Refactor/Rename PlaybackObserver to MediaElementMonitor

src/README.md

@@ -182,9 +182,9 @@ For the subdirectories and files in this directory not represented in that schem
 - `manifest` (_./manifest_): Defines a `Manifest` structure and its properties, a central
   structure of the player describing a content.
 
-- `PlaybackObserver` (./playback_observer): Defines `PlaybackObserver` instances, used by
-  many modules to obtain playback-related properties (such as the playing position, the
-  current playback speed etc.).
+- `MediaElementMonitor` (./media_element_monitor): Defines the `MediaElementMonitor` ,
+  used by many modules to poll the `HTMLMediaElement` for playback-related properties
+  (such as the playing position, the current playback speed etc.).
 
 - `parsers` (_./parsers_): Various parsers for several formats
 

src/compat/__tests__/is_codec_supported.test.ts

@@ -14,20 +14,8 @@ describe("Compat - isCodecSupported", () => {
     });
     const isCodecSupported = (await vi.importActual("../is_codec_supported"))
       .default as typeof IIsCodecSupported;
-    expect(isCodecSupported(document.createElement("video"), "foo")).toEqual(false);
-    expect(isCodecSupported(document.createElement("video"), "")).toEqual(false);
-  });
-
-  it("should return true in any case if the MediaSource does not have the right function", async () => {
-    vi.doMock("../browser_compatibility_types", () => {
-      return {
-        MediaSource_: { isTypeSupported: undefined },
-      };
-    });
-    const isCodecSupported = (await vi.importActual("../is_codec_supported"))
-      .default as typeof IIsCodecSupported;
-    expect(isCodecSupported(document.createElement("video"), "foo")).toEqual(true);
-    expect(isCodecSupported(document.createElement("video"), "")).toEqual(true);
+    expect(isCodecSupported("foo")).toEqual(false);
+    expect(isCodecSupported("")).toEqual(false);
   });
 
   it("should return true if MediaSource.isTypeSupported returns true", async () => {
@@ -42,8 +30,8 @@ describe("Compat - isCodecSupported", () => {
     });
     const isCodecSupported = (await vi.importActual("../is_codec_supported"))
       .default as typeof IIsCodecSupported;
-    expect(isCodecSupported(document.createElement("video"), "foo")).toEqual(true);
-    expect(isCodecSupported(document.createElement("video"), "")).toEqual(true);
+    expect(isCodecSupported("foo")).toEqual(true);
+    expect(isCodecSupported("")).toEqual(true);
   });
 
   it("should return false if MediaSource.isTypeSupported returns false", async () => {
@@ -58,7 +46,7 @@ describe("Compat - isCodecSupported", () => {
     });
     const isCodecSupported = (await vi.importActual("../is_codec_supported"))
       .default as typeof IIsCodecSupported;
-    expect(isCodecSupported(document.createElement("video"), "foo")).toEqual(false);
-    expect(isCodecSupported(document.createElement("video"), "")).toEqual(false);
+    expect(isCodecSupported("foo")).toEqual(false);
+    expect(isCodecSupported("")).toEqual(false);
   });
 });

src/compat/browser_compatibility_types.ts

@@ -114,6 +114,11 @@ export interface IMediaSourceEventMap {
   endstreaming: Event;
 }
 
+export interface IMediaSourceClass {
+  new (): IMediaSource;
+  isTypeSupported(mimetype: string): boolean;
+}
+
 /**
  * Type-compatible with the `MediaSource` type (i.e. a `MediaSource` is a valid
  * `IMediaSource`), the `IMediaSource` type allows to:
@@ -234,7 +239,7 @@ export interface IMediaElement extends IEventTarget<IMediaElementEventMap> {
    * Optional property allowing to force a specific MSE Implementation when
    * relying on a given `IMediaElement`.
    */
-  FORCED_MEDIA_SOURCE?: new () => IMediaSource;
+  FORCED_MEDIA_SOURCE?: IMediaSourceClass;
 
   FORCED_EME_API?: IEmeApiImplementation;
 

src/compat/is_codec_supported.ts

@@ -14,12 +14,10 @@
  * limitations under the License.
  */
 
-import type DummyMediaElement from "../experimental/tools/DummyMediaElement";
 import log from "../log";
-import isNullOrUndefined from "../utils/is_null_or_undefined";
 import isWorker from "../utils/is_worker";
+import type { IMediaSourceClass } from "./browser_compatibility_types";
 import { MediaSource_ } from "./browser_compatibility_types";
-import type { IMediaElement } from "./browser_compatibility_types";
 
 /**
  * Setting this value limit the number of entries in the support map
@@ -32,47 +30,46 @@ const MAX_SUPPORT_MAP_ENTRIES = 200;
  * and help for performance especially on low-end devices.
  */
 const supportMap: Map<string, boolean> = new Map();
+
 /**
  * Returns true if the given codec is supported by the browser's MediaSource
  * implementation.
- * @param {HTMLMediaElement} mediaElement
  * @param {string} mimeType - The MIME media type that you want to test support
  * for in the current browser.
  * This may include the codecs parameter to provide added details about the
  * codecs used within the file.
+ * @param {Object|undefined} [MediaSourceClass] - The `MediaSource` class relied
+ * on to play contents.
+ * `undefined` if unknown or if the `MediaSource` we rely on is in another
+ * environment (e.g. a WebWorker).
  * @returns {Boolean}
  */
 export default function isCodecSupported(
-  mediaElement: IMediaElement,
   mimeType: string,
+  /* eslint-disable-next-line @typescript-eslint/naming-convention */
+  MediaSourceClass?: IMediaSourceClass | undefined,
 ): boolean {
-  // TODO: We only added that as a hotfix for now, to allow support of the right codecs
-  // on a dummy media element
-  if ((mediaElement as DummyMediaElement).isDummy) {
-    return (mediaElement as DummyMediaElement).FORCED_MEDIA_SOURCE.isTypeSupported(
-      mimeType,
-    );
-  }
-  if (isNullOrUndefined(MediaSource_)) {
+  /* eslint-disable @typescript-eslint/unbound-method */
+  const isTypeSupported =
+    MediaSourceClass !== undefined
+      ? MediaSourceClass.isTypeSupported
+      : MediaSource_?.isTypeSupported;
+  if (typeof isTypeSupported !== "function") {
     if (isWorker) {
       log.error("mse", "Cannot request codec support in a worker without MSE.");
     }
     return false;
   }
 
-  if (typeof MediaSource_.isTypeSupported === "function") {
-    const cachedSupport = supportMap.get(mimeType);
-    if (cachedSupport !== undefined) {
-      return cachedSupport;
-    } else {
-      const isSupported = MediaSource_.isTypeSupported(mimeType);
-      if (supportMap.size >= MAX_SUPPORT_MAP_ENTRIES) {
-        supportMap.clear();
-      }
-      supportMap.set(mimeType, isSupported);
-      return isSupported;
+  const cachedSupport = supportMap.get(mimeType);
+  if (cachedSupport !== undefined) {
+    return cachedSupport;
+  } else {
+    const isSupported = isTypeSupported(mimeType);
+    if (supportMap.size >= MAX_SUPPORT_MAP_ENTRIES) {
+      supportMap.clear();
     }
+    supportMap.set(mimeType, isSupported);
+    return isSupported;
   }
-
-  return true;
 }

src/core/adaptive/__tests__/adaptive_representation_selector.test.ts

@@ -38,8 +38,8 @@ function makePlaybackObservation(overrides: Partial<any> = {}) {
   };
 }
 
-/** Build a minimal playback observer around a single observation value. */
-function makePlaybackObserver(obs: any) {
+/** Build a minimal MediaElementMonitor around a single observation value. */
+function makeMediaElementMonitor(obs: any) {
   const ref = new SharedReference(obs);
   return {
     getReference: () => ref,
@@ -87,7 +87,7 @@ describe("createAdaptiveRepresentationSelector", () => {
     const currentRepRef = new SharedReference(null);
     const repsRef = new SharedReference([rep]);
     const obs = makePlaybackObservation({ bufferGap: 0 });
-    const observer = makePlaybackObserver(obs);
+    const observer = makeMediaElementMonitor(obs);
 
     selector(makeContext(), currentRepRef, repsRef, observer, canceller.signal);
 
@@ -104,15 +104,15 @@ describe("createAdaptiveRepresentationSelector", () => {
     const currentRepRef = new SharedReference(null);
     const repsRef = new SharedReference([rep]);
     const obs = makePlaybackObservation();
-    const observer = makePlaybackObserver(obs);
+    const observer = makeMediaElementMonitor(obs);
     const ctx = makeContext();
 
     selector(ctx, currentRepRef, repsRef, observer, canceller.signal);
     selector(
       ctx,
       new SharedReference(null),
       new SharedReference([rep]),
-      makePlaybackObserver(obs),
+      makeMediaElementMonitor(obs),
       canceller.signal,
     );
 
@@ -145,14 +145,14 @@ describe("createAdaptiveRepresentationSelector", () => {
       videoCtx,
       new SharedReference(null),
       new SharedReference([rep]),
-      makePlaybackObserver(obs),
+      makeMediaElementMonitor(obs),
       canceller.signal,
     );
     selector(
       audioCtx,
       new SharedReference(null),
       new SharedReference([rep]),
-      makePlaybackObserver(obs),
+      makeMediaElementMonitor(obs),
       canceller.signal,
     );
 
@@ -170,7 +170,7 @@ describe("createAdaptiveRepresentationSelector", () => {
       const currentRepRef = new SharedReference(null);
       const repsRef = new SharedReference([rep]);
       const obs = makePlaybackObservation();
-      const observer = makePlaybackObserver(obs);
+      const observer = makeMediaElementMonitor(obs);
 
       const { estimates } = selector(
         makeContext(),
@@ -242,7 +242,7 @@ describe("createAdaptiveRepresentationSelector", () => {
       const currentRepRef = new SharedReference(currentRep);
       const repsRef = new SharedReference([repLow, repMid, repHigh]);
       const obs = makePlaybackObservation(obsOverrides);
-      const observer = makePlaybackObserver(obs);
+      const observer = makeMediaElementMonitor(obs);
 
       const result = selector(
         makeContext(isDynamic),
@@ -400,7 +400,7 @@ describe("createAdaptiveRepresentationSelector", () => {
         maximumPosition: 50,
         position: makeObservationPosition(20),
       });
-      const observer = makePlaybackObserver(obs);
+      const observer = makeMediaElementMonitor(obs);
 
       const { estimates } = selector(
         makeContext(true),
@@ -426,7 +426,7 @@ describe("createAdaptiveRepresentationSelector", () => {
       const currentRepRef = new SharedReference(null);
       const repsRef = new SharedReference([repLow, repHigh]);
       const obs = makePlaybackObservation();
-      const observer = makePlaybackObserver(obs);
+      const observer = makeMediaElementMonitor(obs);
 
       const { callbacks } = selector(
         makeContext(),
@@ -577,7 +577,7 @@ describe("createAdaptiveRepresentationSelector", () => {
         makeContext(),
         new SharedReference(null),
         new SharedReference(reps),
-        makePlaybackObserver(makePlaybackObservation()),
+        makeMediaElementMonitor(makePlaybackObservation()),
         canceller.signal,
       );
 
@@ -608,7 +608,7 @@ describe("createAdaptiveRepresentationSelector", () => {
         makeContext(),
         new SharedReference(null),
         new SharedReference(reps),
-        makePlaybackObserver(makePlaybackObservation({ speed: 2 })),
+        makeMediaElementMonitor(makePlaybackObservation({ speed: 2 })),
         canceller.signal,
       );
 
@@ -640,7 +640,7 @@ describe("createAdaptiveRepresentationSelector", () => {
         makeContext(),
         new SharedReference(null),
         new SharedReference(reps),
-        makePlaybackObserver(makePlaybackObservation({ speed: 0 })),
+        makeMediaElementMonitor(makePlaybackObservation({ speed: 0 })),
         canceller.signal,
       );
 
@@ -667,7 +667,7 @@ describe("createAdaptiveRepresentationSelector", () => {
       const currentRepRef = new SharedReference(null);
       const repsRef = new SharedReference([repLow]);
       const obs = makePlaybackObservation();
-      const observer = makePlaybackObserver(obs);
+      const observer = makeMediaElementMonitor(obs);
 
       const { estimates } = selector(
         makeContext(),
@@ -712,7 +712,7 @@ describe("createAdaptiveRepresentationSelector", () => {
       const currentRepRef = new SharedReference(null);
       const repsRef = new SharedReference([rep]);
       const obs = makePlaybackObservation();
-      const observer = makePlaybackObserver(obs);
+      const observer = makeMediaElementMonitor(obs);
 
       const { estimates } = selector(
         makeContext(),