Merge pull request 'Fix host stream freeze when a guest joins an in-progress party' (#26) from fix/guest-join-freezes-host-stream into master

client/src/views/player/Player.ts

@@ -1260,7 +1260,20 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
 
     loadMarkers(party.itemId); // not awaited - see onItemChanged's own comment
     await loadTrackOptions(party.itemId);
-    loadVideo(party.itemId, 0, false);
+    // Unlike onItemChanged's own loadVideo(..., 0, ...) - genuinely correct
+    // there since a fresh item has no position yet - mounting mid-party
+    // (a joining guest, or the host's own page reload) must NOT hardcode 0:
+    // the party's shared Emby transcode (PartyStreamService) is keyed by
+    // partyId alone, one PlaySessionId for every member, so a hls.js
+    // instance requesting segments from 0 against a session that already
+    // progressed well past that forces Emby to seek/restart the shared
+    // transcode - stalling it for every other member, host included, right
+    // as the newcomer joins. Seeding from the host's last-reported position
+    // (already in party.members, sent to every mount) lands the first
+    // segment request near where the shared session already is instead.
+    const hostMember = party.members.find((m) => m.isHost);
+    const initialResumeSeconds = hostMember ? hostMember.positionTicks / TICKS_PER_SECOND : 0;
+    loadVideo(party.itemId, initialResumeSeconds, false);
 
     conn = connectParty(partyId, {
       onMembers: renderMembers,