Fix the performance issue introduced after PR#192 (#220)

* Fix the performance issue introduced after PR#192

* Destroy the current interop memories before reconfiguration

* initialize the interop to 0 after unmapping a surface

* code clean up

* check the mapped device mem/ext mem to be valid before destrying them

* code cleanup - add some comments

* make changes based on the reviewer comments

src/rocdecode/roc_decoder.h

@@ -42,6 +42,16 @@ THE SOFTWARE.
     }\
 }
 
+struct HipInteropDeviceMem {
+    hipExternalMemory_t hip_ext_mem; // Interface to the vaapi-hip interop
+    uint8_t* hip_mapped_device_mem; // Mapped device memory for the YUV plane
+    uint32_t width; // Width of the surface in pixels.
+    uint32_t height; // Height of the surface in pixels.
+    uint32_t offset[3]; // Offset of each plane
+    uint32_t pitch[3]; // Pitch of each plane
+    uint32_t num_layers; // Number of layers making up the surface
+};
+
 class RocDecoder {
 public:
     RocDecoder(RocDecoderCreateInfo &decoder_create_info);
@@ -59,5 +69,5 @@ private:
     RocDecoderCreateInfo decoder_create_info_;
     VaapiVideoDecoder va_video_decoder_;
     hipDeviceProp_t hip_dev_prop_;
-    std::vector<hipExternalMemory_t> hip_ext_mem_;
+    std::vector<HipInteropDeviceMem> hip_interop_;
 };