cuda decoding

About the cuda decoding, if it will affect the rendering efficiency of GPU?

Yes, using CUDA for decoding will consume GPU resources and potentially otherwise impact the performance other CUDA/OpenGL codes also on the GPU. If possible, it’s recommended to utilize the Jetson’s dedicated hardware video decoder which is offloaded and does not impact GPU performance.

You can see example GStreamer pipelines of using the hw decoder included in the L4T Accelerated GStreamer User Guide or via V4L2 in the Multimedia API Reference.