To run AEM instance in dynamic media scene 7 mode , we need to pay additionally for adobe other than AEM license fee ?
You can use the Dm_S7 run mode but Dynamic Media is not free. It is an add-on feature with some additional fee on top AEM Assets license.
Please check the product descriptions here: https://helpx.adobe.com/legal/product-descriptions.html
I suggest you reach out to your Adobe CSM to further discuss this.
Yes. This feature gets enabled when you integrate Dynamic Media (formerly Adobe Scene7) with AEM.
You need to have an S7 login to use smart crop in AEM.