How to get the dynamic binding dimension of an ITensor when creating an INetworkDefinition.

Hi everyone,

I'm trying to construct from scratch a network customizing from Faster-RCNN architecture. The raw input image could have variant/dynamic shape, so after some preprocessing step (like resize + padding + normalize), the input network shape also has dynamic shape. So I will try to add input by using:

nvinfer1::ITensor* input = network->addInput("image", nvinfer1::DataType::kFLOAT, nvinfer1::Dims4(-1, 3, -1, -1));

But my problem is, in some next layer/blocks, I need to restore ROIs to the original image's coordinate (like Decoding bounding box step), and to do that, I need some parameter from preprocessing step like (scale = inputNetworkShape + paddingShape/ rawNetworkShape, ...) and this param is also dynamic. But in the building INetworkDefinition phase, I could not use IExecutionContext to run getBindingDimensions because the context hasn't actually existed yet.
So I wanna ask some advices, how could I solve this problem?

Thanks for reading my post. It's my pleasure to hear response from you guys.