feat(ttml): Add support for SMPTE namespace 2013 (#3062)

david-hm-morgan · web-flow · commit df74eab0ae2d · 2020-12-26T12:35:27.000-08:00
We have TTML SMPTE XML Namespaces support for 2010. Add SMPTE namespace support for 2013. Closes #3061 .
diff --git a/lib/text/ttml_text_parser.js b/lib/text/ttml_text_parser.js
@@ -306,9 +306,16 @@ shaka.text.TtmlTextParser = class {
       const regionId = regionElement.getAttribute('xml:id');
       cue.region = cueRegions.filter((region) => region.id == regionId)[0];
     }
-    const imageElement = shaka.text.TtmlTextParser.getElementsFromCollection_(
-        cueElement, 'backgroundImage', metadataElements, '#',
-        shaka.text.TtmlTextParser.smpteNs_)[0];
+
+    let imageElement = null;
+    for (const nameSpace of shaka.text.TtmlTextParser.smpteNsList_) {
+      imageElement = shaka.text.TtmlTextParser.getElementsFromCollection_(
+          cueElement, 'backgroundImage', metadataElements, '#',
+          nameSpace)[0];
+      if (imageElement) {
+        break;
+      }
+    }
 
     const isLeaf = nestedCues.length == 0;
 
@@ -1243,12 +1250,14 @@ shaka.text.TtmlTextParser.styleNs_ = 'http://www.w3.org/ns/ttml#styling';
 shaka.text.TtmlTextParser.styleEbuttsNs_ = 'urn:ebu:tt:style';
 
 /**
- * The namespace URL for SMPTE fields.
- * @const {string}
+ * The supported namespace URLs for SMPTE fields.
+ * @const {!Array.<string>}
  * @private
  */
-shaka.text.TtmlTextParser.smpteNs_ =
-    'http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt';
+shaka.text.TtmlTextParser.smpteNsList_ = [
+  'http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt',
+  'http://www.smpte-ra.org/schemas/2052-1/2013/smpte-tt',
+];
 
 shaka.text.TextEngine.registerParser(
     'application/ttml+xml', () => new shaka.text.TtmlTextParser());
diff --git a/test/text/ttml_text_parser_unit.js b/test/text/ttml_text_parser_unit.js
@@ -909,6 +909,30 @@ describe('TtmlTextParser', () => {
         {periodStart: 0, segmentStart: 0, segmentEnd: 0});
   });
 
+  it('supports smpte:backgroundImage attribute alt namespace', () => {
+    verifyHelper(
+        [
+          {
+            startTime: 62.05,
+            endTime: 3723.2,
+            payload: '',
+            backgroundImage: 'data:image/png;base64,base64EncodedImage',
+          },
+        ],
+        '<tt ' +
+        'xmlns:ttm="http://www.w3.org/ns/ttml#metadata" ' +
+        'xmlns:smpte="http://www.smpte-ra.org/schemas/2052-1/2013/smpte-tt">' +
+        '<metadata>' +
+        '<smpte:image imagetype="PNG" encoding="Base64" xml:id="img_0">' +
+        'base64EncodedImage</smpte:image>' +
+        '</metadata>' +
+        '<body><div>' +
+        '<p begin="01:02.05" end="01:02:03.200" ' +
+        'smpte:backgroundImage="#img_0" />' +
+        '</div></body></tt>',
+        {periodStart: 0, segmentStart: 0, segmentEnd: 0});
+  });
+
   it('inserts line breaks for <br> tags', () => {
     verifyHelper(
         [{
