feat(dash): Construct ClearKey PSSH based on MPD ContentProtection (#…

…4104)

This PR parses default_KID from ContentProtection in the manifest and constructs a PSSH box from it to feed to the ClearKey CDM only if clear key content is detected.

Example: 

```
<ContentProtection
    schemeIdUri="urn:mpeg:dash:mp4protection:2011" value="cenc"
    cenc:default_KID="9eb4050d-e44b-4802-932e-27d75083e266" />
<ContentProtection
    value="ClearKey1.0" schemeIdUri="urn:uuid:e2719d58-a985-b3c9-781a-b030af78d30e">
         <clearkey:Laurl Lic_type="EME-1.0">https://drm-clearkey-testvectors.axtest.net/AcquireLicense</clearkey:Laurl>
 </ContentProtection>
```

PSSH is based on https://www.w3.org/TR/eme-initdata-cenc/

Tested content: 
https://media.axprod.net/TestVectors/v7-MultiDRM-SingleKey/Manifest_1080p_ClearKey.mpd

lib/dash/content_protection.js

@@ -68,7 +68,7 @@ shaka.dash.ContentProtection = class {
 
       if (parsedNonCenc.length) {
         drmInfos = ContentProtection.convertElements_(
-            defaultInit, parsedNonCenc, keySystemsByURI);
+            defaultInit, parsedNonCenc, keySystemsByURI, keyIds);
 
         // If there are no drmInfos after parsing, then add a dummy entry.
         // This may be removed in parseKeyIds.
@@ -356,7 +356,41 @@ shaka.dash.ContentProtection = class {
       0x9a, 0x04, 0xf0, 0x79, 0x98, 0x40, 0x42, 0x86,
       0xab, 0x92, 0xe6, 0x5b, 0xe0, 0x88, 0x5f, 0x95,
     ]);
-    const pssh = shaka.util.Pssh.createPssh(data, systemId);
+    const keyIds = new Set();
+    const psshVersion = 0;
+    const pssh =
+        shaka.util.Pssh.createPssh(data, systemId, keyIds, psshVersion);
+    return [
+      {
+        initData: pssh,
+        initDataType: 'cenc',
+        keyId: element.keyId,
+      },
+    ];
+  }
+
+  /**
+   * Creates ClearKey initData from Default_KID value retrieved from previously
+   * parsed ContentProtection tag.
+   * @param {shaka.dash.ContentProtection.Element} element
+   * @param {!Set.<string>} keyIds
+   * @return {?Array.<shaka.extern.InitDataOverride>}
+   * @private
+   */
+  static getInitDataClearKey_(element, keyIds) {
+    if (keyIds.size == 0) {
+      return null;
+    }
+
+    const systemId = new Uint8Array([
+      0x10, 0x77, 0xef, 0xec, 0xc0, 0xb2, 0x4d, 0x02,
+      0xac, 0xe3, 0x3c, 0x1e, 0x52, 0xe2, 0xfb, 0x4b,
+    ]);
+    const data = new Uint8Array([]);
+    const psshVersion = 1;
+    const pssh =
+         shaka.util.Pssh.createPssh(data, systemId, keyIds, psshVersion);
+
     return [
       {
         initData: pssh,
@@ -372,10 +406,11 @@ shaka.dash.ContentProtection = class {
    * @param {Array.<shaka.extern.InitDataOverride>} defaultInit
    * @param {!Array.<shaka.dash.ContentProtection.Element>} elements
    * @param {!Object.<string, string>} keySystemsByURI
+   * @param {!Set.<string>} keyIds
    * @return {!Array.<shaka.extern.DrmInfo>}
    * @private
    */
-  static convertElements_(defaultInit, elements, keySystemsByURI) {
+  static convertElements_(defaultInit, elements, keySystemsByURI, keyIds) {
     const ContentProtection = shaka.dash.ContentProtection;
     const ManifestParserUtils = shaka.util.ManifestParserUtils;
     const licenseUrlParsers = ContentProtection.licenseUrlParsers_;
@@ -391,7 +426,14 @@ shaka.dash.ContentProtection = class {
             'Init data must be null or non-empty.');
 
         const proInitData = ContentProtection.getInitDataFromPro_(element);
-        const initData = element.init || defaultInit || proInitData;
+        let clearKeyInitData = null;
+        if (element.schemeUri ===
+              shaka.dash.ContentProtection.ClearKeySchemeUri_) {
+          clearKeyInitData =
+            ContentProtection.getInitDataClearKey_(element, keyIds);
+        }
+        const initData = element.init || defaultInit || proInitData ||
+          clearKeyInitData;
         const info = ManifestParserUtils.createDrmInfo(keySystem, initData);
         const licenseParser = licenseUrlParsers.get(keySystem);
         if (licenseParser) {
@@ -607,3 +649,11 @@ shaka.dash.ContentProtection.CencNamespaceUri_ = 'urn:mpeg:cenc:2013';
  */
 shaka.dash.ContentProtection.ClearKeyNamespaceUri_ =
   'http://dashif.org/guidelines/clearKey';
+
+
+/**
+ * @const {string}
+ * @private
+ */
+shaka.dash.ContentProtection.ClearKeySchemeUri_ =
+    'urn:uuid:e2719d58-a985-b3c9-781a-b030af78d30e';

lib/hls/hls_parser.js

@@ -2529,7 +2529,10 @@ shaka.hls.HlsParser = class {
       0x9a, 0x04, 0xf0, 0x79, 0x98, 0x40, 0x42, 0x86,
       0xab, 0x92, 0xe6, 0x5b, 0xe0, 0x88, 0x5f, 0x95,
     ]);
-    const pssh = shaka.util.Pssh.createPssh(data, systemId);
+    const keyIds = new Set();
+    const psshVersion = 0;
+    const pssh =
+        shaka.util.Pssh.createPssh(data, systemId, keyIds, psshVersion);
     const drmInfo = shaka.util.ManifestParserUtils.createDrmInfo(
         'com.microsoft.playready', [
           {initDataType: 'cenc', initData: pssh},

lib/util/pssh.js

@@ -90,16 +90,21 @@ shaka.util.Pssh = class {
   }
 
   /**
-   * Creates a pssh blob from the given system ID and data.
+   * Creates a pssh blob from the given system ID, data, keyIds and version.
    *
    * @param {!Uint8Array} data
    * @param {!Uint8Array} systemId
+   * @param {!Set.<string>} keyIds
+   * @param {number} version
    * @return {!Uint8Array}
    */
-  static createPssh(data, systemId) {
+  static createPssh(data, systemId, keyIds, version) {
     goog.asserts.assert(systemId.byteLength == 16, 'Invalid system ID length');
     const dataLength = data.length;
-    const psshSize = 0x4 + 0x4 + 0x4 + systemId.length + 0x4 + dataLength;
+    let psshSize = 0x4 + 0x4 + 0x4 + systemId.length + 0x4 + dataLength;
+    if (version > 0) {
+      psshSize += 0x4 + (16 * keyIds.size);
+    }
 
     /** @type {!Uint8Array} */
     const psshBox = new Uint8Array(psshSize);
@@ -111,10 +116,24 @@ shaka.util.Pssh = class {
     byteCursor += 0x4;
     psshData.setUint32(byteCursor, 0x70737368);  // 'pssh'
     byteCursor += 0x4;
-    psshData.setUint32(byteCursor, 0);  // flags
+    (version < 1) ? psshData.setUint32(byteCursor, 0) :
+        psshData.setUint32(byteCursor, 0x01000000); // version + flags
     byteCursor += 0x4;
     psshBox.set(systemId, byteCursor);
     byteCursor += systemId.length;
+
+    // if version > 0, add KID count and kid values.
+    if (version > 0) {
+      psshData.setUint32(byteCursor, keyIds.size); // KID_count
+      byteCursor += 0x4;
+      const Uint8ArrayUtils = shaka.util.Uint8ArrayUtils;
+      for (const keyId of keyIds) {
+        const KID = Uint8ArrayUtils.fromHex(keyId);
+        psshBox.set(KID, byteCursor);
+        byteCursor += KID.length;
+      }
+    }
+
     psshData.setUint32(byteCursor, dataLength);
     byteCursor += 0x4;
     psshBox.set(data, byteCursor);