优化，bug处理

internal/handler/media.go

@@ -810,6 +810,20 @@ func streamHandler(svc *service.Container) gin.HandlerFunc {
 				c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
 				return
 			}
+			// 远程条目可能是「整部剧/季/目录」：这类条目自身没有媒体源，远程 Emby 对它
+			// 们的 /Videos/{id}/stream 会直接回 500（Unable to cast object of type
+			// 'Series' to type 'IHasMediaSources'）。网页端、外部播放器、第三方客户端都
+			// 可能把这种 ID 送进来，这里统一改投第一集：302 让客户端自己跟过去，播放器
+			// 原有的 token / proxy 查询参数一并保留。
+			if playable := svc.EmbyRemote.PlayableRemoteID(ctx, acct, remoteID); playable != "" && playable != remoteID {
+				target := "/api/stream/" + service.EncodeEmbyRemoteID(mountID, playable)
+				if rawQuery := c.Request.URL.RawQuery; rawQuery != "" {
+					target += "?" + rawQuery
+				}
+				setRedirectNoStoreHeaders(c)
+				c.Redirect(http.StatusFound, target)
+				return
+			}
 			// 远程 Emby 条目的同源转发：VR 全景需要浏览器读帧（见 stream_proxy.go），
 			// 与挂载账号的 proxy_play 开关等价。
 			if mount.ProxyPlay || wantSameOriginProxy(c) {

internal/handler/stream_emby_remote_redirect_test.go

@@ -0,0 +1,200 @@
+package handler
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+	"github.com/glebarez/sqlite"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"github.com/truewhile/MeBox/internal/config"
+	"github.com/truewhile/MeBox/internal/model"
+	"github.com/truewhile/MeBox/internal/repository"
+	"github.com/truewhile/MeBox/internal/service"
+)
+
+// 首页轮播/剧集卡片交给播放器的是「整部剧」的伪装 ID，它自身没有媒体源：远程 Emby
+// 对它的取流请求会回 500（Unable to cast 'Series' to 'IHasMediaSources'）。这里锁定
+// 播放接口的行为——改投第一集，且客户端原有的查询参数（token / profile / proxy）
+// 必须原样带过去，否则播放器跟过去之后会掉鉴权。
+func TestStreamRedirectsRemoteContainerToPlayableEpisode(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		switch r.URL.Path {
+		case "/emby/Users/uid-1/Items/series-100":
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"Id": "series-100", "Name": "某部新番", "Type": "Series", "IsFolder": true,
+			})
+		case "/emby/Users/uid-1/Items":
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"Items": []map[string]any{
+					map[string]any{
+						"Id": "ep-1", "Name": "第1集", "Type": "Episode", "SeriesId": "series-100",
+						"ParentIndexNumber": 1, "IndexNumber": 1,
+						"MediaSources": []any{map[string]any{"Id": "ep-1-src"}},
+					},
+				},
+			})
+		default:
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+	defer upstream.Close()
+
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := db.AutoMigrate(
+		&model.User{}, &model.UserPermission{}, &model.Setting{}, &model.Library{}, &model.Media{},
+		&model.StrmAccount{}, &model.EmbyMount{},
+	); err != nil {
+		t.Fatal(err)
+	}
+	repos := repository.New(db)
+	cfg := &config.Config{}
+	cfg.Secrets.JWTSecret = "stream-redirect-secret"
+	log := zap.NewNop()
+
+	remote := service.NewEmbyRemoteService(cfg, log, repos, service.NewCryptoService("", log))
+	svc := &service.Container{Cfg: cfg, Repo: repos, EmbyRemote: remote}
+
+	rawConfig, _ := json.Marshal(map[string]string{
+		"url":            upstream.URL,
+		"api_key":        "test-api-key",
+		"remote_user_id": "uid-1",
+	})
+	if err := repos.StrmAccount.Create(t.Context(), &model.StrmAccount{
+		Base:     model.Base{ID: "acct-1"},
+		Name:     "远程 Emby",
+		Provider: model.StrmProviderEmbyRemote,
+		Config:   string(rawConfig),
+		Enabled:  true,
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if err := repos.EmbyMount.Create(t.Context(), &model.EmbyMount{
+		Base:           model.Base{ID: "mount-1"},
+		AccountID:      "acct-1",
+		RemoteViewID:   "view-1",
+		RemoteViewName: "新番连载",
+		CollectionType: "tvshows",
+		Enabled:        true,
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	router := gin.New()
+	router.GET("/api/stream/:id", streamHandler(svc))
+
+	req := httptest.NewRequest(
+		http.MethodGet,
+		"/api/stream/"+service.EncodeEmbyRemoteID("mount-1", "series-100")+"?token=tok-1&profile=p-1",
+		nil,
+	)
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+
+	if w.Code != http.StatusFound {
+		t.Fatalf("status = %d body=%s, want 302", w.Code, w.Body.String())
+	}
+	want := "/api/stream/" + service.EncodeEmbyRemoteID("mount-1", "ep-1") + "?token=tok-1&profile=p-1"
+	if got := w.Header().Get("Location"); got != want {
+		t.Fatalf("Location = %q, want %q", got, want)
+	}
+}
+
+// 本身可播的远程条目（单集/电影）不能被改写，必须照原样进入原来的代理/直连分支。
+func TestStreamKeepsPlayableRemoteItem(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	var streamCalls int
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		switch r.URL.Path {
+		case "/emby/Users/uid-1/Items/ep-1":
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"Id": "ep-1", "Name": "第1集", "Type": "Episode", "SeriesId": "series-100",
+				"ParentIndexNumber": 1, "IndexNumber": 1,
+				"MediaSources": []any{map[string]any{"Id": "ep-1-src"}},
+			})
+		case "/emby/Videos/ep-1/stream":
+			streamCalls++
+			w.Header().Set("Content-Type", "video/mp4")
+			w.WriteHeader(http.StatusOK)
+			_, _ = w.Write([]byte("bytes"))
+		default:
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+	defer upstream.Close()
+
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := db.AutoMigrate(
+		&model.User{}, &model.UserPermission{}, &model.Setting{}, &model.Library{}, &model.Media{},
+		&model.StrmAccount{}, &model.EmbyMount{},
+	); err != nil {
+		t.Fatal(err)
+	}
+	repos := repository.New(db)
+	cfg := &config.Config{}
+	cfg.Secrets.JWTSecret = "stream-keep-secret"
+	log := zap.NewNop()
+
+	remote := service.NewEmbyRemoteService(cfg, log, repos, service.NewCryptoService("", log))
+	emby := service.NewEmbyService(cfg, log, repos).SetEmbyRemote(remote)
+	svc := &service.Container{Cfg: cfg, Repo: repos, EmbyRemote: remote, Emby: emby}
+
+	rawConfig, _ := json.Marshal(map[string]string{
+		"url":            upstream.URL,
+		"api_key":        "test-api-key",
+		"remote_user_id": "uid-1",
+	})
+	if err := repos.StrmAccount.Create(t.Context(), &model.StrmAccount{
+		Base:     model.Base{ID: "acct-1"},
+		Name:     "远程 Emby",
+		Provider: model.StrmProviderEmbyRemote,
+		Config:   string(rawConfig),
+		Enabled:  true,
+	}); err != nil {
+		t.Fatal(err)
+	}
+	// proxy_play=true：直接走反向代理分支，便于断言确实取到了流。
+	if err := repos.EmbyMount.Create(t.Context(), &model.EmbyMount{
+		Base:           model.Base{ID: "mount-1"},
+		AccountID:      "acct-1",
+		RemoteViewID:   "view-1",
+		RemoteViewName: "新番连载",
+		CollectionType: "tvshows",
+		ProxyPlay:      true,
+		Enabled:        true,
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	router := gin.New()
+	router.GET("/api/stream/:id", streamHandler(svc))
+
+	req := httptest.NewRequest(http.MethodGet, "/api/stream/"+service.EncodeEmbyRemoteID("mount-1", "ep-1"), nil)
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d body=%s, want 200", w.Code, w.Body.String())
+	}
+	if got := w.Body.String(); got != "bytes" {
+		t.Fatalf("body = %q, want the proxied stream", got)
+	}
+	if streamCalls != 1 {
+		t.Fatalf("upstream stream calls = %d, want 1", streamCalls)
+	}
+}

internal/service/emby_remote.go

@@ -1587,7 +1587,22 @@ func (r *EmbyRemoteService) proxyVideoStreamOnLine(ctx context.Context, w http.R
 	defer resp.Body.Close()
 	if resp.StatusCode >= 400 {
 		data, _ := io.ReadAll(io.LimitReader(resp.Body, 256))
-		return redactSensitiveError(fmt.Errorf("远程 Emby 视频流失败(%d): %s", resp.StatusCode, strings.TrimSpace(string(data))))
+		detail := strings.TrimSpace(string(data))
+		// 远程 Emby 对「整部剧/目录」这类自身没有媒体源的条目会直接 500，正文是
+		// 一句 .NET 异常（如 Unable to cast object of type 'Series' to type
+		// 'IHasMediaSources'）。原样丢给用户没人看得懂，也没有排查线索——细节进日志，
+		// 给用户一句能照着做的提示。
+		if r.log != nil {
+			r.log.Warn("remote emby video stream rejected",
+				zap.String("remote_id", remoteID),
+				zap.Int("status", resp.StatusCode),
+				zap.String("detail", detail),
+			)
+		}
+		if resp.StatusCode >= 500 {
+			return redactSensitiveError(fmt.Errorf("远程 Emby 无法播放该条目（HTTP %d）：请在详情页选择具体集数后重试", resp.StatusCode))
+		}
+		return redactSensitiveError(fmt.Errorf("远程 Emby 视频流失败(%d): %s", resp.StatusCode, detail))
 	}
 	for _, header := range []string{"Content-Type", "Content-Length", "Content-Range", "Accept-Ranges", "ETag", "Cache-Control"} {
 		if value := resp.Header.Get(header); value != "" {

internal/service/emby_remote_playable_id_test.go

@@ -0,0 +1,160 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"sync/atomic"
+	"testing"
+
+	"go.uber.org/zap"
+
+	"github.com/truewhile/MeBox/internal/config"
+	"github.com/truewhile/MeBox/internal/model"
+	"github.com/truewhile/MeBox/internal/repository"
+)
+
+// newPlayableIDTestService 起一个假的远程 Emby，并建好账号。
+func newPlayableIDTestService(t *testing.T, handler http.Handler) (*EmbyRemoteService, *model.StrmAccount) {
+	t.Helper()
+	server := httptest.NewServer(handler)
+	t.Cleanup(server.Close)
+
+	db := newServiceTestDB(t, &model.StrmAccount{}, &model.EmbyMount{})
+	repos := repository.New(db)
+	cfg := &config.Config{}
+	remote := NewEmbyRemoteService(cfg, zap.NewNop(), repos, NewCryptoService("", zap.NewNop()))
+	remote.SetRuntimeCache(NewRuntimeCacheService(cfg, zap.NewNop()))
+
+	rawConfig, _ := json.Marshal(map[string]string{
+		"url":            server.URL,
+		"api_key":        "test-api-key",
+		"remote_user_id": "uid-1",
+	})
+	acct := &model.StrmAccount{
+		Base:     model.Base{ID: "acct-1"},
+		Name:     "远程 Emby",
+		Provider: model.StrmProviderEmbyRemote,
+		Config:   string(rawConfig),
+		Enabled:  true,
+	}
+	if err := repos.StrmAccount.Create(t.Context(), acct); err != nil {
+		t.Fatalf("create account: %v", err)
+	}
+	return remote, acct
+}
+
+func playableIDTestEpisode(id string, index, sources int) map[string]any {
+	item := map[string]any{
+		"Id":                id,
+		"Name":              "第" + strconv.Itoa(index) + "集",
+		"Type":              "Episode",
+		"SeriesId":          "series-100",
+		"ParentIndexNumber": 1,
+		"IndexNumber":       index,
+	}
+	if sources > 0 {
+		item["MediaSources"] = []any{map[string]any{"Id": id + "-source"}}
+	}
+	return item
+}
+
+// 整部剧的 ID 自身没有媒体源，远程 Emby 对它的取流请求会回 500
+// （Unable to cast 'Series' to 'IHasMediaSources'）。这条用例保证我们会换成第一集，
+// 而不是把这种 ID 直接交给远程。
+func TestPlayableRemoteIDResolvesContainerToFirstEpisode(t *testing.T) {
+	var itemsCalls int64
+	remote, acct := newPlayableIDTestService(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		switch r.URL.Path {
+		case "/emby/Users/uid-1/Items/series-100":
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"Id": "series-100", "Name": "剧一", "Type": "Series", "IsFolder": true,
+			})
+		case "/emby/Users/uid-1/Items/ep-2":
+			_ = json.NewEncoder(w).Encode(playableIDTestEpisode("ep-2", 2, 1))
+		case "/emby/Users/uid-1/Items":
+			atomic.AddInt64(&itemsCalls, 1)
+			if got := r.URL.Query().Get("ParentId"); got != "series-100" {
+				t.Errorf("ParentId = %q, want series-100", got)
+			}
+			// 故意乱序，并让第一条没有媒体源：只有真按季/集排序、且检查过媒体源，
+			// 才会选中 ep-1。
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"Items": []map[string]any{
+					{"Id": "season-1", "Type": "Season", "IndexNumber": 1},
+					playableIDTestEpisode("ep-3", 3, 1),
+					playableIDTestEpisode("ep-1", 1, 1),
+					playableIDTestEpisode("ep-2", 2, 1),
+				},
+			})
+		default:
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+
+	ctx := context.Background()
+	if got := remote.PlayableRemoteID(ctx, acct, "series-100"); got != "ep-1" {
+		t.Fatalf("series id resolved to %q, want ep-1", got)
+	}
+	// 播放器对同一个地址会反复发 Range 请求，解析结果必须命中缓存，不再打远程。
+	if got := remote.PlayableRemoteID(ctx, acct, "series-100"); got != "ep-1" {
+		t.Fatalf("cached resolve = %q, want ep-1", got)
+	}
+	if n := atomic.LoadInt64(&itemsCalls); n != 1 {
+		t.Fatalf("episode query issued %d times, want 1 (cached)", n)
+	}
+}
+
+// 本身带媒体源的条目（电影/单集）必须原样返回，不能被改写。
+func TestPlayableRemoteIDKeepsPlayableItem(t *testing.T) {
+	var queries int64
+	remote, acct := newPlayableIDTestService(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		atomic.AddInt64(&queries, 1)
+		w.Header().Set("Content-Type", "application/json")
+		if r.URL.Path != "/emby/Users/uid-1/Items/ep-2" {
+			t.Errorf("unexpected upstream path %s", r.URL.Path)
+		}
+		_ = json.NewEncoder(w).Encode(playableIDTestEpisode("ep-2", 2, 1))
+	}))
+
+	if got := remote.PlayableRemoteID(context.Background(), acct, "ep-2"); got != "ep-2" {
+		t.Fatalf("playable item = %q, want ep-2", got)
+	}
+	if n := atomic.LoadInt64(&queries); n != 1 {
+		t.Fatalf("upstream queries = %d, want 1", n)
+	}
+}
+
+// 远程不可用/查不到条目时保持原 ID：让原有流程去报错，别把播放地址改成空。
+func TestPlayableRemoteIDKeepsOriginalOnFailure(t *testing.T) {
+	remote, acct := newPlayableIDTestService(t, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+	}))
+
+	if got := remote.PlayableRemoteID(context.Background(), acct, "series-100"); got != "series-100" {
+		t.Fatalf("failure path = %q, want the original id", got)
+	}
+}
+
+// 容器下没有任何带媒体源的子条目时同样返回原 ID（下一层会给友好报错）。
+func TestPlayableRemoteIDKeepsContainerWithoutPlayableChild(t *testing.T) {
+	remote, acct := newPlayableIDTestService(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		if r.URL.Path == "/emby/Users/uid-1/Items" {
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"Items": []map[string]any{
+					{"Id": "season-1", "Type": "Season", "IndexNumber": 1},
+				},
+			})
+			return
+		}
+		_ = json.NewEncoder(w).Encode(map[string]any{"Id": "series-100", "Type": "Series", "IsFolder": true})
+	}))
+
+	if got := remote.PlayableRemoteID(context.Background(), acct, "series-100"); got != "series-100" {
+		t.Fatalf("container without playable child = %q, want the original id", got)
+	}
+}

internal/service/emby_remote_stream_proxy_test.go

@@ -0,0 +1,84 @@
+package service
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"go.uber.org/zap"
+)
+
+// 远程条目自身没有媒体源时（例如把「整部剧」的 ID 当播放目标），远程 Emby 会回
+// 500 + 一句 .NET 异常。异常原文不能直接丢给用户，但要能从日志里查得到。
+func TestProxyVideoStreamOnLineHidesUpstreamException(t *testing.T) {
+	const upstreamBody = "Unable to cast object of type 'MediaBrowser.Controller.Entities.TV.Series' to type 'MediaBrowser.Controller.Entities.IHasMediaSources'."
+
+	var gotPath, gotStatic, gotRange, gotToken string
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		gotPath = req.URL.Path
+		gotStatic = req.URL.Query().Get("Static")
+		gotRange = req.Header.Get("Range")
+		gotToken = req.Header.Get("X-Emby-Token")
+		w.WriteHeader(http.StatusInternalServerError)
+		_, _ = w.Write([]byte(upstreamBody))
+	}))
+	defer upstream.Close()
+
+	svc := &EmbyRemoteService{stream: upstream.Client(), log: zap.NewNop()}
+	cfg := &EmbyRemoteConfig{BaseURL: upstream.URL, Token: "tok-1"}
+
+	req := httptest.NewRequest(http.MethodGet, "/api/stream/embyremote~acct~222679", nil)
+	req.Header.Set("Range", "bytes=0-1023")
+	rec := httptest.NewRecorder()
+
+	err := svc.proxyVideoStreamOnLine(context.Background(), rec, req, cfg, "222679")
+	if err == nil {
+		t.Fatal("expected an error for upstream 500")
+	}
+	if gotPath != "/emby/Videos/222679/stream" {
+		t.Fatalf("upstream path = %q", gotPath)
+	}
+	if gotStatic != "true" {
+		t.Fatalf("Static = %q, want true", gotStatic)
+	}
+	if gotRange != "bytes=0-1023" {
+		t.Fatalf("Range = %q, want forwarded range", gotRange)
+	}
+	if gotToken != "tok-1" {
+		t.Fatalf("X-Emby-Token = %q", gotToken)
+	}
+	if rec.Body.Len() != 0 {
+		t.Fatalf("nothing should be written to the client on upstream failure, got %q", rec.Body.String())
+	}
+
+	msg := err.Error()
+	if strings.Contains(msg, "Unable to cast") || strings.Contains(msg, "MediaBrowser") {
+		t.Fatalf("raw upstream exception must not leak to clients: %q", msg)
+	}
+	if !strings.Contains(msg, "无法播放该条目") {
+		t.Fatalf("error should tell the user what to do, got %q", msg)
+	}
+}
+
+// 4xx（例如远程条目被删除/无权限）保持原有措辞，带着上游说明便于排查。
+func TestProxyVideoStreamOnLineKeepsClientErrorDetail(t *testing.T) {
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+		_, _ = w.Write([]byte("Item not found"))
+	}))
+	defer upstream.Close()
+
+	svc := &EmbyRemoteService{stream: upstream.Client(), log: zap.NewNop()}
+	cfg := &EmbyRemoteConfig{BaseURL: upstream.URL, Token: "tok-1"}
+
+	req := httptest.NewRequest(http.MethodGet, "/api/stream/embyremote~acct~404", nil)
+	err := svc.proxyVideoStreamOnLine(context.Background(), httptest.NewRecorder(), req, cfg, "404")
+	if err == nil {
+		t.Fatal("expected an error for upstream 404")
+	}
+	if !strings.Contains(err.Error(), "404") || !strings.Contains(err.Error(), "Item not found") {
+		t.Fatalf("client error detail should be kept, got %q", err.Error())
+	}
+}

internal/service/emby_remote_web.go

@@ -820,6 +820,123 @@ func (r *EmbyRemoteService) remoteItemSeriesID(ctx context.Context, acct *model.
 	return remoteItemString(out, "SeriesId")
 }
 
+// PlayableRemoteID 把「自身没有媒体源」的远程条目换成可直接播放的条目 ID。
+//
+// 远程 Emby 只为带媒体源的条目提供 /Videos/{id}/stream：拿整部剧/季/目录的 ID 去
+// 请求，它会回 500 加一句 .NET 异常（Unable to cast object of type 'Series' to
+// type 'IHasMediaSources'）。首页轮播、剧集库卡片、外部播放器与第三方客户端都可能
+// 把这种 ID 交过来，统一在这里回落到第一集，保证拿到的 ID 真能取到流。
+//
+// 条目本身可播、或解析失败时返回原 ID（调用方拿到后用原逻辑处理即可，无需区分错误）。
+func (r *EmbyRemoteService) PlayableRemoteID(ctx context.Context, acct *model.StrmAccount, remoteID string) string {
+	remoteID = strings.TrimSpace(remoteID)
+	if r == nil || acct == nil || remoteID == "" {
+		return remoteID
+	}
+	cfg, err := r.remoteConfigWithToken(ctx, acct)
+	if err != nil {
+		return remoteID
+	}
+	cacheKey := r.remoteCacheKey("playable-remote-id", acct.ID, remoteID)
+	if r.cache != nil {
+		var cached string
+		// 播放器会对同一个地址发很多次 Range 请求，判定结果必须走缓存，否则每次拖动
+		// 进度条都要多打两次远程 Emby。缓存比常规媒体缓存长：条目可播性是静态属性。
+		if r.cache.GetJSON(ctx, cacheKey, &cached) {
+			if cached == "" {
+				return remoteID
+			}
+			return cached
+		}
+	}
+	resolved := r.resolvePlayableRemoteID(ctx, acct, cfg, remoteID)
+	// 解析失败不写缓存：远程抖动时下次照样重试，而不是把「播不了」记住十分钟。
+	if r.cache != nil && resolved != "" {
+		r.cache.SetJSON(ctx, cacheKey, resolved, playableRemoteIDCacheTTL)
+	}
+	if resolved == "" {
+		return remoteID
+	}
+	return resolved
+}
+
+// playableRemoteIDCacheTTL 是「条目可播性」判定的缓存时长。
+const playableRemoteIDCacheTTL = 10 * time.Minute
+
+// resolvePlayableRemoteID 返回 remoteID 对应的可播条目：本身带媒体源时原样返回，
+// 容器条目（整部剧/季/目录）返回排在最前的、确实带媒体源的子条目。
+func (r *EmbyRemoteService) resolvePlayableRemoteID(ctx context.Context, acct *model.StrmAccount, cfg *EmbyRemoteConfig, remoteID string) string {
+	var item map[string]any
+	if err := r.doGet(ctx, acct, cfg, "/Users/"+url.PathEscape(r.remoteUserID(cfg))+"/Items/"+url.PathEscape(remoteID), nil, &item); err != nil {
+		return ""
+	}
+	if remoteItemHasMediaSources(item) || !remoteItemIsContainer(item) {
+		return remoteID
+	}
+
+	q := url.Values{}
+	q.Set("ParentId", remoteID)
+	q.Set("Recursive", "true")
+	q.Set("IncludeItemTypes", "Episode,Movie,Video")
+	q.Set("Fields", "MediaSources")
+	q.Set("SortBy", "ParentIndexNumber,IndexNumber,SortName")
+	q.Set("Limit", "50")
+	var body struct {
+		Items []map[string]any `json:"Items"`
+	}
+	if err := r.doGet(ctx, acct, cfg, "/Users/"+url.PathEscape(r.remoteUserID(cfg))+"/Items", q, &body); err != nil {
+		return ""
+	}
+
+	// 远程 SortBy 只覆盖它认识的字段（不同 Emby/Jellyfin 版本支持度不一），
+	// 这里再按季/集排一次，确保拿到的是第一集而不是服务端返回顺序里的第一条。
+	children := body.Items
+	sort.SliceStable(children, func(i, j int) bool {
+		if a, b := remoteItemInt(children[i], "ParentIndexNumber"), remoteItemInt(children[j], "ParentIndexNumber"); a != b {
+			return a < b
+		}
+		if a, b := remoteItemInt(children[i], "IndexNumber"), remoteItemInt(children[j], "IndexNumber"); a != b {
+			return a < b
+		}
+		return remoteItemString(children[i], "SortName") < remoteItemString(children[j], "SortName")
+	})
+	for _, child := range children {
+		if id := remoteItemString(child, "Id"); id != "" && remoteItemHasMediaSources(child) {
+			return id
+		}
+	}
+	return ""
+}
+
+// remoteItemHasMediaSources 该条目是否自带媒体源（即能直接取流）。
+func remoteItemHasMediaSources(item map[string]any) bool {
+	if item == nil {
+		return false
+	}
+	switch sources := item["MediaSources"].(type) {
+	case []any:
+		return len(sources) > 0
+	case []map[string]any:
+		return len(sources) > 0
+	}
+	return false
+}
+
+// remoteItemIsContainer 该条目是否是「装别人」的容器：整部剧/季/目录/合集。
+func remoteItemIsContainer(item map[string]any) bool {
+	switch remoteItemString(item, "Type") {
+	case "Series", "Season", "Folder", "BoxSet", "CollectionFolder", "AggregateFolder", "Playlist":
+		return true
+	}
+	// 类型缺失时退回 IsFolder（Emby 的目录类条目都会带）。
+	if _, ok := item["Type"]; !ok {
+		if isFolder, okBool := item["IsFolder"].(bool); okBool {
+			return isFolder
+		}
+	}
+	return false
+}
+
 // ─── 远程 item JSON 取值辅助 ────────────────────────────────────────────────
 
 func anyString(v any) string {

web/src/pages/PlayerPage.tsx

@@ -20,7 +20,7 @@ import { useAuthStore } from '../stores/auth'
 import type { Media, PlaybackInfo, PlaybackQuality, PlaybackSegment, PlaybackSegmentKind } from '../types'
 import { getSeriesKey, seriesTitleFromPath } from '../utils/groupSeries'
 import { formatEpisodeLabel } from '../utils/episodeNumber'
-import { mediaVersionMatches, mediaVersionsOf } from '../utils/mediaVersion'
+import { autoPlayEpisodeFor, mediaVersionMatches, mediaVersionsOf } from '../utils/mediaVersion'
 import { DEFAULT_PLAYBACK_RATE, normalizePlaybackRate } from '../utils/playbackRate'
 import { resolveActiveSkip, skippedNoticeText, toSkipSegments, type SkipPrompt } from '../utils/skipSegments'
 import { isRemoteEmbyID } from '../utils/remoteEmby'
@@ -1681,6 +1681,17 @@ export function PlayerPage() {
     return playlistEpisodes.findIndex((e) => mediaVersionMatches(e, media.id))
   }, [media, playlistEpisodes])
 
+  // 用剧集 ID 打开播放器时（首页轮播、剧集库卡片、剧集详情页的播放按钮），先落到第一集：
+  // 这类条目没有可播文件，直接请求 /api/stream/<剧集ID> 会被远程 Emby 以 500 打回。
+  useEffect(() => {
+    const target = autoPlayEpisodeFor(media, id, playlistEpisodes)
+    if (!target) return
+    navigate(
+      { pathname: `/play/${target.id}`, search: location.search },
+      { replace: true, state: location.state },
+    )
+  }, [media, id, playlistEpisodes, navigate, location.search, location.state])
+
   const prevEpisode = useMemo(() => {
     if (currentEpisodeIndex > 0) {
       return playlistEpisodes[currentEpisodeIndex - 1]

web/src/utils/mediaVersion.test.ts

@@ -1,4 +1,5 @@
 import {
+  autoPlayEpisodeFor,
   isStrmMedia,
   mediaVersionFileName,
   mediaVersionLabel,
@@ -64,4 +65,25 @@ check('strm filename drops outer extension', mediaVersionFileName(cloudRow) ===
 check('missing path has no filename', mediaVersionFileName(media({ path: '' })) === '')
 check('isStrmMedia detects strm url', isStrmMedia(cloudRow))
 
+// 首页轮播/剧集卡片交给播放器的是「整部剧」ID：选集列表里没有它自己，
+// 播放器要自动落到第一集，否则 /api/stream/<剧集ID> 会被远程 Emby 打回 500。
+const series = media({ id: 'embyremote~mount-1~222679', title: '某部新番', path: '/anime/某部新番', size_bytes: 0 })
+const ep1 = media({ id: 'embyremote~mount-1~222681', path: '/anime/某部新番/Season 1/S1E01.mp4', size_bytes: 299580311 })
+const ep2 = media({ id: 'embyremote~mount-1~222683', path: '/anime/某部新番/Season 1/S1E02.mp4', size_bytes: 299580312 })
+
+check('series falls back to its first episode', autoPlayEpisodeFor(series, series.id, [ep1, ep2])?.id === ep1.id)
+check('playable episode stays untouched', autoPlayEpisodeFor(ep1, ep1.id, [ep1, ep2]) === null)
+check('single-item movie list stays untouched', autoPlayEpisodeFor(ep1, ep1.id, [{ ...ep1 }]) === null)
+check('waits until the requested item is loaded', autoPlayEpisodeFor(null, series.id, [ep1]) === null)
+check('ignores a response for another id', autoPlayEpisodeFor(ep2, series.id, [ep1]) === null)
+check('empty episode list has no fallback', autoPlayEpisodeFor(series, series.id, []) === null)
+check(
+  'entry present as another version stays untouched',
+  autoPlayEpisodeFor(
+    media({ id: 'v-4k' }),
+    'v-4k',
+    [media({ id: 'v-4k', versions: [local4k, local1080] })],
+  ) === null,
+)
+
 console.log('mediaVersion.test.ts: ok')

web/src/utils/mediaVersion.ts

@@ -195,6 +195,32 @@ export function mediaVersionSourceLabel(media: Media): string {
   return isStrmMedia(media) ? '云端直链' : '本地文件'
 }
 
+/**
+ * 挑出「播放器该自动跳转到的那一集」。
+ *
+ * 传给 /play/:id 的可能是「整部剧」这类自身没有可播文件的条目——首页轮播、远程 Emby
+ * 剧集库的卡片、剧集详情页的播放按钮都会把剧集 ID 直接交给播放器。这种条目的选集接口
+ * 返回的是它下面的剧集，列表里没有它自己；若直接拿剧集 ID 去请求
+ * /api/stream/<剧集ID>，远程 Emby 会返回 HTTP 500（Unable to cast object of type
+ * 'Series' to type 'IHasMediaSources'），用户看到的就是「播放失败」。此时换成第一集，
+ * 播放、进度、上下集都落在真正可播的条目上。
+ *
+ * 返回 null 表示无需跳转：条目还没加载完、条目本身可播（含以其它版本形式出现在列表里）、
+ * 或该条目下没有任何可选剧集。
+ */
+export function autoPlayEpisodeFor(
+  media: Media | null | undefined,
+  requestedId: string,
+  episodes: Media[],
+): Media | null {
+  if (!media || !requestedId || media.id !== requestedId) return null
+  if (episodes.length === 0) return null
+  if (episodes.some((episode) => mediaVersionMatches(episode, media.id))) return null
+  const first = episodes[0]
+  if (!first?.id || first.id === media.id) return null
+  return first
+}
+
 /** 版本文件名（去掉目录，并剥掉 .strm 外层扩展名），用作版本选项的次要说明。 */
 export function mediaVersionFileName(media: Media): string {
   const path = (media.path || '').replace(/\\/g, '/').trim()