fix(playback): reset the media element for rejected DRM and widen ClearKey fallback suppression

- Switching from a playing stream to an unsupported-DRM DASH channel
  loads no new source, but play() still ran and the un-loaded element
  could resume the previous stream underneath the diagnostic banner.
  The HTML5 player now resets the element instead of playing.
- Any inline failure on a KODIPROP ClearKey channel (manifest, codec,
  media, network — not just DRM-category errors) is unsolvable in
  MPV/VLC, which never receive the license config; the external
  fallback hint is now suppressed for all diagnostics of such channels.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

libs/ui/playback/src/lib/html-video-player/html-video-player.component.spec.ts

@@ -224,6 +224,35 @@ describe('HtmlVideoPlayerComponent', () => {
         );
     });
 
+    it('does not resume the previous source when a channel declares unsupported DRM', () => {
+        const video = component.videoPlayer.nativeElement;
+        const loadSpy = jest
+            .spyOn(video, 'load')
+            .mockImplementation(() => undefined);
+        const playSpy = jest.spyOn(video, 'play').mockResolvedValue(undefined);
+
+        component.playChannel({
+            ...TEST_CHANNEL,
+            url: 'https://stream.example/movie.mp4',
+        });
+        playSpy.mockClear();
+        loadSpy.mockClear();
+
+        component.playChannel({
+            ...TEST_CHANNEL,
+            url: 'https://stream.example/enc.mpd',
+            drm: {
+                licenseType: 'com.widevine.alpha',
+                supported: false,
+            },
+        });
+
+        // No source is loaded for unsupported DRM: play() must not run, and
+        // the element is reset so the old stream cannot keep playing.
+        expect(playSpy).not.toHaveBeenCalled();
+        expect(loadSpy).toHaveBeenCalledTimes(1);
+    });
+
     it('emits a playback issue when the native video element reports an unsupported source', () => {
         const issues: unknown[] = [];
         component.channel = TEST_CHANNEL;

libs/ui/playback/src/lib/html-video-player/html-video-player.component.ts

@@ -197,7 +197,14 @@ export class HtmlVideoPlayerComponent implements OnInit, OnChanges, OnDestroy {
                     url,
                     channel.drm
                 );
-                this.handlePlayOperation();
+                if (channel.drm && !channel.drm.supported) {
+                    // No source is loaded for unsupported DRM; reset the
+                    // element so the previous stream cannot resume playing
+                    // underneath the diagnostic banner.
+                    this.videoPlayer.nativeElement.load();
+                } else {
+                    this.handlePlayOperation();
+                }
             } else if (
                 (extension === 'ts' || !extension) &&
                 mpegts.isSupported()

libs/ui/playback/src/lib/shaka-engine/shaka-video-session.spec.ts

@@ -114,7 +114,7 @@ describe('ShakaVideoSession', () => {
         expect(session.getPlayer()).toBeNull();
     });
 
-    it('drops the external-fallback hint for DRM errors on ClearKey channels', async () => {
+    it('drops the external-fallback hint for every failure on ClearKey channels', async () => {
         const environment = createFakeShakaEnvironment();
         const session = createSession(environment);
         session.start(video, 'http://example.com/enc.mpd', {
@@ -135,6 +135,24 @@ describe('ShakaVideoSession', () => {
         // MPV/VLC never receive the KODIPROP license config, so they are not
         // offered as a fallback for key failures on ClearKey channels.
         expect(issues[0].externalFallbackRecommended).toBe(false);
+
+        // Non-DRM failures (media/codec/manifest/…) are equally unsolvable
+        // externally while the stream itself stays encrypted.
+        session.start(video, 'http://example.com/enc.mpd', {
+            licenseType: 'clearkey',
+            supported: true,
+            clearKeys: { abc: 'def' },
+        });
+        await flush();
+        environment.instances[1].dispatch('error', {
+            severity: 2,
+            category: 3,
+            code: 3016,
+        });
+
+        expect(issues).toHaveLength(2);
+        expect(issues[1].code).toBe(PlaybackDiagnosticCode.MediaDecodeError);
+        expect(issues[1].externalFallbackRecommended).toBe(false);
     });
 
     it('emits a diagnostic and tears the engine down when load rejects', async () => {

libs/ui/playback/src/lib/shaka-engine/shaka-video-session.ts

@@ -228,15 +228,16 @@ export class ShakaVideoSession {
     }
 
     /**
-     * For channels carrying KODIPROP ClearKey config, DRM failures (wrong or
-     * rotated keys, …) cannot be solved by MPV/VLC either — they never
-     * receive the license config — so the diagnostic must not offer them.
+     * Channels carrying KODIPROP ClearKey config cannot be handed to MPV/VLC
+     * at all — external players never receive the license config, so the
+     * encrypted stream fails there regardless of what broke inline (DRM,
+     * manifest, codec, network, …). Suppress the fallback hint entirely.
      */
     private withoutUnusableDrmFallback(
         issue: PlaybackDiagnostic,
         drmProvided: boolean
     ): PlaybackDiagnostic {
-        if (!drmProvided || issue.code !== DiagnosticCode.DrmOrEncryption) {
+        if (!drmProvided || !issue.externalFallbackRecommended) {
             return issue;
         }
         return { ...issue, externalFallbackRecommended: false };