Cover iOS in isBrowserSupported and probeSupport

Now iOS is supported for HLS through src=, so isBrowserSupported
needs to reflect that.  This makes MediaSource optional for any
browser with src= playback of HLS.

This also fixes probeSupport() to reflect the capabilities of non-MSE
platforms such as iOS, which is critical for our demo app to be able
to show the correct set of playable assets.

Issue #997
Closes #1857

Change-Id: Ic6e18587db90fff2b097a2038c16cc928e2b9438

lib/media/manifest_parser.js

@@ -22,6 +22,7 @@ goog.require('goog.asserts');
 goog.require('shaka.log');
 goog.require('shaka.net.NetworkingEngine');
 goog.require('shaka.util.Error');
+goog.require('shaka.util.Platform');
 
 
 /**
@@ -81,18 +82,23 @@ shaka.media.ManifestParser.registerParserByMime = function(
  * @return {!Object.<string, boolean>}
  */
 shaka.media.ManifestParser.probeSupport = function() {
-  // Make sure all registered parsers are shown.
+  const ManifestParser = shaka.media.ManifestParser;
   let support = {};
-  for (let type in shaka.media.ManifestParser.parsersByMime) {
-    support[type] = true;
-  }
-  for (let type in shaka.media.ManifestParser.parsersByExtension) {
-    support[type] = true;
+
+  // Make sure all registered parsers are shown, but only for MSE-enabled
+  // platforms where our parsers matter.
+  if (shaka.util.Platform.supportsMediaSource()) {
+    for (let type in ManifestParser.parsersByMime) {
+      support[type] = true;
+    }
+    for (let type in ManifestParser.parsersByExtension) {
+      support[type] = true;
+    }
   }
 
   // Make sure all well-known types are tested as well, just to show an explicit
   // false for things people might be expecting.
-  let testMimeTypes = [
+  const testMimeTypes = [
     // DASH
     'application/dash+xml',
     // HLS
@@ -101,21 +107,36 @@ shaka.media.ManifestParser.probeSupport = function() {
     // SmoothStreaming
     'application/vnd.ms-sstr+xml',
   ];
-  let testExtensions = [
+  const testExtensions = {
     // DASH
-    'mpd',
+    'mpd': 'application/dash+xml',
     // HLS
-    'm3u8',
+    'm3u8': 'application/x-mpegurl',
     // SmoothStreaming
-    'ism',
-  ];
+    'ism': 'application/vnd.ms-sstr+xml',
+  };
+
+  for (let type of testMimeTypes) {
+    // Only query our parsers for MSE-enabled platforms.  Otherwise, query a
+    // temporary media element for native support for these types.
+    if (shaka.util.Platform.supportsMediaSource()) {
+      support[type] = !!ManifestParser.parsersByMime[type];
+    } else {
+      support[type] = shaka.util.Platform.supportsMediaType(type);
+    }
+  }
 
-  testMimeTypes.forEach(function(type) {
-    support[type] = !!shaka.media.ManifestParser.parsersByMime[type];
-  });
-  testExtensions.forEach(function(type) {
-    support[type] = !!shaka.media.ManifestParser.parsersByExtension[type];
-  });
+  for (let extension in testExtensions) {
+    // Only query our parsers for MSE-enabled platforms.  Otherwise, query a
+    // temporary media element for native support for these MIME type for the
+    // extension.
+    if (shaka.util.Platform.supportsMediaSource()) {
+      support[extension] = !!ManifestParser.parsersByExtension[extension];
+    } else {
+      const type = testExtensions[extension];
+      support[extension] = shaka.util.Platform.supportsMediaType(type);
+    }
+  }
 
   return support;
 };

lib/media/media_source_engine.js

@@ -161,12 +161,7 @@ shaka.media.MediaSourceEngine.isStreamSupported = function(stream) {
  * @return {!Object.<string, boolean>}
  */
 shaka.media.MediaSourceEngine.probeSupport = function() {
-  goog.asserts.assert(
-      shaka.util.Platform.supportsMediaSource(),
-      'Requires basic support');
-
-  let support = {};
-  let testMimeTypes = [
+  const testMimeTypes = [
     // MP4 types
     'video/mp4; codecs="avc1.42E01E"',
     'video/mp4; codecs="avc3.42E01E"',
@@ -202,13 +197,23 @@ shaka.media.MediaSourceEngine.probeSupport = function() {
     'application/mp4; codecs="stpp"',
   ];
 
-  testMimeTypes.forEach(function(type) {
-    support[type] = shaka.text.TextEngine.isTypeSupported(type) ||
-        MediaSource.isTypeSupported(type) ||
-        shaka.media.Transmuxer.isSupported(type);
-    let basicType = type.split(';')[0];
+  let support = {};
+  for (let type of testMimeTypes) {
+    if (shaka.util.Platform.supportsMediaSource()) {
+      // Our TextEngine is only effective for MSE platforms at the moment.
+      if (shaka.text.TextEngine.isTypeSupported(type)) {
+        support[type] = true;
+      } else {
+        support[type] = MediaSource.isTypeSupported(type) ||
+                        shaka.media.Transmuxer.isSupported(type);
+      }
+    } else {
+      support[type] = shaka.util.Platform.supportsMediaType(type);
+    }
+
+    const basicType = type.split(';')[0];
     support[basicType] = support[basicType] || support[type];
-  });
+  }
 
   return support;
 };

lib/player.js

@@ -50,6 +50,7 @@ goog.require('shaka.util.ManifestParserUtils');
 goog.require('shaka.util.MimeUtils');
 goog.require('shaka.util.MultiMap');
 goog.require('shaka.util.Periods');
+goog.require('shaka.util.Platform');
 goog.require('shaka.util.PlayerConfiguration');
 goog.require('shaka.util.Stats');
 goog.require('shaka.util.StreamUtils');
@@ -679,12 +680,22 @@ shaka.Player.registerSupportPlugin = function(name, callback) {
  */
 shaka.Player.isBrowserSupported = function() {
   // Basic features needed for the library to be usable.
-  let basic = !!window.Promise && !!window.Uint8Array &&
-              !!Array.prototype.forEach;
-
-  return basic &&
-         shaka.util.Platform.supportsMediaSource() &&
-         shaka.media.DrmEngine.isBrowserSupported();
+  const basicSupport = !!window.Promise && !!window.Uint8Array &&
+                       !!Array.prototype.forEach;
+  if (!basicSupport) return false;
+
+  // DRM support is not strictly necessary, but the APIs at least need to be
+  // there.  Our no-op DRM polyfill should handle that.
+  // TODO(#1017): Consider making even DrmEngine optional.
+  const drmSupport = shaka.media.DrmEngine.isBrowserSupported();
+  if (!drmSupport) return false;
+
+  // If we have MediaSource (MSE) support, we should be able to use Shaka.
+  if (shaka.util.Platform.supportsMediaSource()) return true;
+
+  // If we don't have MSE, we _may_ be able to use Shaka.  Look for native HLS
+  // support, and call this platform usable if we have it.
+  return shaka.util.Platform.supportsMediaType('application/x-mpegurl');
 };
 
 

lib/util/platform.js

@@ -17,6 +17,8 @@
 
 goog.provide('shaka.util.Platform');
 
+goog.require('shaka.util.Timer');
+
 
 /**
  * A wrapper for platform-specific functions.
@@ -39,14 +41,25 @@ shaka.util.Platform = class {
       return false;
     }
 
-    // TODO: Document when |isTypeSupported| would be missing.
+    // Some very old MediaSource implementations didn't have isTypeSupported.
     if (!MediaSource.isTypeSupported) {
       return false;
     }
 
     return true;
   }
 
+  /**
+   * Returns true if the media type is supported natively by the platform.
+   *
+   * @param {string} mimeType
+   * @return {boolean}
+   */
+  static supportsMediaType(mimeType) {
+    const video = shaka.util.Platform.anyMediaElement_();
+    return video.canPlayType(mimeType) != '';
+  }
+
   /**
    * Check if the current platform is MS Edge.
    *
@@ -126,4 +139,45 @@ shaka.util.Platform = class {
     const userAgent = navigator.userAgent || '';
     return userAgent.includes(key);
   }
+
+  /**
+   * For canPlayType queries, we just need any instance.
+   *
+   * First, use a cached element from a previous query.
+   * Second, search the page for one.
+   * Third, create a temporary one.
+   *
+   * Cached elements expire in one second so that they can be GC'd or removed.
+   *
+   * @return {!HTMLMediaElement}
+   */
+  static anyMediaElement_() {
+    const Platform = shaka.util.Platform;
+    if (Platform.cachedMediaElement_) {
+      return Platform.cachedMediaElement_;
+    }
+
+    if (!Platform.cacheExpirationTimer_) {
+      Platform.cacheExpirationTimer_ = new shaka.util.Timer(() => {
+        Platform.cachedMediaElement_ = null;
+      });
+    }
+
+    Platform.cachedMediaElement_ = /** @type {HTMLMediaElement} */(
+        document.querySelector('video') || document.querySelector('audio'));
+
+    if (!Platform.cachedMediaElement_) {
+      Platform.cachedMediaElement_ = /** @type {!HTMLMediaElement} */(
+          document.createElement('video'));
+    }
+
+    Platform.cacheExpirationTimer_.tickAfter(/* seconds= */ 1);
+    return Platform.cachedMediaElement_;
+  }
 };
+
+/** @private {shaka.util.Timer} */
+shaka.util.Platform.cacheExpirationTimer_ = null;
+
+/** @private {HTMLMediaElement} */
+shaka.util.Platform.cachedMediaElement_ = null;