3339/ISO 8601 format)
-	expiryStr, ok := expiry.(string)
-	if !ok {
+	if metadataConfig.DistributionPolicy.DeleteAfter == nil {
 		return nil
 	}
 
-	expiryTime, err := time.Parse(time.RFC3339, expiryStr)
-	if err != nil {
-		return nil
-	}
+	// deleteAfter contains an offset in seconds from creation time
+	deleteAfterSeconds := *metadataConfig.DistributionPolicy.DeleteAfter
 
 	return &model.DistributionPolicy{
-		ExpiresAt: &expiryTime,
+		DeleteAfterSeconds: &deleteAfterSeconds,
 	}
 }
 
-// extractDistributionPolicy extracts the place.stream.metadata.configuration from the C2PA manifest
+// extractMetadataConfiguration extracts the place.stream.metadata.configuration from the C2PA manifest
 func extractMetadataConfiguration(mani *c2patypes.Manifest) *streamplace.MetadataConfiguration {
 	ass := findAssertion(mani, "place.stream.metadata.configuration")
 	if ass == nil {

pkg/media/validate.go

···
 		return err
 	}
 	var deleteAfter *time.Time
-	if meta.DistributionPolicy != nil && meta.DistributionPolicy.ExpiresAt != nil {
-		deleteAfter = meta.DistributionPolicy.ExpiresAt
+	if meta.DistributionPolicy != nil && meta.DistributionPolicy.DeleteAfterSeconds != nil {
+		expiryTime := meta.StartTime.Time().Add(time.Duration(*meta.DistributionPolicy.DeleteAfterSeconds) * time.Second)
+		deleteAfter = &expiryTime
 	}
 	seg := &model.Segment{
 		ID:                 *label,
···
 
 	// Check distribution policy (if enabled)
 	if mm.cli.ContentFilters.DistributionPolicy.Enabled && meta.DistributionPolicy != nil {
-		if meta.DistributionPolicy.ExpiresAt != nil {
-			if time.Now().After(*meta.DistributionPolicy.ExpiresAt) {
-				reason := fmt.Sprintf("distribution policy expired: segment expires at %s", meta.DistributionPolicy.ExpiresAt)
+		if meta.DistributionPolicy.DeleteAfterSeconds != nil {
+			expiresAt := meta.StartTime.Time().Add(time.Duration(*meta.DistributionPolicy.DeleteAfterSeconds) * time.Second)
+			if time.Now().After(expiresAt) {
+				reason := fmt.Sprintf("distribution policy expired: segment expires at %s", expiresAt)
 				log.Log(ctx, "content filtered",
 					"reason", reason,
 					"filter_type", "distribution_policy",
 					"creator", meta.Creator,
 					"start_time", meta.StartTime,
-					"expires_at", *meta.DistributionPolicy.ExpiresAt)
+					"expires_at", expiresAt)
 				return fmt.Errorf("content filtered: %s", reason)
 			}
 		}

pkg/model/segment.go

···
 
 // DistributionPolicy represents distribution policy information
 type DistributionPolicy struct {
-	ExpiresAt *time.Time `json:"expiresAt,omitempty"`
+	DeleteAfterSeconds *int64 `json:"deleteAfterSeconds,omitempty"`
 }
 
 // Scan scan value into DistributionPolicy, implements sql.Scanner interface
···
 	}
 
 	var distributionPolicy *streamplace.MetadataDistributionPolicy
-	if s.DistributionPolicy != nil && s.DistributionPolicy.ExpiresAt != nil {
-		// Convert the absolute timestamp back to a duration (in seconds) from segment start
-		startTimeUnix := s.StartTime.Unix()
-		expiresAtUnix := s.DistributionPolicy.ExpiresAt.Unix()
-		deleteAfterSecs := expiresAtUnix - startTimeUnix
+	if s.DistributionPolicy != nil && s.DistributionPolicy.DeleteAfterSeconds != nil {
 		distributionPolicy = &streamplace.MetadataDistributionPolicy{
-			DeleteAfter: &deleteAfterSecs,
+			DeleteAfter: s.DistributionPolicy.DeleteAfterSeconds,
 		}
 	}