fix: Fix support for TTAF1 namespace (old version of TTML) (#3864)

Fixes #3009
shaka-project · Jan 25, 2022 · 771619f · 771619f
1 parent dfb3699
commit 771619f
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Showing 3 changed files with 66 additions and 13 deletions.
diff --git a/lib/text/ttml_text_parser.js b/lib/text/ttml_text_parser.js
@@ -86,16 +86,17 @@ shaka.text.TtmlTextParser = class {
       }
 
       // Get the framerate, subFrameRate and frameRateMultiplier if applicable.
-      const frameRate = XmlUtils.getAttributeNS(tt, ttpNs, 'frameRate');
-      const subFrameRate = XmlUtils.getAttributeNS(tt, ttpNs, 'subFrameRate');
+      const frameRate = XmlUtils.getAttributeNSList(tt, ttpNs, 'frameRate');
+      const subFrameRate = XmlUtils.getAttributeNSList(
+          tt, ttpNs, 'subFrameRate');
       const frameRateMultiplier =
-          XmlUtils.getAttributeNS(tt, ttpNs, 'frameRateMultiplier');
-      const tickRate = XmlUtils.getAttributeNS(tt, ttpNs, 'tickRate');
+          XmlUtils.getAttributeNSList(tt, ttpNs, 'frameRateMultiplier');
+      const tickRate = XmlUtils.getAttributeNSList(tt, ttpNs, 'tickRate');
 
-      const cellResolution = XmlUtils.getAttributeNS(
+      const cellResolution = XmlUtils.getAttributeNSList(
           tt, ttpNs, 'cellResolution');
       const spaceStyle = tt.getAttribute('xml:space') || 'default';
-      const extent = XmlUtils.getAttributeNS(tt, ttsNs, 'extent');
+      const extent = XmlUtils.getAttributeNSList(tt, ttsNs, 'extent');
 
       if (spaceStyle != 'default' && spaceStyle != 'preserve') {
         throw new shaka.util.Error(
@@ -797,7 +798,7 @@ shaka.text.TtmlTextParser = class {
       return null;
     }
 
-    const attr = XmlUtils.getAttributeNS(region, ttsNs, attribute);
+    const attr = XmlUtils.getAttributeNSList(region, ttsNs, attribute);
     if (attr) {
       return attr;
     }
@@ -822,7 +823,7 @@ shaka.text.TtmlTextParser = class {
 
     // Styling on elements should take precedence
     // over the main styling attributes
-    const elementAttribute = XmlUtils.getAttributeNS(
+    const elementAttribute = XmlUtils.getAttributeNSList(
         cueElement,
         ttsNs,
         attribute);
@@ -865,7 +866,7 @@ shaka.text.TtmlTextParser = class {
 
       if (!styleAttributeValue) {
         // Fall back to tts namespace.
-        styleAttributeValue = XmlUtils.getAttributeNS(
+        styleAttributeValue = XmlUtils.getAttributeNSList(
             inheritedStyles[i],
             ttsNs,
             attribute);
@@ -1320,20 +1321,26 @@ shaka.text.TtmlTextParser.textAlignToPositionAlign_ = {
  * document, not just "ttp:", so we use this with getAttributeNS() to ensure
  * that we support arbitrary namespace names.
  *
- * @const {string}
+ * @const {!Array.<string>}
  * @private
  */
-shaka.text.TtmlTextParser.parameterNs_ = 'http://www.w3.org/ns/ttml#parameter';
+shaka.text.TtmlTextParser.parameterNs_ = [
+  'http://www.w3.org/ns/ttml#parameter',
+  'http://www.w3.org/2006/10/ttaf1#parameter',
+];
 
 /**
  * The namespace URL for TTML styles.  Can be assigned any name in the TTML
  * document, not just "tts:", so we use this with getAttributeNS() to ensure
  * that we support arbitrary namespace names.
  *
- * @const {string}
+ * @const {!Array.<string>}
  * @private
  */
-shaka.text.TtmlTextParser.styleNs_ = 'http://www.w3.org/ns/ttml#styling';
+shaka.text.TtmlTextParser.styleNs_ = [
+  'http://www.w3.org/ns/ttml#styling',
+  'http://www.w3.org/2006/10/ttaf1#styling',
+];
 
 /**
  * The namespace URL for EBU TTML styles.  Can be assigned any name in the TTML

diff --git a/lib/util/xml_utils.js b/lib/util/xml_utils.js
@@ -103,6 +103,25 @@ shaka.util.XmlUtils = class {
   }
 
 
+  /**
+   * Gets a namespace-qualified attribute.
+   * @param {!Element} elem The element to get from.
+   * @param {!Array.<string>} nsList The lis of namespace URIs.
+   * @param {string} name The local name of the attribute.
+   * @return {?string} The attribute's value, or null if not present.
+   */
+  static getAttributeNSList(elem, nsList, name) {
+    // Some browsers return the empty string when the attribute is missing,
+    // so check if it exists first.  See: https://mzl.la/2L7F0UK
+    for (const ns of nsList) {
+      if (elem.hasAttributeNS(ns, name)) {
+        return elem.getAttributeNS(ns, name);
+      }
+    }
+    return null;
+  }
+
+
   /**
    * Gets the text contents of a node.
    * @param {!Node} elem The XML element.

diff --git a/test/text/ttml_text_parser_unit.js b/test/text/ttml_text_parser_unit.js
@@ -1358,6 +1358,33 @@ describe('TtmlTextParser', () => {
         {startTime: 62.05, endTime: 3723.2});
   });
 
+  it('allows old-standard namespace', () => {
+    verifyHelper(
+        [
+          {
+            startTime: 1,
+            endTime: 2,
+            payload: 'Test',
+            cellResolution: {
+              columns: 60,
+              rows: 20,
+            },
+            fontSize: '67%',
+          },
+        ],
+        '<tt ' +
+        'xmlns:ttp="http://www.w3.org/2006/10/ttaf1#parameter" ' +
+        'xmlns:tts="http://www.w3.org/2006/10/ttaf1#styling" ' +
+        'ttp:cellResolution="60 20">' +
+        '<styling>' +
+        '<style xml:id="s1" tts:fontSize="67%"/>' +
+        '</styling>' +
+        '<body><div>' +
+        '<p begin="00:01.00" end="00:02.00" style="s1">Test</p>' +
+        '</div></body></tt>',
+        {periodStart: 0, segmentStart: 0, segmentEnd: 0});
+  });
+
   it('parses cue alignment from textAlign attribute', () => {
     verifyHelper(
         [