diff --git a/alias.go b/alias.go
index f5aff6b..3e9262d 100644
--- a/alias.go
+++ b/alias.go
@@ -121,7 +121,7 @@ func (s *Server) SetStreamAlias(ctx context.Context, req *pb.SetStreamAliasReque
 					} else {
 						s.Waiting.WakeUp(req.Alias, publisher)
 					}
-				} else {
+				} else if ok {
 					aliasInfo.Publisher = aliasStream
 				}
 				if aliasInfo.Publisher != nil {
diff --git a/api.go b/api.go
index 5d7af0d..407a4fc 100644
--- a/api.go
+++ b/api.go
@@ -556,6 +556,7 @@ func (s *Server) SetStreamSpeed(ctx context.Context, req *pb.SetStreamSpeedReque
 		if s, ok := s.Streams.Get(req.StreamPath); ok {
 			s.Speed = float64(req.Speed)
 			s.Scale = float64(req.Speed)
+			s.Info("set stream speed", "speed", req.Speed)
 		}
 		return nil
 	})
diff --git a/doc_CN/relay.md b/doc_CN/relay.md
new file mode 100644
index 0000000..c1c856c
--- /dev/null
+++ b/doc_CN/relay.md
@@ -0,0 +1,47 @@
+# 核心转发流程
+
+## 发布者
+
+发布者（Publisher） 是用来在服务器上向 RingBuffer 中写入音视频数据的对象。对外暴露 WriteVideo 和 WriteAudio 方法。
+在写入 WriteVideo 和 WriteAudio 时会创建 Track，解析数据，生成 ICodecCtx。启动发布只需要调用 Plugin 的 Publish 方法即可。
+
+### 接受推流
+
+rtmp、rtsp 等插件会监听一个端口用来接受推流。
+
+### 从远端拉流
+
+- 实现了 OnPullProxyAdd 方法的插件，可以从远端拉流。
+- 继承自 HTTPFilePuller 的插件，可以从 http 或文件中拉流。
+
+### 从本地录像文件中拉流
+
+继承自 RecordFilePuller 的插件，可以从本地录像文件中拉流。
+
+
+## 订阅者
+
+订阅者（Subscriber） 是用来从 RingBuffer 中读取音视频数据的对象。订阅流分两个步骤：
+
+1. 调用 Plugin 的 Subscribe 方法，传入 StreamPath 和 Subscribe 配置。
+2. 调用 PlayBlock 方法，开始读取数据，这个方法会阻塞直到订阅结束。
+
+之所以分两个步骤的原因是，第一步可能会失败（超时等），也可能需要等待第一步成功后进行一些交互工作。
+第一步会有一定时间的阻塞，会等待发布者（如果开始没有发布者）、会等待发布者的轨道创建完成。
+
+### 接受拉流
+
+例如 rtmp、rtsp 插件，会监听一个端口，来接受播放的请求。
+
+### 向远端推流
+
+- 实现了 OnPushProxyAdd 方法的插件，可以向远端推流。
+
+### 写入本地文件
+
+包含录像功能的插件，需要先订阅流，才能写入本地文件。
+
+## 按需拉流（发布）
+
+由订阅者触发，当调用 plugin 的 OnSubscribe 时，会通知所有插件，有订阅的需求，此时插件可以响应这个需求，发布一个流。例如拉取录像流，就是这一类。此时必须要注意的是需要通过正则表达式配置，防止同时发布。
+
diff --git a/pkg/util/collection.go b/pkg/util/collection.go
index 9833020..7d7130a 100644
--- a/pkg/util/collection.go
+++ b/pkg/util/collection.go
@@ -130,9 +130,9 @@ func (c *Collection[K, T]) Get(key K) (item T, ok bool) {
 	}
 	if c.m != nil {
 		item, ok = c.m[key]
-		return item, ok
+		return
 	}
-	for _, item = range c.Items {
+	for _, item := range c.Items {
 		if item.GetKey() == key {
 			return item, true
 		}
@@ -145,7 +145,7 @@ func (c *Collection[K, T]) Find(f func(T) bool) (item T, ok bool) {
 		c.L.RLock()
 		defer c.L.RUnlock()
 	}
-	for _, item = range c.Items {
+	for _, item := range c.Items {
 		if f(item) {
 			return item, true
 		}
diff --git a/pkg/util/collection_test.go b/pkg/util/collection_test.go
new file mode 100644
index 0000000..e6fdc30
--- /dev/null
+++ b/pkg/util/collection_test.go
@@ -0,0 +1,170 @@
+package util
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+)
+
+type Class struct {
+	name string
+	Id   int
+}
+
+func (n *Class) GetKey() string {
+	return n.name
+}
+
+var cc Collection[string, *Class]
+
+func TestCollection(t *testing.T) {
+
+	for i := 0; i < 10; i++ {
+		cc.Add(&Class{name: fmt.Sprintf("%d", i), Id: i})
+	}
+	cc.RemoveByKey("1")
+	if item, ok := cc.Get("1"); ok {
+		fmt.Println(item)
+	} else {
+		fmt.Println("not found", item)
+	}
+}
+
+// TestItem 是用于测试的结构体
+type TestItem struct {
+	ID   string
+	Data string
+}
+
+func (t TestItem) GetKey() string {
+	return t.ID
+}
+
+func TestCollection_BasicOperations(t *testing.T) {
+	c := &Collection[string, TestItem]{
+		L: &sync.RWMutex{},
+	}
+
+	// 测试 Add
+	item1 := TestItem{ID: "1", Data: "test1"}
+	c.Add(item1)
+	if c.Length != 1 {
+		t.Errorf("Expected length 1, got %d", c.Length)
+	}
+
+	// 测试 Get
+	got, ok := c.Get("1")
+	if !ok || got != item1 {
+		t.Errorf("Expected to get item1, got %v", got)
+	}
+
+	// 测试 AddUnique
+	ok = c.AddUnique(item1)
+	if ok || c.Length != 1 {
+		t.Error("AddUnique should not add duplicate item")
+	}
+
+	// 测试 Set
+	item1Modified := TestItem{ID: "1", Data: "test1-modified"}
+	added := c.Set(item1Modified)
+	if added {
+		t.Error("Set should not return true for existing item")
+	}
+	got, _ = c.Get("1")
+	if got.Data != "test1-modified" {
+		t.Errorf("Expected modified data, got %s", got.Data)
+	}
+
+	// 测试 Remove
+	if !c.Remove(item1) {
+		t.Error("Remove should return true for existing item")
+	}
+	if c.Length != 0 {
+		t.Errorf("Expected length 0 after remove, got %d", c.Length)
+	}
+}
+
+func TestCollection_Events(t *testing.T) {
+	c := &Collection[string, TestItem]{}
+
+	var addCalled, removeCalled bool
+	c.OnAdd(func(item TestItem) {
+		addCalled = true
+		if item.ID != "1" {
+			t.Errorf("Expected item ID 1, got %s", item.ID)
+		}
+	})
+
+	c.OnRemove(func(item TestItem) {
+		removeCalled = true
+		if item.ID != "1" {
+			t.Errorf("Expected item ID 1, got %s", item.ID)
+		}
+	})
+
+	item := TestItem{ID: "1", Data: "test"}
+	c.Add(item)
+	if !addCalled {
+		t.Error("Add listener was not called")
+	}
+
+	c.Remove(item)
+	if !removeCalled {
+		t.Error("Remove listener was not called")
+	}
+}
+
+func TestCollection_Search(t *testing.T) {
+	c := &Collection[string, TestItem]{}
+	items := []TestItem{
+		{ID: "1", Data: "test1"},
+		{ID: "2", Data: "test2"},
+		{ID: "3", Data: "test1"},
+	}
+
+	for _, item := range items {
+		c.Add(item)
+	}
+
+	// 测试 Find
+	found, ok := c.Find(func(item TestItem) bool {
+		return item.Data == "test1"
+	})
+	if !ok || found.ID != "1" {
+		t.Error("Find should return first matching item")
+	}
+
+	// 测试 Search
+	count := 0
+	search := c.Search(func(item TestItem) bool {
+		return item.Data == "test1"
+	})
+	search(func(item TestItem) bool {
+		count++
+		return true
+	})
+	if count != 2 {
+		t.Errorf("Search should find 2 items, found %d", count)
+	}
+}
+
+func TestCollection_ConcurrentAccess(t *testing.T) {
+	c := &Collection[string, TestItem]{
+		L: &sync.RWMutex{},
+	}
+
+	var wg sync.WaitGroup
+	for i := 0; i < 100; i++ {
+		wg.Add(1)
+		go func(id int) {
+			defer wg.Done()
+			item := TestItem{ID: string(rune(id)), Data: "test"}
+			c.Add(item)
+		}(i)
+	}
+	wg.Wait()
+
+	if c.Length != 100 {
+		t.Errorf("Expected 100 items, got %d", c.Length)
+	}
+}
diff --git a/plugin/README.md b/plugin/README.md
new file mode 100644
index 0000000..e60c3c3
--- /dev/null
+++ b/plugin/README.md
@@ -0,0 +1,306 @@
+# Plugin Development Guide
+
+## 1. Prerequisites
+
+### Development Tools
+- Visual Studio Code
+- Goland
+- Cursor
+
+### Install gRPC
+```shell
+$ go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.28
+$ go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.2
+```
+
+### Install gRPC-Gateway
+```shell
+$ go install github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-grpc-gateway@latest
+$ go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
+$ go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest
+```
+
+### Project Setup
+- Create a Go project, e.g., `MyPlugin`
+- Create a `pkg` directory for exportable code
+- Create a `pb` directory for gRPC proto files
+- Create an `example` directory for testing the plugin
+
+> You can also create a directory `xxx` directly in the monibuca project's plugin folder to store your plugin code
+
+## 2. Create a Plugin
+
+```go
+package plugin_myplugin
+import (
+    "m7s.live/v5"
+)
+
+var _ = m7s.InstallPlugin[MyPlugin]()
+
+type MyPlugin struct {
+    m7s.Plugin
+    Foo string
+}
+```
+- `MyPlugin` struct is the plugin definition, `Foo` is a plugin property that can be configured in the configuration file
+- Must embed `m7s.Plugin` struct to provide basic plugin functionality
+- `m7s.InstallPlugin[MyPlugin](...)` registers the plugin so it can be loaded by monibuca
+
+### Provide Default Configuration
+Example:
+```go
+const defaultConfig = m7s.DefaultYaml(`tcp:
+  listenaddr: :5554`)
+
+var _ = m7s.InstallPlugin[MyPlugin](defaultConfig)
+```
+
+## 3. Implement Event Callbacks (Optional)
+
+### Initialization Callback
+```go
+func (config *MyPlugin) OnInit() (err error) {
+    // Initialize things
+    return
+}
+```
+Used for plugin initialization after configuration is loaded. Return an error if initialization fails, and the plugin will be disabled.
+
+### TCP Request Callback
+```go
+func (config *MyPlugin) OnTCPConnect(conn *net.TCPConn) task.ITask {
+    
+}
+```
+Called when receiving TCP connection requests if TCP listening port is configured.
+
+### UDP Request Callback
+```go
+func (config *MyPlugin) OnUDPConnect(conn *net.UDPConn) task.ITask {
+
+}
+```
+Called when receiving UDP connection requests if UDP listening port is configured.
+
+### QUIC Request Callback
+```go
+func (config *MyPlugin) OnQUICConnect(quic.Connection) task.ITask {
+
+}
+```
+Called when receiving QUIC connection requests if QUIC listening port is configured.
+
+## 4. HTTP Interface Callbacks
+
+### Legacy v4 Callback Style
+```go
+func (config *MyPlugin) API_test1(rw http.ResponseWriter, r *http.Request) {
+    // do something
+}
+```
+Accessible via `http://ip:port/myplugin/api/test1`
+
+### Route Mapping Configuration
+This method supports parameterized routing:
+```go
+func (config *MyPlugin) RegisterHandler() map[string]http.HandlerFunc {
+    return map[string]http.HandlerFunc{
+        "/test1/{streamPath...}": config.test1,
+    }
+}
+func (config *MyPlugin) test1(rw http.ResponseWriter, r *http.Request) {
+    streamPath := r.PathValue("streamPath")
+    // do something
+}
+```
+
+## 5. Implement Push/Pull Clients
+
+### Implement Push Client
+Push client needs to implement IPusher interface and pass the creation method to InstallPlugin.
+```go
+type Pusher struct {
+    pullCtx m7s.PullJob
+}
+
+func (c *Pusher) GetPullJob() *m7s.PullJob {
+    return &c.pullCtx
+}
+
+func NewPusher(_ config.Push) m7s.IPusher {
+    return &Pusher{}
+}
+var _ = m7s.InstallPlugin[MyPlugin](NewPusher)
+```
+
+### Implement Pull Client
+Pull client needs to implement IPuller interface and pass the creation method to InstallPlugin.
+The following Puller inherits from m7s.HTTPFilePuller for basic file and HTTP pulling:
+```go
+type Puller struct {
+    m7s.HTTPFilePuller
+}
+
+func NewPuller(_ config.Pull) m7s.IPuller {
+    return &Puller{}
+}
+var _ = m7s.InstallPlugin[MyPlugin](NewPuller)
+```
+
+## 6. Implement gRPC Service
+
+### Create `myplugin.proto` in `pb` Directory
+```proto
+syntax = "proto3";
+import "google/api/annotations.proto";
+import "google/protobuf/empty.proto";
+package myplugin;
+option go_package="m7s.live/v5/plugin/myplugin/pb";
+
+service api {
+    rpc MyMethod (MyRequest) returns (MyResponse) {
+        option (google.api.http) = {
+            post: "/myplugin/api/bar"
+            body: "foo"
+        };
+    }
+}
+message MyRequest {
+    string foo = 1;
+}
+message MyResponse {
+    string bar = 1;
+}
+```
+
+### Generate gRPC Code
+Add to VSCode task.json:
+```json
+{
+    "type": "shell",
+    "label": "build pb myplugin",
+    "command": "protoc",
+    "args": [
+        "-I.",
+        "-I${workspaceRoot}/pb",
+        "--go_out=.",
+        "--go_opt=paths=source_relative",
+        "--go-grpc_out=.",
+        "--go-grpc_opt=paths=source_relative",
+        "--grpc-gateway_out=.",
+        "--grpc-gateway_opt=paths=source_relative",
+        "myplugin.proto"
+    ],
+    "options": {
+        "cwd": "${workspaceRoot}/plugin/myplugin/pb"
+    }
+}
+```
+Or run command in pb directory:
+```shell
+protoc -I. -I$ProjectFileDir$/pb --go_out=. --go_opt=paths=source_relative --go-grpc_out=. --go-grpc_opt=paths=source_relative --grpc-gateway_out=. --grpc-gateway_opt=paths=source_relative  myplugin.proto
+```
+Replace `$ProjectFileDir$` with the directory containing global pb files.
+
+### Implement gRPC Service
+Create api.go:
+```go
+package plugin_myplugin
+import (
+    "context"
+    "m7s.live/m7s/v5"
+    "m7s.live/m7s/v5/plugin/myplugin/pb"
+)
+
+func (config *MyPlugin) MyMethod(ctx context.Context, req *pb.MyRequest) (*pb.MyResponse, error) {
+    return &pb.MyResponse{Bar: req.Foo}, nil
+}
+```
+
+### Register gRPC Service
+```go
+package plugin_myplugin
+import (
+    "m7s.live/v5"
+    "m7s.live/v5/plugin/myplugin/pb"
+)
+
+var _ = m7s.InstallPlugin[MyPlugin](&pb.Api_ServiceDesc, pb.RegisterApiHandler)
+
+type MyPlugin struct {
+    pb.UnimplementedApiServer
+    m7s.Plugin
+    Foo string
+}
+```
+
+### Additional RESTful Endpoints
+Same as v4:
+```go
+func (config *MyPlugin) API_test1(rw http.ResponseWriter, r *http.Request) {
+    // do something
+}
+```
+Accessible via GET request to `/myplugin/api/test1`
+
+## 7. Publishing Streams
+
+```go
+publisher, err = p.Publish(streamPath, connectInfo)
+```
+The last two parameters are optional.
+
+After obtaining the `publisher`, you can publish audio/video data using `publisher.WriteAudio` and `publisher.WriteVideo`.
+
+### Define Audio/Video Data
+If existing audio/video data formats don't meet your needs, you can define custom formats by implementing this interface:
+```go
+IAVFrame interface {
+    GetAllocator() *util.ScalableMemoryAllocator
+    SetAllocator(*util.ScalableMemoryAllocator)
+    Parse(*AVTrack) error
+    ConvertCtx(codec.ICodecCtx) (codec.ICodecCtx, IAVFrame, error)
+    Demux(codec.ICodecCtx) (any, error)
+    Mux(codec.ICodecCtx, *AVFrame)
+    GetTimestamp() time.Duration
+    GetCTS() time.Duration
+    GetSize() int
+    Recycle()
+    String() string
+    Dump(byte, io.Writer)
+}
+```
+> Define separate types for audio and video
+
+- GetAllocator/SetAllocator: Automatically implemented when embedding RecyclableMemory
+- Parse: Identifies key frames, sequence frames, and other important information
+- ConvertCtx: Called when protocol conversion is needed
+- Demux: Called when audio/video data needs to be demuxed
+- Mux: Called when audio/video data needs to be muxed
+- Recycle: Automatically implemented when embedding RecyclableMemory
+- String: Prints audio/video data information
+- GetSize: Gets the size of audio/video data
+- GetTimestamp: Gets the timestamp in nanoseconds
+- GetCTS: Gets the Composition Time Stamp in nanoseconds (PTS = DTS+CTS)
+- Dump: Prints binary audio/video data
+
+## 8. Subscribing to Streams
+```go
+var suber *m7s.Subscriber
+suber, err = p.Subscribe(ctx,streamPath)
+go m7s.PlayBlock(suber, handleAudio, handleVideo)
+```
+Note that handleAudio and handleVideo are callback functions you need to implement. They take an audio/video format type as input and return an error. If the error is not nil, the subscription is terminated.
+
+## 9. Prometheus Integration
+Just implement the Collector interface, and the system will automatically collect metrics from all plugins:
+```go
+func (p *MyPlugin) Describe(ch chan<- *prometheus.Desc) {
+  
+}
+
+func (p *MyPlugin) Collect(ch chan<- prometheus.Metric) {
+  
+}
+``` 
\ No newline at end of file
diff --git a/plugin/snap/pkg/transform.go b/plugin/snap/pkg/transform.go
index 1b2914c..a1e733d 100644
--- a/plugin/snap/pkg/transform.go
+++ b/plugin/snap/pkg/transform.go
@@ -58,7 +58,7 @@ func GetVideoFrame(streamPath string, server *m7s.Server) (pkg.AnnexB, *pkg.AVTr
 		return pkg.AnnexB{}, nil, err
 	}
 	if track.ICodecCtx == nil {
-		return pkg.AnnexB{}, nil, fmt.Errorf("unsupported codec")
+		return pkg.AnnexB{}, nil, pkg.ErrUnsupportCodec
 	}
 	annexb.Mux(track.ICodecCtx, &reader.Value)
 
diff --git a/server.go b/server.go
index b128971..f0cf565 100644
--- a/server.go
+++ b/server.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"net"
 	"net/http"
 	"net/url"
 	"os"
@@ -14,6 +15,8 @@ import (
 	"strings"
 	"time"
 
+	"github.com/gobwas/ws"
+	"github.com/gobwas/ws/wsutil"
 	"github.com/shirou/gopsutil/v4/cpu"
 	"google.golang.org/protobuf/proto"
 
@@ -268,6 +271,7 @@ func (s *Server) Start() (err error) {
 		"/api/stream/annexb/{streamPath...}":  s.api_Stream_AnnexB_,
 		"/api/videotrack/sse/{streamPath...}": s.api_VideoTrack_SSE,
 		"/api/audiotrack/sse/{streamPath...}": s.api_AudioTrack_SSE,
+		"/annexb/{streamPath...}":             s.annexB,
 	})
 
 	if s.config.DSN != "" {
@@ -763,3 +767,41 @@ func (s *Server) AuthInterceptor() grpc.UnaryServerInterceptor {
 		return handler(newCtx, req)
 	}
 }
+
+func (s *Server) annexB(w http.ResponseWriter, r *http.Request) {
+	streamPath := r.PathValue("streamPath")
+
+	if r.URL.RawQuery != "" {
+		streamPath += "?" + r.URL.RawQuery
+	}
+	var conf = s.config.Subscribe
+	conf.SubType = SubscribeTypeServer
+	conf.SubAudio = false
+	suber, err := s.SubscribeWithConfig(r.Context(), streamPath, conf)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	var conn net.Conn
+	conn, err = suber.CheckWebSocket(w, r)
+	if err != nil {
+		return
+	}
+	if conn == nil {
+		w.Header().Set("Content-Type", "application/octet-stream")
+		w.Header().Set("Transfer-Encoding", "identity")
+		w.WriteHeader(http.StatusOK)
+	}
+
+	PlayBlock(suber, func(frame *pkg.AVFrame) (err error) {
+		return nil
+	}, func(frame *pkg.AnnexB) (err error) {
+		if conn != nil {
+			return wsutil.WriteServerMessage(conn, ws.OpBinary, util.ConcatBuffers(frame.Memory.Buffers))
+		}
+		var buf net.Buffers
+		buf = append(buf, frame.Memory.Buffers...)
+		buf.WriteTo(w)
+		return nil
+	})
+}