Update parent_claim value, Le is not updated yet.

Signed-off-by: Bofu Chen (bafu) <bofu@numbersprotocol.io>
numbersprotocol · Feb 10, 2021 · e4a6d7e · e4a6d7e
1 parent cfdd942
commit e4a6d7e
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Showing 2 changed files with 33 additions and 10 deletions.
diff --git a/cai/core.py b/cai/core.py
@@ -87,11 +87,20 @@ def insert_xmp_key(data_bytes, store_label='cai/cb.starling_1'):
     metadata = pyexiv2.ImageMetadata.from_buffer(data_bytes)
     metadata.read()
     metadata['Xmp.dcterms.provenance'] = pyexiv2.XmpTag('Xmp.dcterms.provenance',
-                                                        'self#jumbf=' + store_label)
+                                                        'self#jumbf=cai/' + store_label)
     metadata.write()
     return metadata.buffer
 
 
+def get_xmp_tag(data_bytes, tag='Xmp.dcterms.provenance'):
+    metadata = pyexiv2.ImageMetadata.from_buffer(data_bytes)
+    metadata.read()
+    if tag in metadata.xmp_keys:
+        return metadata[tag].raw_value
+    else:
+        return ''
+
+
 class CaiAssertionStore(SuperBox):
     def __init__(self, assertions):
         super(CaiAssertionStore, self).__init__()
@@ -104,7 +113,8 @@ def __init__(self, assertions):
 class CaiClaim(SuperBox):
     def __init__(self, assertion_store,
                  store_label='cb.starling_1',
-                 recorder='Starling Capture using Numbers Protocol'):
+                 recorder='Starling Capture using Numbers Protocol',
+                 parent_claim=''):
         super(CaiClaim, self).__init__()
         self.description_box = DescriptionBox(
                                    content_type=Cai_content_types['claim'],
@@ -113,13 +123,15 @@ def __init__(self, assertion_store,
         content_box.payload = json_to_bytes(
             self.create_claim(assertion_store,
                               store_label=store_label,
-                              recorder=recorder)
+                              recorder=recorder,
+                              parent_claim=parent_claim)
         )
         self.content_boxes.append(content_box)
 
     def create_claim(self, assertion_store,
                      store_label='cb.starling_1',
-                     recorder='Starling Capture'):
+                     recorder='Starling Capture',
+                     parent_claim=''):
         '''Create a Claim JSON object
         '''
         claim = {}
@@ -134,6 +146,8 @@ def create_claim(self, assertion_store,
             for assertion in assertion_store.content_boxes
         ]
         claim['asset_hashes'] = Claim_asset_hashes_mockup
+        if parent_claim != '':
+            claim['parent_claim'] = parent_claim
         return claim
 
 
@@ -186,13 +200,14 @@ class CaiStore(SuperBox):
     def __init__(self, label='cb.starling_1',
                  assertions=[],
                  recorder='Starling Capture',
+                 parent_claim='',
                  key=[]):
         super(CaiStore, self).__init__()
         self.description_box = DescriptionBox(
                                    content_type=Cai_content_types['store'],
                                    label=label)
         self.assertion_store = CaiAssertionStore(assertions)
-        self.claim = CaiClaim(self.assertion_store, recorder=recorder)
+        self.claim = CaiClaim(self.assertion_store, recorder=recorder, parent_claim=parent_claim)
         if len(key) == 0:
             self.signature = CaiClaimSignature()
         else:

diff --git a/cai/starling.py b/cai/starling.py
@@ -23,6 +23,7 @@
 from cai.core import CaiStore
 from cai.jumbf import App11Box
 
+from cai.core import get_xmp_tag
 from cai.core import insert_xmp_key
 from cai.jumbf import create_codestream_superbox
 from cai.jumbf import create_json_superbox
@@ -83,6 +84,13 @@ def main():
         print(assertion_labels)
         print(store_label)
 
+    # read media content if injection is enabled
+    with open(args.inject, 'rb') as f:
+        raw_bytes = f.read()
+    parent_claim = get_xmp_tag(raw_bytes)
+    print('parent_claim: ', parent_claim)
+
+    # create CAI metadata
     assertions = []
     for filepath, label in zip(assertion_filepaths, assertion_labels):
         with open(filepath, 'rb') as f:
@@ -102,7 +110,11 @@ def main():
     else:
         key = []
 
-    cai_store = CaiStore(label=store_label, assertions=assertions, recorder=recorder, key=key)
+    cai_store = CaiStore(label=store_label,
+                         assertions=assertions,
+                         recorder=recorder,
+                         parent_claim=parent_claim,
+                         key=key)
     cai_claim_block = CaiClaimBlock()
     cai_claim_block.content_boxes.append(cai_store)
     cai_segment = App11Box()
@@ -118,10 +130,6 @@ def main():
     # inject CAI metadata
     if len(args.inject) > 0:
         fname, fext = os.path.splitext(args.inject)
-
-        with open(args.inject, 'rb') as f:
-            raw_bytes = f.read()
-
         fpath = fname + '-cai' + fext
         with open(fpath, 'wb') as f:
             data_bytes = raw_bytes[0:2] + cai_segment.convert_bytes() + raw_bytes[2:]