Emby is Jellyfin's upstream ancestor and speaks a near-identical MediaBrowser
API, so the existing Jellyfin stack is parameterised by a `MediaBrowserDialect`
rather than forked. `JellyfinClient`, its auth service, endpoint discovery, LAN
discovery, and the add/edit connection screens all take the dialect and keep one
implementation; `MediaBackend.emby` and `ConnectionKind.emby` carry it through
the neutral models, the Drift `kind` discriminator, downloads, and caches.
Every divergence below was measured against a live Emby 4.9.5 server, not
inferred from documentation, and each is documented at its capability getter.
Jellyfin's request strings stay byte-identical so nothing about its behaviour
changes.
Routes and auth
- Emby only accepts the pre-10.9 user-scoped item routes (`/Users/{id}/Items/…`,
`/Users/{id}/PlayedItems/…`, `/Users/{id}/FavoriteItems/…`); the unprefixed
forms Jellyfin 10.11 added return 404.
- The API is also served under a legacy `/emby` prefix, and both dialects accept
the token as `X-Emby-Token` or `api_key=`.
- Emby answers only its own LAN discovery datagram ("who is EmbyServer?") and
ignores Jellyfin's; its default HTTPS port is 8920.
- No `/QuickConnect` route exists, so Quick Connect stays Jellyfin-only.
Row fields Emby withholds
- `ProductionYear`, `OfficialRating`, `PremiereDate` and `DateCreated` are absent
from list rows unless named in `Fields`, which would otherwise strip the year
and age-rating badge from every card in the app.
- `UserData.LastPlayedDate` never appears on a list row under `Fields=UserData`,
`EnableUserData=true` or the user-scoped `Ids=` form — only on the single-item
detail route, or when the Emby-specific `UserDataLastPlayedDate` token is
requested. Without it every recency-ordered surface silently degrades to
library-add time, and `JellyfinApiCache.applyWatchState` stamps
`DateTime.now()` on watched rows, so an offline watch-state pull would rewrite
the cached play time of everything it walked.
Continue Watching and Next Up
- Emby computes Next Up per series only: the library-wide `/Shows/NextUp` query
returns nothing under every parameter combination tried. The shelf is
therefore reconstructed from a played-episode recency scan plus one
`/Shows/NextUp?SeriesId=` per distinct series, bounded by a shared wall clock
that covers the scan as well — per-request timeouts cannot bound the pass
because `MediaServerHttpClient` times the connect and receive phases
independently. Rows are stamped with their series' newest play from the same
response that ordered them, so no per-series enrichment request is needed.
- `/Shows/NextUp` ignores `NextUpDateCutoff`, and no server-side played-date
filter exists to delegate to (`MinDatePlayed` and `MinDateLastPlayed` are
ignored; `MinDateLastSaved`, `MinDateCreated` and `MinPremiereDate` filter
unrelated dates), so the 365-day window is applied to the scanned dates.
- The resume route returns items with no saved position, including plain next
episodes, so the Emby resume leg reads from `/Items?Filters=IsResumable`.
- Emby is ahead of Jellyfin in one place: `/Users/{id}/Items/{id}/HideFromResume`
makes Continue Watching removal a real capability.
Everything else
- `/Sessions/Playing` and `/Sessions/Playing/Progress` reject a body with no
`PlaySessionId` (HTTP 400), so playback reporting always sends one.
- Passing any `MediaTypes` value to the playlist query returns an empty list.
- There is no aggregate `/Items/Filters` route; the four filter facets are
reassembled from `/Genres`, `/OfficialRatings`, `/Studios` and `/Tags`.
- Metadata writes take name-pair lists (`Genres: [{'Name': 'Action'}]`); the
plain string array is accepted and then silently discarded.
- Custom artwork uploads must be base64 text, not raw bytes — which was broken
for Jellyfin too and is fixed for both.
- Trickplay, media segments and lyrics 404 on Emby, so scrub previews are absent
and intro/credit markers fall back to chapter names.
Verified against a local Emby 4.9.5 and a Jellyfin 10.11.11 control server:
onboarding, browse, detail, playable stream URLs serving real bytes, subtitle
sidecars, watch-state write and restore, hubs, cross-server aggregation and
search across both backends simultaneously.
The wrong-type recovery only covered reads that went through a
BaseSharedPreferencesService instance. The three stores that hold
credentials read the shared cache directly, so a mistyped value there
still threw a raw TypeError or, for Seerr, was swallowed by a catch-all
and reported as "no session" — the registry documented protection it did
not actually provide.
readPreferenceTolerantly now takes the cache, so CredentialVault,
TrackerAccountStore and SeerrSessionStore get the same classification as
the settings layer. CredentialVault's post-write re-read moves outside
its catch: a wrong-typed value written by another isolate was swallowed
there, and the process then returned a key that never durably landed,
making every ciphertext written under it unreadable on the next launch.
Those stores are consulted long after startup, where a throw is an
unhandled provider error rather than a repair prompt, so SettingsService
initialization now walks the cached key set once and reads every
sensitive key. That puts the failure inside a fatal gate step while the
store is still open and a surgical single-key repair is possible.
The remaining direct reads in settings and storage are routed too; the
only ones left are the library-density dual-type migration, which probes
both types deliberately, and an untyped switch that is type-safe by
construction.
A failed MAC check (key/ciphertext divergence: restored backup,
clobbered prefs, racing key generation across isolates) threw from
CredentialVault.reveal on the startup profile-settings path and
crash-looped the app until data was wiped — one device logged 31
fatals in 16 minutes on 2.8.0.
Decrypt failure now means the credential is lost, never a crash:
reveal() returns null, ProfileConnectionRegistry maps it onto the
existing empty-token lazy-fetch sentinel and heals the row so later
boots re-acquire the token instead of re-failing, and
revealConnectionConfig degrades tokens to empty strings without
marking them migrated. Key init also reloads prefs before deciding to
generate and re-reads after writing, adopting whatever landed so all
isolates converge on a single key instead of orphaning ciphertext.
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