增加windows端屏幕捕获编码demo

demo/windows_sender/VideoEncoder.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <d3d11.h>
+#include <wrl/client.h>
+#include <vector>
+#include <cstdint>
+
+extern "C" {
+#include <libavcodec/avcodec.h>
+#include <libavutil/imgutils.h>
+#include <libavutil/opt.h>
+#include <libswscale/swscale.h>
+}
+
+using Microsoft::WRL::ComPtr;
+
+class VideoEncoder {
+public:
+    VideoEncoder();
+    ~VideoEncoder();
+
+    bool Initialize(ID3D11Device* device, int width, int height, int fps, int bitrate);
+    bool EncodeFrame(ID3D11Texture2D* texture, std::vector<uint8_t>& outputData, bool& isKeyFrame);
+
+private:
+    ID3D11Device* device_ = nullptr;
+    ID3D11DeviceContext* context_ = nullptr;
+    ComPtr<ID3D11Texture2D> stagingTexture_;
+
+    AVCodecContext* codecContext_ = nullptr;
+    AVFrame* frame_ = nullptr;
+    AVPacket* packet_ = nullptr;
+    SwsContext* swsContext_ = nullptr;
+
+    int width_ = 0;
+    int height_ = 0;
+    int pts_ = 0;
+};