[feat] optimize Windows native video encoding

apps/desktop/src/screen_capturer/captured_nv12_frame.h

@@ -0,0 +1,78 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-09-04
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _CAPTURED_NV12_FRAME_H_
+#define _CAPTURED_NV12_FRAME_H_
+
+#include <atomic>
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <mutex>
+#include <vector>
+
+#include "minirtc.h"
+
+namespace crossdesk {
+
+class CapturedNv12Frame;
+
+// Owns the pixels behind captured native frames. A frame may outlive the
+// capture callback while MiniRTC waits for its asynchronous encoder, so capture
+// buffers cannot be borrowed directly. Released allocations are cached to keep
+// that ownership transfer inexpensive after the pipeline is warm.
+class CapturedNv12FramePool final
+    : public std::enable_shared_from_this<CapturedNv12FramePool> {
+ public:
+  static std::shared_ptr<CapturedNv12FramePool> Create(
+      size_t max_cached_buffers = 4);
+
+  CapturedNv12Frame* CopyFrom(const uint8_t* data, size_t size,
+                              uint32_t width, uint32_t height);
+
+ private:
+  explicit CapturedNv12FramePool(size_t max_cached_buffers);
+  void Recycle(std::vector<uint8_t> storage);
+
+  friend class CapturedNv12Frame;
+
+  const size_t max_cached_buffers_;
+  std::mutex mutex_;
+  std::vector<std::vector<uint8_t>> free_buffers_;
+};
+
+class CapturedNv12Frame final {
+ public:
+  const XNativeVideoFrame* Descriptor() const { return &descriptor_; }
+  size_t Size() const { return storage_.size(); }
+
+  void AddRef();
+  void Release();
+
+ private:
+  friend class CapturedNv12FramePool;
+
+  CapturedNv12Frame(std::shared_ptr<CapturedNv12FramePool> pool,
+                    std::vector<uint8_t> storage, uint32_t width,
+                    uint32_t height);
+  ~CapturedNv12Frame();
+
+  static void RetainOwner(void* owner);
+  static void ReleaseOwner(void* owner);
+  static int CopyToNv12(void* owner, uint8_t* destination,
+                        size_t destination_size);
+
+  std::atomic<uint32_t> references_{1};
+  std::shared_ptr<CapturedNv12FramePool> pool_;
+  std::vector<uint8_t> storage_;
+  uint32_t width_ = 0;
+  uint32_t height_ = 0;
+  XNativeVideoFrame descriptor_{};
+};
+
+}  // namespace crossdesk
+
+#endif