How to correctly format data on the client side to send to dali/triton

I’m trying to make a dali preprocessing pipeline extremely similar to the inception example but I can’t seem to figure out how to get the correct format on the client side. Here is the code I have now on the client side:

def prepare_batches(data_loader):
    batches = []
    for dataiter in data_loader:
        images, labels = dataiter['image'], dataiter['label']
        #images is a list of encoded images as strings
        images_np = np.array(images, dtype=object)
        batches.append((images_np, labels))
    return batches

def infer_batch(client, batch):
    images_np, labels = batch
    inputs = grpcclient.InferInput("x", [len(images_np)], datatype="BYTES")

        detection_response = client.infer(model_name="simple_ensemble", inputs=[inputs])
        predictions = detection_response.as_numpy('classifier')
        return predictions, labels.numpy()
    except Exception as exc:
        print(f"Exception during inference: {exc}")
        return None, None

However this code doesnt work with the dali pipeline config file from the example:

max_batch_size: 256
input [
    name: "DALI_INPUT_0"
    data_type: TYPE_UINT8
    dims: [ -1 ]

because triton is expecting input with a shape [-1, -1] but its getting data in the format [ -1 ].

unexpected shape for input 'x' for model 'simple_ensemble'. Expected [-1,-1], got [4].

What would be the correct way to format the data on the client side?