Fix tvOS MPV startup playback stability

Yattee/Services/Player/MPV/MPVClient.swift

@@ -456,8 +456,19 @@ final class MPVClient: @unchecked Sendable {
 
         // Cache settings for network streams
         setOptionSync("cache", "yes")
+        #if os(tvOS)
+        // Apple TV can decode 1080p60 easily, but aggressively filling a large
+        // demuxer cache during startup competes with the first seconds of
+        // rendering. Keep enough readahead for smooth playback without racing
+        // hundreds of seconds ahead immediately after load/seek.
+        setOptionSync("cache-secs", "30")
+        setOptionSync("demuxer-readahead-secs", "20")
+        setOptionSync("demuxer-max-bytes", "24MiB")
+        setOptionSync("demuxer-max-back-bytes", "8MiB")
+        #else
         setOptionSync("demuxer-max-bytes", "50MiB")
         setOptionSync("demuxer-max-back-bytes", "25MiB")
+        #endif
 
         // Logging - minimal logging for release builds
         setOptionSync("terminal", "no")

Yattee/Services/Player/MPVBackend.swift

@@ -464,6 +464,8 @@ final class MPVBackend: PlayerBackend {
         currentTime = 0
         duration = 0
         bufferedTime = 0
+        containerFps = 0
+        renderView?.videoFPS = 60
         // When loading with external audio (non-EDL mode), wait for PLAYBACK_RESTART after audio is added
         // With EDL, both streams load atomically so no waiting needed
         isWaitingForExternalAudio = audioStream != nil && !useEDL
@@ -474,6 +476,7 @@ final class MPVBackend: PlayerBackend {
 
         // Reset first-frame tracking for new content
         renderView?.resetFirstFrameTracking()
+        applyStreamFrameRateHint(stream)
 
         // Pause MPV before loading new content to prevent audio from playing
         // before the thumbnail hides. This is critical when reusing the backend
@@ -1743,6 +1746,17 @@ extension MPVBackend: MPVClientDelegate {
     }
     #endif
 
+    /// Seed render/display cadence from API metadata before MPV finishes probing.
+    /// MPV will overwrite this later with the exact container FPS when available.
+    private func applyStreamFrameRateHint(_ stream: Stream) {
+        guard let fps = stream.fps, fps > 0 else { return }
+        containerFps = Double(fps)
+        updateRenderViewFPS()
+        #if os(tvOS)
+        applyTVDisplayCriteria()
+        #endif
+    }
+
     /// Update render view's video FPS for display link frame rate matching
     private func updateRenderViewFPS() {
         // Use cached container-fps (set via property observation to avoid sync fetch on main thread)
@@ -1778,6 +1792,12 @@ extension MPVBackend: MPVClientDelegate {
     /// This is a fallback when no video frames or dimensions are available
     private func checkAndMarkReadyIfAudioOnlyDetected() {
         guard !isReady, !isSeeking else { return }
+        // Only apply this path for streams the user actually selected as audio-only.
+        // For video streams with a separate audio track (DASH), PLAYBACK_RESTART can
+        // fire before mpv has demuxed the video — videoWidth/codec are still 0 — and
+        // we'd incorrectly mark ready as audio-only and start playback before video
+        // decoding catches up, producing an audible startup A/V desync.
+        guard currentStream?.isAudioOnly == true else { return }
         // Detect audio-only: no video codec and no video dimensions from MPV
         guard videoCodec.isEmpty, videoWidth == 0, videoHeight == 0 else { return }
         // Ensure stream metadata is loaded

Yattee/Services/Player/PlayerService.swift

@@ -404,7 +404,9 @@ final class PlayerService {
             // Check for cancellation after stream load completes
             try Task.checkCancellation()
 
-            await backend.seek(to: seekTime, showLoading: false)
+            if seekTime > 0 {
+                await backend.seek(to: seekTime, showLoading: false)
+            }
 
             // Wait for player sheet animation to complete before starting playback
             await navigationCoordinator?.waitForPlayerSheetAnimation()

Yattee/Services/Player/TVDisplayModeManager.swift

@@ -78,8 +78,8 @@ final class TVDisplayModeManager {
     /// Pass `nil` for fields you don't have yet; this method is safe to call
     /// repeatedly as more info becomes available (e.g. fps arrives before gamma).
     func apply(fps: Double?, gamma: String?) {
-        let matchFrameRate = readBoolDefaultFalse(key: "tvMatchDisplayFrameRate")
+        let matchFrameRate = readBool(key: "tvMatchDisplayFrameRate", default: false)
-        let matchDynamicRange = readBoolDefaultFalse(key: "tvMatchDisplayDynamicRange")
+        let matchDynamicRange = readBool(key: "tvMatchDisplayDynamicRange", default: false)
 
         guard matchFrameRate || matchDynamicRange else {
             clear()
@@ -136,10 +136,13 @@ final class TVDisplayModeManager {
 
     // MARK: - Helpers
 
-    private func readBoolDefaultFalse(key: String) -> Bool {
+    private func readBool(key: String, default defaultValue: Bool) -> Bool {
         // The SettingsManager stores these unprefixed (not platform-specific keys),
-        // so we can read them directly from standard UserDefaults. Missing key = off.
+        // so we can read them directly from standard UserDefaults.
-        UserDefaults.standard.bool(forKey: key)
+        guard UserDefaults.standard.object(forKey: key) != nil else {
+            return defaultValue
+        }
+        return UserDefaults.standard.bool(forKey: key)
     }
 
     private func activeDisplayManager() -> AVDisplayManager? {