Add standalone NVENC encoder

src/nvenc/nvenc_encoded_frame.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <cstdint>
+#include <vector>
+
+namespace nvenc {
+  struct nvenc_encoded_frame {
+    std::vector<uint8_t> data;
+    uint64_t frame_index = 0;
+    bool idr = false;
+    bool after_ref_frame_invalidation = false;
+  };
+}  // namespace nvenc