diff --git a/doc/track.md b/doc/track.md
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index 0000000..2874642
--- /dev/null
+++ b/doc/track.md
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+# Track 模块设计文档
+
+## 概述
+Track 模块用于描述媒体通道，支持视频和音频轨道的处理，包括帧的输入输出、SDP生成、比特率设置等功能。该模块是流媒体处理的核心组件，确保不同协议间的媒体数据正确传输和转换。
+
+## 接口设计
+### Track 接口
+```go
+type Track interface {
+    Ready() bool
+    Clone() Track
+    GetSdp(payloadType uint8) *Sdp
+    GetBitRate() int
+    SetBitRate(bitRate int)
+    GetCodecId() CodecId
+    GetExtraData() []byte
+    SetExtraData(data []byte)
+}
+```
+
+### VideoTrack 接口
+```go
+type VideoTrack interface {
+    Track
+    GetVideoWidth() int
+    GetVideoHeight() int
+    GetVideoFps() float32
+    GetConfigFrames() []Frame
+}
+```
+
+### AudioTrack 接口
+```go
+type AudioTrack interface {
+    Track
+    GetAudioSampleRate() int
+    GetAudioSampleBit() int
+    GetAudioChannel() int
+}
+```
+
+## 实现说明
+- **并发安全**：所有结构体内部状态通过 `sync.Mutex` 保护，确保多线程环境下的数据一致性。
+- **代码复用**：通过嵌入 `BaseTrack` 结构体实现公共方法（如比特率管理），避免重复代码。
+- **接口隔离**：视频和音频轨道通过独立接口定义，明确职责边界。
+- **内存管理**：依赖 Go 的 GC 机制，避免手动内存管理，但注意减少不必要的数据拷贝。
+
+## 示例代码
+```go
+// 创建视频轨道
+videoTrack := extension.NewVideoTrackImp(extension.CodecH264, 1920, 1080, 30)
+sdp := videoTrack.GetSdp(96)
+
+// 创建音频轨道
+audioTrack := extension.NewAudioTrackImp(extension.CodecAAC, 44100, 2, 16)
+```
+
+## 与 C++ 实现的差异
+| C++ 特性          | Go 实现方案                     |
+|-------------------|-------------------------------|
+| 虚函数            | 接口定义                       |
+| 继承              | 结构体嵌入                     |
+| 共享指针          | Go 原生指针 + GC               |
+| 私有字段          | 首字母小写字段 + 公开访问方法  |
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diff --git a/extension/track.go b/extension/track.go
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index 0000000..5e3e466
--- /dev/null
+++ b/extension/track.go
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+package extension
+
+import (
+    "sync"
+)
+
+// CodecId 媒体编解码类型
+type CodecId int
+
+const (
+    CodecH264 CodecId = iota + 96
+    CodecH265
+    CodecAAC
+    CodecG711A
+    CodecG711U
+    CodecOpus
+)
+
+// Track 媒体通道描述接口
+type Track interface {
+    Ready() bool
+    Clone() Track
+    GetSdp(payloadType uint8) *Sdp
+    GetBitRate() int
+    SetBitRate(bitRate int)
+    GetCodecId() CodecId
+    GetExtraData() []byte
+    SetExtraData(data []byte)
+}
+
+// BaseTrack 实现Track的公共方法
+type BaseTrack struct {
+    mutex    sync.Mutex
+    bitRate  int
+    codecId  CodecId
+    extraData []byte
+}
+
+func (b *BaseTrack) GetBitRate() int {
+    b.mutex.Lock()
+    defer b.mutex.Unlock()
+    return b.bitRate
+}
+
+func (b *BaseTrack) SetBitRate(bitRate int) {
+    b.mutex.Lock()
+    defer b.mutex.Unlock()
+    b.bitRate = bitRate
+}
+
+func (b *BaseTrack) GetCodecId() CodecId {
+    return b.codecId
+}
+
+func (b *BaseTrack) GetExtraData() []byte {
+    b.mutex.Lock()
+    defer b.mutex.Unlock()
+    return b.extraData
+}
+
+func (b *BaseTrack) SetExtraData(data []byte) {
+    b.mutex.Lock()
+    defer b.mutex.Unlock()
+    b.extraData = data
+}
+
+// VideoTrack 视频轨道接口
+type VideoTrack interface {
+    Track
+    GetVideoWidth() int
+    GetVideoHeight() int
+    GetVideoFps() float32
+    GetConfigFrames() []Frame
+}
+
+// VideoTrackImp 视频轨道具体实现
+type VideoTrackImp struct {
+    BaseTrack
+    width  int
+    height int
+    fps    float32
+}
+
+// NewVideoTrackImp 创建视频轨道实例
+func NewVideoTrackImp(codecId CodecId, width, height, fps int) *VideoTrackImp {
+    return &VideoTrackImp{
+        BaseTrack: BaseTrack{codecId: codecId},
+        width:     width,
+        height:    height,
+        fps:       float32(fps),
+    }
+}
+
+func (v *VideoTrackImp) Ready() bool {
+    return true
+}
+
+func (v *VideoTrackImp) Clone() Track {
+    v.mutex.Lock()
+    defer v.mutex.Unlock()
+    return &VideoTrackImp{
+        BaseTrack: BaseTrack{
+            bitRate:  v.bitRate,
+            codecId:  v.codecId,
+            extraData: v.extraData,
+        },
+        width:  v.width,
+        height: v.height,
+        fps:    v.fps,
+    }
+}
+
+func (v *VideoTrackImp) GetSdp(payloadType uint8) *Sdp {
+    // 实际实现应生成SDP描述
+    return NewDefaultSdp(payloadType, v)
+}
+
+func (v *VideoTrackImp) GetVideoWidth() int {
+    return v.width
+}
+
+func (v *VideoTrackImp) GetVideoHeight() int {
+    return v.height
+}
+
+func (v *VideoTrackImp) GetVideoFps() float32 {
+    return v.fps
+}
+
+func (v *VideoTrackImp) GetConfigFrames() []Frame {
+    // 根据编解码器返回sps/pps等配置帧
+    return nil
+}
+
+// AudioTrack 音频轨道接口
+type AudioTrack interface {
+    Track
+    GetAudioSampleRate() int
+    GetAudioSampleBit() int
+    GetAudioChannel() int
+}
+
+// AudioTrackImp 音频轨道具体实现
+type AudioTrackImp struct {
+    BaseTrack
+    sampleRate int
+    channels   int
+    sampleBit  int
+}
+
+// NewAudioTrackImp 创建音频轨道实例
+func NewAudioTrackImp(codecId CodecId, sampleRate, channels, sampleBit int) *AudioTrackImp {
+    return &AudioTrackImp{
+        BaseTrack:  BaseTrack{codecId: codecId},
+        sampleRate: sampleRate,
+        channels:   channels,
+        sampleBit:  sampleBit,
+    }
+}
+
+func (a *AudioTrackImp) Ready() bool {
+    return true
+}
+
+func (a *AudioTrackImp) Clone() Track {
+    a.mutex.Lock()
+    defer a.mutex.Unlock()
+    return &AudioTrackImp{
+        BaseTrack: BaseTrack{
+            bitRate:  a.bitRate,
+            codecId:  a.codecId,
+            extraData: a.extraData,
+        },
+        sampleRate: a.sampleRate,
+        channels:   a.channels,
+        sampleBit:  a.sampleBit,
+    }
+}
+
+func (a *AudioTrackImp) GetSdp(payloadType uint8) *Sdp {
+    return NewDefaultSdp(payloadType, a)
+}
+
+func (a *AudioTrackImp) GetAudioSampleRate() int {
+    if a.sampleRate != 0 {
+        return a.sampleRate
+    }
+    return GetClockRateByCodec(a.codecId)
+}
+
+func (a *AudioTrackImp) GetAudioSampleBit() int {
+    if a.sampleBit != 0 {
+        return a.sampleBit
+    }
+    return 16
+}
+
+func (a *AudioTrackImp) GetAudioChannel() int {
+    if a.channels != 0 {
+        return a.channels
+    }
+    return 1
+}
+
+// 辅助函数
+func GetClockRateByCodec(codecId CodecId) int {
+    switch codecId {
+    case CodecAAC:
+        return 44100
+    case CodecG711A, CodecG711U:
+        return 8000
+    case CodecOpus:
+        return 48000
+    default:
+        return 0
+    }
+}
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